/* ============================================================ */
/*  DS 6042 — shared lab stylesheet                              */
/*  Every lab page MUST link this file BEFORE its own styles.css */
/*    <link rel="stylesheet" href="../_shared/lab-base.css?v=N"> */
/*    <link rel="stylesheet" href="styles.css?v=N">              */
/*                                                                */
/*  This file owns: the design tokens, base typography, page     */
/*  chrome (TOC + header + footer), generic widget primitives    */
/*  (.viz, .callout, .chat-downloads), the presentation-mode     */
/*  toggle, and the 2-D plane widget primitives. Per-lab CSS     */
/*  should only contain widget-specific extensions, NOT the      */
/*  base palette or chrome.                                      */
/* ============================================================ */

:root {
  --bg: #fbfaf7;
  --bg-elev: #ffffff;
  --bg-code: #f4f1ea;
  --bg-viz: #fbf8f2;
  --ink: #1f1d1a;
  --ink-soft: #4a4742;
  --ink-mute: #8a857d;
  --rule: #e6e1d6;
  --accent: #b14a2e;
  --accent-soft: #e6c7bd;
  --link: #8e3a22;
  --highlight: #fff3d6;
  --pos: #fde0d2;
  --pos-stroke: #d8a48a;
  --neg: #d5e6dc;
  --neg-stroke: #9ec3ae;
  --zero: #f0eee5;
  --serif: "Iowan Old Style", "Charter", Georgia, "Hoefler Text", Cambria, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif;
  --mono: "JetBrains Mono", "SF Mono", "Fira Code", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 24px 28px 80px;
}

p { margin: 0 0 18px 0; }
strong { color: var(--ink); }
em { font-style: italic; color: var(--ink); }

h1, h2, h3, h4 {
  font-family: var(--serif);
  color: var(--ink);
  line-height: 1.2;
  margin: 28px 0 12px 0;
}
h1 { font-size: 38px; letter-spacing: -0.01em; margin-top: 6px; }
h2 {
  font-size: 22px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-top: 1px solid var(--rule);
  padding-top: 24px;
  margin-top: 36px;
}
h3 { font-size: 18px; font-weight: 700; }

a { color: var(--link); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent); }

code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--bg-code);
  padding: 1px 5px;
  border-radius: 3px;
}
pre {
  background: var(--bg-code);
  border-radius: 6px;
  padding: 14px 16px;
  overflow-x: auto;
  margin: 14px 0;
}
pre code {
  background: transparent;
  padding: 0;
  font-size: 14px;
}
pre.equation {
  background: var(--bg-elev);
  border-left: 3px solid var(--accent);
  border-radius: 0 4px 4px 0;
}
pre.equation code { font-size: 15px; }

/* Prism CDN theme sets font-size: 1em on .language-* code/pre. The CDN sheet
 * loads after this one, so plain selectors lose; prepending `main` wins on
 * specificity (0,1,2) > Prism's (0,1,1). */
main code[class*="language-"],
main pre[class*="language-"] {
  font-size: 0.85em;
}

table {
  font-family: var(--sans);
  font-size: 14px;
  border-collapse: collapse;
  margin: 8px 0 18px 0;
}
th, td { padding: 6px 12px; }
thead th { text-align: left; border-bottom: 1px solid var(--rule); font-weight: 600; }
tbody td { border-bottom: 1px solid var(--rule); }
tbody tr:last-child td { border-bottom: none; }

ul, ol { margin: 0 0 18px 0; padding-left: 22px; }
li { margin-bottom: 6px; }

/* ============================================================ */
/* TOC sidebar                                                  */
/* ============================================================ */
aside.toc {
  position: fixed;
  left: 24px;
  top: 24px;
  width: 220px;
  max-height: calc(100vh - 48px);
  overflow-y: auto;
  font-family: var(--sans);
  font-size: 13px;
  color: var(--ink-soft);
  z-index: 50;
}
aside.toc .toc-title {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-mute);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 8px;
}
aside.toc ul { list-style: none; padding: 0; margin: 0; }
aside.toc li { margin-bottom: 4px; }
aside.toc a {
  color: var(--ink-soft);
  text-decoration: none;
  display: block;
  padding: 4px 8px;
  border-radius: 4px;
  border-left: 2px solid transparent;
}
aside.toc a:hover { background: var(--bg-elev); }
aside.toc a.active {
  color: var(--ink);
  border-left-color: var(--accent);
  background: var(--bg-elev);
}
aside.toc .toc-foot { margin-top: 14px; padding-top: 10px; border-top: 1px solid var(--rule); font-size: 11px; }

