/* ==========================================================================
   WHAT I TEACH — shared stylesheet
   Palette: warm ivory / paper, deep ink, graphite, muted navy, academic
   green, subtle amber, restrained red. Serif for statement, sans for
   interface, mono for data & notation. No images anywhere — every visual
   comes from type, rules, grids and SVG.
   ========================================================================== */

:root{
  --ivory:#F6F1E6;
  --paper:#EDE6D3;
  --paper-2:#E4DBC3;
  --ink:#20201B;
  --graphite:#5B5748;
  --navy:#28405C;
  --navy-2:#1D3049;
  --green:#3E6B4F;
  --amber:#9C6B14;
  --red:#8C3630;
  --line:#D7CBAA;
  --line-strong:#B9AC84;
  --white:#FFFDF8;

  --serif: "Source Serif 4", "Iowan Old Style", Georgia, serif;
  --sans: "IBM Plex Sans", "Segoe UI", Arial, sans-serif;
  --mono: "IBM Plex Mono", "SF Mono", Menlo, Consolas, monospace;

  --maxw: 1240px;
  --reading-w: 680px;
  --radius: 3px;
  --dur: .2s;
}

[data-theme="dark"]{
  --ivory:#1B1A16;
  --paper:#242219;
  --paper-2:#2C2A1E;
  --ink:#F2EEE1;
  --graphite:#C9C2A9;
  --navy:#8FB3DE;
  --navy-2:#B9D3F0;
  --green:#8FC49F;
  --amber:#E0AE55;
  --red:#E19187;
  --line:#3B3826;
  --line-strong:#57512F;
  --white:#171611;
}

*{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;}
html[data-textsize="lg"]{ font-size:18px; }
html[data-textsize="sm"]{ font-size:15px; }

body{
  margin:0;
  background:var(--ivory);
  color:var(--ink);
  font-family:var(--sans);
  line-height:1.5;
  transition:background var(--dur), color var(--dur);
}

a{ color:inherit; text-decoration:none; }
img,svg{ max-width:100%; display:block; }
button{ font-family:inherit; cursor:pointer; }
input,select,textarea{ font-family:inherit; }

.wrap{ max-width:var(--maxw); margin:0 auto; padding:0 28px; }
.section{ padding:76px 0; border-bottom:1px solid var(--line); }
.section.tight{ padding:48px 0; }
.section.no-border{ border-bottom:none; }
.section.on-dark{ background:var(--navy-2); color:var(--white); border-bottom:none; }
.section.on-paper{ background:var(--paper); }

.eyebrow{
  font-family:var(--mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--graphite);
  margin:0 0 14px;
}
.on-dark .eyebrow{ color:rgba(255,253,248,.62); }

h1,h2,h3,h4{ font-family:var(--serif); font-weight:600; margin:0 0 .5em; color:var(--ink); }
.on-dark h1,.on-dark h2,.on-dark h3{ color:var(--white); }
h1{ font-size:clamp(2.4rem, 5vw, 4rem); line-height:1.05; }
h2{ font-size:clamp(1.7rem, 3vw, 2.3rem); line-height:1.15; }
h3{ font-size:1.3rem; }
p{ margin:0 0 1em; }
.lede{ font-size:1.15rem; color:var(--graphite); max-width:640px; }
.on-dark .lede{ color:rgba(255,253,248,.78); }

.section-head{ max-width:720px; margin-bottom:44px; }
.quote-lg{
  font-family:var(--serif);
  font-size:clamp(1.5rem, 3vw, 2.1rem);
  line-height:1.35;
  max-width:820px;
  margin:0 0 .6em;
}

.mono{ font-family:var(--mono); }
.small{ font-size:.85rem; }
.muted{ color:var(--graphite); }

