/* SFT Course — shared editorial system
   Surface: Decide / Learn (teaching notes)
   Hierarchy via type & rhythm, not decoration */

@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500&family=Source+Sans+3:ital,wght@0,400;0,500;0,600;0,700;1,400&family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,500;0,8..60,600;0,8..60,700;1,8..60,400;1,8..60,500&display=swap");

:root {
  --bg: #f4f1ea;
  --bg-elevated: #fbf9f4;
  --ink: #1c1917;
  --ink-soft: #44403c;
  --muted: #78716c;
  --faint: #a8a29e;
  --rule: #e7e0d4;
  --rule-strong: #d6cfc0;
  --accent: #9a3412;          /* burnt umber — deliberate, not indigo */
  --accent-2: #1e3a5f;        /* ink blue for secondary structure */
  --accent-soft: #f5ebe3;
  --accent-ring: color-mix(in srgb, var(--accent) 22%, transparent);
  --good: #166534;
  --good-bg: #ecf8ef;
  --good-border: #b7e0c2;
  --bad: #991b1b;
  --bad-bg: #fef2f2;
  --bad-border: #f0c4c4;
  --code-bg: #1c1917;
  --code-ink: #f5f5f4;
  --code-muted: #a8a29e;
  --shadow-sm: 0 1px 0 rgba(28, 25, 23, 0.04), 0 8px 24px -16px rgba(28, 25, 23, 0.18);
  --radius: 12px;
  --radius-sm: 8px;
  --measure: 38rem;
  --page-pad: clamp(1.25rem, 4vw, 2.5rem);
  --serif: "Source Serif 4", "Iowan Old Style", Palatino, Georgia, serif;
  --sans: "Source Sans 3", "Segoe UI", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141210;
    --bg-elevated: #1c1917;
    --ink: #f5f5f4;
    --ink-soft: #d6d3d1;
    --muted: #a8a29e;
    --faint: #78716c;
    --rule: #2a2622;
    --rule-strong: #3f3a34;
    --accent: #fb923c;
    --accent-2: #93c5fd;
    --accent-soft: #2a1c12;
    --accent-ring: color-mix(in srgb, var(--accent) 28%, transparent);
    --good: #86efac;
    --good-bg: #14261a;
    --good-border: #245c38;
    --bad: #fca5a5;
    --bad-bg: #2a1414;
    --bad-border: #7f1d1d;
    --code-bg: #0c0a09;
    --code-ink: #e7e5e4;
    --code-muted: #a8a29e;
    --shadow-sm: 0 1px 0 rgba(0, 0, 0, 0.35), 0 12px 32px -18px rgba(0, 0, 0, 0.65);
  }
}

*,
*::before,
*::after { box-sizing: border-box; }

html {
  font-size: 18px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, color-mix(in srgb, var(--accent) 8%, transparent), transparent 55%),
    radial-gradient(900px 400px at 100% 0%, color-mix(in srgb, var(--accent-2) 7%, transparent), transparent 50%),
    var(--bg);
  font-family: var(--serif);
  font-optical-sizing: auto;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

/* —— Layout —— */
.page {
  width: min(100% - 2 * var(--page-pad), calc(var(--measure) + 8rem));
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 3.5rem) 0 clamp(4rem, 8vw, 6rem);
}

.page-inner {
  max-width: var(--measure);
}

/* wide pages (reference) can opt in */
.page.wide .page-inner {
  max-width: 48rem;
}

/* —— Header —— */
.course-header {
  position: relative;
  margin-bottom: 2.25rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--rule);
}

.course-header::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 3.5rem;
  height: 2px;
  background: var(--accent);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 0.85rem;
  margin: 0 0 1rem;
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.meta-row .dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--faint);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 18%, transparent);
}

.eyebrow {
  margin: 0;
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

h1 {
  margin: 0 0 0.85rem;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(2rem, 4.5vw, 2.65rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-wrap: pretty;
}

.lede {
  margin: 0;
  max-width: 36rem;
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 400;
  line-height: 1.55;
  color: var(--ink-soft);
  text-wrap: pretty;
}

