/* ============================================================
   TDAA-Go — Editorial / Lab-Notebook Theme
   ------------------------------------------------------------
   Paper-cream background, deep ink type, single brick accent.
   Fraunces (display) + Newsreader (body) + JetBrains Mono.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght,SOFT,WONK@0,9..144,300..900,0..100,0..1;1,9..144,300..900,0..100,0..1&family=Newsreader:ital,opsz,wght@0,6..72,200..800;1,6..72,200..800&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* — Palette — */
  --paper:        #f5f0e6;
  --paper-deep:   #ebe3d2;
  --paper-edge:   #d8cdb5;
  --ink:          #181210;
  --ink-soft:     #524437;
  --ink-faint:    #8a7a6a;
  --accent:       #b83a1f;   /* brick red */
  --accent-deep:  #8a2a14;
  --accent-wash:  #f0d9c8;
  --rule:         #2a1f15;
  --hairline:     rgba(24, 18, 16, 0.18);
  --hairline-soft:rgba(24, 18, 16, 0.10);

  /* — Type — */
  --serif-display: 'Fraunces', 'Iowan Old Style', 'Charter', Georgia, serif;
  --serif-body:    'Newsreader', 'Iowan Old Style', Georgia, 'Times New Roman', serif;
  --mono:          'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* — Spacing — */
  --col: min(72ch, calc(100vw - 4rem));
}

/* — Reset — */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--serif-body);
  font-optical-sizing: auto;
  font-weight: 400;
  font-size: 18px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  /* Paper grain — subtle SVG noise overlay */
  background-image:
    radial-gradient(circle at 20% 18%, rgba(184, 58, 31, 0.04) 0, transparent 32%),
    radial-gradient(circle at 82% 78%, rgba(24, 18, 16, 0.05) 0, transparent 38%),
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='220' height='220'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.09  0 0 0 0 0.07  0 0 0 0 0.06  0 0 0 0.06 0'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
  background-attachment: fixed;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ============================================================
   HEADER — minimal monospace bar with hairline rule
   ============================================================ */

body > header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(245, 240, 230, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hairline);
}

.header-content {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0.85rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.header-title {
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
}

.header-title::before {
  content: "";
  display: inline-block;
  width: 0.55rem;
  height: 0.55rem;
  background: var(--accent);
  transform: translateY(0.05em);
}

.header-title-mark {
  color: var(--ink-faint);
  font-weight: 400;
}

.header-nav { display: flex; gap: 0.25rem; }

.nav-link {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  text-decoration: none;
  padding: 0.45rem 0.8rem;
  border-radius: 0;
  transition: color 0.15s ease;
  position: relative;
}

.nav-link:hover { color: var(--accent); text-decoration: none; }
.nav-link.active { color: var(--ink); }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0.8rem;
  right: 0.8rem;
  bottom: 0.18rem;
  height: 1px;
  background: var(--accent);
}

/* ============================================================
   MAIN — single editorial column
   ============================================================ */

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 4rem 2rem 6rem;
}

/* ============================================================
   HERO — chapter mark, oversized serif, ruler tick line
   ============================================================ */

.hero {
  padding: 3rem 0 4.5rem;
  border-bottom: 1px solid var(--hairline);
  position: relative;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
}

.hero-eyebrow .dot {
  width: 6px; height: 6px; background: var(--accent); border-radius: 50%;
}

.hero h1 {
  font-family: var(--serif-display);
  font-weight: 350;
  font-size: clamp(2.6rem, 6.5vw, 5.4rem);
  line-height: 0.98;
  letter-spacing: -0.03em;
  color: var(--ink);
  margin-bottom: 1.6rem;
  font-variation-settings: "opsz" 96, "SOFT" 50;
  max-width: 18ch;
}

.hero h1 em {
  font-style: italic;
  font-weight: 350;
  color: var(--accent);
  font-variation-settings: "opsz" 96, "SOFT" 100, "WONK" 1;
}

.hero-subtitle {
  font-family: var(--serif-body);
  font-size: clamp(1.05rem, 1.6vw, 1.3rem);
  line-height: 1.55;
  color: var(--ink-soft);
  max-width: 56ch;
  margin-bottom: 2.5rem;
  font-style: italic;
  font-weight: 350;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem 2.4rem;
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  text-transform: uppercase;
}