/* ---------- buttons & links ---------- */
.btn{
  display:inline-flex; align-items:center; gap:8px;
  font-family:var(--sans); font-weight:600; font-size:.95rem;
  padding:13px 22px; border-radius:var(--radius);
  background:var(--navy); color:var(--white);
  border:1px solid var(--navy);
  transition:background var(--dur), transform var(--dur), border-color var(--dur);
}
.btn:hover{ background:var(--navy-2); border-color:var(--navy-2); }
.btn:active{ transform:translateY(1px); }
.btn.ghost{ background:transparent; color:var(--ink); border-color:var(--line-strong); }
.btn.ghost:hover{ border-color:var(--navy); color:var(--navy); background:transparent; }
.btn.ghost-dark{ background:transparent; color:var(--white); border-color:rgba(255,253,248,.5); }
.btn.ghost-dark:hover{ border-color:var(--white); }
.btn.small{ padding:9px 16px; font-size:.85rem; }
.btn.danger{ background:var(--red); border-color:var(--red); }
.btn:disabled{ opacity:.45; cursor:not-allowed; }

.text-link{
  font-family:var(--mono); font-size:.85rem; letter-spacing:.02em;
  color:var(--navy); border-bottom:1px solid var(--line-strong);
  padding-bottom:2px; display:inline-block;
}
.on-dark .text-link{ color:var(--navy); border-color:rgba(255,253,248,.4); }
.text-link:hover{ border-color:var(--navy); }

/* ---------- header ---------- */
.site-header{
  position:sticky; top:0; z-index:60;
  background:rgba(246,241,230,.94);
  border-bottom:1px solid var(--line);
  backdrop-filter:blur(6px);
  transition:padding var(--dur), background var(--dur);
}
[data-theme="dark"] .site-header{ background:rgba(27,26,22,.94); }
.site-header.shrink{ box-shadow:0 1px 0 var(--line); }
.nav{
  max-width:var(--maxw); margin:0 auto; padding:18px 28px;
  display:flex; align-items:center; justify-content:space-between; gap:24px;
  transition:padding var(--dur);
}
.site-header.shrink .nav{ padding:12px 28px; }
.brand{ display:flex; flex-direction:column; line-height:1.15; }
.brand .name{ font-family:var(--serif); font-weight:600; font-size:1.15rem; }
.brand .role{ font-family:var(--mono); font-size:.68rem; color:var(--graphite); letter-spacing:.03em; margin-top:2px; }
.nav-links{ display:flex; gap:22px; font-size:.92rem; flex:1; justify-content:center; }
.nav-links a{ position:relative; padding:4px 0; color:var(--ink); }
.nav-links a:hover{ color:var(--navy); }
.nav-links a.active{ color:var(--navy); }
.nav-links a.active::after{ content:""; position:absolute; left:0; right:0; bottom:-2px; height:2px; background:var(--navy); }
.nav-right{ display:flex; align-items:center; gap:12px; }
.icon-btn{
  background:none; border:1px solid var(--line-strong); border-radius:var(--radius);
  width:36px; height:36px; display:flex; align-items:center; justify-content:center;
  color:var(--ink); font-family:var(--mono); font-size:.8rem;
}
.icon-btn:hover{ border-color:var(--navy); color:var(--navy); }
.nav-toggle{ display:none; background:none; border:none; width:36px; height:30px; position:relative; }
.nav-toggle span,.nav-toggle::before,.nav-toggle::after{
  content:""; position:absolute; left:6px; right:6px; height:2px; background:var(--ink);
}
.nav-toggle span{ top:14px; }
.nav-toggle::before{ top:8px; }
.nav-toggle::after{ top:20px; }
.desktop-only{ display:inline-flex; }

/* mobile drawer */
.mobile-panel{
  position:fixed; inset:0; z-index:80; background:var(--navy-2); color:var(--white);
  transform:translateX(100%); transition:transform .28s ease; overflow-y:auto;
}
.mobile-panel.open{ transform:translateX(0); }
.mobile-panel-top{ display:flex; justify-content:space-between; align-items:center; padding:22px 24px; border-bottom:1px solid rgba(255,253,248,.15); }
.mobile-close{ background:none; border:1px solid rgba(255,253,248,.4); border-radius:var(--radius); width:36px; height:36px; color:var(--white); font-size:1.1rem; }
.mobile-links{ display:flex; flex-direction:column; padding:12px 24px; }
.mobile-links a{ display:flex; gap:14px; padding:16px 0; border-bottom:1px solid rgba(255,253,248,.12); font-family:var(--serif); font-size:1.3rem; color:var(--white); }
.mobile-links a span{ font-family:var(--mono); font-size:.85rem; color:rgba(255,253,248,.55); }
.mobile-meta{ padding:20px 24px 40px; font-family:var(--mono); font-size:.8rem; color:rgba(255,253,248,.6); }

