:root {
  --bg: #f4f0e8;
  --panel: #fffdf8;
  --ink: #1d2730;
  --muted: #5f6b76;
  --accent: #0e6d77;
  --accent-soft: #d8eef0;
  --border: #d8d2c7;
  --shadow: 0 10px 30px rgba(24, 30, 34, 0.08);
  --body-font: "Source Serif 4", "Palatino Linotype", "Book Antiqua", Georgia, serif;
  --ui-font: "Avenir Next", "Gill Sans", "Trebuchet MS", sans-serif;
}

html {
  scroll-behavior: smooth;
  font-size: 18px;
}

body {
  margin: 0;
  max-width: none !important;
  width: 100%;
  padding: 0 !important;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 10%, #f7f3ea 0%, transparent 40%),
    radial-gradient(circle at 90% 10%, #e8f3f2 0%, transparent 32%),
    var(--bg);
  font-family: var(--body-font);
  line-height: 1.72;
}

a {
  color: #0a6570;
  text-decoration-thickness: 1.5px;
  text-underline-offset: 0.14em;
}

a:hover {
  color: #084c53;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Title page. It is authored as raw HTML in the LaTeX source, so it arrives ahead of
   the site shell with no classes of its own and none of the column rules reach it --
   which left it pinned to the left edge with the copyright notice touching the window.
   Center the two pieces it is made of: the source's flex row (thumbnails + title and
   authors) and the copyright paragraphs that follow it.

   Style those children, never the .cell.markdown wrapper: Pandoc leaves that div
   unclosed, so the browser auto-closes it at </body> and the whole site shell ends up
   inside it -- capping the wrapper would shrink the entire book. Neither selector can
   reach .site-shell, which is not a <p> and carries no inline flex style.
   These rules key on structure alone, so edits to the title, authors or dates are safe. */
body > .cell.markdown > div[style*="flex"],
body > .cell.markdown > p {
  box-sizing: border-box;
  max-width: min(62rem, 100%);
  margin-left: auto;
  margin-right: auto;
  padding-left: clamp(1.1rem, 2.8vw, 3.2rem);
  padding-right: clamp(1.1rem, 2.8vw, 3.2rem);
}

/* A little air between the copyright notice and the table of contents below it. */
body > .cell.markdown > p:last-of-type {
  margin-bottom: 1.6rem;
}

.site-shell {
  display: grid;
  grid-template-columns: clamp(15rem, 18vw, 20rem) minmax(0, 1fr);
  gap: 1rem;
  align-items: start;
  max-width: 1900px;
  margin: 0 auto;
  padding: 0.6rem 0.8rem 2rem;
}

.site-nav {
  position: sticky;
  top: 0.75rem;
  max-height: calc(100vh - 1.5rem);
  overflow-x: hidden;
  overflow-y: auto;
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: linear-gradient(180deg, #fffefb 0%, #f8f5ee 100%);
  box-shadow: var(--shadow);
}

.toc-toggle {
  display: none;
  width: 100%;
  border: 0;
  border-bottom: 1px solid var(--border);
  padding: 0.7rem 0.9rem;
  background: #f5fbfb;
  font: 600 0.9rem/1.2 var(--ui-font);
  letter-spacing: 0.02em;
  color: #0e5560;
  text-align: left;
  cursor: pointer;
}

/* Chevron beside the "Contents" label, so it is clear the panel can be collapsed.
   It follows the button's own aria-expanded state (book.js keeps that current in both
   layouts), pointing left to close and right to reopen. Floated rather than flexed so
   the button keeps the display: block the media queries give it. */
.toc-toggle::after {
  content: "\00AB";
  float: right;
  margin-left: 0.5rem;
  font-size: 0.95rem;
  line-height: 1.2;
  opacity: 0.7;
}

.toc-toggle[aria-expanded="false"]::after {
  content: "\00BB";
}

#TOC.book-toc {
  margin: 0;
  padding: 0.9rem 0.95rem 1rem;
}

#TOC h2 {
  margin: 0 0 0.7rem;
  font: 700 0.93rem/1.2 var(--ui-font);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: #0f4f58;
}

.book-toc ul {
  margin: 0;
  padding-left: 0;
}

.book-toc li {
  list-style: none;
  margin: 0.1rem 0;
}

.book-toc .toc-part > a {
  display: block;
  padding: 0.16rem 0.32rem;
  border-radius: 0.35rem;
  color: #17333a;
  font: 700 0.88rem/1.3 var(--ui-font);
  text-decoration: none;
}

.book-toc .toc-part > ul {
  margin: 0.16rem 0 0.36rem;
  padding-left: 0.78rem;
  border-left: 2px solid #d7e4e6;
}

.book-toc .toc-chapter > a {
  display: block;
  padding: 0.12rem 0.28rem;
  border-radius: 0.3rem;
  color: #3d4a54;
  font: 500 0.82rem/1.35 var(--ui-font);
  text-decoration: none;
}

.book-toc a.is-active {
  background: var(--accent-soft);
  color: #083f46;
}

#book-content {
  /* border-box so the side padding stays inside the grid column: with content-box,
     width: 100% plus the padding made the panel wider than the page. */
  box-sizing: border-box;
  min-width: 0;
  width: 100%;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0.95rem;
  box-shadow: var(--shadow);
  padding: 1rem clamp(1.1rem, 2.8vw, 3.2rem) 2rem;
  overflow: visible;
}

#book-content > h1,
#book-content > h2,
#book-content > h3,
#book-content > p,
#book-content > figure,
#book-content > ul,
#book-content > ol,
#book-content > table,
#book-content > blockquote,
#book-content > pre {
  max-width: min(112ch, 100%);
}

/* Embedded apps are authored in the LaTeX source with viewport-relative widths
   (e.g. width:min(98vw,1100px)), which ignores the text column. Cap them here so
   they fit whatever column they land in; the inline width still governs below the cap. */
#book-content iframe,
#book-content embed,
#book-content video {
  max-width: 100%;
}

/* A few displayed equations (wide matrices) are simply wider than a narrow text
   column. Let those scroll inside their own box rather than making the whole page
   scroll sideways. Equations that already fit are unchanged, down to the pixel. */
#book-content .math.display,
#book-content mjx-container[display="true"] {
  max-width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
}

#book-content > div,
#book-content .cell,
#book-content .jp-RenderedHTMLCommon {
  width: 100% !important;
  max-width: none !important;
}

h1, h2, h3, h4 {
  color: #10212a;
  margin-top: 1.45em;
  margin-bottom: 0.45em;
}

h1 {
  font-size: clamp(1.6rem, 1.2rem + 1.4vw, 2.25rem);
  line-height: 1.2;
}

h2 {
  font-size: clamp(1.2rem, 1.05rem + 0.7vw, 1.55rem);
}

h3 {
  font-size: clamp(1.04rem, 0.98rem + 0.35vw, 1.2rem);
}

p, li, td, th {
  font-size: 1rem;
}

.header-section-number {
  color: #1f6c76;
  font-family: var(--ui-font);
  font-weight: 700;
  margin-right: 0.35em;
}

.book-part {
  max-width: min(112ch, 100%);
  margin: 3.2rem 0 2rem;
  padding: clamp(1.35rem, 3vw, 2.6rem);
  border: 1px solid #c9dde0;
  border-radius: 1rem;
  background:
    linear-gradient(135deg, rgba(216, 238, 240, 0.92), rgba(255, 253, 248, 0.95)),
    radial-gradient(circle at 88% 18%, rgba(14, 109, 119, 0.14), transparent 34%);
  box-shadow: var(--shadow);
}

.part-kicker {
  margin: 0 0 0.35rem;
  color: #0c5963;
  font: 800 clamp(1.45rem, 1rem + 2vw, 2.75rem)/1 var(--ui-font);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.part-title {
  margin: 0;
  color: #112d35;
  font: 700 clamp(1.65rem, 1.15rem + 1.9vw, 3rem)/1.08 var(--body-font);
}

h2.section-design-study,
h3.section-example {
  background: #f4f9fa;
  border: 1px solid #d9e8ea;
  border-radius: 0.6rem;
  padding: 0.45rem 0.7rem;
}

h2.section-notes {
  color: #5a4115;
  border-bottom: 2px solid #e7d5ae;
  padding-bottom: 0.16rem;
}

h3.section-solution {
  color: #17615d;
}

figure {
  margin: 1.2rem auto;
  text-align: center;
  max-width: min(92ch, 100%);
}

figure img,
.cell img,
p > img {
  display: block;
  margin: 0.15rem auto 0.7rem;
  max-width: min(86ch, 100%);
  height: auto;
}

figcaption {
  font-size: 0.92rem;
  color: var(--muted);
}

/* Tighten oversized Chapter 8 pendulum block diagrams to match PDF feel. */
#fig\:hw_pendulum_PD_inner img,
#fig\:hw_pendulum_PD_outer img {
  width: min(70ch, 68%) !important;
}

.fig-number {
  color: #1e5860;
  font-weight: 700;
}

pre, code {
  font-family: "Iosevka", "Menlo", "Monaco", "Courier New", monospace;
}

pre {
  border: 1px solid #d8dfe2;
  border-radius: 0.5rem;
  padding: 0.8rem 0.95rem;
  background: #f6fafb;
}

blockquote {
  margin: 1.1rem 0;
  padding: 0.65rem 0.95rem;
  border-left: 4px solid #b0ccd0;
  background: #f7fbfc;
}

.site-footer {
  margin: 2.2rem 0 0.6rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1rem;
  align-items: center;
  justify-content: space-between;
  font-family: var(--ui-font);
}

.back-to-top {
  font-size: 0.84rem;
}

.book-index-anchor {
  position: relative;
  top: -0.7rem;
  display: inline-block;
  width: 0;
  height: 0;
  overflow: hidden;
}

.book-index {
  max-width: min(112ch, 100%);
  column-count: 3;
  column-gap: 2.2rem;
  margin: 1rem 0 2rem;
}

.book-index-letter {
  break-after: avoid;
  break-inside: avoid;
  margin: 1.1rem 0 0.35rem;
  padding-bottom: 0.12rem;
  border-bottom: 1px solid var(--border);
  color: #0f5963;
  font: 800 1rem/1.2 var(--ui-font);
  letter-spacing: 0.08em;
}

.book-index-entry {
  break-inside: avoid;
  display: grid;
  grid-template-columns: minmax(0, 1fr) max-content;
  column-gap: 0.55rem;
  margin: 0.08rem 0;
  font-size: 0.92rem;
  line-height: 1.35;
}

.book-index-term {
  min-width: 0;
}

.book-index-refs {
  color: var(--muted);
  font-family: var(--ui-font);
  font-size: 0.85rem;
  white-space: nowrap;
}

.book-index-ref {
  border-radius: 0.25rem;
  padding: 0 0.08rem;
  text-decoration-thickness: 1px;
}

.book-index-ref:hover,
.book-index-ref:focus-visible {
  background: var(--accent-soft);
}

.knowledge-check {
  margin: 1.6rem 0 1.1rem;
  padding: 0.9rem 1rem;
  border: 1px solid #d7e6e9;
  border-radius: 0.75rem;
  background: #f7fbfc;
}

