:root {
  color-scheme: dark;
  /* Palette matched to Chapter 4's exact purple theme, at the user's
     request -- deliberately the same values, not a new palette. */
  --bg: #0c0318;
  --bg-soft: #170729;
  --panel: #1f0a3d;
  --panel-strong: #2b0f4a;
  --panel-soft: #251140;
  --line: #4a2270;
  --text: #f3ecfa;
  --muted: #bfa8d6;
  --accent: #b565d9;
  --accent-strong: #d199ea;
  --warm: #e68c57;
  --code-bg: #120426;
  --code-line: #3a1a5c;
  --shadow: 0 24px 54px rgba(15, 0, 35, 0.48);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 85% 8%, rgba(181, 101, 217, 0.22), transparent 32%),
    radial-gradient(circle at 10% 85%, rgba(230, 140, 87, 0.06), transparent 30%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-soft) 100%);
  color: var(--text);
  font-family: "Source Sans 3", "Segoe UI", "Inter", system-ui, sans-serif;
}

a {
  color: inherit;
}

code {
  padding: 0.12em 0.4em;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(10, 2, 22, 0.75);
  color: #f0dcf9;
  font-family: "DejaVu Sans Mono", "Ubuntu Mono", monospace;
  font-size: 0.94em;
  line-height: 1;
}

.shell {
  width: min(1140px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 32px 0 72px;
}

.site-nav-panel {
  margin: 0 0 18px;
  padding: 16px 18px;
  border-radius: 18px;
  border: 1px solid rgba(181, 101, 217, 0.12);
  background: rgba(255, 255, 255, 0.04);
}

.site-nav-panel p {
  margin: 0 0 10px;
  color: var(--warm);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.page-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-links a {
  padding: 8px 14px;
  border-radius: 10px;
  color: var(--muted);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.88rem;
  transition: color 140ms ease, background 140ms ease;
}

.page-links a:hover,
.page-links a:focus-visible {
  color: var(--text);
  background: rgba(181, 101, 217, 0.14);
}

@media (max-width: 720px) {
  .site-nav-panel {
    padding: 14px 16px;
  }
}

.hero,
.section {
  border: 1px solid var(--line);
  border-radius: 20px;
  box-shadow: var(--shadow);
}

.hero {
  padding: 30px 30px 34px;
  background: linear-gradient(150deg, #1a0733 0%, #331550 45%, #5a2680 100%);
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 90% -10%, rgba(230, 140, 87, 0.16), transparent 40%);
  pointer-events: none;
}

.eyebrow {
  position: relative;
  margin: 0 0 12px;
  color: var(--warm);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4,
p,
figure {
  margin: 0;
}

h1,
h2,
h3,
h4 {
  font-family: "Charter", "Source Serif Pro", "Iowan Old Style", Georgia, serif;
  font-weight: 700;
}

h1 {
  position: relative;
  max-width: 860px;
  font-size: clamp(2.1rem, 3.8vw, 3.4rem);
  line-height: 1.06;
}

h2 {
  color: var(--accent-strong);
  font-size: 1.6rem;
  line-height: 1.1;
  border-bottom: 1px solid var(--line);
  padding-bottom: 10px;
}

h3 {
  color: var(--warm);
  font-size: 1.06rem;
  line-height: 1.28;
}

h4 {
  color: var(--accent-strong);
  font-size: 0.98rem;
  line-height: 1.32;
}

.hero-copy {
  position: relative;
  max-width: 820px;
  margin-top: 14px;
  color: rgba(243, 236, 250, 0.92);
  font-size: 1.02rem;
  line-height: 1.65;
}

.meta-row,
.quick-nav,
.figure-grid,
.term-grid {
  display: grid;
  gap: 14px;
}

.meta-row {
  position: relative;
  margin-top: 22px;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
}

.quick-nav {
  position: relative;
  margin-top: 22px;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.figure-grid {
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
}

.term-grid {
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
}

.meta-card,
.manuscript-section,
.figure-card,
.term-card,
.note-panel,
.warning-panel,
.step-block {
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid rgba(255, 255, 255, 0.09);
  border-radius: 16px;
}

.meta-card,
.note-panel,
.warning-panel {
  padding: 15px 17px;
}

.manuscript-section,
.figure-card,
.term-card {
  padding: 22px 20px 20px;
}

.mini-label {
  display: block;
  margin-bottom: 7px;
  color: var(--warm);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.meta-card strong {
  display: block;
  margin-bottom: 6px;
}

.nav-link {
  display: inline-block;
  width: fit-content;
  padding: 11px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.045);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
}

.nav-link:hover {
  border-color: rgba(181, 101, 217, 0.5);
  background: rgba(181, 101, 217, 0.14);
}