/* ---------- footer ---------- */
.site-footer{ background:var(--navy-2); color:var(--white); padding:64px 0 28px; }
.footer-top{ display:flex; justify-content:space-between; align-items:flex-end; flex-wrap:wrap; gap:24px; padding-bottom:40px; border-bottom:1px solid rgba(255,253,248,.15); }
.footer-statement{ font-family:var(--serif); font-size:clamp(1.6rem,3vw,2.2rem); line-height:1.2; }
.footer-cols{ display:grid; grid-template-columns:repeat(4,1fr); gap:24px; padding:36px 0; }
.footer-col h5{ font-family:var(--mono); font-size:.75rem; letter-spacing:.06em; color:rgba(255,253,248,.55); margin:0 0 14px; text-transform:uppercase; }
.footer-col a,.footer-col p{ display:block; color:rgba(255,253,248,.85); font-size:.92rem; padding:5px 0; margin:0; }
.footer-col a:hover{ color:var(--navy); }
.footer-bottom{ display:flex; justify-content:space-between; flex-wrap:wrap; gap:10px; padding-top:22px; font-family:var(--mono); font-size:.78rem; color:rgba(255,253,248,.55); }

/* ---------- hero board (SVG teaching board) ---------- */
.hero{ padding:64px 0 0; }
.hero-grid{ display:grid; grid-template-columns:1.1fr .9fr; gap:48px; align-items:center; }
.hero-eyebrow{ font-family:var(--mono); font-size:.82rem; color:var(--graphite); letter-spacing:.05em; margin-bottom:18px; }
.hero-actions{ display:flex; gap:14px; margin-top:30px; flex-wrap:wrap; }
.board{ background:var(--ink); border-radius:6px; padding:26px; position:relative; overflow:hidden; }
[data-theme="dark"] .board{ background:#0E0D0A; }
.board svg{ width:100%; height:auto; display:block; }
.board-caption{ font-family:var(--mono); font-size:.72rem; color:rgba(255,253,248,.5); margin-top:12px; text-align:right; }

/* ---------- section grid layouts ---------- */
.grid-3{ display:grid; grid-template-columns:repeat(3,1fr); gap:22px; }
.grid-2{ display:grid; grid-template-columns:repeat(2,1fr); gap:22px; }
.grid-4{ display:grid; grid-template-columns:repeat(4,1fr); gap:20px; }

/* subject / topic cards */
.subj-card{ border:1px solid var(--line); border-radius:var(--radius); padding:26px; background:var(--paper); display:flex; flex-direction:column; gap:12px; transition:border-color var(--dur); }
.subj-card:hover{ border-color:var(--navy); }
.subj-num{ font-family:var(--mono); font-size:.85rem; color:var(--graphite); }
.subj-card h3{ margin:0; }
.subj-tags{ font-family:var(--mono); font-size:.78rem; color:var(--graphite); }
.subj-meta{ display:flex; gap:16px; font-family:var(--mono); font-size:.78rem; color:var(--graphite); margin-top:auto; padding-top:6px; }

/* ---------- currently teaching / progress card ---------- */
.board-card{ border:1px solid var(--line); border-radius:var(--radius); padding:30px; background:var(--paper); }
.progress-bar{ height:8px; background:var(--paper-2); border-radius:5px; overflow:hidden; margin:10px 0; border:1px solid var(--line); }
.progress-bar > span{ display:block; height:100%; background:var(--green); }
.progress-label{ font-family:var(--mono); font-size:.8rem; color:var(--graphite); display:flex; justify-content:space-between; }

/* ---------- lesson index / rows ---------- */
.row-list{ display:flex; flex-direction:column; }
.row{
  display:grid; grid-template-columns:70px 1fr auto auto auto; gap:18px; align-items:center;
  padding:18px 0; border-bottom:1px solid var(--line);
}
.row:hover{ background:var(--paper); }
.row .rnum{ font-family:var(--mono); color:var(--graphite); font-size:.85rem; }
.row .rtitle{ font-family:var(--serif); font-size:1.1rem; }
.row .rmeta{ font-family:var(--mono); font-size:.76rem; color:var(--graphite); }
.pill{ font-family:var(--mono); font-size:.72rem; padding:4px 9px; border-radius:20px; border:1px solid var(--line-strong); color:var(--graphite); white-space:nowrap; }
.pill.done{ border-color:var(--green); color:var(--green); }
.pill.progress{ border-color:var(--amber); color:var(--amber); }