.hero-meta dt {
  color: var(--ink-faint);
  margin-bottom: 0.25rem;
  font-weight: 400;
}

.hero-meta dd {
  color: var(--ink);
  font-weight: 500;
}

/* Ruler tick decoration along bottom */
.hero::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -1px;
  height: 12px;
  background-image:
    linear-gradient(to right, var(--rule) 1px, transparent 1px);
  background-size: 80px 12px;
  background-repeat: repeat-x;
  opacity: 0.25;
  pointer-events: none;
}

/* ============================================================
   SECTIONS — chapter-numbered editorial sections
   ============================================================ */

.section {
  padding: 5rem 0 4rem;
  border-bottom: 1px solid var(--hairline);
  position: relative;
}

.section:last-of-type { border-bottom: none; }

.section-header {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--hairline-soft);
}

.section-number {
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--accent);
  flex-shrink: 0;
}

.section-title {
  font-family: var(--serif-display);
  font-weight: 400;
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
  font-variation-settings: "opsz" 48;
}

.section-title em {
  font-style: italic;
  color: var(--accent);
  font-variation-settings: "opsz" 48, "WONK" 1;
}

.section-lede {
  font-family: var(--serif-body);
  font-size: 1.06rem;
  line-height: 1.65;
  color: var(--ink-soft);
  max-width: 60ch;
  margin-bottom: 2.5rem;
}

/* ============================================================
   WEEKLY MATERIALS — book-spine cards in a clean grid
   ============================================================ */

.week-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 0;
  border-top: 1px solid var(--hairline);
  border-left: 1px solid var(--hairline);
}

.week-card {
  display: flex;
  align-items: stretch;
  gap: 0;
  padding: 1.5rem 1.5rem 1.6rem;
  background: transparent;
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  text-decoration: none;
  color: inherit;
  transition: background 0.2s ease;
  position: relative;
  overflow: hidden;
}

.week-card::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.25s ease;
}

.week-card:hover {
  background: var(--paper-deep);
  text-decoration: none;
}

.week-card:hover::before { transform: scaleY(1); }

.week-number {
  font-family: var(--serif-display);
  font-weight: 350;
  font-size: 2.6rem;
  line-height: 1;
  color: var(--accent);
  flex-shrink: 0;
  margin-right: 1.1rem;
  min-width: 2.4ch;
  font-variation-settings: "opsz" 60;
  font-style: italic;
}

.week-content { flex: 1; min-width: 0; }

.week-eyebrow {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 0.35rem;
}

.week-title {
  font-family: var(--serif-body);
  font-size: 1.08rem;
  font-weight: 500;
  line-height: 1.3;
  color: var(--ink);
  margin-bottom: 0.45rem;
  letter-spacing: -0.005em;
}

.week-desc {
  font-family: var(--serif-body);
  font-size: 0.85rem;
  line-height: 1.45;
  color: var(--ink-soft);
  font-style: italic;
}

.empty-state {
  grid-column: 1 / -1;
  padding: 4rem 2rem;
  text-align: center;
  color: var(--ink-soft);
  font-style: italic;
  font-family: var(--serif-body);
  border: 1px dashed var(--hairline);
  margin: 0;
}

.empty-state-mark {
  font-family: var(--serif-display);
  font-style: italic;
  font-size: 3rem;
  color: var(--accent);
  display: block;
  margin-bottom: 0.6rem;
  font-weight: 350;
}

/* ============================================================
   HANDS-ON — numbered timeline with code
   ============================================================ */

.steps {
  list-style: none;
  counter-reset: step;
  padding: 0;
  margin: 0;
}

.step {
  counter-increment: step;
  position: relative;
  padding: 0 0 2.5rem 4.5rem;
  border-left: 1px solid var(--hairline);
  margin-left: 1.4rem;
}

.step:last-child { border-left-color: transparent; padding-bottom: 0.5rem; }

.step::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: -1.4rem;
  top: -0.4rem;
  width: 2.8rem;
  height: 2.8rem;
  background: var(--paper);
  border: 1px solid var(--rule);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
}