@media (max-width: 1180px) {
  aside.toc { display: none; }
}

/* ============================================================ */
/* Header / hero / lede / cite                                  */
/* ============================================================ */
.hero { margin-bottom: 14px; }
.eyebrow {
  font-family: var(--sans);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-mute);
  margin-bottom: 6px;
}
.subtitle {
  font-family: var(--serif);
  font-style: italic;
  font-size: 22px;
  color: var(--ink-soft);
  margin: 6px 0 14px 0;
}
.byline {
  font-family: var(--sans);
  font-size: 14px;
  color: var(--ink-mute);
}
.lede {
  font-size: 19px;
  line-height: 1.6;
  margin-bottom: 18px;
}
.cite {
  font-family: var(--sans);
  font-size: 13px;
  color: var(--ink-mute);
  margin: 18px 0 24px 0;
  padding: 12px 16px;
  background: var(--bg-elev);
  border-radius: 6px;
}
.cite a { color: var(--ink-soft); }

/* ============================================================ */
/* Generic viz container + callouts                             */
/* ============================================================ */
.viz {
  background: var(--bg-viz);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 18px 20px;
  margin: 20px 0 24px 0;
}
.viz-title {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
  margin-bottom: 8px;
}
.viz-title code { font-size: 11px; padding: 0 4px; }
.viz-title::before {
  content: "● ";
  color: var(--accent);
}
.viz-description {
  font-family: var(--serif);
  font-size: 14px;
  color: var(--ink-soft);
  margin-bottom: 14px;
  line-height: 1.55;
}
.viz-caption {
  margin-top: 10px;
  font-family: var(--serif);
  font-size: 13px;
  color: var(--ink-mute);
  font-style: italic;
}

.callout {
  margin: 18px 0;
  padding: 14px 18px;
  border-radius: 8px;
  border: 1px solid var(--rule);
}
.callout.insight {
  background: #fffaef;
  border-left: 3px solid var(--accent);
}
.callout.note {
  background: var(--bg-elev);
  border-left: 3px solid #cfdbf2;
}
.callout .label {
  display: block;
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
  margin-bottom: 8px;
}
.callout p { margin-bottom: 8px; font-size: 15px; }
.callout p:last-child { margin-bottom: 0; }

/* Exercise blocks (collapsible answer pattern) */
.exercise {
  margin: 18px 0;
  padding: 14px 18px;
  background: #fffdf5;
  border: 1px solid #ead990;
  border-left: 3px solid #c89b1f;
  border-radius: 6px;
}
.exercise .ex-label {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #8a6f1a;
  margin-bottom: 8px;
}
.exercise details { margin-top: 8px; font-size: 14px; color: var(--ink-soft); }
.exercise summary { cursor: pointer; font-family: var(--sans); font-size: 13px; color: var(--ink-mute); }

/* ============================================================ */
/* Buttons + slider controls (generic — labs reuse these)       */
/* ============================================================ */
.btn {
  font-family: var(--sans);
  font-size: 13px;
  padding: 6px 14px;
  background: var(--bg-elev);
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 5px;
  cursor: pointer;
  transition: background 0.08s, border-color 0.08s, opacity 0.08s;
}
.btn:hover { background: #f0eee5; border-color: var(--ink-mute); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn.primary { background: var(--accent); color: white; border-color: var(--accent); }
.btn.primary:hover { filter: brightness(1.08); }

/* ============================================================ */
/* Download pill row (used in demos + assignments)              */
/* ============================================================ */
.chat-downloads {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--rule);
  flex-wrap: wrap;
}
.chat-downloads-label {
  font-family: var(--sans);
  font-size: 12px;
  color: var(--ink-mute);
  letter-spacing: 0.03em;
}
.chat-dl-btn {
  font-family: var(--mono);
  font-size: 12px;
  padding: 5px 11px;
  border: 1px solid var(--rule);
  background: var(--bg-elev);
  color: var(--ink-soft);
  border-radius: 14px;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.08s, border-color 0.08s, color 0.08s;
}
.chat-dl-btn:hover {
  background: #fff3d6;
  border-color: var(--accent);
  color: var(--ink);
}