/* filter bar */
.filter-bar{ display:flex; gap:12px; flex-wrap:wrap; align-items:center; margin-bottom:28px; padding:16px; background:var(--paper); border:1px solid var(--line); border-radius:var(--radius); }
.filter-bar select, .filter-bar input[type="text"]{
  font-family:var(--mono); font-size:.82rem; padding:9px 10px; border:1px solid var(--line-strong);
  border-radius:var(--radius); background:var(--white); color:var(--ink);
}
.filter-bar label{ font-family:var(--mono); font-size:.72rem; color:var(--graphite); display:flex; flex-direction:column; gap:4px; }

/* ---------- lesson page ---------- */
.lesson-layout{ display:grid; grid-template-columns:210px 1fr 220px; gap:40px; align-items:start; }
.lesson-rail{ font-family:var(--mono); font-size:.8rem; color:var(--graphite); position:sticky; top:100px; }
.lesson-rail dt{ text-transform:uppercase; letter-spacing:.05em; color:var(--graphite); margin-top:18px; }
.lesson-rail dd{ margin:4px 0 0; color:var(--ink); }
.lesson-main{ max-width:var(--reading-w); }
.lesson-header .eyebrow{ margin-bottom:6px; }
.lesson-header h1{ margin-bottom:6px; }
.objectives-box{ background:var(--paper); border:1px solid var(--line); border-radius:var(--radius); padding:22px; margin:26px 0; }
.objectives-box h4{ font-family:var(--mono); font-size:.78rem; letter-spacing:.04em; text-transform:uppercase; color:var(--graphite); margin-bottom:12px; }
.objectives-box ul{ margin:0; padding-left:20px; }
.objectives-box li{ margin-bottom:6px; }

.equation-block{
  font-family:var(--mono); background:var(--ink); color:var(--white); border-radius:var(--radius);
  padding:22px 24px; margin:24px 0; overflow-x:auto; line-height:1.7; font-size:.95rem;
}
[data-theme="dark"] .equation-block{ background:#0E0D0A; }

.worked-example{ border:1px solid var(--line); border-radius:var(--radius); margin:26px 0; overflow:hidden; }
.worked-head{ background:var(--paper); padding:16px 20px; border-bottom:1px solid var(--line); font-family:var(--mono); font-size:.85rem; }
.worked-steps{ padding:6px 20px 20px; }
.worked-step{ display:none; padding:14px 0; border-top:1px solid var(--line); }
.worked-step:first-child{ border-top:none; }
.worked-step.shown{ display:block; }
.worked-step .stepnum{ font-family:var(--mono); font-size:.75rem; color:var(--navy); margin-right:8px; }
.worked-actions{ padding:0 20px 20px; }

.mistake-box{ border:1px solid var(--line); border-radius:var(--radius); margin:26px 0; padding:20px 22px; background:var(--paper); }
.mistake-box h4{ font-family:var(--mono); font-size:.78rem; text-transform:uppercase; letter-spacing:.04em; color:var(--graphite); margin-bottom:12px; }
.mistake-row{ display:flex; gap:14px; align-items:flex-start; margin-bottom:10px; }
.mistake-tag{ font-family:var(--mono); font-size:.72rem; padding:3px 8px; border-radius:3px; white-space:nowrap; margin-top:2px; }
.mistake-tag.wrong{ background:rgba(140,54,48,.14); color:var(--red); }
.mistake-tag.right{ background:rgba(62,107,79,.14); color:var(--green); }
.mistake-row .mono{ font-size:.95rem; }