.section {
  margin-top: 26px;
  padding: 32px 24px 26px;
  background: var(--panel);
}

.section-intro {
  margin: 10px 0 20px;
  color: var(--muted);
  line-height: 1.68;
}

.manuscript-stack {
  display: grid;
  gap: 16px;
}

.manuscript-section {
  background: rgba(255, 255, 255, 0.03);
  min-width: 0;
}

.manuscript-section h3 {
  margin-bottom: 14px;
}

.manuscript-section h4 {
  margin: 18px 0 10px;
}

.manuscript-section p {
  line-height: 1.74;
}

.manuscript-section p + p,
.manuscript-section p + ul,
.manuscript-section p + ol,
.manuscript-section p + pre,
.manuscript-section pre + p,
.manuscript-section ul + p,
.manuscript-section .figure-embed + p,
.note-panel p + p {
  margin-top: 14px;
}

.manuscript-section table {
  margin: 14px 0 0;
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
  font-size: 0.92rem;
}

.manuscript-section th,
.manuscript-section td {
  padding: 10px 14px;
  text-align: left;
  border-bottom: 1px solid var(--line);
}

.manuscript-section thead th {
  background: rgba(181, 101, 217, 0.14);
  color: var(--accent-strong);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.76rem;
  letter-spacing: 0.08em;
}

.manuscript-section tbody tr:last-child td {
  border-bottom: none;
}

.checklist,
.ordered-list {
  margin: 14px 0 0;
  padding-left: 18px;
}

.checklist li,
.ordered-list li {
  margin-bottom: 9px;
  line-height: 1.66;
}

.checklist li:last-child,
.ordered-list li:last-child {
  margin-bottom: 0;
}

.code-block {
  margin: 14px 0 0;
  padding: 16px 18px;
  overflow-x: auto;
  white-space: pre-wrap;
  border-radius: 14px;
  border: 1px solid var(--code-line);
  background: var(--code-bg);
  color: #e6d6f2;
  font-family: "DejaVu Sans Mono", "Ubuntu Mono", monospace;
  font-size: 0.92rem;
  line-height: 1.55;
}

.code-file-label {
  display: inline-block;
  margin: 14px 0 -6px;
  padding: 5px 11px;
  border-radius: 8px 8px 0 0;
  background: rgba(230, 140, 87, 0.14);
  border: 1px solid rgba(230, 140, 87, 0.3);
  border-bottom: none;
  color: var(--warm);
  font-family: "DejaVu Sans Mono", "Ubuntu Mono", monospace;
  font-size: 0.78rem;
  font-weight: 600;
}

.callout {
  margin-top: 16px;
  padding: 16px 18px;
  border-radius: 14px;
  border: 1px solid rgba(181, 101, 217, 0.3);
  background:
    linear-gradient(160deg, rgba(181, 101, 217, 0.14), rgba(181, 101, 217, 0.04)),
    rgba(255, 255, 255, 0.02);
}

.callout p {
  line-height: 1.7;
}

.callout .callout-label {
  display: block;
  margin-bottom: 8px;
  color: var(--accent-strong);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.figure-embed {
  margin: 16px auto 0;
  padding: 12px;
  max-width: 640px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: rgba(6, 1, 16, 0.85);
}

.figure-link {
  display: block;
  width: 100%;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: zoom-in;
}

.figure-embed img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 10px;
  background: #ffffff;
}

.figure-link:focus-visible img,
.figure-link:hover img {
  outline: 2px solid rgba(181, 101, 217, 0.55);
  outline-offset: 4px;
}

.figure-caption {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

.figure-hint {
  margin-top: 8px;
  color: var(--accent-strong);
  font-size: 0.82rem;
  font-weight: 600;
}

.note-panel {
  margin-top: 16px;
  border-color: rgba(181, 101, 217, 0.28);
  background:
    linear-gradient(160deg, rgba(181, 101, 217, 0.16), rgba(181, 101, 217, 0.05)),
    rgba(255, 255, 255, 0.025);
}

.warning-panel {
  margin-top: 16px;
  border-color: rgba(230, 140, 87, 0.3);
  background:
    linear-gradient(180deg, rgba(230, 140, 87, 0.1), rgba(230, 140, 87, 0.03)),
    rgba(255, 255, 255, 0.02);
}

.term-card {
  background:
    linear-gradient(180deg, rgba(181, 101, 217, 0.08), rgba(181, 101, 217, 0.02)),
    rgba(255, 255, 255, 0.025);
}

