/* Claude Cert Trainer — design system
   Warm-clay accent on deep slate. Mobile-first. Left-aligned body copy. */

:root {
  --bg: #0b0d12;
  --bg-1: #12151d;
  --bg-2: #181c26;
  --bg-3: #1f2430;
  --line: #2a3040;
  --line-2: #363d4f;
  --ink: #f4f1ec;
  --ink-2: #c3c8d4;
  --ink-3: #8b93a5;
  --clay: #d97757;
  --clay-soft: #e79a80;
  --clay-dim: rgba(217, 119, 87, 0.14);
  --cyan: #4cc3d9;
  --green: #58c98a;
  --amber: #e6b566;
  --red: #e07070;
  --violet: #9b8cf0;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }

body {
  background:
    radial-gradient(900px 500px at 85% -10%, rgba(217, 119, 87, 0.10), transparent 60%),
    radial-gradient(700px 500px at -10% 10%, rgba(76, 195, 217, 0.06), transparent 55%),
    var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

/* ---------- layout ---------- */
#app { max-width: 860px; margin: 0 auto; padding: 20px 18px 140px; }
.stack > * + * { margin-top: 14px; }
.muted { color: var(--ink-3); }
.small { font-size: 14px; }
.center { text-align: center; }

h1, h2, h3 { line-height: 1.2; letter-spacing: -0.01em; margin: 0; }
h1 { font-size: clamp(26px, 6vw, 38px); font-weight: 700; }
h2 { font-size: clamp(20px, 4.5vw, 26px); font-weight: 700; }
h3 { font-size: 17px; font-weight: 650; }
p { margin: 0; }

a { color: var(--clay-soft); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- top bar ---------- */
.topbar {
  display: flex; align-items: center; gap: 12px;
  padding: 6px 2px 16px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.brand .dot { width: 12px; height: 12px; border-radius: 50%; background: var(--clay); box-shadow: 0 0 16px var(--clay); }
.topbar .spacer { flex: 1; }
.streak {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--bg-2); border: 1px solid var(--line);
  padding: 7px 12px; border-radius: 999px; font-size: 14px; font-weight: 600;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 11px 18px;
  border-radius: 12px; border: 1px solid var(--line-2);
  background: var(--bg-2); color: var(--ink);
  font: inherit; font-weight: 600; font-size: 15px;
  cursor: pointer; transition: transform .08s ease, background .15s ease, border-color .15s ease;
  -webkit-tap-highlight-color: transparent; user-select: none;
}
.btn:hover { background: var(--bg-3); border-color: var(--line-2); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--clay); border-color: var(--clay); color: #1a1109; }
.btn.primary:hover { background: var(--clay-soft); }
.btn.ghost { background: transparent; }
.btn.small { min-height: 38px; padding: 8px 14px; font-size: 14px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.block { width: 100%; }

/* ---------- cards ---------- */
.card {
  background: linear-gradient(180deg, var(--bg-1), var(--bg-1));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}
.card.pad-lg { padding: 22px; }
.grid { display: grid; gap: 14px; }
@media (min-width: 620px) { .grid.cols-2 { grid-template-columns: 1fr 1fr; } }

/* ---------- progress ring ---------- */
.ring-wrap { display: flex; align-items: center; gap: 20px; flex-wrap: wrap; }
.ring { --p: 0; width: 132px; height: 132px; flex: 0 0 auto; position: relative; }
.ring svg { transform: rotate(-90deg); display: block; }
.ring .track { stroke: var(--bg-3); }
.ring .fill { stroke: var(--clay); stroke-linecap: round; transition: stroke-dashoffset .7s cubic-bezier(.4,0,.2,1); }
.ring .label { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; }
.ring .label .num { font-size: 30px; font-weight: 750; letter-spacing: -0.02em; }
.ring .label .cap { font-size: 14px; color: var(--ink-3); text-transform: uppercase; letter-spacing: .08em; }

/* ---------- progress bar ---------- */
.bar { height: 8px; border-radius: 999px; background: var(--bg-3); overflow: hidden; }
.bar > span { display: block; height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--clay), var(--clay-soft)); transition: width .6s ease; }
.bar.thin { height: 6px; }