/* —— Type —— */
h2 {
  margin: 2.75rem 0 0.85rem;
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent-2);
}

h2 .num {
  display: inline-block;
  margin-right: 0.45rem;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

h3 {
  margin: 1.75rem 0 0.5rem;
  font-family: var(--sans);
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  color: var(--ink);
}

p {
  margin: 0.8rem 0;
  text-wrap: pretty;
}

p + p { margin-top: 0.7rem; }

ul, ol {
  margin: 0.75rem 0 1rem;
  padding-left: 1.2rem;
}

li { margin: 0.4rem 0; }
li::marker { color: var(--faint); }

strong { font-weight: 650; color: var(--ink); }

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  text-decoration-color: color-mix(in srgb, var(--accent) 45%, transparent);
  transition: text-decoration-color 0.15s ease, color 0.15s ease;
}

a:hover {
  color: var(--ink);
  text-decoration-color: var(--accent);
}

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

/* —— Callouts (no left-rail accent strip) —— */
.win,
.callout,
.card {
  margin: 1.4rem 0;
  padding: 1.1rem 1.2rem 1.15rem;
  background: var(--bg-elevated);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.win {
  display: grid;
  gap: 0.35rem;
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--accent) 6%, var(--bg-elevated)), var(--bg-elevated));
  border-color: color-mix(in srgb, var(--accent) 22%, var(--rule));
}

.win .label,
.callout .label {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.win p,
.callout p,
.card p { margin: 0; }

.callout.accent {
  background: color-mix(in srgb, var(--accent-soft) 70%, var(--bg-elevated));
  border-color: color-mix(in srgb, var(--accent) 20%, var(--rule));
}

.callout.warn {
  background: color-mix(in srgb, #fef3c7 55%, var(--bg-elevated));
  border-color: color-mix(in srgb, #d97706 25%, var(--rule));
}

.callout.good {
  background: var(--good-bg);
  border-color: var(--good-border);
}

.callout.warn .label { color: #b45309; }
.callout.good .label { color: var(--good); }

@media (prefers-color-scheme: dark) {
  .callout.warn {
    background: #241c10;
    border-color: #5c4518;
  }
  .callout.warn .label { color: #fbbf24; }
}

/* legacy class aliases used in pages */
.card.accent { composes: none; }
.card.accent,
.card.warn,
.card.good {
  /* keep working if pages still use .card.* */
}

.card.accent {
  background: color-mix(in srgb, var(--accent-soft) 70%, var(--bg-elevated));
  border-color: color-mix(in srgb, var(--accent) 20%, var(--rule));
}
.card.warn {
  background: color-mix(in srgb, #fef3c7 55%, var(--bg-elevated));
  border-color: color-mix(in srgb, #d97706 25%, var(--rule));
}
.card.good {
  background: var(--good-bg);
  border-color: var(--good-border);
}

/* —— Pipeline (timeline, not equal tiles) —— */
.pipeline {
  --rail: 1.5rem;
  position: relative;
  margin: 1.35rem 0 1.5rem;
  padding: 0;
  list-style: none;
  font-family: var(--sans);
}

.pipeline::before {
  content: "";
  position: absolute;
  left: calc(var(--rail) / 2 - 1px);
  top: 0.6rem;
  bottom: 0.6rem;
  width: 2px;
  background: linear-gradient(180deg, var(--rule-strong), var(--rule));
  border-radius: 2px;
}

.pipeline .step {
  position: relative;
  display: grid;
  grid-template-columns: var(--rail) 1fr;
  gap: 0.85rem;
  padding: 0.55rem 0 0.9rem;
  background: transparent;
  border: 0;
  box-shadow: none;
}

.pipeline .step .n {
  position: relative;
  z-index: 1;
  width: var(--rail);
  height: var(--rail);
  display: grid;
  place-items: center;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--muted);
  background: var(--bg);
  border: 1.5px solid var(--rule-strong);
  font-variant-numeric: tabular-nums;
}

.pipeline .step.highlight .n {
  color: #fff;
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-ring);
}

.pipeline .body {
  min-width: 0;
  padding: 0.15rem 0 0.15rem 0.15rem;
}

.pipeline .label {
  font-weight: 700;
  font-size: 0.98rem;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.pipeline .step.highlight .label { color: var(--accent); }

.pipeline .hint {
  margin-top: 0.2rem;
  font-size: 0.9rem;
  line-height: 1.45;
  color: var(--muted);
}

.pipeline .step.highlight .body {
  padding: 0.7rem 0.85rem;
  background: var(--bg-elevated);
  border: 1px solid color-mix(in srgb, var(--accent) 25%, var(--rule));
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