.term-card h4 {
  margin-bottom: 8px;
  color: var(--warm);
}

.lightbox {
  width: min(1300px, calc(100vw - 48px));
  max-width: 1300px;
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 20px;
  background: rgba(12, 3, 24, 0.97);
  color: var(--text);
  box-shadow: 0 30px 68px rgba(0, 0, 0, 0.5);
}

.lightbox::backdrop {
  background: rgba(3, 0, 10, 0.82);
  backdrop-filter: blur(4px);
}

.lightbox-panel {
  padding: 20px;
}

.lightbox-close {
  display: block;
  margin-left: auto;
  margin-bottom: 16px;
  padding: 10px 14px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.lightbox-close:hover,
.lightbox-close:focus-visible {
  border-color: rgba(181, 101, 217, 0.5);
  background: rgba(181, 101, 217, 0.14);
}

.lightbox-image {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: #fff;
}

.lightbox-caption {
  margin-top: 14px;
  color: rgba(243, 236, 250, 0.85);
  font-size: 0.94rem;
  line-height: 1.65;
}

.footer-note {
  margin-top: 22px;
  color: var(--muted);
  text-align: center;
  font-size: 0.84rem;
  line-height: 1.65;
}

@media (max-width: 720px) {
  .shell {
    width: min(1140px, calc(100vw - 20px));
    padding-top: 20px;
  }

  .hero,
  .section {
    border-radius: 16px;
    padding: 20px 16px;
  }

  .code-block {
    font-size: 0.86rem;
  }

  .lightbox {
    width: min(1300px, calc(100vw - 20px));
  }
}

/* Print / PDF: black-and-grey, matching the existing chapter preview PDFs.
   The screen theme above (purple gradient, dark panels) is intentionally
   replaced here, not just dimmed -- printed pages use this block only. */
@media print {
  :root {
    color-scheme: light;
  }

  body {
    background: #fff !important;
    color: #111 !important;
  }

  .shell {
    width: 100%;
    padding: 0;
  }

  .hero,
  .section {
    box-shadow: none;
    border: 1px solid #ccc;
    border-radius: 12px;
    background: #fff !important;
    color: #111 !important;
  }

  .hero {
    margin: 18px;
    background: #fff !important;
    break-inside: avoid;
    page-break-inside: avoid;
  }

  .hero::after {
    display: none;
  }

  .section {
    margin: 18px;
  }

  .meta-card,
  .figure-card,
  .figure-embed,
  .figure-section,
  .term-card,
  .note-panel,
  .warning-panel,
  .callout,
  .code-block {
    break-inside: avoid;
    page-break-inside: avoid;
  }

  h2,
  h3,
  h4 {
    break-after: avoid;
    page-break-after: avoid;
  }

  .code-file-label {
    display: block;
    width: fit-content;
  }

  .code-step-section {
    break-inside: avoid;
    page-break-inside: avoid;
  }

  .code-block-flows {
    break-inside: auto;
    page-break-inside: auto;
  }

  .figure-section img {
    max-height: 6in;
    width: auto;
    max-width: 100%;
    margin: 0 auto;
  }

  .code-block {
    font-size: 0.72rem;
    line-height: 1.3;
    padding: 10px 12px;
  }

  .eyebrow {
    color: #444 !important;
  }

  h1,
  h2,
  h3,
  h4 {
    color: #111 !important;
  }

  h2 {
    border-bottom-color: #ccc;
  }

  .hero-copy,
  .section-intro,
  .manuscript-section p,
  .checklist li,
  .ordered-list li {
    color: #222 !important;
  }

  .meta-card,
  .manuscript-section,
  .figure-card,
  .term-card,
  .note-panel,
  .warning-panel,
  .callout {
    background: #f4f4f4 !important;
    border: 1px solid #ccc !important;
    color: #111 !important;
    box-shadow: none;
  }

  .code-block {
    background: #f0f0f0 !important;
    color: #111 !important;
    border: 1px solid #bbb !important;
  }

  .manuscript-section table {
    break-inside: avoid;
    page-break-inside: avoid;
    border-color: #ccc;
  }

  .manuscript-section th,
  .manuscript-section td {
    border-bottom-color: #ccc;
    color: #111 !important;
  }

  .manuscript-section thead th {
    background: #eee !important;
    color: #444 !important;
  }

  code {
    background: #eaeaea !important;
    color: #111 !important;
    border-color: #ccc;
  }

  .mini-label,
  .callout-label,
  .figure-hint {
    color: #555 !important;
  }

  .figure-embed {
    background: #fff !important;
    border-color: #ccc;
  }

  .lightbox,
  .quick-nav,
  .figure-hint {
    display: none !important;
  }

  a {
    color: #111 !important;
    text-decoration: underline;
  }
}