.knowledge-check p {
  margin: 0;
}

.coding-lab-copy {
  line-height: 1.48;
}

.coding-lab-copy p + p {
  margin-top: 0.5rem;
}

.quiz-list {
  display: grid;
  gap: 0.95rem;
  margin: 1rem 0 0;
}

.quiz-section-note {
  border-left: 4px solid #7a9a01;
  background: #f7f9ec;
  color: #37430b;
  padding: 0.65rem 0.85rem;
  border-radius: 0.45rem;
}

.quiz-section-note p {
  margin: 0;
}

.quiz-card {
  border: 1px solid #d7dfe3;
  border-radius: 0.7rem;
  background: #fff;
  padding: 0.8rem 0.9rem;
}

.quiz-card h4 {
  margin: 0 0 0.45rem;
  font-size: 1rem;
}

.quiz-prompt {
  margin: 0 0 0.6rem;
}

.quiz-given-list {
  margin: 0 0 0.75rem 1.2rem;
  padding: 0;
}

.quiz-given-list li {
  margin: 0.18rem 0;
}

.quiz-equation {
  display: block;
  width: fit-content;
  max-width: 100%;
  margin: 0 0 0.8rem;
  padding: 0.55rem 0.7rem;
  border: 1px solid #dbe7ea;
  border-radius: 0.6rem;
  background: #f7fbfc;
  color: #172d33;
  font-size: 1rem;
}

.quiz-options {
  display: grid;
  gap: 0.35rem;
  margin: 0 0 0.65rem;
}

.quiz-options label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  align-items: center;
  column-gap: 0.55rem;
  width: 100%;
  box-sizing: border-box;
  padding: 0.38rem 0.5rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
  cursor: pointer;
}

.quiz-card[data-quiz-type="mcq"] .quiz-options input[type="radio"] {
  justify-self: center;
  align-self: center;
  margin: 0;
}

.quiz-card[data-quiz-type="mcq"] .quiz-option-text {
  display: block;
  min-width: 0;
  line-height: 1.35;
  overflow-wrap: normal;
  word-break: normal;
}

.quiz-card[data-quiz-type="mcq"] .quiz-option-text .math,
.quiz-card[data-quiz-type="mcq"] .quiz-option-text .inline-equation {
  display: inline;
}

.quiz-matrix {
  position: relative;
  display: inline-grid;
  gap: 0.12rem 0.48rem;
  align-items: center;
  justify-items: center;
  margin: 0 0.18rem;
  padding: 0.18rem 0.52rem;
  color: #172d33;
  font-family: "STIX Two Math", "Cambria Math", "Times New Roman", serif;
  font-size: 1.06em;
  line-height: 1.08;
  vertical-align: middle;
}

.quiz-matrix::before,
.quiz-matrix::after {
  content: "";
  position: absolute;
  top: 0.04rem;
  bottom: 0.04rem;
  width: 0.28rem;
  border-color: #244b54;
  border-style: solid;
  pointer-events: none;
}

.quiz-matrix::before {
  left: 0;
  border-width: 1.5px 0 1.5px 1.5px;
}

.quiz-matrix::after {
  right: 0;
  border-width: 1.5px 1.5px 1.5px 0;
}

.quiz-matrix-2x2,
.quiz-matrix-row {
  grid-template-columns: repeat(2, minmax(0.85rem, max-content));
}

.state-ch12-q2-options .quiz-options label {
  align-items: center;
}

.state-ch12-q2-options .quiz-option-text {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  min-height: 1.45rem;
  line-height: 1.25;
}

.ch9-transfer-q1 .quiz-options label {
  align-items: center;
}

.quiz-card[data-quiz-type="mcq"] .quiz-options {
  grid-template-columns: 1fr;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] .quiz-options,
.quiz-card.ch8-mcq .quiz-options {
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] .quiz-options label,
.quiz-card.ch8-mcq .quiz-options label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  align-items: center;
  column-gap: 0.55rem;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > label,
.quiz-card.ch8-mcq > label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  align-items: center;
  column-gap: 0.55rem;
  width: 100%;
  box-sizing: border-box;
  margin-bottom: 0.35rem;
  padding: 0.38rem 0.5rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
  cursor: pointer;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > label input[type="radio"],
.quiz-card.ch8-mcq > label input[type="radio"] {
  justify-self: center;
  align-self: center;
  margin: 0;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] .quiz-actions,
.quiz-card.ch8-mcq .quiz-actions {
  display: flex;
  width: 100%;
  margin-top: 0.7rem;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > button.quiz-check,
#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > button.quiz-reset,
.quiz-card.ch8-mcq > button.quiz-check,
.quiz-card.ch8-mcq > button.quiz-reset {
  display: inline-flex;
  align-items: center;
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  font: 600 0.84rem/1.2 var(--ui-font);
  margin: 0.35rem 0.4rem 0.45rem 0;
  padding: 0.34rem 0.62rem;
  cursor: pointer;
}

#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > button.quiz-check:hover,
#pid-ch8-knowledge-check .quiz-card[data-quiz-type="mcq"] > button.quiz-reset:hover,
.quiz-card.ch8-mcq > button.quiz-check:hover,
.quiz-card.ch8-mcq > button.quiz-reset:hover {
  background: #e9f4f6;
}

.quiz-card[data-quiz-type="short"] .quiz-options label {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: 0.35rem;
  cursor: default;
}

.quiz-card[data-quiz-type="reflection"] .quiz-options label {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: 0.4rem;
  cursor: default;
}

.quiz-card[data-quiz-type="short"] > label {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: 0.35rem;
  width: 100%;
  box-sizing: border-box;
  margin: 0 0 0.65rem;
  padding: 0.38rem 0.5rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
}

.quiz-card[data-quiz-type="reflection"] > label {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: 0.4rem;
  width: 100%;
  box-sizing: border-box;
  margin: 0 0 0.65rem;
  padding: 0.38rem 0.5rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
}

.quiz-input-label {
  display: block;
  min-width: 0;
  color: #21343b;
  line-height: 1.35;
}

.quiz-options input {
  margin-right: 0.38rem;
}

.quiz-options input[type="text"],
.quiz-options textarea {
  box-sizing: border-box;
  width: 100%;
  margin: 0.35rem 0 0;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.48rem 0.58rem;
}

.quiz-card[data-quiz-type="short"] .quiz-options input[type="text"],
.quiz-card[data-quiz-type="short"] .quiz-options textarea {
  margin: 0;
}

.quiz-card[data-quiz-type="reflection"] .quiz-options textarea {
  margin: 0;
}

.quiz-card[data-quiz-type="short"] > label input[type="text"],
.quiz-card[data-quiz-type="short"] > label textarea {
  box-sizing: border-box;
  width: 100%;
  margin: 0;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.48rem 0.58rem;
}

.quiz-card[data-quiz-type="reflection"] > label textarea {
  box-sizing: border-box;
  width: 100%;
  margin: 0;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.48rem 0.58rem;
}

.quiz-options textarea {
  resize: vertical;
}

.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: flex-start;
  width: 100%;
  clear: both;
  margin-top: 0.25rem;
  margin-bottom: 0.45rem;
}

.quiz-card.ch3-q5-actions-below .quiz-options {
  display: block;
  width: 100%;
  margin-bottom: 0.75rem;
}

.quiz-card.ch3-q5-actions-below .quiz-actions {
  display: flex;
  width: 100%;
  clear: both;
  margin-top: 0.75rem;
}

.quiz-card.ch3-q5-actions-below > label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  align-items: center;
  column-gap: 0.55rem;
  width: 100%;
  box-sizing: border-box;
  margin-bottom: 0.35rem;
  padding: 0.38rem 0.5rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
  cursor: pointer;
}

.quiz-card.ch3-q5-actions-below > label input[type="radio"] {
  justify-self: center;
  align-self: center;
  margin: 0;
}

.quiz-card.ch3-q5-actions-below > br {
  display: none;
}

.quiz-card.ch3-q5-actions-below > button.quiz-check,
.quiz-card.ch3-q5-actions-below > button.quiz-reset {
  display: inline-flex;
  align-items: center;
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  font: 600 0.84rem/1.2 var(--ui-font);
  margin: 0.4rem 0.4rem 0.45rem 0;
  padding: 0.34rem 0.62rem;
  cursor: pointer;
}

.quiz-card.ch3-q5-actions-below > button.quiz-check:hover,
.quiz-card.ch3-q5-actions-below > button.quiz-reset:hover {
  background: #e9f4f6;
}

.quiz-actions button {
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  font: 600 0.84rem/1.2 var(--ui-font);
  padding: 0.34rem 0.62rem;
  cursor: pointer;
}

.quiz-actions button:hover {
  background: #e9f4f6;
}

.quiz-card[data-quiz-type="short"] > button.quiz-check,
.quiz-card[data-quiz-type="short"] > button.quiz-reset {
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  font: 600 0.84rem/1.2 var(--ui-font);
  margin: 0.25rem 0.4rem 0.45rem 0;
  padding: 0.34rem 0.62rem;
  cursor: pointer;
}

.quiz-card[data-quiz-type="short"] > button.quiz-check:hover,
.quiz-card[data-quiz-type="short"] > button.quiz-reset:hover {
  background: #e9f4f6;
}

.quiz-feedback {
  min-height: 1.2rem;
  margin: 0.1rem 0 0.35rem;
  color: #4f5b64;
  font-size: 0.92rem;
}

.quiz-feedback.is-correct {
  color: #125b38;
}

.quiz-feedback.is-wrong {
  color: #8c2f2d;
}

.quiz-answer details {
  margin-top: 0.3rem;
}

.quiz-answer {
  display: none;
}

.quiz-card.is-checked .quiz-answer {
  display: block;
}

.quiz-card[data-quiz-type="short"] > details {
  display: none;
}

.quiz-card[data-quiz-type="short"].is-checked > details {
  display: block;
}

.quiz-answer summary {
  cursor: pointer;
  font-family: var(--ui-font);
  font-size: 0.86rem;
  color: #14505a;
}

.quiz-answer strong {
  display: block;
  margin-bottom: 0.25rem;
}

.quiz-card[data-quiz-type="short"] > details summary {
  cursor: pointer;
  font-family: var(--ui-font);
  font-size: 0.86rem;
  color: #14505a;
}

.chapter-one-panel {
  max-width: min(112ch, 100%);
  margin: 1.4rem 0;
  padding: 1rem;
  border: 1px solid #d7e6e9;
  border-radius: 0.85rem;
  background: linear-gradient(135deg, #fffdf8 0%, #f6fbfc 100%);
  box-shadow: 0 8px 22px rgba(24, 30, 34, 0.06);
}

.chapter-one-kicker {
  margin: 0 0 0.3rem;
  color: #0f5963;
  font: 700 0.85rem/1.2 var(--ui-font);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.workflow-steps,
.design-study-grid {
  display: grid;
  gap: 0.75rem;
  margin-top: 1rem;
}

.workflow-steps {
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
}

.design-study-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.workflow-steps details,
.design-study-grid details {
  border: 1px solid #cfdfe2;
  border-radius: 0.9rem;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.96), rgba(241, 248, 249, 0.96)),
    #fff;
  box-shadow: 0 8px 20px rgba(24, 30, 34, 0.07);
  padding: 0.85rem 0.95rem;
}