/* —— Code —— */
code, .mono {
  font-family: var(--mono);
  font-size: 0.86em;
  font-weight: 500;
  background: color-mix(in srgb, var(--rule) 55%, transparent);
  padding: 0.12em 0.38em;
  border-radius: 4px;
}

pre {
  position: relative;
  margin: 1.1rem 0 1.3rem;
  padding: 1.05rem 1.15rem;
  overflow-x: auto;
  border-radius: var(--radius);
  background: var(--code-bg);
  color: var(--code-ink);
  box-shadow: var(--shadow-sm);
  font-family: var(--mono);
  font-size: 0.8rem;
  line-height: 1.55;
  -webkit-overflow-scrolling: touch;
}

pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  font-weight: 400;
  font-size: inherit;
}

/* —— Tables —— */
.table-wrap {
  margin: 1.15rem 0 1.4rem;
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  box-shadow: var(--shadow-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.9rem;
  margin: 0;
}

th, td {
  text-align: left;
  padding: 0.75rem 0.95rem;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

tr:last-child td { border-bottom: 0; }

th {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  background: color-mix(in srgb, var(--rule) 35%, transparent);
}

td { color: var(--ink-soft); }
td strong { color: var(--ink); }

/* —— Compare panels —— */
.grid-2 {
  display: grid;
  gap: 0.85rem;
  margin: 1.15rem 0;
}

@media (min-width: 640px) {
  .grid-2 { grid-template-columns: 1fr 1fr; }
}

.panel {
  padding: 1rem 1.05rem 1.1rem;
  border-radius: var(--radius);
  border: 1px solid var(--rule);
  background: var(--bg-elevated);
}

.panel h3 {
  margin: 0 0 0.55rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.panel.yes {
  border-color: var(--good-border);
  background: var(--good-bg);
}
.panel.yes h3 { color: var(--good); }

.panel.no {
  border-color: color-mix(in srgb, #d97706 30%, var(--rule));
  background: color-mix(in srgb, #fef3c7 45%, var(--bg-elevated));
}
.panel.no h3 { color: #b45309; }

@media (prefers-color-scheme: dark) {
  .panel.no {
    background: #241c10;
    border-color: #5c4518;
  }
  .panel.no h3 { color: #fbbf24; }
}

.panel ul { margin: 0; padding-left: 1.05rem; }
.panel li { margin: 0.35rem 0; font-size: 0.92rem; color: var(--ink-soft); }

/* —— Glossary / terms —— */
.term {
  margin: 1rem 0;
  padding-bottom: 0.9rem;
  border-bottom: 1px dashed var(--rule);
}
.term:last-child { border-bottom: 0; }

.term dt {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.term dd {
  margin: 0.25rem 0 0;
  color: var(--ink-soft);
}

.avoid {
  margin-top: 0.3rem;
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--muted);
}

/* —— Citations —— */
.cite {
  margin: 0.55rem 0 0;
  font-family: var(--sans);
  font-size: 0.82rem;
  line-height: 1.45;
  color: var(--muted);
}

/* —— Quiz —— */
.quiz {
  margin: 1.35rem 0 1.6rem;
  padding: 1.15rem 1.15rem 1.2rem;
  border-radius: var(--radius);
  border: 1px solid var(--rule);
  background: var(--bg-elevated);
  box-shadow: var(--shadow-sm);
}

.quiz-q {
  margin: 0 0 0.85rem;
  font-family: var(--sans);
  font-weight: 650;
  font-size: 1rem;
  letter-spacing: -0.01em;
  line-height: 1.4;
  color: var(--ink);
}

.quiz-options {
  display: grid;
  gap: 0.5rem;
}

.quiz-options button {
  appearance: none;
  width: 100%;
  min-height: 48px;
  padding: 0.75rem 0.95rem;
  text-align: left;
  font-family: var(--sans);
  font-size: 0.94rem;
  line-height: 1.4;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.12s ease, border-color 0.12s ease, transform 0.08s ease;
}

.quiz-options button:hover:not(:disabled) {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--rule-strong));
  background: color-mix(in srgb, var(--accent-soft) 55%, var(--bg));
}

.quiz-options button:active:not(:disabled) {
  transform: translateY(1px);
}

.quiz-options button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.quiz-options button:disabled { cursor: default; }

