:root {
  --bg: #F5F3EE;
  --panel: #EFECE5;
  --card: #FFFFFF;
  --ink: #16181D;
  --muted: #565B66;
  --line: #D6D1C4;
  --line-soft: #E3DFD5;
  --accent: #1F5FBF;
  --accent-text: #1F5FBF;
  --on-accent: #FFFFFF;
  --tint: #E8EFFB;
  --badge: #F1EEE7;
  --ok: #1E7B4F;
  --ok-bg: #E4F3EA;
  --ok-ink: #1E6B45;
  --bad: #B3261E;
  --bad-bg: #FBE9E7;
  --bad-ink: #A1231B;
  --warn: #B45309;
  --code-bg: #16181D;
  --code-ink: #F5F3EE;
  --display: 'Fraunces', Georgia, 'Times New Roman', serif;
  --sans: 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --mono: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121418;
    --panel: #171A1F;
    --card: #1C1F25;
    --ink: #ECEAE4;
    --muted: #A3A7B0;
    --line: #30343C;
    --line-soft: #262A31;
    --accent: #2F6CD0;
    --accent-text: #8FB4F5;
    --tint: #1B2A45;
    --badge: #262A31;
    --ok: #3FA46A;
    --ok-bg: #15301F;
    --ok-ink: #7FD3A0;
    --bad: #E0605A;
    --bad-bg: #3A1816;
    --bad-ink: #F2A29D;
    --warn: #E08A3C;
    --code-bg: #0B0C0F;
    --code-ink: #ECEAE4;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
button { font: inherit; color: inherit; cursor: pointer; -webkit-tap-highlight-color: transparent; }
button:disabled { opacity: .45; cursor: not-allowed; }
:focus-visible { outline: 2px solid var(--accent-text); outline-offset: 2px; }
a { color: var(--accent-text); }
.noscript { padding: 24px; }

/* ---------- Shared pieces ---------- */
.eyebrow { margin: 0; font-family: var(--mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
.display { margin: 0; font-family: var(--display); font-weight: 600; font-size: 44px; line-height: 1.05; letter-spacing: -.01em; }
.lede { margin: 0; font-size: 15px; color: var(--muted); }
.setup-title { margin: 0; font-family: var(--display); font-size: 26px; font-weight: 600; }
.stack { display: flex; flex-direction: column; gap: 12px; }
.stack.tight { gap: 6px; }
.group { display: flex; flex-direction: column; gap: 10px; }
.grow { flex: 1; min-width: 0; }
.mono { font-family: var(--mono); }
.muted { color: var(--muted); }
.b { font-weight: 500; }
.note { margin: 0; font-size: 13px; line-height: 1.5; color: var(--muted); }
.note.big { font-size: 15px; }
.msg { margin: 0; font-size: 14px; line-height: 1.45; }
.msg.ok { color: var(--ok-ink); }
.msg.bad { color: var(--bad-ink); }

.btn-primary {
  min-height: 52px; padding: 0 20px; border: 0; border-radius: 12px;
  background: var(--accent); color: var(--on-accent); font-size: 16px; font-weight: 600;
}
.btn-secondary {
  min-height: 48px; padding: 0 16px; border: 1px solid var(--line); border-radius: 12px;
  background: var(--card); font-size: 15px; font-weight: 500;
}
.btn-outline {
  min-height: 48px; padding: 0 16px; border: 1px solid var(--ink); border-radius: 12px;
  background: transparent; font-size: 15px; font-weight: 600;
}
.with-icon { display: inline-flex; align-items: center; justify-content: center; gap: 8px; align-self: flex-start; }
.link {
  min-height: 44px; padding: 0; border: 0; background: none; color: var(--muted);
  font-size: 14px; text-decoration: underline; text-underline-offset: 3px;
}
.row-links { display: flex; flex-wrap: wrap; gap: 20px; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  min-height: 44px; padding: 0 14px; border-radius: 999px; border: 1px solid var(--line);
  background: var(--card); font-size: 14px; font-weight: 500; display: inline-flex; align-items: center; gap: 6px;
}
.chip .count { font-family: var(--mono); font-size: 12px; opacity: .75; }
.chip[aria-pressed="true"] { background: var(--ink); color: var(--bg); border-color: var(--ink); }

.modes { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.mode {
  min-height: 76px; padding: 12px 14px; text-align: left; border-radius: 12px;
  border: 1.5px solid var(--line); background: var(--card); display: flex; flex-direction: column; gap: 4px;
}
.mode .t { font-size: 16px; font-weight: 600; }
.mode .s { font-size: 13px; line-height: 1.35; color: var(--muted); }
.mode[aria-pressed="true"] { background: var(--tint); border-color: var(--accent); }

.stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; }
.stat { padding: 12px; background: var(--card); border: 1px solid var(--line); border-radius: 12px; }
.stat .v { font-family: var(--display); font-size: 26px; font-weight: 600; line-height: 1.2; }
.stat .l { font-size: 12px; color: var(--muted); }

.upload {
  position: relative; min-height: 48px; padding: 0 16px; border: 1px dashed var(--muted); border-radius: 12px;
  background: var(--card); display: flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 500; cursor: pointer;
}
.upload input { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0; cursor: pointer; }
.upload:focus-within { outline: 2px solid var(--accent-text); outline-offset: 2px; }

.ext-card {
  min-height: 56px; padding: 14px 16px; border: 1px solid var(--line); border-radius: 12px; background: var(--card);
  display: flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none;
}
.ext-card svg { flex-shrink: 0; color: var(--accent-text); }
.ext-title { font-size: 15px; font-weight: 600; }
@media (hover: hover) { .ext-card:hover { border-color: var(--accent); } }
a.note { color: var(--accent-text); align-self: flex-start; min-height: 24px; }

.actions {
  position: sticky; bottom: 0; z-index: 4;
  padding: 16px 20px calc(20px + var(--safe-bottom));
  background: var(--bg); border-top: 1px solid var(--line);
  display: flex; flex-direction: column; gap: 10px;
}
.two { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }

/* ---------- Home ---------- */
.home { min-height: 100dvh; display: flex; flex-direction: column; }
.home-left, .home-right { display: contents; }
.home-intro { order: 1; padding: calc(32px + var(--safe-top)) 20px 4px; display: flex; flex-direction: column; gap: 24px; }
.home-setup { order: 2; padding: 28px 20px 0; display: flex; flex-direction: column; gap: 24px; }
.home-setup .setup-title { display: none; }
.home-extra { order: 3; padding: 28px 20px 28px; display: flex; flex-direction: column; gap: 16px; flex: 1; }
.home .actions { order: 4; }

@media (min-width: 900px) {
  .home { flex-direction: row; height: 100dvh; min-height: 0; }
  .home-left, .home-right { display: flex; flex-direction: column; min-height: 0; }
  .home-left { width: 44%; max-width: 540px; flex-shrink: 0; overflow-y: auto; }
  .home-right { flex: 1; background: var(--card); border-left: 1px solid var(--line); }
  .home-intro { padding: calc(64px + var(--safe-top)) 56px 0; gap: 32px; }
  .home-extra { padding: 32px 56px 48px; flex: 0 0 auto; }
  .home-setup { flex: 1; overflow-y: auto; padding: calc(64px + var(--safe-top)) 56px 32px; gap: 32px; }
  .home-setup .setup-title { display: block; font-size: 30px; }
  .display { font-size: 72px; line-height: 1; letter-spacing: -.02em; }
  .lede { font-size: 17px; }
  .stats { gap: 12px; }
  .stat { padding: 16px; border-radius: 14px; }
  .stat .v { font-size: 34px; }
  .stat .l { font-size: 13px; }
  .home .actions { flex-direction: row; padding: 20px 56px calc(36px + var(--safe-bottom)); background: var(--card); border-top-color: var(--line-soft); }
  .home .actions .btn-primary { flex: 1; min-height: 56px; font-size: 17px; }
  .home .actions .btn-secondary { width: 240px; min-height: 56px; }
  .chip { font-size: 15px; padding: 0 16px; }
  .mode { min-height: 88px; padding: 16px 18px; border-radius: 14px; }
  .mode .t { font-size: 18px; }
  .mode .s { font-size: 14px; }
}

/* ---------- Quiz ---------- */
.quiz { min-height: 100dvh; display: flex; flex-direction: column; }
.quiz-top {
  position: sticky; top: 0; z-index: 5; background: var(--bg);
  padding: calc(8px + var(--safe-top)) 16px 10px 8px; border-bottom: 1px solid var(--line-soft);
}
.quiz-top .row { display: flex; align-items: center; gap: 6px; }
.home-btn {
  min-width: 44px; min-height: 44px; padding: 0 6px; border: 0; background: transparent; border-radius: 10px;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; font-size: 15px; font-weight: 500;
}
.home-btn .label { display: none; }
.counter { flex: 1; font-size: 15px; font-weight: 600; }
.pill {
  padding: 4px 10px; border-radius: 999px; border: 1px solid var(--line);
  font-family: var(--mono); font-size: 12px; letter-spacing: .06em; text-transform: uppercase; color: var(--muted);
}
.progress { height: 4px; margin: 10px 0 0 12px; background: var(--line-soft); border-radius: 2px; overflow: hidden; }
.progress > span { display: block; height: 100%; background: var(--accent); transition: width .2s ease; }