.workflow-steps summary,
.design-study-grid summary {
  cursor: pointer;
  color: #10212a;
  font: 700 0.95rem/1.25 var(--ui-font);
}

.workflow-steps summary span {
  display: inline-grid;
  width: 1.55rem;
  height: 1.55rem;
  margin-right: 0.35rem;
  place-items: center;
  border-radius: 999px;
  background: #d8eef0;
  color: #0b5961;
}

.workflow-steps details p,
.design-study-grid details p {
  margin: 0.55rem 0 0;
}

.design-study-grid dl {
  display: grid;
  gap: 0.2rem 0.55rem;
  grid-template-columns: max-content minmax(0, 1fr);
  margin: 0.65rem 0 0;
}

.design-study-grid dt {
  color: #44515b;
  font: 700 0.82rem/1.35 var(--ui-font);
}

.design-study-grid dd {
  margin: 0;
}

.workflow-map {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(18rem, 0.8fr);
  gap: 1rem;
  align-items: stretch;
  margin-top: 1rem;
}

.workflow-image-wrap {
  position: relative;
  overflow: hidden;
  border: 1px solid #cfdfe2;
  border-radius: 0.85rem;
  background: #fff;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.6);
}

.workflow-image-wrap img {
  display: block;
  width: 100%;
  height: auto;
  margin: 0;
}

.workflow-hotspot {
  position: absolute;
  border: 2px solid rgba(14, 109, 119, 0.32);
  border-radius: 0.6rem;
  background: rgba(216, 238, 240, 0.18);
  color: transparent;
  cursor: pointer;
  transition:
    background 160ms ease,
    border-color 160ms ease,
    box-shadow 160ms ease,
    transform 160ms ease;
}

.workflow-hotspot:hover,
.workflow-hotspot:focus-visible,
.workflow-hotspot.is-active {
  border-color: rgba(14, 109, 119, 0.92);
  background: rgba(216, 238, 240, 0.42);
  box-shadow: 0 0 0 4px rgba(14, 109, 119, 0.14);
  transform: translateY(-1px);
}

.workflow-hotspot-physical {
  left: 36.1%;
  top: 72.4%;
  width: 19.6%;
  height: 25.1%;
}

.workflow-hotspot-simulation {
  left: 67.2%;
  top: 58.9%;
  width: 18.8%;
  height: 17.1%;
}

.workflow-hotspot-transfer {
  left: 43.8%;
  top: 4.9%;
  width: 27.4%;
  height: 20.3%;
}

.workflow-hotspot-state {
  left: 44.1%;
  top: 34.8%;
  width: 27%;
  height: 19%;
}

.workflow-hotspot-control {
  left: 13.4%;
  top: 0%;
  width: 23.5%;
  height: 52.8%;
}

.workflow-hotspot-test {
  left: 10%;
  top: 67.1%;
  width: 59.5%;
  height: 9.5%;
}

.workflow-hotspot-implementation {
  left: 0%;
  top: 84.4%;
  width: 38.3%;
  height: 9.8%;
}

.workflow-info {
  border: 1px solid #cfdfe2;
  border-radius: 0.9rem;
  background: linear-gradient(180deg, #fff 0%, #f4fafb 100%);
  box-shadow: 0 8px 20px rgba(24, 30, 34, 0.07);
  padding: 1rem;
}

.workflow-info h3 {
  margin-top: 0;
}

.workflow-chapters {
  margin-top: 0.75rem;
  padding: 0.65rem 0.75rem;
  border-left: 4px solid #0e6d77;
  background: #eef8f9;
  color: #274f56;
}

.ch1-feedback-figure {
  max-width: min(980px, 100%);
  text-align: left;
}

.ch1-feedback-controls {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(12rem, 0.35fr) minmax(12rem, 0.35fr);
  gap: 0.9rem;
  align-items: end;
  margin-bottom: 0.85rem;
}

.ch1-feedback-controls h3 {
  margin: 0.2rem 0 0.25rem;
}

.ch1-feedback-title {
  margin: 0.2rem 0 0.25rem;
  color: #10212a;
  font: 700 1.08rem/1.25 var(--ui-font);
}

.ch1-feedback-controls label {
  display: grid;
  gap: 0.35rem;
  color: #274f56;
  font: 700 0.86rem/1.3 var(--ui-font);
}

.ch1-feedback-controls input[type="range"] {
  width: 100%;
  accent-color: #0e6d77;
}

.ch1-feedback-figure svg {
  display: block;
  width: 100%;
  height: auto;
}

.ch1-caption {
  margin-top: 0.65rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.92rem;
}

.ch1-reflection h3 {
  margin-top: 0;
}

.reflection-note {
  padding: 0.65rem 0.8rem;
  border-left: 4px solid #0e6d77;
  background: #f7fbfc;
}

.chapter-nine-panel {
  max-width: min(112ch, 100%);
  margin: 1.4rem 0;
  padding: 1rem;
  border: 1px solid #d8e0d2;
  border-radius: 0.85rem;
  background: linear-gradient(135deg, #fffdf7 0%, #f7fbf1 100%);
  box-shadow: 0 8px 22px rgba(24, 30, 34, 0.06);
}

.chapter-nine-kicker {
  margin: 0 0 0.3rem;
  color: #5b6716;
  font: 700 0.85rem/1.2 var(--ui-font);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.chapter-nine-panel h3,
.chapter-nine-panel h4 {
  margin-top: 0.25rem;
}

.ch9-control-grid,
.ch9-result-grid,
.ch9-disturbance-grid,
.ch9-transfer-grid {
  display: grid;
  gap: 0.85rem;
  margin-top: 0.85rem;
}

.ch9-control-grid {
  grid-template-columns: repeat(3, minmax(10rem, 1fr));
}

.ch9-result-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.ch9-disturbance-grid {
  grid-template-columns: minmax(15rem, 0.7fr) minmax(0, 1fr);
}

.ch9-transfer-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.ch9-problem5-figure {
  margin: 1rem 0;
  border: 1px solid #d8e0d2;
  border-radius: 0.85rem;
  background: #fff;
  overflow: hidden;
}

.ch9-problem5-figure svg {
  display: block;
  width: 100%;
  height: auto;
}

.ch9-problem5-figure figcaption {
  margin: 0;
  padding: 0.65rem 0.8rem 0.75rem;
  border-top: 1px solid #d8e0d2;
  color: #526047;
  font-size: 0.9rem;
  line-height: 1.35;
}

.ch9-final-table-card {
  margin-top: 1rem;
}

.ch9-final-value-table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.8rem 0;
  background: #fff;
}

.ch9-final-value-table th,
.ch9-final-value-table td {
  border: 1px solid #d8e0d2;
  padding: 0.55rem;
  text-align: center;
}

.ch9-final-value-table th {
  background: #f1f6df;
  color: #253217;
  font: 700 0.9rem/1.25 var(--ui-font);
}

.ch9-final-value-table input {
  width: min(8rem, 100%);
  border: 1px solid #cbd6bd;
  border-radius: 0.45rem;
  padding: 0.38rem 0.45rem;
  text-align: center;
}

.ch9-final-value-table input.is-correct {
  border-color: #337a4c;
  background: #eff9f1;
}

.ch9-final-value-table input.is-wrong {
  border-color: #9c4735;
  background: #fff3ee;
}

.advanced-activity {
  max-width: min(112ch, 100%);
  margin: 1.25rem 0;
  padding: 1rem;
  border: 1px solid #d8e2e5;
  border-radius: 0.85rem;
  background:
    radial-gradient(circle at 12% 12%, rgba(222, 242, 245, 0.8), transparent 34%),
    linear-gradient(135deg, #ffffff 0%, #f7fbfc 100%);
  box-shadow: 0 8px 22px rgba(24, 30, 34, 0.055);
}

.advanced-activity h3,
.advanced-activity h4 {
  margin-top: 0.2rem;
}

.advanced-kicker {
  margin: 0 0 0.25rem;
  color: #0f6070;
  font: 700 0.82rem/1.2 var(--ui-font);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.advanced-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.9rem;
  align-items: start;
  margin-top: 0.85rem;
}

.advanced-grid--visual {
  grid-template-columns: minmax(15rem, 0.85fr) minmax(18rem, 1.15fr);
}

.advanced-grid–visual {
  grid-template-columns: minmax(15rem, 0.85fr) minmax(18rem, 1.15fr);
}

.advanced-activity[data-advanced-activity="transfer-function"] .advanced-controls {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.advanced-activity[data-advanced-activity="inertia"] .advanced-controls {
  grid-template-columns: 1fr;
}

.advanced-activity[data-advanced-activity="lagrange"] .advanced-controls {
  grid-template-columns: 1fr;
}

.ch8-first-order-layout {
  grid-template-columns: 1fr;
}

.ch8-first-order-controls {
  grid-template-columns: repeat(2, minmax(14rem, 1fr));
}

.ch8-first-order-readout {
  grid-template-columns: repeat(3, minmax(9rem, 1fr));
}

.ch8-first-order-readout .advanced-metric {
  grid-template-columns: 1fr;
  align-content: start;
}

.ch8-first-order-readout .advanced-metric strong {
  white-space: nowrap;
}

.ch8-first-order-readout-table {
  width: 100%;
  table-layout: fixed;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border: 1px solid #dbe7ea;
  border-radius: 0.65rem;
  background: rgba(255, 255, 255, 0.86);
}

.ch8-first-order-readout-table th,
.ch8-first-order-readout-table td {
  padding: 0.65rem 0.75rem;
  text-align: left;
  vertical-align: top;
  border-right: 1px solid #dbe7ea;
}

.ch8-first-order-readout-table th:last-child,
.ch8-first-order-readout-table td:last-child {
  border-right: 0;
}

.ch8-first-order-readout-table th {
  color: #244b54;
  font: 700 0.8rem/1.25 var(--ui-font);
}

.ch8-first-order-readout-table td {
  color: #172d33;
  font-size: 1rem;
}

.ch15-sine-layout {
  grid-template-columns: 1fr;
  align-items: start;
}

.ch15-sine-layout .advanced-visual {
  min-width: 0;
}

.ch15-sine-controls {
  grid-template-columns: 1fr;
}

.ch15-sine-figure {
  box-sizing: border-box;
  width: 100%;
}

.ch15-sine-figure canvas {
  width: 100%;
}

.ch15-sine-readout {
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
}

.ch15-term-controls {
  align-content: start;
}

.ch15-example1-layout {
  grid-template-columns: 1fr;
}

.ch15-example1-controls {
  grid-template-columns: minmax(12rem, 0.7fr) minmax(18rem, 1.3fr);
  align-items: start;
}

.ch15-example1-term {
  grid-column: 1;
}

.ch15-example1-frequency {
  grid-column: 2;
  grid-row: 1 / span 3;
}

.ch15-example1-prediction {
  grid-row: 4;
}

.ch15-example1-check-panel {
  grid-column: 1 / -1;
  grid-row: 5;
  grid-template-columns: max-content minmax(0, 1fr);
  align-items: center;
}