.quiz-options button.correct {
  background: var(--good-bg);
  border-color: var(--good);
  color: var(--good);
  font-weight: 600;
}

.quiz-options button.wrong {
  background: var(--bad-bg);
  border-color: var(--bad);
  color: var(--bad);
}

.quiz-feedback {
  margin-top: 0.85rem;
  font-family: var(--sans);
  font-size: 0.9rem;
  line-height: 1.45;
  min-height: 1.3em;
}

.quiz-feedback.ok { color: var(--good); }
.quiz-feedback.no { color: var(--bad); }

/* —— Footer / nav —— */
.course-footer {
  margin-top: 3.25rem;
  padding-top: 1.35rem;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--muted);
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 0.65rem;
  margin: 1rem 0 0.5rem;
}

.nav-links a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--rule-strong);
  background: var(--bg-elevated);
  color: var(--ink-soft);
  text-decoration: none;
  font-family: var(--sans);
  font-size: 0.86rem;
  font-weight: 600;
  transition: border-color 0.12s ease, background 0.12s ease, color 0.12s ease;
}

.nav-links a:hover {
  border-color: color-mix(in srgb, var(--accent) 40%, var(--rule-strong));
  color: var(--accent);
  background: color-mix(in srgb, var(--accent-soft) 50%, var(--bg-elevated));
}

/* —— Teacher prompt —— */
.teacher {
  margin-top: 2rem;
  padding: 1.15rem 1.2rem;
  border-radius: var(--radius);
  border: 1px dashed color-mix(in srgb, var(--accent) 35%, var(--rule));
  background: color-mix(in srgb, var(--accent-soft) 45%, var(--bg));
}

.teacher .label {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.35rem;
}

.teacher p { margin: 0; color: var(--ink-soft); }

/* —— Ordered steps —— */
.steps {
  margin: 1rem 0 1.25rem;
  padding: 0;
  list-style: none;
  counter-reset: step;
  font-family: var(--sans);
}

.steps li {
  position: relative;
  margin: 0;
  padding: 0.7rem 0 0.7rem 2.4rem;
  border-bottom: 1px solid var(--rule);
  color: var(--ink-soft);
}

.steps li:last-child { border-bottom: 0; }

.steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0.7rem;
  width: 1.65rem;
  height: 1.65rem;
  display: grid;
  place-items: center;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent);
}

.steps li strong { color: var(--ink); }

/* —— Lesson audio (machine-generated TTS) —— */
.audio-disclaimer {
  font-family: var(--sans);
  font-size: 0.88rem;
  line-height: 1.45;
  color: var(--ink-soft);
  background: var(--bg-elevated);
  border: 1px dashed var(--rule-strong);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  margin: 0 0 1.25rem;
}
.audio-disclaimer strong {
  color: var(--ink);
  font-weight: 600;
}

.audio-block {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 0.85rem;
  align-items: center;
  margin: 0.4rem 0 0.15rem;
}

.audio-block audio {
  display: block;
  height: 2rem;
  max-width: min(100%, 18rem);
  vertical-align: middle;
}

.audio-pair {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.audio-label {
  font-family: var(--sans);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  min-width: 3.4rem;
}

/* vocab / num / dir cells: stack kn text + compact player */
.vocab-grid .row .audio-block,
.num-grid .cell .audio-block,
.dir-grid .cell .audio-block {
  margin-top: 0.35rem;
  justify-content: center;
}
.num-grid .cell .audio-block audio,
.dir-grid .cell .audio-block audio {
  max-width: 100%;
  height: 1.75rem;
}
.vocab-grid .row .audio-block audio {
  max-width: 100%;
  height: 1.85rem;
}

/* —— Print —— */
@media print {
  .audio-block,
  .audio-disclaimer {
    display: none !important;
  }

  html { font-size: 12pt; }
  body {
    background: white;
    color: black;
  }
  .page { width: 100%; padding: 0; }
  .win, .callout, .card, .quiz, .panel, .table-wrap, pre {
    box-shadow: none;
    break-inside: avoid;
  }
  .quiz-options button { border: 1px solid #999; }
  a { color: inherit; text-decoration: underline; }
  .nav-links a {
    border: 0;
    padding: 0;
    background: none;
    text-decoration: underline;
  }
  .course-header::after { background: black; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .quiz-options button { transition: none; }
}