.practice-card{ border:1px solid var(--line); border-radius:var(--radius); padding:22px; margin:20px 0; background:var(--white); }
[data-theme="dark"] .practice-card{ background:var(--paper); }
.practice-q{ font-family:var(--serif); font-size:1.1rem; margin-bottom:16px; }
.practice-opts{ display:flex; flex-direction:column; gap:8px; margin-bottom:14px; }
.opt-btn{ text-align:left; border:1px solid var(--line-strong); border-radius:var(--radius); padding:12px 14px; background:transparent; font-family:var(--sans); font-size:.92rem; color:var(--ink); }
.opt-btn:hover{ border-color:var(--navy); }
.opt-btn.selected{ border-color:var(--navy); background:rgba(40,64,92,.08); }
.opt-btn.correct{ border-color:var(--green); background:rgba(62,107,79,.12); }
.opt-btn.incorrect{ border-color:var(--red); background:rgba(140,54,48,.12); }
.numeric-row{ display:flex; gap:10px; margin-bottom:14px; }
.numeric-row input{ flex:1; padding:11px 12px; border:1px solid var(--line-strong); border-radius:var(--radius); font-family:var(--mono); background:var(--white); color:var(--ink); }
.practice-actions{ display:flex; gap:10px; flex-wrap:wrap; align-items:center; }
.practice-feedback{ margin-top:14px; padding:14px; border-radius:var(--radius); font-size:.92rem; display:none; }
.practice-feedback.show{ display:block; }
.practice-feedback.correct{ background:rgba(62,107,79,.12); color:var(--green); }
.practice-feedback.incorrect{ background:rgba(140,54,48,.12); color:var(--red); }
.hint-text{ font-size:.88rem; color:var(--graphite); margin-top:10px; display:none; border-left:2px solid var(--amber); padding-left:12px; }
.hint-text.show{ display:block; }

.lesson-side{ position:sticky; top:100px; }
.side-box{ border:1px solid var(--line); border-radius:var(--radius); padding:18px; background:var(--paper); margin-bottom:18px; }
.side-box h4{ font-family:var(--mono); font-size:.72rem; text-transform:uppercase; letter-spacing:.04em; color:var(--graphite); margin-bottom:10px; }

.lesson-nav{ display:flex; justify-content:space-between; margin-top:40px; padding-top:20px; border-top:1px solid var(--line); gap:14px; }
.lesson-nav a{ font-family:var(--mono); font-size:.85rem; }

/* completion banner */
.complete-banner{ border:1px solid var(--green); background:rgba(62,107,79,.1); border-radius:var(--radius); padding:26px; margin:30px 0; text-align:center; }
.complete-banner h3{ color:var(--green); }

/* ---------- timeline ---------- */
.timeline{ position:relative; padding-left:36px; }
.timeline::before{ content:""; position:absolute; left:6px; top:6px; bottom:6px; width:2px; background:var(--line-strong); }
.tl-item{ position:relative; padding-bottom:34px; }
.tl-item::before{ content:""; position:absolute; left:-36px; top:4px; width:10px; height:10px; border-radius:50%; background:var(--navy); border:2px solid var(--ivory); }
.tl-year{ font-family:var(--mono); font-size:.85rem; color:var(--navy); margin-bottom:4px; }
.tl-tag{ font-family:var(--mono); font-size:.7rem; color:var(--graphite); text-transform:uppercase; letter-spacing:.04em; margin-bottom:4px; display:block; }

/* ---------- roadmap ---------- */
.roadmap-select{ display:flex; gap:14px; flex-wrap:wrap; margin:26px 0; }
.roadmap-select button{ font-family:var(--serif); font-size:1.05rem; padding:16px 26px; border:1px solid var(--line-strong); border-radius:var(--radius); background:var(--paper); color:var(--ink); }
.roadmap-select button.active{ border-color:var(--navy); background:var(--navy); color:var(--white); }
.roadmap-stage{ margin-bottom:34px; }
.roadmap-stage h4{ font-family:var(--mono); font-size:.78rem; text-transform:uppercase; letter-spacing:.05em; color:var(--graphite); margin-bottom:14px; }
.roadmap-nodes{ display:flex; flex-wrap:wrap; gap:14px; }
.rmnode{ border:1px solid var(--line-strong); border-radius:var(--radius); padding:14px 16px; min-width:220px; background:var(--white); text-align:left; }
[data-theme="dark"] .rmnode{ background:var(--paper); }
.rmnode .rmnum{ font-family:var(--mono); font-size:.75rem; color:var(--graphite); }
.rmnode .rmtitle{ font-family:var(--serif); font-size:1rem; margin:4px 0; }
.rmnode .rmstate{ font-family:var(--mono); font-size:.7rem; text-transform:uppercase; letter-spacing:.03em; }
.rmnode[data-state="complete"]{ border-color:var(--green); }
.rmnode[data-state="complete"] .rmstate{ color:var(--green); }
.rmnode[data-state="available"]{ border-color:var(--navy); }
.rmnode[data-state="available"] .rmstate{ color:var(--navy); }
.rmnode[data-state="in-progress"]{ border-color:var(--amber); }
.rmnode[data-state="in-progress"] .rmstate{ color:var(--amber); }
.rmnode[data-state="locked"]{ opacity:.55; }