.ch15-example1-check-panel .quiz-feedback {
  min-height: 0;
  margin: 0;
}

.ch15-example1-figure,
.ch15-example1-readout {
  grid-column: 1 / -1;
}

.ch15-example1-readout {
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
}

.ch15-example1-readout .advanced-metric {
  margin: 0;
}

.ch15-example-builder-layout {
  grid-template-columns: 1fr;
}

.ch15-example-builder-controls {
  grid-template-columns: minmax(12rem, 0.7fr) minmax(18rem, 1.3fr);
  align-items: start;
}

.ch15-example-builder-select {
  grid-column: 1 / -1;
}

.ch15-example-term-grid {
  display: grid;
  grid-column: 1;
  grid-template-columns: 1fr;
  gap: 0.45rem;
}

.ch15-example-builder-frequency {
  grid-column: 2;
  grid-row: 2;
}

.ch15-example-builder-prediction {
  grid-row: 3;
}

.ch15-example-builder-check-panel {
  grid-column: 1 / -1;
  grid-row: 4;
  grid-template-columns: max-content minmax(0, 1fr);
  align-items: center;
}

.ch15-example-builder-check-panel .quiz-feedback {
  min-height: 0;
  margin: 0;
}

.ch15-example-term[hidden] {
  display: none !important;
}

.ch15-example-builder-figure,
.ch15-example-builder-readout {
  grid-column: 1 / -1;
}

.ch15-example-builder-readout {
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
}

.ch15-example-builder-readout .advanced-metric {
  margin: 0;
}

.ch15-complex-layout {
  grid-template-columns: 1fr;
}

.ch15-complex-controls {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
}

.ch15-complex-figure,
.ch15-complex-readout {
  grid-column: 1 / -1;
}

.ch15-complex-readout {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
}

.ch15-complex-readout .advanced-metric {
  margin: 0;
}

@media (max-width: 860px) {
  .ch15-complex-controls,
  .ch15-complex-readout {
    grid-template-columns: 1fr;
  }

}

@media (max-width: 560px) {
  .ch15-example1-controls,
  .ch15-example-builder-controls,
  .ch15-example-term-grid {
    grid-template-columns: 1fr;
  }

  .ch15-example1-check-panel,
  .ch15-example-builder-check-panel {
    grid-column: 1 / -1;
    grid-row: auto;
  }

  .ch15-example1-term,
  .ch15-example1-frequency,
  .ch15-example1-prediction,
  .ch15-example-builder-select,
  .ch15-example-term-grid,
  .ch15-example-builder-frequency,
  .ch15-example-builder-prediction {
    grid-column: 1 / -1;
    grid-row: auto;
  }
}

.advanced-checkbox {
  display: flex !important;
  grid-template-columns: none !important;
  align-items: center;
  gap: 0.45rem !important;
}

.advanced-checkbox input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  accent-color: #0e6d77;
}

.ch15-scale-layout {
  grid-template-columns: 1fr;
  align-items: start;
}

.ch15-scale-controls,
.ch15-scale-figure,
.ch15-scale-readout,
.ch15-db-reference,
.ch15-scale-question {
  grid-column: 1 / -1;
}

.ch15-scale-controls {
  grid-template-columns: 1fr;
}

.ch15-scale-frequency-label {
  display: inline-block;
  white-space: nowrap;
}

.ch15-scale-readout {
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
}

.ch15-db-reference {
  display: grid;
  grid-template-columns: max-content repeat(4, minmax(8rem, 1fr));
  gap: 0.45rem 0.75rem;
  align-items: center;
}

.ch15-db-reference span {
  display: inline-block;
  padding: 0.32rem 0.48rem;
  border: 1px solid #eadcbf;
  border-radius: 0.45rem;
  background: rgba(255, 255, 255, 0.72);
}

.ch15-scale-question {
  margin-top: 0;
}

.ch18-block-layout {
  grid-template-columns: 1fr;
  align-items: start;
}

.ch18-block-controls {
  grid-template-columns: minmax(16rem, 0.9fr) minmax(18rem, 1.1fr);
  align-content: start;
  border: 1px solid #cfe1df;
  border-radius: 0.85rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(233, 244, 241, 0.74));
  padding: 0.85rem;
}

.ch18-block-selector-column,
.ch18-block-slider-column {
  display: grid;
  gap: 0.75rem;
  align-content: start;
  min-width: 0;
}

.ch18-block-controls [hidden] {
  display: none !important;
}

.ch18-block-hint {
  margin: 0;
}

.ch18-block-control {
  align-content: start;
}

.ch18-block-control .advanced-control-label,
.ch18-block-control .advanced-control-value {
  display: block;
  min-width: 0;
  overflow-wrap: normal;
  text-wrap: balance;
}

.ch18-block-control .advanced-control-value {
  color: #526047;
  font: 700 0.9rem/1.25 var(--ui-font);
  white-space: nowrap;
}

.ch18-block-figure {
  box-sizing: border-box;
  width: 100%;
}

.ch18-block-figure canvas {
  width: 100%;
  height: auto;
  min-height: 28rem;
  background: #fbfdfe;
}

.ch18-block-readout {
  grid-template-columns: repeat(3, minmax(14rem, 1fr));
  align-content: start;
}

.ch18-block-readout .advanced-metric:first-child {
  background: #172d33;
  border-color: #172d33;
}

.ch18-block-readout .advanced-metric:first-child strong,
.ch18-block-readout .advanced-metric:first-child span {
  color: #fff;
}

.ch18-block-readout .metric-equation {
  font-size: 1.04rem;
}

.ch18-block-check {
  max-width: min(112ch, 100%);
  margin: 1rem 0 1.4rem;
}

.ch18-slc-layout {
  grid-template-columns: 1fr;
  align-items: start;
}

.ch18-slc-controls {
  grid-template-columns: minmax(20rem, 1fr) minmax(22rem, 1.2fr);
  align-content: start;
  border: 1px solid #d7e2c5;
  border-radius: 0.85rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(246, 249, 235, 0.78));
  padding: 0.85rem;
}

.ch18-slc-step-grid {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.65rem;
}

.ch18-slc-step {
  display: grid;
  gap: 0.3rem;
  min-height: 6.5rem;
  padding: 0.8rem;
  border: 1px solid #dbe7ea;
  border-radius: 0.85rem;
  background: #fff;
  color: #172d33;
  text-align: left;
  cursor: pointer;
  box-shadow: 0 0.45rem 1.25rem rgba(23, 45, 51, 0.08);
}

.ch18-slc-step strong {
  font-size: 0.95rem;
  line-height: 1.2;
}

.ch18-slc-step span {
  color: #526047;
  font-size: 0.82rem;
  line-height: 1.3;
}

.ch18-slc-step.is-active {
  border-color: #0e6d77;
  background: #e4f4f2;
  box-shadow: 0 0.55rem 1.45rem rgba(14, 109, 119, 0.18);
}

.ch18-slc-step-select {
  display: none;
}

.ch18-slc-readout {
  grid-template-columns: repeat(5, minmax(12rem, 1fr));
  align-content: start;
}

.ch18-slc-readout .advanced-metric:first-child {
  background: #172d33;
  border-color: #172d33;
}

.ch18-slc-readout .advanced-metric:first-child strong,
.ch18-slc-readout .advanced-metric:first-child span {
  color: #fff;
}

.ch18-slc-layout .advanced-visual {
  min-width: 0;
}

.ch18-slc-layout svg {
  min-height: 26rem;
}

@media (max-width: 900px) {
  .ch18-slc-step-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .ch18-slc-step-grid {
    grid-template-columns: 1fr;
  }
}

.ch18-prefilter-layout {
  grid-template-columns: 1fr;
}

.ch18-prefilter-controls {
  grid-template-columns: minmax(18rem, 34rem);
}

.ch18-prefilter-figure {
  box-sizing: border-box;
  width: 100%;
}

.ch18-prefilter-figure canvas {
  width: 100%;
}

.ch18-prefilter-readout {
  grid-template-columns: repeat(3, minmax(14rem, 1fr));
}

.ch18-dashboard-layout {
  grid-template-columns: 1fr;
}

.ch18-dashboard-controls {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
  align-content: start;
  border: 1px solid #cfe1df;
  border-radius: 0.85rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(233, 244, 241, 0.74));
  padding: 0.85rem;
}

.ch18-dashboard-figure {
  box-sizing: border-box;
  width: 100%;
}

.ch18-dashboard-figure canvas {
  width: 100%;
}

.ch18-dashboard-readout {
  grid-template-columns: repeat(3, minmax(15rem, 1fr));
}

.ch18-dashboard-readout .advanced-metric:first-child {
  background: #172d33;
  border-color: #172d33;
}

.ch18-dashboard-readout .advanced-metric:first-child strong,
.ch18-dashboard-readout .advanced-metric:first-child span {
  color: #fff;
}

@media (max-width: 860px) {
  .ch18-block-controls,
  .ch18-block-readout,
  .ch18-slc-controls,
  .ch18-slc-readout,
  .ch18-prefilter-controls,
  .ch18-prefilter-readout,
  .ch18-dashboard-controls,
  .ch18-dashboard-readout {
    grid-template-columns: 1fr;
  }
}

.ch15-pz-layout {
  grid-template-columns: 1fr;
}

.ch15-pz-controls {
  grid-template-columns: minmax(16rem, 0.8fr) minmax(20rem, 1.2fr);
}

.ch15-pz-factor-equation {
  font-size: 1.12rem;
}

.ch15-pz-corner-label {
  display: inline-block;
  max-width: 100%;
  overflow-x: auto;
  white-space: nowrap;
}

.ch15-pz-figure,
.ch15-pz-readout {
  grid-column: 1 / -1;
}

.ch15-pz-readout {
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
}

.ch15-pz-readout .advanced-metric {
  margin: 0;
}

.ch15-second-order-layout {
  grid-template-columns: 1fr;
}

.ch15-second-order-controls {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
}

.ch15-second-order-figure,
.ch15-second-order-readout {
  grid-column: 1 / -1;
}

.ch15-second-order-readout {
  grid-template-columns: repeat(3, minmax(13rem, 1fr));
}

.ch15-second-order-readout .advanced-metric {
  margin: 0;
}

.advanced-controls,
.advanced-readout {
  display: grid;
  gap: 0.65rem;
}

.advanced-controls--compact {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.advanced-activity[data-advanced-activity="inertia"] .advanced-controls--compact {
  grid-template-columns: 1fr;
}

.advanced-activity[data-advanced-activity="lagrange"] .advanced-controls--compact {
  grid-template-columns: 1fr;
}

.advanced-activity[data-advanced-activity="lagrange"] .advanced-grid--visual {
  grid-template-columns: minmax(14rem, 0.72fr) minmax(24rem, 1.28fr);
}

.advanced-activity[data-advanced-activity="lagrange"] .advanced-controls label {
  width: 100%;
}

.advanced-activity[data-advanced-activity="lagrange"] .advanced-controls input[type="range"] {
  width: 100%;
}

.ch16-frequency-spec-layout {
  grid-template-columns: 1fr;
}

.ch16-frequency-spec-controls {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
  align-content: start;
}