.step-title {
  font-family: var(--serif-display);
  font-size: 1.4rem;
  font-weight: 400;
  line-height: 1.2;
  color: var(--ink);
  margin-bottom: 0.6rem;
  font-variation-settings: "opsz" 36;
  letter-spacing: -0.01em;
}

.step-title em {
  font-style: italic;
  color: var(--accent);
  font-variation-settings: "opsz" 36, "WONK" 1;
}

.step-content {
  color: var(--ink-soft);
  font-size: 0.98rem;
  line-height: 1.6;
}

.step-content p { margin-bottom: 0.85rem; }
.step-content p:last-child { margin-bottom: 0; }

.step-content code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--paper-deep);
  padding: 0.12em 0.4em;
  border-radius: 2px;
  color: var(--accent-deep);
}

.step-content pre {
  background: var(--ink);
  color: #e8dcc8;
  border-radius: 4px;
  padding: 1.1rem 1.3rem;
  margin: 0.9rem 0;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.6;
  border-left: 3px solid var(--accent);
}

.step-content pre code {
  background: none; padding: 0; color: inherit;
}

/* Inline prompt examples */
.prompt-line {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--ink-faint);
  letter-spacing: 0.04em;
}

.prompt-line .caret { color: var(--accent); margin-right: 0.4rem; }

/* ============================================================
   FAQ — native <details> accordion, editorial style
   ============================================================ */

.faq {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--hairline);
}

.faq details {
  border-bottom: 1px solid var(--hairline);
  padding: 0;
}

.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 1.4rem 0;
  display: flex;
  align-items: baseline;
  gap: 1.2rem;
  font-family: var(--serif-display);
  font-size: 1.18rem;
  font-weight: 400;
  line-height: 1.35;
  color: var(--ink);
  letter-spacing: -0.01em;
  font-variation-settings: "opsz" 24;
  transition: color 0.15s ease;
}

.faq summary::-webkit-details-marker { display: none; }
.faq summary::marker { display: none; }

.faq summary::before {
  content: "+";
  font-family: var(--mono);
  font-weight: 400;
  font-size: 1.3rem;
  color: var(--accent);
  width: 1.2rem;
  flex-shrink: 0;
  transition: transform 0.2s ease;
  line-height: 1;
}

.faq details[open] summary::before {
  content: "—";
  transform: translateY(-0.05em);
}

.faq summary:hover { color: var(--accent); }

.faq-answer {
  padding: 0 0 1.6rem 2.4rem;
  color: var(--ink-soft);
  font-size: 0.98rem;
  line-height: 1.65;
  max-width: 65ch;
}

.faq-answer p { margin-bottom: 0.8rem; }
.faq-answer p:last-child { margin-bottom: 0; }

.faq-answer code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--paper-deep);
  padding: 0.12em 0.4em;
  border-radius: 2px;
  color: var(--accent-deep);
}

.faq-answer a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent-wash);
  transition: border-color 0.15s ease;
}

.faq-answer a:hover { border-bottom-color: var(--accent); }

/* ============================================================
   GENERAL TYPE
   ============================================================ */

h2 {
  font-family: var(--serif-display);
  font-weight: 400;
  font-size: 1.8rem;
  line-height: 1.2;
  margin: 2.5rem 0 1rem;
  color: var(--ink);
  letter-spacing: -0.015em;
  font-variation-settings: "opsz" 36;
}

h3 {
  font-family: var(--serif-display);
  font-weight: 500;
  font-size: 1.25rem;
  margin: 2rem 0 0.85rem;
  color: var(--ink);
  font-variation-settings: "opsz" 24;
  letter-spacing: -0.01em;
}

p { margin-bottom: 1rem; color: var(--ink); }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent-wash);
  transition: border-color 0.15s ease;
}
a:hover { border-bottom-color: var(--accent); }

ul, ol { margin: 1rem 0; padding-left: 1.4rem; }
ul li, ol li { margin-bottom: 0.4rem; }
ul li::marker { color: var(--accent); }

code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--paper-deep);
  padding: 0.12em 0.4em;
  border-radius: 2px;
  color: var(--accent-deep);
}

pre {
  background: var(--ink);
  color: #e8dcc8;
  border-radius: 4px;
  padding: 1.1rem 1.3rem;
  overflow-x: auto;
  margin: 1rem 0;
  font-family: var(--mono);
  font-size: 0.84rem;
  line-height: 1.6;
  border-left: 3px solid var(--accent);
}

pre code {
  background: none; padding: 0; color: inherit; font-size: inherit;
}

/* ============================================================
   CALLOUTS
   ============================================================ */