/* ============================================================ */
/* Footer                                                       */
/* ============================================================ */
footer {
  margin-top: 60px;
  padding-top: 18px;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 13px;
  color: var(--ink-mute);
}

/* ============================================================ */
/* Presentation-mode controls (top-left, fixed) — REQUIRED       */
/* See CLAUDE.md "Presentation mode" for the contract.           */
/* The lab page only needs a single #present-toggle button;      */
/* lab-base.js wraps it in .present-controls and auto-injects    */
/* Back / Forward navigation buttons that show in presentation. */
/* ============================================================ */
.present-controls {
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 1000;
  display: flex;
  gap: 6px;
  align-items: center;
}
.present-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  background: var(--bg-elev);
  border: 1px solid var(--rule);
  border-radius: 18px;
  font-family: var(--sans);
  font-size: 12px;
  color: var(--ink-soft);
  cursor: pointer;
  box-shadow: 0 1px 4px rgba(0,0,0,0.05);
  transition: background 0.1s, color 0.1s, border-color 0.1s;
}
.present-toggle:hover { background: #fff3d6; color: var(--ink); border-color: var(--accent); }
.present-toggle:active { transform: translateY(1px); }
.present-toggle .present-icon { font-size: 16px; line-height: 1; }

/* The main Present/Exit toggle goes accent-red while in presentation mode. */
body.presentation-mode #present-toggle {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* Back / Forward are hidden until presentation mode is on. */
.present-toggle.present-nav {
  display: none;
  padding: 6px 10px;
  min-width: 36px;
  justify-content: center;
}
body.presentation-mode .present-toggle.present-nav {
  display: inline-flex;
}

/* "← Index" link that sits leftmost in .present-controls.            */
/* Same chip shape as the other buttons; subtler color so it doesn't  */
/* shout louder than Present.                                         */
.lab-index-link {
  text-decoration: none;
  color: var(--ink-mute);
  background: var(--bg);
}
.lab-index-link:hover {
  background: var(--bg-elev);
  color: var(--ink);
  border-color: var(--accent-soft);
}
.lab-index-link .present-icon { font-size: 15px; }
body.presentation-mode .lab-index-link {
  /* Still visible in presentation mode so the instructor can bail.   */
  background: var(--bg);
  color: var(--ink-mute);
  border-color: var(--rule);
}

/* ============================================================ */
/* Prev / Index / Next strip at the end of each lab page         */
/* Injected by lab-base.js · placed inside <main> before footer  */
/* ============================================================ */
.lab-prev-next {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 12px;
  margin: 56px 0 24px;
  padding-top: 24px;
  border-top: 1px solid var(--rule);
}
@media (max-width: 760px) {
  .lab-prev-next { grid-template-columns: 1fr; }
}
.lab-prev-next-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  background: var(--bg-elev);
  border: 1px solid var(--rule);
  border-radius: 6px;
  text-decoration: none;
  color: var(--ink);
  transition: border-color 120ms, transform 120ms, background 120ms;
  min-height: 88px;
}
.lab-prev-next-card:hover {
  border-color: var(--accent);
  background: white;
  transform: translateY(-1px);
}
.lab-prev-next-card.lab-prev-next-next {
  text-align: right;
  align-items: flex-end;
}
.lab-prev-next-card.lab-prev-next-home {
  text-align: center;
  align-items: center;
  background: #fff8e8;
  border-color: #e7d9a8;
}
.lab-prev-next-card.lab-prev-next-home:hover {
  background: #fff0c8;
  border-color: var(--accent);
}
.lab-prev-next-dir {
  font-family: var(--sans);
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--accent);
}
.lab-prev-next-num {
  font-family: var(--mono);
  font-size: 12px; font-weight: 600;
  color: var(--ink-mute);
}
.lab-prev-next-title {
  font-family: var(--serif);
  font-size: 16px; font-weight: 600;
  line-height: 1.25;
  color: var(--ink);
}
.lab-prev-next-empty {
  /* keeps the 3-col grid intact when no prev/next exists (first/last lab) */
  visibility: hidden;
}

/* In presentation mode, hide the prev/next strip (it's chrome). */
body.presentation-mode .lab-prev-next { display: none; }