.ch16-frequency-spec-amplitude-note {
  grid-column: 1 / -1;
  margin-top: 0.15rem;
}

.ch16-frequency-spec-figure {
  width: 100%;
  box-sizing: border-box;
}

.ch16-frequency-spec-figure canvas {
  width: 100%;
}

.ch16-frequency-spec-figure figcaption {
  line-height: 1.45;
}

.ch16-frequency-spec-solution .advanced-equation {
  line-height: 1.45;
}

.ch16-frequency-spec-solution .metric-equation {
  display: inline;
  overflow-wrap: normal;
}

.ch16-frequency-spec-controls .advanced-control-label,
.ch16-frequency-spec-controls .advanced-control-value,
.ch16-frequency-spec-solution .inline-equation {
  white-space: nowrap;
}

.ch4-taylor-controls {
  grid-template-columns: 1fr;
}

.ch10-dirty-derivative-layout {
  grid-template-columns: 1fr;
}

.ch10-dirty-derivative-controls {
  grid-template-columns: minmax(18rem, 32rem);
}

.ch10-anti-windup-controls {
  grid-template-columns: repeat(4, minmax(9rem, 1fr));
}

.ch16-signal-path-layout {
  grid-template-columns: 1fr;
}

.ch16-signal-path-layout .advanced-controls {
  justify-items: center;
}

.ch16-signal-path-layout .advanced-controls label {
  width: fit-content;
  min-width: min(18rem, 100%);
}

.ch16-signal-path-figure {
  box-sizing: border-box;
  width: 100%;
  margin: 0 auto;
}

.ch16-signal-path-solution {
  overflow: visible;
}

.advanced-equation.ch16-signal-path-result {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  align-items: start;
  gap: 0.35rem 0.6rem;
}

.advanced-equation.ch16-signal-path-result [data-output] {
  display: block;
  min-width: 0;
  max-width: 100%;
  text-align: left;
  white-space: normal;
  overflow-wrap: anywhere;
}

.advanced-equation.ch16-signal-path-result .inline-frac {
  vertical-align: middle;
}

@media (max-width: 720px) {
  .advanced-equation.ch16-signal-path-result {
    grid-template-columns: 1fr;
  }
}

.ch16-system-type-layout {
  grid-template-columns: 1fr;
}

.ch16-system-type-controls {
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  align-items: start;
}

.ch16-system-type-controls .advanced-button-row,
.ch16-system-type-controls .quiz-feedback {
  align-self: start;
}

.ch16-system-type-step,
.ch16-system-type-marker-note,
.ch16-system-type-marker-readout,
.ch16-system-type-slope-formula,
.ch16-system-type-reference {
  grid-column: 1 / -1;
}

.ch16-system-type-step {
  margin: 0;
}

.ch16-system-type-marker-note,
.ch16-system-type-slope-formula {
  margin: 0;
}

.ch16-system-type-marker-readout {
  grid-template-columns: repeat(2, minmax(14rem, 1fr));
}

.ch16-system-type-marker-readout .advanced-metric {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 0.55rem;
  align-items: baseline;
  margin: 0;
}

.ch16-system-type-marker-gain {
  display: grid !important;
  grid-template-columns: max-content max-content;
  gap: 0.25rem 0.55rem;
  align-items: baseline;
  overflow-x: auto;
  white-space: nowrap;
}

.ch16-system-type-gain-value {
  white-space: nowrap;
}

.ch16-system-type-reference {
  display: grid;
  grid-template-columns: max-content repeat(3, minmax(10rem, 1fr));
  gap: 0.45rem 0.65rem;
  align-items: center;
  margin: 0;
}

.ch16-system-type-reference span {
  display: inline-block;
  padding: 0.28rem 0.45rem;
  border: 1px solid #eadcbf;
  border-radius: 0.45rem;
  background: rgba(255, 255, 255, 0.72);
}

.ch16-system-type-figure {
  box-sizing: border-box;
  width: 100%;
  margin: 0 auto;
}

.ch16-system-type-measure-controls label,
.ch16-system-type-error-controls label {
  min-width: 0;
}

.ch16-system-type-value-unit {
  white-space: nowrap;
}

.ch16-system-type-amplitude-label {
  display: inline-block;
  max-width: 100%;
  overflow-x: auto;
  white-space: nowrap;
}

.ch16-system-type-guess-control {
  grid-column: 1 / 2;
}

.advanced-button-row.ch16-system-type-check-panel {
  display: grid;
  grid-column: 2 / -1;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0.5rem 0.8rem;
  align-items: center;
}

.advanced-button-row.ch16-system-type-check-panel .quiz-feedback {
  min-height: 0;
  margin: 0;
}

.ch16-system-type-input-note {
  grid-column: 1 / -1;
  margin: 0;
}

.ch16-system-type-results {
  display: grid;
  gap: 0.55rem;
}

.ch16-system-type-result-row {
  display: grid;
  grid-template-columns: minmax(10rem, max-content) minmax(0, 1fr);
  gap: 0.5rem 0.9rem;
  align-items: baseline;
}

.ch16-system-type-result-row strong {
  color: #172d33;
}

.ch16-system-type-result-row [data-output] {
  display: block;
  min-width: 0;
  text-align: left;
}

@media (max-width: 720px) {
  .ch16-system-type-guess-control,
  .ch16-system-type-check-panel {
    grid-column: 1 / -1;
  }

  .advanced-button-row.ch16-system-type-check-panel {
    grid-template-columns: 1fr;
  }

  .ch16-system-type-marker-readout,
  .ch16-system-type-reference,
  .ch16-system-type-result-row {
    grid-template-columns: 1fr;
  }
}

.ch17-margin-layout {
  grid-template-columns: 1fr;
}

.ch17-margin-controls {
  grid-row: 1;
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
  align-content: start;
}

.ch17-margin-controls label {
  min-width: 0;
}

.ch17-margin-control-note {
  grid-column: 1 / -1;
  margin: 0;
}

.ch17-margin-readout {
  grid-column: 1 / -1;
  grid-row: 3;
  grid-template-columns: repeat(5, minmax(10rem, 1fr));
}

.ch17-margin-readout .advanced-metric {
  margin: 0;
}

.ch17-margin-figure {
  grid-row: 2;
  box-sizing: border-box;
  width: 100%;
  margin: 0 auto;
}

.ch17-margin-figure svg {
  display: block;
  width: 100%;
  min-height: clamp(34rem, 62vw, 46rem);
}

.ch17-phase-response-layout,
.ch17-crossover-layout,
.ch17-loopshape-layout {
  grid-template-columns: 1fr;
}

.ch17-phase-response-controls,
.ch17-crossover-controls,
.ch17-loopshape-controls {
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  align-content: start;
}

.ch17-phase-response-figure,
.ch17-crossover-figure,
.ch17-loopshape-figure {
  box-sizing: border-box;
  width: 100%;
}

.ch17-crossover-figure svg,
.ch17-loopshape-figure svg {
  display: block;
  width: 100%;
  min-height: clamp(32rem, 62vw, 46rem);
}

.ch17-phase-response-figure svg {
  display: block;
  width: 100%;
  height: auto;
  min-height: 0;
  aspect-ratio: 900 / 660;
}

.ch17-crossover-readout,
.ch17-loopshape-readout {
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
}

.ch17-loopshape-tabs {
  display: grid;
  grid-column: 1 / -1;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.5rem;
}

.ch17-loopshape-tabs button {
  border: 1px solid #cbdadd;
  border-radius: 999px;
  background: #fff;
  color: #244b54;
  cursor: pointer;
  font: 700 0.86rem/1.2 var(--ui-font);
  padding: 0.55rem 0.75rem;
}

.ch17-loopshape-tabs button:hover,
.ch17-loopshape-tabs button:focus-visible,
.ch17-loopshape-tabs button.is-active {
  border-color: #0e6d77;
  background: #e8f6f7;
  color: #0e6d77;
}

.ch17-phase-response-readout {
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
}

.ch17-phase-response-readout .advanced-metric,
.ch17-crossover-readout .advanced-metric,
.ch17-loopshape-readout .advanced-metric {
  margin: 0;
}

.ch17-loopshape-focus {
  grid-column: 1 / -1;
}

.ch17-loopshape-focus strong {
  color: #0e6d77;
  font-size: 1.02rem;
}

.ch17-loopshape-check {
  grid-column: 1 / -1;
}

.ch17-loopshape-answer-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
  margin-top: 0.6rem;
}

.ch17-loopshape-answer-row button {
  border: 1px solid #cbdadd;
  border-radius: 0.65rem;
  background: #fff;
  color: #172d33;
  cursor: pointer;
  font: 600 0.88rem/1.25 var(--ui-font);
  padding: 0.55rem 0.65rem;
  text-align: left;
}

.ch17-loopshape-answer-row button:hover,
.ch17-loopshape-answer-row button:focus-visible {
  border-color: #0e6d77;
  background: #f2fafb;
}

.ch17-loopshape-answer-row button.is-correct {
  border-color: #337a4c;
  background: #eff9f1;
}

.ch17-loopshape-answer-row button.is-wrong {
  border-color: #9c4735;
  background: #fff3ee;
}

@media (max-width: 860px) {
  .ch17-margin-controls,
  .ch17-margin-readout,
  .ch17-phase-response-controls,
  .ch17-crossover-controls,
  .ch17-loopshape-controls,
  .ch17-loopshape-tabs {
    grid-template-columns: 1fr;
  }

  .ch17-loopshape-answer-row {
    grid-template-columns: 1fr;
  }
}

.ch18-loopshape-layout {
  grid-template-columns: 1fr;
}

.ch18-step-card-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(8.5rem, 1fr));
  gap: 0.7rem;
}

.ch18-step-card {
  display: grid;
  gap: 0.35rem;
  min-height: 5.25rem;
  border: 1px solid #c9dadd;
  border-radius: 0.8rem;
  background: rgba(255, 255, 255, 0.86);
  color: #172d33;
  font: 600 0.88rem/1.25 var(--ui-font);
  padding: 0.72rem 0.78rem;
  text-align: left;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(24, 30, 34, 0.04);
}

.ch18-step-card strong {
  color: #174a54;
  font-size: 0.95rem;
}

.ch18-step-card span {
  color: #526047;
  font-weight: 500;
}

.ch18-step-card:hover,
.ch18-step-card:focus-visible {
  border-color: #7fb0b8;
  background: #f2fafb;
}

.ch18-step-card.is-active {
  border-color: #0e6d77;
  background: linear-gradient(135deg, #e7f5f7, #ffffff);
  box-shadow: 0 0 0 2px rgba(14, 109, 119, 0.16);
}

.ch18-loopshape-figure {
  box-sizing: border-box;
  width: 100%;
  margin: 0 auto;
}

.ch18-loopshape-readout {
  grid-template-columns: repeat(2, minmax(18rem, 1fr));
}

.ch18-status-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.ch18-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  border: 1px solid #cddade;
  border-radius: 999px;
  background: #f7fbfc;
  color: #526047;
  font: 700 0.78rem/1.2 var(--ui-font);
  padding: 0.22rem 0.48rem;
}