.callout {
  background: var(--paper-deep);
  border-left: 3px solid var(--accent);
  padding: 1.1rem 1.3rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  line-height: 1.55;
}

.callout-title {
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

/* ============================================================
   METHOD FIGURE
   ============================================================ */

.method-figure {
  box-sizing: border-box;
  width: 100%;
  min-width: 0;
  max-width: 100%;
  margin: 1.5rem 0 1.8rem;
  padding: 1rem 0;
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  overflow-x: hidden;
}

.method-figure img {
  display: block;
  width: 100%;
  min-width: 0;
  max-width: 100%;
  height: auto;
  object-fit: contain;
}

.method-figure figcaption {
  margin-top: 0.75rem;
  color: var(--ink-soft);
  font-family: var(--serif-body);
  font-size: 0.9rem;
  font-style: italic;
  line-height: 1.45;
}

/* ============================================================
   FOOTER
   ============================================================ */

footer {
  border-top: 1px solid var(--hairline);
  margin-top: 3rem;
  padding: 2.5rem 2rem 3rem;
  background: var(--paper-deep);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  align-items: baseline;
  justify-content: space-between;
}

.footer-mark {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
}

.footer-mark::before {
  content: "";
  display: inline-block;
  width: 0.5rem;
  height: 0.5rem;
  background: var(--accent);
  transform: translateY(0.05em);
}

.footer-text {
  font-family: var(--serif-body);
  font-style: italic;
  font-size: 0.88rem;
  color: var(--ink-soft);
}

.footer-text a {
  color: var(--ink-soft);
  border-bottom-color: var(--hairline);
}
.footer-text a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ============================================================
   MODEL CARDS (used on setup-guide)
   ============================================================ */

.model-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0;
  border-top: 1px solid var(--hairline);
  border-left: 1px solid var(--hairline);
  margin: 1.5rem 0;
}

.model-card {
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  padding: 1.25rem 1.4rem;
  background: transparent;
}

.model-name {
  font-family: var(--serif-display);
  font-size: 1.15rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  color: var(--ink);
  font-variation-settings: "opsz" 24;
}

.model-tag {
  font-family: var(--mono);
  font-size: 0.6rem;
  background: var(--accent);
  color: var(--paper);
  padding: 0.18rem 0.45rem;
  border-radius: 2px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 500;
}

.model-desc {
  font-family: var(--serif-body);
  font-size: 0.92rem;
  line-height: 1.5;
  color: var(--ink-soft);
  font-style: italic;
}

/* ============================================================
   TOC (used on setup-guide)
   ============================================================ */

.toc {
  border: 1px solid var(--hairline);
  padding: 1.4rem 1.6rem;
  margin: 2rem 0 3rem;
  background: var(--paper-deep);
}

.toc-title {
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.85rem;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  padding: 0;
}

.toc-list a {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  color: var(--ink);
  font-family: var(--serif-body);
  font-size: 1rem;
  padding: 0.3rem 0;
  border: none;
  transition: color 0.15s ease;
}

.toc-list a:hover { color: var(--accent); }

.toc-number {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--ink-faint);
  letter-spacing: 0.06em;
  flex-shrink: 0;
}

/* ============================================================
   VIEWER PAGE — full-bleed PDF iframe
   ============================================================ */

body.viewer {
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

body.viewer .header-content {
  padding: 0.7rem 1.5rem;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1rem;
  align-items: center;
}

.viewer-center {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  justify-content: center;
}

.week-badge {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: var(--accent);
  color: var(--paper);
  padding: 0.22rem 0.55rem;
  border-radius: 2px;
  font-weight: 500;
}

.page-title {
  font-family: var(--serif-display);
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--ink);
  font-style: italic;
  font-variation-settings: "opsz" 24;
}

.download-btn {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--rule);
  background: transparent;
  color: var(--ink);
  text-decoration: none;
  border-radius: 0;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.15s ease;
}