/* ---------- track / module list ---------- */
.track-head { display: flex; align-items: center; gap: 12px; }
.track-badge { width: 42px; height: 42px; border-radius: 12px; display: grid; place-content: center; font-weight: 750; font-size: 18px; color: #0c0f16; flex: 0 0 auto; }
.chevron { transition: transform .2s ease; }
.open .chevron { transform: rotate(90deg); }

.lesson-row {
  display: flex; align-items: center; gap: 12px;
  padding: 13px 12px; border-radius: 12px;
  border: 1px solid transparent; cursor: pointer;
}
.lesson-row:hover { background: var(--bg-2); border-color: var(--line); }
.lesson-row .tick {
  width: 26px; height: 26px; border-radius: 50%; flex: 0 0 auto;
  border: 2px solid var(--line-2); display: grid; place-content: center; font-size: 14px; color: var(--ink-3);
}
.lesson-row.done .tick { background: var(--green); border-color: var(--green); color: #08130c; }
.lesson-row .meta { flex: 1; min-width: 0; }
.lesson-row .meta .t { font-weight: 600; font-size: 15px; }
.lesson-row .meta .s { font-size: 14px; color: var(--ink-3); }
.lesson-row .type-chip { font-size: 14px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-3); border: 1px solid var(--line); border-radius: 6px; padding: 3px 8px; }

.pill {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 14px; font-weight: 600; padding: 4px 11px; border-radius: 999px;
  background: var(--clay-dim); color: var(--clay-soft);
}
.pill.gray { background: var(--bg-3); color: var(--ink-2); }
.pill.green { background: rgba(88,201,138,.15); color: var(--green); }

/* ---------- lesson view ---------- */
.lesson-body { font-size: 16px; color: var(--ink-2); line-height: 1.7; text-align: left; }
.lesson-body strong { color: var(--ink); }
.kbd, code { font-family: var(--mono); font-size: .92em; background: var(--bg-3); border: 1px solid var(--line); border-radius: 6px; padding: 1px 6px; color: var(--clay-soft); }
.callout { border-left: 3px solid var(--clay); background: var(--clay-dim); padding: 12px 14px; border-radius: 0 10px 10px 0; font-size: 15px; }
.callout.cyan { border-color: var(--cyan); background: rgba(76,195,217,.10); }

.diagram { background: var(--bg-1); border: 1px solid var(--line); border-radius: 14px; padding: 16px; overflow-x: auto; }
.diagram svg { display: block; margin: 0 auto; max-width: 100%; height: auto; }

/* ---------- tts bar ---------- */
.tts-bar {
  position: fixed; left: 50%; transform: translateX(-50%);
  bottom: calc(84px + env(safe-area-inset-bottom, 0px));
  z-index: 40; display: flex; align-items: center; gap: 10px;
  background: rgba(24,28,38,.96); backdrop-filter: blur(10px);
  border: 1px solid var(--line-2); border-radius: 999px;
  padding: 7px 8px 7px 14px; box-shadow: var(--shadow);
}
.tts-bar .now { font-size: 14px; color: var(--ink-2); max-width: 42vw; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tts-bar button { min-height: 40px; }

/* ---------- bottom nav ---------- */
.nav {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 30;
  display: flex; justify-content: center; gap: 4px;
  background: rgba(11,13,18,.9); backdrop-filter: blur(12px);
  border-top: 1px solid var(--line);
  padding: 8px 8px calc(8px + env(safe-area-inset-bottom, 0px));
}
.nav a {
  flex: 1; max-width: 120px; text-align: center; padding: 8px 4px; border-radius: 12px;
  color: var(--ink-3); font-size: 14px; font-weight: 600; text-decoration: none;
  display: flex; flex-direction: column; align-items: center; gap: 3px;
}
.nav a .ico { font-size: 20px; line-height: 1; }
.nav a.active { color: var(--clay-soft); background: var(--clay-dim); }