.ch18-status-pill.is-pass {
  border-color: #9fc7a9;
  background: #eef8f0;
  color: #2f6b42;
}

.ch18-status-pill.is-warn {
  border-color: #e2c58c;
  background: #fff8e8;
  color: #7a5718;
}

.ch18-status-pill.is-fail {
  border-color: #d9a394;
  background: #fff1ec;
  color: #8b3d2c;
}

@media (max-width: 980px) {
  .ch18-step-card-grid,
  .ch18-loopshape-readout {
    grid-template-columns: 1fr;
  }
}

.advanced-button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.ch14-observer-layout {
  grid-template-columns: minmax(15rem, 0.62fr) minmax(31rem, 1.38fr);
}

.ch14-observer-layout .advanced-controls {
  align-content: start;
}

.ch14-disturbance-observer-stack {
  grid-template-columns: minmax(0, 1fr);
}

.ch14-disturbance-observer-stack .advanced-controls,
.ch14-disturbance-observer-stack .advanced-visual {
  min-width: 0;
}

.ch14-disturbance-observer-stack .advanced-visual {
  width: 100%;
  box-sizing: border-box;
}

.ch14-disturbance-observer-stack canvas[data-plot="disturbance-observer"],
.ch14-disturbance-observer-stack canvas[data-plot="disturbance-observer-comparison"] {
  display: block;
  width: 100%;
  max-width: 100%;
  box-sizing: border-box;
  border-radius: 0.55rem;
}

.ch14-observability-steps {
  display: grid;
  gap: 0.45rem;
  margin: 0.85rem 0 1rem;
  padding-left: 1.25rem;
  color: #244b54;
}

.ch14-observability-flow {
  display: grid;
  gap: 0.95rem;
}

.ch14-observability-controls {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
}

.ch14-observability-controls select {
  width: 100%;
  max-width: 100%;
}

.ch14-observability-visual {
  grid-column: 1 / -1;
  padding: 0.85rem;
}

.ch14-observability-readout {
  grid-column: 1 / -1;
  grid-template-columns: minmax(16rem, 1.1fr) minmax(8rem, 0.45fr) minmax(18rem, 1.2fr);
}

.ch14-observability-readout .advanced-metric {
  align-content: start;
}

.ch14-observability-readout .metric-equation {
  font-family: var(--mono-font, ui-monospace, SFMono-Regular, Menlo, Consolas, monospace);
  font-size: 1.02rem;
}

.ch14-code-map-layout {
  grid-template-columns: minmax(0, 1.08fr) minmax(16rem, 0.92fr);
}

.ch14-code-map-layout code {
  color: #172d33;
  font-size: 0.88rem;
  white-space: normal;
}

.ch14-code-map-layout .advanced-controls label {
  min-width: 0;
}

.ch14-code-map-layout .advanced-readout,
.ch14-code-map-layout .advanced-metric {
  min-width: 0;
}

.ch14-code-map-layout .advanced-readout {
  width: 100%;
}

.ch14-code-map-layout .advanced-metric {
  grid-template-columns: 1fr;
}

.ch14-code-line {
  display: grid;
  gap: 0.18rem;
  min-width: 0;
}

.ch14-code-line .math {
  color: #526047;
  font-size: 1.12rem;
  font-weight: 600;
  line-height: 1.4;
  white-space: normal;
}

.ch14-code-map-layout select {
  margin-top: 0.35rem;
  justify-self: stretch;
  width: 100%;
  inline-size: 100%;
  max-width: 100%;
  max-inline-size: 100%;
  min-width: 0;
  min-inline-size: 0;
  text-overflow: ellipsis;
}

.advanced-controls label {
  display: grid;
  gap: 0.35rem;
  color: #244b54;
  font: 700 0.86rem/1.3 var(--ui-font);
}

.advanced-control-value {
  color: #526047;
  font: 600 0.82rem/1.25 var(--ui-font);
}

.advanced-control-label {
  display: inline-block;
  text-align: left;
}

#observer-ch13-interactive-check .advanced-control-label {
  display: block;
  white-space: nowrap;
}

#observer-ch13-interactive-check .advanced-grid > label {
  display: grid;
  gap: 0.35rem;
  color: #244b54;
  font: 700 0.86rem/1.3 var(--ui-font);
}

.advanced-controls input[type="range"] {
  width: 100%;
  accent-color: #0e6d77;
}

#observer-ch13-interactive-check .advanced-grid > label input[type="range"] {
  width: 100%;
  accent-color: #0e6d77;
}

.advanced-readout {
  grid-template-columns: 1fr;
}

.advanced-readout.ch15-complex-readout {
  grid-template-columns: repeat(2, minmax(16rem, 1fr));
}

.advanced-readout-lines {
  grid-template-columns: 1fr;
}

.advanced-metric {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0.35rem 0.8rem;
  align-items: baseline;
  border: 1px solid #dbe7ea;
  border-radius: 0.65rem;
  background: rgba(255, 255, 255, 0.82);
  padding: 0.65rem 0.75rem;
}

.advanced-metric strong {
  display: block;
  color: #244b54;
  font: 700 0.8rem/1.25 var(--ui-font);
}

.advanced-metric > span {
  display: block;
  margin-top: 0;
  color: #172d33;
  font-size: 1rem;
}

.advanced-metric .metric-equation {
  display: block;
  line-height: 1.35;
}

.inline-equation {
  font-family: "STIX Two Math", "Cambria Math", "Times New Roman", serif;
  font-style: italic;
  white-space: nowrap;
}

.advanced-visual {
  border: 1px solid #dbe7ea;
  border-radius: 0.8rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(239, 248, 250, 0.78));
  padding: 0.75rem;
}

.advanced-visual-stack {
  display: grid;
  gap: 0.85rem;
}

.advanced-visual svg,
.advanced-visual canvas {
  display: block;
  width: 100%;
  max-width: 100%;
  border-radius: 0.55rem;
}

.advanced-visual--auto {
  margin-top: 0.85rem;
}

.advanced-visual--auto svg text {
  font-family: var(--ui-font);
}

.advanced-visual figcaption,
.advanced-caption {
  margin-top: 0.45rem;
  color: #526047;
  font-size: 0.88rem;
}

.advanced-solution {
  display: grid;
  gap: 0.45rem;
  margin-top: 0.85rem;
  padding: 0.75rem 0.85rem;
  border: 1px solid #dbe7ea;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.86);
}

.advanced-solution h4 {
  margin: 0;
  color: #244b54;
  font: 800 0.86rem/1.25 var(--ui-font);
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.advanced-equation {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.25rem 0.5rem;
  margin: 0;
  color: #172d33;
  font-size: 0.98rem;
}

.advanced-equation [data-output] {
  display: inline-block;
  min-width: 3.2rem;
  padding: 0.08rem 0.35rem;
  border-radius: 0.35rem;
  background: #edf7f8;
  color: #0d5f69;
  font-weight: 800;
  text-align: center;
}

.advanced-equation .advanced-unit {
  color: #526047;
}

.math-frac {
  display: inline-block;
  white-space: nowrap;
}

.inline-frac {
  display: inline-grid;
  grid-template-rows: auto auto;
  justify-items: center;
  width: max-content;
  margin: 0 0.15rem;
  text-align: center;
  vertical-align: middle;
  line-height: 1.12;
}

.inline-frac .frac-top {
  display: inline-block;
  min-width: 0;
  padding: 0 0.35rem 0.08rem;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.inline-frac .frac-bottom {
  display: inline-block;
  min-width: 0;
  padding: 0.08rem 0.35rem 0;
  border-top: 1.5px solid currentColor;
  border-radius: 0;
  background: transparent;
}

.overdot {
  position: relative;
  display: inline-block;
  padding-top: 0.12em;
}

.overdot::before {
  content: ".";
  position: absolute;
  top: -0.42em;
  left: 50%;
  transform: translateX(-50%);
  font-weight: 700;
}

.hat {
  position: relative;
  display: inline-block;
  padding-top: 0.02em;
}

.hat::before {
  content: "\02C6";
  position: absolute;
  top: -0.32em;
  left: 50%;
  transform: translateX(-50%);
  font-weight: 700;
  line-height: 1;
}

.advanced-note {
  grid-column: 1 / -1;
  margin: 0;
  padding: 0.65rem 0.8rem;
  border-left: 4px solid #0e6d77;
  background: rgba(255, 255, 255, 0.78);
  color: #526047;
  font-size: 0.92rem;
}

.advanced-callout {
  margin: 0.8rem 0 0;
  padding: 0.7rem 0.8rem;
  border-radius: 0.65rem;
  background: #fff8e8;
  color: #57411d;
  font-size: 0.93rem;
}

.guided-design-study,
.guided-observer-activity,
.guided-design-activity {
  max-width: min(112ch, 100%);
  margin: 1.25rem 0;
  padding: 1rem;
  border: 1px solid #d8e2e5;
  border-radius: 0.85rem;
  background:
    radial-gradient(circle at 90% 10%, rgba(222, 242, 245, 0.75), transparent 32%),
    linear-gradient(135deg, #ffffff 0%, #f7fbfc 100%);
  box-shadow: 0 8px 22px rgba(24, 30, 34, 0.055);
}

.guided-step {
  display: grid;
  gap: 0.55rem;
  margin-top: 0.85rem;
  padding: 0.85rem;
  border: 1px solid #dbe7ea;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.84);
}

.guided-design-study-setup-figure {
  max-width: min(38rem, 100%);
  margin: 0.85rem auto 1rem;
  padding: 0.7rem;
  border: 1px solid #d7e5e8;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 6px 16px rgba(24, 30, 34, 0.05);
}

.guided-design-study-setup-figure--wide {
  max-width: min(56rem, 100%);
}

.guided-design-study-setup-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 34rem;
  object-fit: contain;
}

.guided-design-study-setup-figure .advanced-caption {
  margin-top: 0.55rem;
  color: #4b626a;
  font: 0.88rem/1.35 var(--ui-font);
}

.guided-system-display {
  width: min(28rem, 100%);
  max-width: 100%;
  margin: 0.95rem auto 1.1rem;
  padding: 0.9rem 1rem;
  border: 1px solid #d7e5e8;
  border-radius: 0.75rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(247, 251, 252, 0.9));
  box-shadow: 0 6px 16px rgba(24, 30, 34, 0.05);
  overflow-x: auto;
}

.guided-system-equations {
  display: grid;
  gap: 0.7rem;
  color: #182f36;
  font: 1.08rem/1.25 "STIX Two Math", "Cambria Math", "Times New Roman", serif;
}

.guided-system-svg {
  display: block;
  width: 100%;
  max-width: 28rem;
  height: auto;
  margin: 0 auto;
}

.guided-system-svg-text {
  fill: #182f36;
  font: italic 25px "STIX Two Math", "Cambria Math", "Times New Roman", serif;
}

.guided-system-table {
  margin: 0 auto;
  border-collapse: separate;
  border-spacing: 0.48rem 0.58rem;
  color: #182f36;
  font: 1.08rem/1.25 "STIX Two Math", "Cambria Math", "Times New Roman", serif;
}