.quiz-body { flex: 1; display: flex; }
.quiz-nav, .quiz-aside { display: none; }
.quiz-main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.quiz-content { flex: 1; width: 100%; max-width: 760px; margin: 0 auto; padding: 20px 20px 24px; display: flex; flex-direction: column; gap: 16px; }
.domain-tag { margin: 0; font-family: var(--mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--accent-text); }
.qtext { margin: 0; font-size: 18px; line-height: 1.5; font-weight: 500; }
.code {
  margin: 0; padding: 14px 16px; background: var(--code-bg); color: var(--code-ink); border-radius: 10px;
  font-family: var(--mono); font-size: 13px; line-height: 1.55; overflow-x: auto;
}
.need { margin: 0; font-size: 14px; font-weight: 600; color: var(--muted); }

.options { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 10px; }
.opt {
  width: 100%; min-height: 56px; padding: 12px 14px; display: flex; align-items: flex-start; gap: 12px; text-align: left;
  background: var(--card); border: 1.5px solid var(--line); border-radius: 12px; font-size: 15px; line-height: 1.45;
  transition: border-color .12s ease, background-color .12s ease;
}
.opt .badge {
  flex-shrink: 0; width: 28px; height: 28px; border-radius: 8px; display: flex; align-items: center; justify-content: center;
  background: var(--badge); font-family: var(--mono); font-size: 13px; font-weight: 500;
}
.opt .txt { flex: 1; padding-top: 3px; }
.opt .mark { flex-shrink: 0; margin-top: 4px; display: flex; }
.opt.locked { cursor: default; }
@media (hover: hover) { .opt:not(.locked):not(.sel):hover { border-color: var(--muted); } }
.opt.sel { background: var(--tint); border-color: var(--accent); }
.opt.sel .badge { background: var(--accent); color: var(--on-accent); }
.opt.right { background: var(--ok-bg); border-color: var(--ok); }
.opt.right .badge { background: var(--ok); color: #FFFFFF; }
.opt.right .mark { color: var(--ok); }
.opt.wrong { background: var(--bad-bg); border-color: var(--bad); }
.opt.wrong .badge { background: var(--bad); color: #FFFFFF; }
.opt.wrong .mark { color: var(--bad); }

.expl { padding: 16px; background: var(--card); border: 1px solid var(--line); border-radius: 12px; display: flex; flex-direction: column; gap: 8px; scroll-margin-bottom: 100px; }
.verdict { display: flex; align-items: center; gap: 8px; font-size: 16px; font-weight: 600; }
.verdict.ok { color: var(--ok-ink); }
.verdict.bad { color: var(--bad-ink); }
.verdict.big { font-family: var(--display); font-size: 28px; }
.ans { font-family: var(--mono); font-size: 13px; font-weight: 500; color: var(--muted); }
.why { margin: 0; font-size: 15px; line-height: 1.55; }
.learn-more {
  align-self: flex-start; min-height: 44px; display: inline-flex; align-items: center; gap: 6px;
  color: var(--accent-text); font-size: 15px; font-weight: 600; text-decoration: none;
}
.learn-more:hover { text-decoration: underline; text-underline-offset: 3px; }

.quiz-foot {
  position: sticky; bottom: 0; z-index: 4; background: var(--bg); border-top: 1px solid var(--line);
  padding: 12px 20px calc(16px + var(--safe-bottom)); display: flex; gap: 10px;
}
.prev {
  flex-shrink: 0; min-width: 52px; height: 52px; border: 1px solid var(--line); background: var(--card); border-radius: 12px;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; font-size: 15px; font-weight: 500;
}
.prev .label { display: none; }
.quiz-foot .btn-primary { flex: 1; }

.nav-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 8px; padding: 4px; }
.nav-btn {
  height: 44px; border-radius: 10px; border: 1.5px solid var(--line); background: var(--card);
  font-family: var(--mono); font-size: 14px; font-weight: 500;
}
.nav-btn.sel { background: var(--tint); border-color: var(--accent); }
.nav-btn.right { background: var(--ok); border-color: var(--ok); color: #FFFFFF; }
.nav-btn.wrong { background: var(--bad); border-color: var(--bad); color: #FFFFFF; }
.nav-btn.current { box-shadow: 0 0 0 2px var(--panel), 0 0 0 4px var(--ink); }
.legend { display: flex; flex-direction: column; gap: 8px; font-size: 13px; color: var(--muted); }
.legend span { display: flex; align-items: center; gap: 8px; }
.sw { width: 12px; height: 12px; border-radius: 3px; display: inline-block; }
.sw.sel { background: var(--tint); border: 1.5px solid var(--accent); }
.sw.right { background: var(--ok); }
.sw.wrong { background: var(--bad); }