/* In presentation mode:                                       */
/*   - hide narrative prose (any <p> without .keep-in-present) */
/*   - hide TOC + footer + byline chrome                       */
/*   - keep .viz, svg, pre, headings, tables, callouts         */
/*   - keep .viz-description and .viz-caption (they explain    */
/*     what the slide is showing)                              */
/*   - keep every interaction live                             */
/*   - bump fonts ~1.2x, more whitespace                       */
body.presentation-mode aside.toc,
body.presentation-mode footer,
body.presentation-mode .hero .byline,
body.presentation-mode .lede,
body.presentation-mode .cite,
body.presentation-mode p:not(.keep-in-present):not(.viz-description):not(.viz-caption) {
  display: none;
}
body.presentation-mode main {
  max-width: 1040px;
  font-size: 22px;
  padding: 70px 40px 60px;
}
body.presentation-mode h1 { font-size: 56px; }
body.presentation-mode h2 {
  font-size: 30px;
  margin-top: 60px;
  padding-top: 30px;
}
body.presentation-mode h3 { font-size: 22px; }
body.presentation-mode pre code,
body.presentation-mode pre { font-size: 17px; }
body.presentation-mode pre.equation code { font-size: 20px; }
body.presentation-mode .viz {
  margin: 32px 0 40px 0;
  padding: 24px 28px;
}
body.presentation-mode .viz-description { font-size: 17px; }
body.presentation-mode .callout { font-size: 18px; padding: 22px 28px; }
body.presentation-mode table { font-size: 17px; }

/* ============================================================ */
/*  Inline glossary widget — shared across labs                   */
/*  See CLAUDE.md "Inline glossary explainer" for the contract.   */
/*  Lab markup:                                                   */
/*    <span class="gloss" data-gloss="key">term</span>            */
/*    <p class="glossary-hint">…</p>                              */
/*    <div class="glossary-panel" id="glossary-panel" hidden>     */
/*      <button id="glossary-close">×</button>                    */
/*      <div id="glossary-content"></div>                         */
/*    </div>                                                      */
/*  Lab viz.js holds the GLOSSARY = { key: { title, body } } dict */
/*  and re-parents the panel under the term's nearest block.      */
/* ============================================================ */
.gloss {
  cursor: help;
  border-bottom: 1px dotted var(--accent);
  padding-bottom: 0.5px;
  transition: background 0.12s, color 0.12s;
}
.gloss:hover, .gloss:focus, .gloss.active {
  background: var(--accent-soft);
  color: var(--ink);
  outline: none;
  border-radius: 2px;
}
.gloss code {
  background: transparent;
  padding: 0;
}

.glossary-hint {
  font-family: var(--sans);
  font-size: 13.5px;
  line-height: 1.55;
  color: var(--ink-soft);
  background: var(--bg-elev);
  padding: 12px 16px;
  border-radius: 6px;
  border-left: 3px solid var(--rule);
  margin: 18px 0 10px 0;
}
.glossary-hint code {
  background: var(--bg-code);
  font-size: 0.92em;
  padding: 1px 5px;
  border-radius: 3px;
}
.glossary-hint .gloss-demo {
  border-bottom: 1px dotted var(--accent);
  padding-bottom: 0.5px;
}

.glossary-panel {
  position: relative;
  background: #fffaef;
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  border-radius: 0 6px 6px 0;
  padding: 14px 44px 12px 18px;
  margin: 0 0 22px 0;
  animation: gloss-fade-in 0.18s ease-out;
}
.glossary-panel[hidden] { display: none; }
@keyframes gloss-fade-in {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}
.glossary-panel-title {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
  margin-bottom: 8px;
}
.glossary-content {
  font-family: var(--serif);
  font-size: 15px;
  line-height: 1.55;
  color: var(--ink);
}
.glossary-content p { margin: 0 0 8px 0; }
.glossary-content p:last-child { margin-bottom: 0; }
.glossary-content code {
  font-family: var(--mono);
  font-size: 0.92em;
  background: var(--bg-code);
  padding: 1px 5px;
  border-radius: 3px;
}
.glossary-close {
  position: absolute;
  top: 8px; right: 10px;
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--sans);
  font-size: 20px;
  line-height: 1;
  color: var(--ink-mute);
  padding: 2px 6px;
  border-radius: 4px;
}
.glossary-close:hover { color: var(--accent); background: var(--bg-elev); }
body.presentation-mode .glossary-content { font-size: 18px; }
body.presentation-mode .glossary-panel { padding: 18px 50px 16px 22px; }