.download-btn:hover {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
  text-decoration: none;
}

/* ============================================================
   CTA button — used for primary actions on About / docs pages
   ============================================================ */

.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.75rem 1.3rem;
  background: var(--accent);
  color: var(--paper);
  text-decoration: none;
  border: 1px solid var(--accent);
  border-radius: 0;
  transition: background 0.15s ease, color 0.15s ease;
  margin-top: 0.6rem;
}

.cta-btn:hover {
  background: transparent;
  color: var(--accent);
  text-decoration: none;
}

.cta-btn .arrow {
  display: inline-block;
  transition: transform 0.15s ease;
}

.cta-btn:hover .arrow { transform: translateX(3px); }

.pdf-container {
  flex: 1;
  display: flex;
  background: var(--paper-edge);
}

.pdf-frame {
  width: 100%;
  height: 100%;
  border: none;
  background: var(--paper-edge);
}

/* ============================================================
   LANDING — index page: compact hero, materials grid eager.
   Activated by `<body class="landing">`.
   ============================================================ */

body.landing .container {
  padding: 1.75rem 2rem 4rem;
}

body.landing .hero.hero-compact {
  padding: 0.5rem 0 1.75rem;
}

body.landing .hero.hero-compact::after {
  background-size: 60px 10px;
  height: 8px;
  opacity: 0.2;
}

body.landing .hero.hero-compact .hero-eyebrow {
  margin-bottom: 0.85rem;
}

body.landing .hero.hero-compact h1 {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  line-height: 1.0;
  margin-bottom: 0.95rem;
  max-width: 22ch;
}

body.landing .hero.hero-compact .hero-subtitle {
  font-size: clamp(1rem, 1.4vw, 1.18rem);
  line-height: 1.5;
  margin-bottom: 0.9rem;
  max-width: 60ch;
}

body.landing .hero-aux {
  font-family: var(--serif-body);
  font-style: italic;
  font-size: 0.92rem;
  color: var(--ink-faint);
  margin: 0;
}

body.landing .hero-aux a { color: var(--ink-soft); }
body.landing .hero-aux a:hover { color: var(--accent); }

body.landing .section.section-flush {
  padding: 1.75rem 0 1rem;
  border-bottom: none;
}

/* "This week" flag on the latest card */
.week-flag {
  display: inline-block;
  margin-left: 0.5rem;
  padding: 0.1rem 0.45rem;
  background: var(--accent);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 0.6rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  vertical-align: middle;
}

.week-card-current { background: rgba(165, 93, 26, 0.04); }
.week-card-current::before { transform: scaleY(1); }

/* ============================================================
   COMPACT — non-index docs pages (student-guide, about,
   instructor-guide, setup-guide). Editorial design stays the
   same; vertical rhythm tightens and line length narrows for
   content-focused reading. Activated by `<body class="compact">`.
   ============================================================ */

body.compact .container {
  max-width: 880px;
  padding: 2rem 2rem 3.5rem;
}

body.compact .hero {
  padding: 1rem 0 1.75rem;
}

body.compact .hero::after { display: none; }

body.compact .hero-eyebrow {
  margin-bottom: 0.75rem;
}

body.compact .hero h1 {
  font-size: clamp(1.95rem, 4vw, 3.1rem);
  line-height: 1.02;
  margin-bottom: 0.9rem;
  max-width: 24ch;
}

body.compact .hero-subtitle {
  font-size: clamp(0.98rem, 1.3vw, 1.12rem);
  line-height: 1.5;
  margin-bottom: 1rem;
  max-width: 62ch;
}

body.compact .toc {
  margin: 0.5rem 0 1.75rem;
  padding: 0.9rem 1.15rem;
}

body.compact .toc-title { margin-bottom: 0.6rem; }
body.compact .toc-list { gap: 0.2rem; }
body.compact .toc-list a { padding: 0.18rem 0; font-size: 0.95rem; }

body.compact .section {
  padding: 2rem 0 1.5rem;
}

body.compact .section-header {
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  gap: 1rem;
}