/* ---------- glossary ---------- */
.glossary-list dt{ font-family:var(--serif); font-size:1.15rem; margin-top:22px; }
.glossary-list dd{ margin:6px 0 0; }
.alpha-nav{ display:flex; flex-wrap:wrap; gap:6px; margin-bottom:26px; }
.alpha-nav button{ width:30px; height:30px; border:1px solid var(--line-strong); border-radius:3px; background:transparent; font-family:var(--mono); font-size:.8rem; }
.alpha-nav button.active{ background:var(--navy); color:var(--white); border-color:var(--navy); }

/* ---------- checklist ---------- */
.checklist{ list-style:none; margin:0; padding:0; }
.checklist li{ display:flex; align-items:flex-start; gap:12px; padding:12px 0; border-bottom:1px solid var(--line); }
.checklist input[type="checkbox"]{ width:18px; height:18px; margin-top:2px; accent-color:var(--navy); }
.checklist li.checked span{ text-decoration:line-through; color:var(--graphite); }

/* ---------- forms ---------- */
.form-field{ margin-bottom:20px; }
.form-field label{ display:block; font-family:var(--mono); font-size:.8rem; color:var(--graphite); margin-bottom:6px; }
.form-field input, .form-field select, .form-field textarea{
  width:100%; padding:12px 14px; border:1px solid var(--line-strong); border-radius:var(--radius);
  background:var(--white); color:var(--ink); font-size:.95rem;
}
[data-theme="dark"] .form-field input,[data-theme="dark"] .form-field select,[data-theme="dark"] .form-field textarea{ background:var(--paper); }
.form-field textarea{ min-height:130px; resize:vertical; }
.field-error{ color:var(--red); font-size:.8rem; margin-top:6px; display:none; }
.field-error.show{ display:block; }
.form-status{ margin-top:18px; padding:14px; border-radius:var(--radius); display:none; font-size:.92rem; }
.form-status.show{ display:block; }
.form-status.success{ background:rgba(62,107,79,.12); color:var(--green); }
.form-status.error{ background:rgba(140,54,48,.12); color:var(--red); }

/* ---------- modal ---------- */
.modal-backdrop{ position:fixed; inset:0; background:rgba(20,20,16,.55); z-index:100; display:none; align-items:center; justify-content:center; padding:20px; }
.modal-backdrop.open{ display:flex; }
.modal{ background:var(--ivory); border-radius:6px; max-width:520px; width:100%; padding:30px; position:relative; max-height:85vh; overflow-y:auto; }
.modal-close{ position:absolute; top:16px; right:16px; background:none; border:1px solid var(--line-strong); border-radius:var(--radius); width:32px; height:32px; }

/* ---------- toast ---------- */
.toast-stack{ position:fixed; bottom:22px; left:50%; transform:translateX(-50%); z-index:120; display:flex; flex-direction:column; gap:8px; align-items:center; }
.toast{ background:var(--navy-2); color:var(--white); font-size:.88rem; padding:12px 20px; border-radius:24px; box-shadow:0 6px 20px rgba(0,0,0,.2); opacity:0; transform:translateY(8px); transition:opacity .2s, transform .2s; }
.toast.show{ opacity:1; transform:translateY(0); }