@media (min-width: 1000px) {
  .quiz { height: 100dvh; min-height: 0; }
  .quiz-top { position: static; padding: calc(12px + var(--safe-top)) 24px 12px 16px; }
  .home-btn { padding: 0 12px 0 6px; }
  .home-btn .label { display: inline; }
  .progress { margin-left: 0; }
  .quiz-body { min-height: 0; }
  .quiz-nav {
    display: flex; flex-direction: column; gap: 20px; width: 260px; flex-shrink: 0; padding: 24px;
    background: var(--panel); border-right: 1px solid var(--line); overflow-y: auto;
  }
  .quiz-main { overflow-y: auto; }
  .quiz-content { padding: 40px 48px 32px; gap: 20px; }
  .qtext { font-size: 21px; }
  .code { font-size: 14px; padding: 16px 20px; border-radius: 12px; }
  .opt { min-height: 60px; padding: 14px 18px; gap: 14px; font-size: 16px; border-radius: 14px; }
  .opt .badge { width: 30px; height: 30px; font-size: 14px; }
  .expl-inline { display: none; }
  .quiz-aside {
    display: flex; flex-direction: column; gap: 16px; width: 340px; flex-shrink: 0; padding: 40px 32px;
    background: var(--card); border-left: 1px solid var(--line); overflow-y: auto;
  }
  .quiz-aside .ans { font-size: 14px; }
  .quiz-aside .why { font-size: 16px; line-height: 1.6; }
  .quiz-foot { justify-content: flex-end; padding: 16px 48px calc(24px + var(--safe-bottom)); gap: 12px; }
  .quiz-foot .btn-primary { flex: 0 0 220px; }
  .prev { padding: 0 20px 0 14px; }
  .prev .label { display: inline; }
}
@media (min-width: 1000px) and (hover: none) { .keys { display: none; } }
@media (max-width: 999px) { .keys { display: none; } }

/* ---------- Results ---------- */
.result { min-height: 100dvh; display: flex; flex-direction: column; }
.result-left { display: contents; }
.result-summary { order: 1; padding: calc(32px + var(--safe-top)) 20px 8px; display: flex; flex-direction: column; gap: 28px; }
.result-list { order: 2; padding: 24px 20px 28px; display: flex; flex-direction: column; gap: 8px; }
.result-list .setup-title { font-size: 22px; margin-bottom: 4px; }
.result .actions { order: 3; }
.score { font-family: var(--display); font-size: 88px; line-height: 1; font-weight: 600; letter-spacing: -.02em; }
.score-line { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; font-size: 15px; }
.pass-pill { padding: 4px 10px; border-radius: 999px; font-size: 13px; font-weight: 600; }
.pass-pill.ok { background: var(--ok-bg); color: var(--ok-ink); }
.pass-pill.bad { background: var(--bad-bg); color: var(--bad-ink); }
.bar-row { display: flex; flex-direction: column; gap: 6px; }
.bar-head { display: flex; justify-content: space-between; gap: 12px; font-size: 14px; }
.bar { height: 8px; background: var(--line-soft); border-radius: 4px; overflow: hidden; }
.bar > span { display: block; height: 100%; background: var(--accent); }
.bar > span.low { background: var(--warn); }
.rq {
  width: 100%; min-height: 56px; padding: 12px 14px; display: flex; align-items: flex-start; gap: 12px; text-align: left;
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
}
.rq .num { flex-shrink: 0; width: 24px; padding-top: 2px; font-family: var(--mono); font-size: 13px; color: var(--muted); }
.rq-text { font-size: 14px; line-height: 1.45; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.mark-ok, .mark-bad { flex-shrink: 0; display: flex; }
.mark-ok { color: var(--ok); }
.mark-bad { color: var(--bad); }

@media (min-width: 900px) {
  .result { flex-direction: row; height: 100dvh; min-height: 0; }
  .result-left { display: flex; flex-direction: column; width: 460px; flex-shrink: 0; overflow-y: auto; }
  .result-summary { flex: 1; padding: calc(64px + var(--safe-top)) 56px 32px; }
  .score { font-size: 128px; letter-spacing: -.03em; }
  .result .actions { position: static; padding: 0 56px calc(48px + var(--safe-bottom)); border-top: 0; background: transparent; }
  .result-list { flex: 1; overflow-y: auto; padding: calc(64px + var(--safe-top)) 56px 56px; background: var(--card); border-left: 1px solid var(--line); gap: 10px; }
  .result-list .setup-title { font-size: 30px; margin-bottom: 8px; }
  .rq { background: var(--bg); border-color: var(--line-soft); padding: 14px 18px; }
  .rq-text { font-size: 15px; }
}

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