/* ---------- labs (drag/drop) ---------- */
.lab { }
.lab-pool, .lab-target { display: flex; flex-direction: column; gap: 8px; }
.lab-cols { display: grid; gap: 14px; }
@media (min-width: 620px) { .lab-cols.two { grid-template-columns: 1fr 1fr; } }
.chip {
  background: var(--bg-2); border: 1px solid var(--line-2); border-radius: 10px;
  padding: 12px 14px; font-size: 14px; font-weight: 550; cursor: grab;
  display: flex; align-items: center; gap: 10px; touch-action: none; user-select: none;
}
.chip:active { cursor: grabbing; }
.chip .grip { color: var(--ink-3); font-size: 16px; }
.chip.dragging { opacity: .4; }
.chip.correct { border-color: var(--green); background: rgba(88,201,138,.12); }
.chip.wrong { border-color: var(--red); background: rgba(224,112,112,.12); }
.slot {
  min-height: 50px; border: 1.5px dashed var(--line-2); border-radius: 10px;
  padding: 6px; display: flex; align-items: center; gap: 8px; transition: border-color .15s, background .15s;
}
.slot.over { border-color: var(--clay); background: var(--clay-dim); }
.slot .idx { color: var(--ink-3); font-size: 14px; font-weight: 700; min-width: 20px; text-align: center; }
.bucket { border: 1.5px solid var(--line); border-radius: 12px; padding: 12px; min-height: 90px; }
.bucket.over { border-color: var(--clay); background: var(--clay-dim); }
.bucket .bkt-title { font-weight: 650; font-size: 14px; margin-bottom: 8px; color: var(--ink); }

/* ---------- flashcards ---------- */
.flip { perspective: 1200px; }
.flip-inner { position: relative; transition: transform .5s; transform-style: preserve-3d; min-height: 220px; }
.flip.flipped .flip-inner { transform: rotateY(180deg); }
.flip-face {
  position: absolute; inset: 0; backface-visibility: hidden;
  display: grid; place-content: center; text-align: center; padding: 26px;
  border-radius: var(--radius); border: 1px solid var(--line); background: var(--bg-1);
}
.flip-face.back { transform: rotateY(180deg); background: var(--bg-2); }
.flip-face .q { font-size: 20px; font-weight: 650; }
.flip-face .a { font-size: 16px; color: var(--ink-2); line-height: 1.6; text-align: left; }

/* ---------- quiz ---------- */
.q-stem { font-size: 17px; font-weight: 600; line-height: 1.5; }
.option {
  display: flex; align-items: flex-start; gap: 12px; width: 100%; text-align: left;
  padding: 14px; border-radius: 12px; border: 1px solid var(--line-2); background: var(--bg-1);
  font: inherit; font-size: 15px; color: var(--ink); cursor: pointer; margin-top: 10px;
}
.option:hover { border-color: var(--line-2); background: var(--bg-2); }
.option .box { width: 22px; height: 22px; border-radius: 6px; border: 2px solid var(--line-2); flex: 0 0 auto; display: grid; place-content: center; font-size: 14px; }
.option.multi .box { border-radius: 6px; }
.option.sel { border-color: var(--clay); }
.option.sel .box { background: var(--clay); border-color: var(--clay); color: #1a1109; }
.option.correct { border-color: var(--green); background: rgba(88,201,138,.10); }
.option.correct .box { background: var(--green); border-color: var(--green); color: #08130c; }
.option.incorrect { border-color: var(--red); background: rgba(224,112,112,.10); }
.option.incorrect .box { background: var(--red); border-color: var(--red); color: #180909; }
.explain { margin-top: 12px; font-size: 14px; color: var(--ink-2); border-left: 3px solid var(--cyan); background: rgba(76,195,217,.08); padding: 10px 12px; border-radius: 0 8px 8px 0; }

/* ---------- score report ---------- */
.score-hero { text-align: center; padding: 8px 0 4px; }
.score-hero .n { font-size: 64px; font-weight: 800; letter-spacing: -0.03em; line-height: 1; }
.dom-row { display: flex; align-items: center; gap: 12px; padding: 8px 0; }
.dom-row .name { flex: 1; font-size: 14px; }
.dom-row .bar { width: 42%; }
.dom-row .pct { width: 44px; text-align: right; font-variant-numeric: tabular-nums; font-weight: 650; font-size: 14px; }

/* ---------- misc ---------- */
.divider { height: 1px; background: var(--line); margin: 4px 0; }
.tag-row { display: flex; flex-wrap: wrap; gap: 8px; }
.link-list a { display: flex; align-items: center; gap: 10px; padding: 12px; border: 1px solid var(--line); border-radius: 12px; color: var(--ink); }
.link-list a:hover { background: var(--bg-2); text-decoration: none; }
.link-list .ext { margin-left: auto; color: var(--ink-3); }
.hide { display: none !important; }
.fade-in { animation: fade .35s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}