/* ---------- command palette ---------- */
.cmdk-backdrop{ position:fixed; inset:0; background:rgba(20,20,16,.55); z-index:110; display:none; align-items:flex-start; justify-content:center; padding-top:14vh; }
.cmdk-backdrop.open{ display:flex; }
.cmdk{ background:var(--ivory); border-radius:8px; width:100%; max-width:560px; overflow:hidden; box-shadow:0 20px 50px rgba(0,0,0,.3); }
.cmdk input{ width:100%; border:none; padding:18px 20px; font-size:1rem; font-family:var(--sans); background:transparent; color:var(--ink); border-bottom:1px solid var(--line); outline:none; }
.cmdk-list{ max-height:340px; overflow-y:auto; }
.cmdk-item{ padding:13px 20px; font-size:.92rem; display:flex; justify-content:space-between; cursor:pointer; }
.cmdk-item.active,.cmdk-item:hover{ background:var(--paper); }
.cmdk-item span{ font-family:var(--mono); font-size:.72rem; color:var(--graphite); }

/* ---------- misc components ---------- */
.stat-row{ display:flex; gap:44px; flex-wrap:wrap; }
.stat{ display:flex; flex-direction:column; }
.stat-num{ font-family:var(--serif); font-size:2.2rem; }
.stat-label{ font-family:var(--mono); font-size:.75rem; color:var(--graphite); }
.on-dark .stat-label{ color:rgba(255,253,248,.6); }

.cta-band{ background:var(--navy-2); color:var(--white); padding:64px 0; text-align:center; }
.cta-band h2{ color:var(--white); }
.cta-band .btn{ margin-top:18px; }

.controls-row{ display:flex; gap:20px; flex-wrap:wrap; align-items:center; margin-bottom:30px; font-family:var(--mono); font-size:.8rem; }
.seg{ display:flex; border:1px solid var(--line-strong); border-radius:var(--radius); overflow:hidden; }
.seg button{ background:transparent; border:none; padding:8px 12px; font-family:var(--mono); font-size:.78rem; color:var(--ink); border-right:1px solid var(--line-strong); }
.seg button:last-child{ border-right:none; }
.seg button.active{ background:var(--navy); color:var(--white); }

.empty-state{ text-align:center; padding:60px 20px; color:var(--graphite); }
.empty-state h3{ color:var(--ink); }

.diagram-chain{ display:flex; flex-wrap:wrap; align-items:center; gap:10px; font-family:var(--mono); font-size:.85rem; }
.diagram-chain span.node{ padding:8px 14px; border:1px solid var(--line-strong); border-radius:20px; }
.diagram-chain span.arrow{ color:var(--graphite); }

/* ---------- print ---------- */
@media print{
  .site-header,.site-footer,.mobile-panel,.filter-bar,.controls-row,.toast-stack,.cmdk-backdrop,.modal-backdrop,.no-print{ display:none !important; }
  body{ background:#fff; color:#000; }
  .section{ padding:14px 0; border-bottom:none; }
  a{ color:#000; }
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  *{ animation-duration:.001ms !important; animation-iteration-count:1 !important; transition-duration:.001ms !important; }
}

/* ---------- focus ---------- */
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible{
  outline:2px solid var(--navy); outline-offset:2px;
}

/* ---------- responsive ---------- */
@media (max-width: 1080px){
  .lesson-layout{ grid-template-columns:1fr; }
  .lesson-rail{ position:static; display:flex; gap:24px; flex-wrap:wrap; margin-bottom:24px; }
  .lesson-side{ position:static; display:grid; grid-template-columns:1fr 1fr; gap:14px; }
  .footer-cols{ grid-template-columns:repeat(2,1fr); }
  .grid-4{ grid-template-columns:repeat(2,1fr); }
}
@media (max-width: 860px){
  .hero-grid{ grid-template-columns:1fr; }
  .grid-3{ grid-template-columns:1fr 1fr; }
  .nav-links{ display:none; }
  .desktop-only{ display:none; }
  .nav-toggle{ display:block; }
  .row{ grid-template-columns:1fr; gap:6px; }
  .row .rmeta{ display:flex; gap:10px; }
}
@media (max-width: 560px){
  .wrap{ padding:0 18px; }
  .section{ padding:52px 0; }
  .grid-3,.grid-2,.grid-4{ grid-template-columns:1fr; }
  .footer-cols{ grid-template-columns:1fr 1fr; }
  .footer-top{ align-items:flex-start; }
  .lesson-side{ grid-template-columns:1fr; }
  h1{ font-size:2.1rem; }
}