.guided-system-table td {
  padding: 0;
  border: 0;
  vertical-align: middle;
}

.guided-system-row {
  display: grid;
  grid-template-columns: 2.25rem max-content max-content max-content max-content max-content max-content max-content;
  gap: 0.48rem;
  align-items: center;
  white-space: nowrap;
}

.guided-system-row:nth-child(2) {
  grid-template-columns: 2.25rem max-content max-content max-content;
}

.guided-system-left {
  justify-self: end;
  font-style: italic;
}

.guided-system-symbol,
.guided-system-plus,
.guided-system-equals {
  font-style: italic;
}

.guided-system-matrix {
  position: relative;
  display: inline-grid;
  gap: 0.28rem 0.58rem;
  padding: 0.3rem 0.65rem;
  align-items: center;
  justify-items: center;
  vertical-align: middle;
}

.guided-system-matrix::before,
.guided-system-matrix::after {
  content: "";
  position: absolute;
  top: 0.05rem;
  bottom: 0.05rem;
  width: 0.36rem;
  border-color: #244b54;
  border-style: solid;
  pointer-events: none;
}

.guided-system-matrix::before {
  left: 0;
  border-width: 1.7px 0 1.7px 1.7px;
}

.guided-system-matrix::after {
  right: 0;
  border-width: 1.7px 1.7px 1.7px 0;
}

.guided-system-matrix-2x2,
.guided-system-vector-row {
  grid-template-columns: repeat(2, minmax(1.2rem, max-content));
}

.guided-system-vector-column {
  grid-template-columns: minmax(1.2rem, max-content);
}

.guided-system-matrix-table {
  position: relative;
  display: inline-table;
  margin: 0;
  padding: 0.22rem 0.62rem;
  border-collapse: separate;
  border-spacing: 0.58rem 0.16rem;
  vertical-align: middle;
}

.guided-system-matrix-table::before,
.guided-system-matrix-table::after {
  content: "";
  position: absolute;
  top: 0.04rem;
  bottom: 0.04rem;
  width: 0.36rem;
  border-color: #244b54;
  border-style: solid;
  pointer-events: none;
}

.guided-system-matrix-table::before {
  left: 0;
  border-width: 1.7px 0 1.7px 1.7px;
}

.guided-system-matrix-table::after {
  right: 0;
  border-width: 1.7px 1.7px 1.7px 0;
}

.guided-system-matrix-table td {
  min-width: 1.1rem;
  padding: 0;
  border: 0;
  text-align: center;
}

.guided-system-target {
  margin: 0.75rem 0 0;
  padding-top: 0.65rem;
  border-top: 1px solid #dfe9ec;
  color: #375760;
  font: 0.95rem/1.35 var(--ui-font);
}

.guided-step h4 {
  margin: 0;
}

.guided-step > .quiz-answer {
  display: block;
}

.guided-step > .quiz-answer[hidden] {
  display: none;
}

.guided-step-solution {
  margin-top: 0.2rem;
  padding: 0.7rem 0.8rem;
  border-left: 4px solid #4d8a63;
  border-radius: 0.45rem;
  background: #eff8f1;
  color: #244432;
}

.guided-step-solution summary {
  cursor: pointer;
  color: #125b38;
  font: 800 0.9rem/1.3 var(--ui-font);
}

.guided-step-solution p {
  margin: 0.45rem 0 0;
}

.guided-step--reflection {
  border-color: #d7d9c5;
  background: linear-gradient(180deg, rgba(255, 253, 242, 0.92), rgba(248, 244, 221, 0.78));
}

.guided-design-study-pseudocode {
  width: 100%;
  box-sizing: border-box;
  min-height: 8rem;
  resize: vertical;
  border: 1px solid #cfd8c4;
  border-radius: 0.6rem;
  background: #fffef8;
  color: var(--ink);
  font: 0.95rem/1.45 var(--mono-font, ui-monospace, SFMono-Regular, Menlo, Consolas, monospace);
  padding: 0.7rem 0.8rem;
}

.guided-design-study-pseudocode:focus {
  outline: 3px solid rgba(170, 132, 58, 0.22);
  border-color: #aa843a;
}

.guided-input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(7.5rem, 1fr));
  gap: 0.6rem;
  align-items: center;
}

.guided-input-grid label {
  display: grid;
  gap: 0.3rem;
  color: #244b54;
  font: 700 0.84rem/1.25 var(--ui-font);
}

.guided-input-grid input {
  width: 100%;
  box-sizing: border-box;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.45rem 0.55rem;
}

.guided-input-grid-matrix-rank {
  grid-template-columns: max-content minmax(10rem, max-content) minmax(7rem, 10rem);
  justify-content: start;
}

.guided-input-grid-augmented {
  grid-template-columns: max-content minmax(13rem, max-content) max-content minmax(5.5rem, max-content);
  justify-content: start;
}

.guided-input-grid-scalars {
  grid-template-columns: repeat(auto-fit, minmax(12rem, max-content));
}

.guided-math-label {
  display: inline-block;
  margin-right: 0.5rem;
  color: #244b54;
  font: italic 1.08rem/1.2 "STIX Two Math", "Cambria Math", "Times New Roman", serif;
}

.guided-step > .guided-math-label + .guided-matrix {
  display: inline-grid;
  width: fit-content;
  vertical-align: middle;
}

.guided-matrix {
  position: relative;
  display: grid;
  gap: 0.35rem;
  padding: 0.55rem 0.75rem;
}

.guided-matrix::before,
.guided-matrix::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 0.45rem;
  border-color: #244b54;
  border-style: solid;
  pointer-events: none;
}

.guided-matrix::before {
  left: 0;
  border-width: 2px 0 2px 2px;
  border-radius: 0.35rem 0 0 0.35rem;
}

.guided-matrix::after {
  right: 0;
  border-width: 2px 2px 2px 0;
  border-radius: 0 0.35rem 0.35rem 0;
}

.guided-matrix-2x2,
.guided-vector-row {
  grid-template-columns: repeat(2, minmax(4.75rem, 5.4rem));
}

.guided-matrix-3x3,
.guided-vector-row-3 {
  grid-template-columns: repeat(3, minmax(4.75rem, 5.4rem));
}

.guided-vector-column {
  grid-template-columns: minmax(4.75rem, 5.4rem);
}

.guided-matrix label {
  position: relative;
  display: grid;
  gap: 0.2rem;
  color: #46616a;
  text-align: center;
  font-size: 0.76rem;
  z-index: 1;
}

.guided-matrix input {
  width: 100%;
  min-width: 0;
  box-sizing: border-box;
  height: 2.35rem;
  border-radius: 0.32rem;
  border-color: #aebfc5;
  background: #fbfdfe;
  text-align: center;
  font: 1rem/1.2 "STIX Two Math", "Cambria Math", "Times New Roman", serif;
  padding: 0.25rem;
}

.guided-scalar-entry {
  display: grid;
  grid-template-columns: max-content minmax(4.5rem, 7rem);
  align-items: center;
  min-width: 8rem;
  max-width: 13rem;
}

@media (max-width: 720px) {
  .guided-input-grid-matrix-rank,
  .guided-input-grid-augmented,
  .guided-input-grid-scalars {
    grid-template-columns: 1fr;
  }

  .guided-matrix-2x2,
  .guided-vector-row {
    grid-template-columns: repeat(2, minmax(3.8rem, 1fr));
  }

  .guided-matrix-3x3,
  .guided-vector-row-3 {
    grid-template-columns: repeat(3, minmax(3.4rem, 1fr));
  }
}

@media (max-width: 900px) {
  .ch15-scale-layout,
  .ch15-scale-readout,
  .ch15-db-reference,
  .ch15-pz-controls,
  .ch15-pz-readout,
  .ch15-second-order-controls,
  .ch15-second-order-readout {
    grid-template-columns: 1fr;
  }
}

.guided-input-grid input.is-correct {
  border-color: #337a4c;
  background: #eff9f1;
}

.guided-input-grid input.is-wrong {
  border-color: #9c4735;
  background: #fff3ee;
}

.guided-step > button {
  justify-self: start;
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  cursor: pointer;
  font: 700 0.84rem/1.2 var(--ui-font);
  padding: 0.42rem 0.7rem;
}

.guided-design-study__solution,
.guided-design-study-solution {
  display: grid;
  gap: 0.65rem;
  margin-top: 1rem;
  padding: 0.9rem;
  border: 1px solid #cfe1df;
  border-radius: 0.75rem;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(233, 244, 241, 0.72));
}

.guided-design-study__solution[hidden],
.guided-design-study-solution[hidden] {
  display: none;
}

.guided-design-study__solution h4,
.guided-design-study-solution h4 {
  margin: 0;
}

.advanced-button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  align-items: center;
  margin-top: 0.9rem;
}

.advanced-button-row button {
  border: 1px solid #b7cdd0;
  border-radius: 0.45rem;
  background: #f4fafb;
  color: #17454c;
  cursor: pointer;
  font: 700 0.84rem/1.2 var(--ui-font);
  padding: 0.42rem 0.7rem;
}

.advanced-button-row button:hover {
  background: #e9f4f6;
}

.guided-step > button:hover {
  background: #e9f4f6;
}

.chapter-nine-panel label,
.ch9-control-label {
  display: grid;
  gap: 0.35rem;
  color: #364523;
  font: 700 0.86rem/1.3 var(--ui-font);
}

.chapter-nine-panel .quiz-card[data-quiz-type="mcq"] .quiz-options label,
#pid-ch9-knowledge-check .quiz-card[data-quiz-type="mcq"] .quiz-options label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  align-items: center;
  column-gap: 0.55rem;
  width: 100%;
  box-sizing: border-box;
  color: inherit;
  font: 400 1rem/1.45 var(--body-font);
}

.chapter-nine-panel .quiz-card[data-quiz-type="mcq"] .quiz-options input[type="radio"],
#pid-ch9-knowledge-check .quiz-card[data-quiz-type="mcq"] .quiz-options input[type="radio"] {
  justify-self: center;
  align-self: center;
  margin: 0;
}

#pid-ch9-knowledge-check .ch9-numeric-check > label,
#pid-ch9-knowledge-check .ch9-numeric-check .quiz-options label {
  display: grid;
  gap: 0.35rem;
  width: min(26rem, 100%);
  box-sizing: border-box;
  margin: 0 0 0.7rem;
  padding: 0.45rem 0.55rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
  color: #364523;
  font: 700 0.9rem/1.3 var(--ui-font);
}

#pid-ch9-knowledge-check .ch9-numeric-check input[type="text"] {
  box-sizing: border-box;
  width: 100%;
  margin: 0;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.48rem 0.58rem;
}

#pid-ch9-knowledge-check .ch9-numeric-check > button.quiz-check {
  margin-left: 0;
}

#pid-ch9-knowledge-check .ch9-numeric-check > button.quiz-check,
#pid-ch9-knowledge-check .ch9-numeric-check > button.quiz-reset {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

#pid-ch9-knowledge-check .ch9-numeric-check > .quiz-feedback,
#pid-ch9-knowledge-check .ch9-numeric-check > p.quiz-feedback {
  clear: both;
  display: block;
  margin-top: 0.15rem;
}