body.compact .section-title {
  font-size: clamp(1.3rem, 2.2vw, 1.7rem);
}

body.compact .section-lede {
  font-size: 1rem;
  margin-bottom: 1.25rem;
}

body.compact h3 {
  margin-top: 1.4rem;
  margin-bottom: 0.55rem;
}

body.compact .step {
  padding: 0 0 1.35rem 3.4rem;
  margin-left: 1.1rem;
}

body.compact .step::before {
  width: 2.4rem;
  height: 2.4rem;
  font-size: 0.7rem;
  left: -1.1rem;
}

body.compact .step-title {
  font-size: 1.18rem;
  margin-bottom: 0.4rem;
}

body.compact .step-content { font-size: 0.95rem; line-height: 1.55; }
body.compact .step-content p { margin-bottom: 0.65rem; }

body.compact .callout {
  margin: 1rem 0;
  padding: 0.85rem 1.1rem;
  font-size: 0.92rem;
}

body.compact .method-figure {
  margin: 1rem 0 1.25rem;
  padding: 0.75rem 0;
}

body.compact pre {
  margin: 0.55rem 0 0.85rem;
}

body.compact ul, body.compact ol { margin: 0.75rem 0; }
body.compact ul li, body.compact ol li { margin-bottom: 0.3rem; }

body.compact .faq summary { font-size: 1.02rem; padding: 0.85rem 0; }
body.compact .faq-answer { padding: 0 0 1rem 1.4rem; }

body.compact .model-grid { margin: 1rem 0; }
body.compact .model-card { padding: 1rem 1.15rem; }

body.compact footer {
  margin-top: 1.5rem;
  padding: 1.6rem 2rem 1.9rem;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 720px) {
  body { font-size: 17px; }
  .container { padding: 2.5rem 1.25rem 4rem; }
  .method-figure { max-width: calc(100vw - 2.5rem); }
  .method-figure img { width: 100%; }

  /* Header: stack title row above the nav row instead of squeezing. */
  .header-content {
    flex-direction: column;
    align-items: stretch;
    gap: 0.4rem;
    padding: 0.55rem 1.1rem 0.5rem;
  }
  .header-title { font-size: 0.78rem; }
  .header-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.15rem;
    margin-left: -0.4rem;   /* visually align tap targets with title */
  }
  .nav-link { padding: 0.35rem 0.55rem; font-size: 0.7rem; }
  .nav-link.active::after { left: 0.55rem; right: 0.55rem; bottom: 0.1rem; }

  .hero { padding: 2rem 0 3rem; }
  .hero h1 { font-size: 2.6rem; }
  .section { padding: 3.5rem 0 3rem; }
  .section-header { flex-direction: column; gap: 0.5rem; align-items: flex-start; }
  .week-grid { grid-template-columns: 1fr; }
  .step { padding-left: 3.5rem; margin-left: 1.2rem; }
  .step::before { width: 2.4rem; height: 2.4rem; left: -1.2rem; font-size: 0.72rem; }
  .footer-inner { flex-direction: column; gap: 0.75rem; }
  .hero-meta { gap: 1rem 1.5rem; }
  body.viewer .header-content { grid-template-columns: 1fr; gap: 0.5rem; }
  .viewer-center { justify-content: flex-start; }
}

@media (max-width: 380px) {
  /* On the narrowest phones, drop the "/ COURSE_NAME" suffix —
     the hero h1 already shows it, so the header stays uncrowded. */
  .header-title-mark { display: none; }
  .nav-link { padding: 0.3rem 0.45rem; font-size: 0.68rem; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 2.1rem; }
  .week-number { font-size: 2rem; }
  .step-title { font-size: 1.2rem; }
  .faq summary { font-size: 1.05rem; }
}

/* ============================================================
   PRINT
   ============================================================ */

@media print {
  body { background: white; }
  header, footer, .download-btn { display: none; }
}

/* ============================================================
   MOTION — single orchestrated entrance
   ============================================================ */

@media (prefers-reduced-motion: no-preference) {
  .hero-eyebrow { animation: rise 0.6s ease 0.05s both; }
  .hero h1 { animation: rise 0.7s ease 0.15s both; }
  .hero-subtitle { animation: rise 0.7s ease 0.28s both; }
  .hero-meta { animation: rise 0.7s ease 0.4s both; }

  @keyframes rise {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
  }
}