#pid-ch10-knowledge-check .ch10-numeric-check > label,
#pid-ch10-knowledge-check .ch10-numeric-check .quiz-options label {
  display: grid;
  gap: 0.35rem;
  width: min(26rem, 100%);
  box-sizing: border-box;
  margin: 0 0 0.7rem;
  padding: 0.45rem 0.55rem;
  border: 1px solid #dfe6e9;
  border-radius: 0.5rem;
  background: #fbfdfe;
  color: #244b54;
  font: 700 0.9rem/1.3 var(--ui-font);
}

#pid-ch10-knowledge-check .ch10-numeric-check input[type="text"] {
  box-sizing: border-box;
  width: 100%;
  margin: 0;
  border: 1px solid #cddade;
  border-radius: 0.5rem;
  background: #fff;
  color: var(--ink);
  font: 0.98rem/1.45 var(--body-font);
  padding: 0.48rem 0.58rem;
}

#pid-ch10-knowledge-check .ch10-numeric-check > button.quiz-check,
#pid-ch10-knowledge-check .ch10-numeric-check > button.quiz-reset {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.chapter-nine-panel select,
.ch9-inline-select,
.advanced-activity select {
  width: auto;
  max-width: max-content;
  min-width: 0;
  font: inherit;
  line-height: inherit;
}

.advanced-activity .ch14-code-map-layout select {
  justify-self: stretch;
  width: 100%;
  inline-size: 100%;
  max-width: 100%;
  max-inline-size: 100%;
  min-width: 0;
  min-inline-size: 0;
}

.chapter-nine-panel input[type="range"] {
  width: 100%;
  accent-color: #69751d;
}

.chapter-nine-panel .ch9-inline-select {
  width: auto;
  max-width: 100%;
  font: inherit;
  line-height: inherit;
}

.ch9-compact-control {
  margin-top: 0.85rem;
}

.ch9-compact-control label {
  display: inline-grid;
  width: auto;
  color: inherit;
  font: 400 1rem/1.45 var(--body-font);
}

.ch9-fvt-workflow {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 0.85rem;
}

.ch9-fvt-prediction {
  margin-top: 0.85rem;
  padding: 0.85rem;
  border: 1px solid #d8e0d2;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.72);
}

.ch9-fvt-prediction > strong {
  display: block;
  margin-bottom: 0.55rem;
  color: #253217;
  font: 700 0.92rem/1.25 var(--ui-font);
}

.ch9-prediction-options {
  display: grid;
  gap: 0.4rem;
  margin-bottom: 0.7rem;
}

.ch9-prediction-options label,
.ch9-fvt-prediction > label {
  display: grid;
  grid-template-columns: 1.2rem minmax(0, 1fr);
  column-gap: 0.55rem;
  align-items: center;
  width: fit-content;
  max-width: 100%;
  margin-bottom: 0.4rem;
  color: #253217;
  font: 400 0.96rem/1.4 var(--body-font);
}

.ch9-prediction-options input[type="radio"],
.ch9-fvt-prediction > label input[type="radio"] {
  justify-self: center;
  align-self: center;
  margin: 0;
}

.ch9-fvt-prediction > button.quiz-check,
.ch9-fvt-prediction > button.quiz-reset {
  margin-top: 0.3rem;
}

.ch9-pole-check,
.ch9-fvt-process {
  margin: 0.45rem 0 0;
  padding-left: 1.25rem;
}

.ch9-pole-check li,
.ch9-fvt-process li {
  margin-top: 0.25rem;
}

.ch9-fvt-results[hidden] {
  display: none;
}

.ch9-fvt-plot {
  margin-top: 0.85rem;
}

.ch9-fvt-numeric {
  margin-top: 0.85rem;
}

.ch9-result-card,
.ch9-transfer-card {
  border: 1px solid #d8e0d2;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.78);
  padding: 0.8rem;
}

.ch9-result-card strong,
.ch9-transfer-card strong {
  display: block;
  margin-bottom: 0.35rem;
  color: #253217;
  font: 700 0.88rem/1.25 var(--ui-font);
}

.ch9-equation {
  font: 700 1rem/1.45 var(--mono-font, ui-monospace, SFMono-Regular, Menlo, monospace);
  color: #253217;
}

.ch9-plot {
  margin-top: 0.9rem;
  border: 1px solid #d8e0d2;
  border-radius: 0.85rem;
  background: #fff;
  overflow: hidden;
}

.ch9-tracking-plot-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
  margin-top: 0.9rem;
}

.ch9-tracking-plot-grid .ch9-plot {
  margin: 0;
}

.ch9-plot figcaption {
  margin: 0;
  padding: 0.65rem 0.8rem 0.75rem;
  border-top: 1px solid #d8e0d2;
  color: #526047;
  font-size: 0.9rem;
  line-height: 1.35;
}

.ch9-plot svg {
  display: block;
  width: 100%;
  height: auto;
}

.ch9-badge {
  display: inline-block;
  margin-top: 0.6rem;
  padding: 0.3rem 0.55rem;
  border-radius: 999px;
  background: #edf3da;
  color: #4a5516;
  font: 700 0.78rem/1.2 var(--ui-font);
}

.ch9-button-stack {
  display: grid;
  gap: 0.5rem;
}

.ch9-choice-button {
  width: 100%;
  border: 1px solid #cbd6bd;
  border-radius: 0.72rem;
  background: #fff;
  color: #253217;
  cursor: pointer;
  font: 700 0.88rem/1.25 var(--ui-font);
  padding: 0.65rem 0.75rem;
  text-align: left;
  transition:
    background 160ms ease,
    border-color 160ms ease,
    box-shadow 160ms ease,
    transform 160ms ease;
}

.ch9-choice-button:hover,
.ch9-choice-button:focus-visible,
.ch9-choice-button.is-active {
  border-color: #69751d;
  background: #f1f6df;
  box-shadow: 0 0 0 4px rgba(105, 117, 29, 0.14);
  transform: translateY(-1px);
}

.ch9-disturbance-loop {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 0.45rem;
  border: 1px solid #d8e0d2;
  border-radius: 0.75rem;
  background: #fff;
}

.ch9-disturbance-path {
  opacity: 0;
  pointer-events: none;
  transition: opacity 160ms ease;
}

.ch9-disturbance-path.is-active {
  opacity: 0.78;
}

[data-ch9-disturbance-block-highlight] {
  transition:
    filter 160ms ease,
    stroke-width 160ms ease;
}

[data-ch9-disturbance-block-highlight].is-active {
  filter: drop-shadow(0 0 5px rgba(170, 82, 58, 0.55));
  stroke-width: 4;
}

.ch9-diagram-caption {
  margin: 0.6rem 0 0;
  padding: 0.65rem 0.8rem;
  border-left: 4px solid rgb(170, 82, 58);
  background: rgba(255, 255, 255, 0.78);
  color: #526047;
  font-size: 0.92rem;
}

.ch9-diagram-note {
  margin-top: 0.75rem;
  background: #fff8e8;
  color: #5f4122;
}

@media (max-width: 980px) {
  .site-shell {
    grid-template-columns: 1fr;
  }

  .site-nav {
    position: static;
    max-height: none;
  }

  .toc-toggle {
    display: block;
  }

  .site-nav.is-collapsed #TOC {
    display: none;
  }

  .workflow-map,
  .ch1-feedback-controls,
  .ch9-control-grid,
  .ch9-result-grid,
  .ch9-tracking-plot-grid,
  .ch9-disturbance-grid,
  .ch9-transfer-grid,
  .advanced-grid,
  .advanced-readout {
    grid-template-columns: 1fr;
  }

  .advanced-controls--compact,
  .ch16-frequency-spec-controls {
    grid-template-columns: 1fr;
  }

  .ch8-first-order-readout {
    grid-template-columns: repeat(3, minmax(8rem, 1fr));
  }

  .design-study-grid {
    grid-template-columns: 1fr;
  }

  .book-index {
    column-count: 1;
  }
}

/* Link at the foot of the TOC to the unsplit single-page book. Understated on
   purpose: it is the heavy path. Added by scripts/split_html_chapters.py. */
.toc-fullbook {
  margin: 1rem 0 0;
  padding-top: 0.8rem;
  border-top: 1px solid var(--border);
}

.toc-fullbook a {
  display: block;
  padding: 0.5rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 0.45rem;
  background: #fffefb;
  font: 600 0.78rem/1.3 var(--ui-font);
  color: var(--muted);
  text-align: center;
  text-decoration: none;
  cursor: help;
}

.toc-fullbook a:hover,
.toc-fullbook a:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}

/* Previous/next links at the foot of each chapter page. Added by
   scripts/split_html_chapters.py. */
.chapter-nav {
  max-width: min(112ch, 100%);
  margin: 2.6rem auto 0;
  padding-top: 1.1rem;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 1rem;
  font-family: var(--ui-font);
}

.chapter-nav a {
  flex: 1 1 0;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding: 0.7rem 0.95rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  text-decoration: none;
  color: var(--ink);
}

.chapter-nav a:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.chapter-nav-next {
  margin-left: auto;
  text-align: right;
}

.chapter-nav-dir {
  font-size: 0.74rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.chapter-nav-title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--accent);
}

/* Images carry width/height attributes (scripts/add_image_attrs.py) so the browser
   reserves their space; keep proportions wherever CSS or an inline style sets width. */
img[width][height] {
  height: auto;
}

/* Collapsible table of contents on wide screens. Open, it is the sticky column.
   Collapsed, the column is gone -- the text uses the full width -- and the sidebar
   becomes a small button pinned over the text's left edge. book.js puts .is-collapsed
   on both .site-shell and .site-nav, and remembers the reader's choice. */
@media (min-width: 981px) {
  .toc-toggle {
    display: block;
  }

  .site-shell.is-collapsed {
    grid-template-columns: minmax(0, 1fr);
  }

  .site-shell.is-collapsed .site-nav {
    position: fixed;
    top: 0.35rem;
    left: 0.35rem;
    z-index: 20;
    width: auto;
    max-height: none;
    overflow: visible;
    border: 0;
    border-radius: 0.5rem;
    background: none;
    box-shadow: none;
  }

  .site-shell.is-collapsed #TOC {
    display: none;
  }

  /* Icon-only button when collapsed. font-size: 0 hides the "Contents" label while
     keeping it as the button's accessible name for screen readers. */
  /* Small and tucked into the corner: while reading, the button sits beside the first
     words of every line, so it stays quiet until pointed at. */
  .site-shell.is-collapsed .toc-toggle {
    width: auto;
    border: 1px solid var(--border);
    border-radius: 0.45rem;
    padding: 0.26rem 0.36rem;
    box-shadow: var(--shadow);
    font-size: 0;
    opacity: 0.55;
    transition: opacity 0.15s ease-in-out;
  }

  .site-shell.is-collapsed .toc-toggle:hover,
  .site-shell.is-collapsed .toc-toggle:focus-visible {
    opacity: 1;
  }

  .site-shell.is-collapsed .toc-toggle::before {
    content: "\2630";
    display: block;
    font-size: 1.425rem;
    line-height: 1.05;
  }

  /* Collapsed to the corner button, the menu icon says it all: drop the chevron. */
  .site-shell.is-collapsed .toc-toggle::after {
    content: none;
  }
}