:root {
  color-scheme: light;
  --bg: #f6f7f8;
  --surface: #ffffff;
  --surface-2: #f1f3f5;
  --surface-3: #e7eaee;
  --border: #dde1e6;
  --border-strong: #c5ccd4;
  --text: #0f1720;
  --text-2: #475260;
  --text-3: #6b7684;
  --accent: #0e7c74;
  --accent-strong: #0a625c;
  --accent-soft: #e0f2ef;
  --accent-ink: #ffffff;
  --good: #0f7a3d;
  --good-soft: #e3f4e9;
  --bad: #c0362c;
  --bad-soft: #fbe9e7;
  --warn: #a15c00;
  --warn-soft: #fdf1dc;
  --info: #2a78d6;
  --info-soft: #e5effb;
  --mark: #fde68a;
  --mark-ink: #1f1a00;
  --series-1: #2a78d6;
  --div-lo: #d03b3b;
  --div-mid: #eceae6;
  --div-hi: #2a78d6;
  --shadow-1: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .06);
  --shadow-2: 0 8px 24px rgba(16, 24, 40, .10), 0 2px 6px rgba(16, 24, 40, .06);
  --radius: 12px;
  --radius-sm: 8px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --serif: "Source Serif 4", Georgia, serif;
  --stem-size: 16px;
  --topbar-h: 60px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0b1016;
    --surface: #121922;
    --surface-2: #18212c;
    --surface-3: #212c39;
    --border: #253141;
    --border-strong: #34445a;
    --text: #e8edf2;
    --text-2: #b3bfcc;
    --text-3: #8795a5;
    --accent: #2bb3a6;
    --accent-strong: #5fd0c4;
    --accent-soft: #10322f;
    --accent-ink: #04201d;
    --good: #4cc584;
    --good-soft: #10301f;
    --bad: #f07a6f;
    --bad-soft: #3a1714;
    --warn: #f0b44c;
    --warn-soft: #382809;
    --info: #3987e5;
    --info-soft: #11263f;
    --mark: #7a6414;
    --mark-ink: #fff6d0;
    --series-1: #3987e5;
    --div-lo: #d55252;
    --div-mid: #383835;
    --div-hi: #3987e5;
    --shadow-1: 0 1px 2px rgba(0, 0, 0, .4);
    --shadow-2: 0 10px 30px rgba(0, 0, 0, .5);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0b1016;
  --surface: #121922;
  --surface-2: #18212c;
  --surface-3: #212c39;
  --border: #253141;
  --border-strong: #34445a;
  --text: #e8edf2;
  --text-2: #b3bfcc;
  --text-3: #8795a5;
  --accent: #2bb3a6;
  --accent-strong: #5fd0c4;
  --accent-soft: #10322f;
  --accent-ink: #04201d;
  --good: #4cc584;
  --good-soft: #10301f;
  --bad: #f07a6f;
  --bad-soft: #3a1714;
  --warn: #f0b44c;
  --warn-soft: #382809;
  --info: #3987e5;
  --info-soft: #11263f;
  --mark: #7a6414;
  --mark-ink: #fff6d0;
  --series-1: #3987e5;
  --div-lo: #d55252;
  --div-mid: #383835;
  --div-hi: #3987e5;
  --shadow-1: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-2: 0 10px 30px rgba(0, 0, 0, .5);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text); font-family: var(--font);
  font-size: 15px; line-height: 1.5; -webkit-font-smoothing: antialiased;
  font-feature-settings: "cv11", "ss01";
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
button { font: inherit; color: inherit; }
h1, h2, h3, h4 { margin: 0; line-height: 1.25; letter-spacing: -0.01em; }
h1 { font-size: 26px; font-weight: 700; }
h2 { font-size: 19px; font-weight: 650; }
h3 { font-size: 15px; font-weight: 650; }
p { margin: 0 0 10px; }
.num { font-variant-numeric: tabular-nums; }
.muted { color: var(--text-3); }
.small { font-size: 13px; }
.tiny { font-size: 12px; }
.hidden { display: none !important; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 40; height: var(--topbar-h);
  display: flex; align-items: center; gap: 20px; padding: 0 20px;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px); -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none !important; }
.brand span { display: flex; flex-direction: column; line-height: 1.1; }
.brand b { font-size: 16px; letter-spacing: -0.02em; }
.brand small { font-size: 11px; color: var(--text-3); font-weight: 500; letter-spacing: .02em; }
.mainnav { display: flex; gap: 2px; flex: 1; }
.mainnav a {
  color: var(--text-2); padding: 7px 12px; border-radius: 8px; font-weight: 500; font-size: 14px;
  text-decoration: none; display: inline-flex; align-items: center; gap: 6px; transition: background .15s, color .15s;
}
.mainnav a:hover { background: var(--surface-2); color: var(--text); }
.mainnav a.active { background: var(--accent-soft); color: var(--accent-strong); }
.pill-count { background: var(--accent); color: var(--accent-ink); font-size: 11px; font-weight: 700; border-radius: 99px; padding: 1px 7px; }
.top-actions { display: flex; gap: 6px; margin-left: auto; }
.icon-btn {
  width: 38px; height: 38px; display: inline-grid; place-items: center; border-radius: 10px;
  border: 1px solid transparent; background: transparent; color: var(--text-2); cursor: pointer; transition: background .15s;
}
.icon-btn:hover { background: var(--surface-2); color: var(--text); }
.icon-btn.on { color: var(--accent); background: var(--accent-soft); }
.demo-banner {
  background: var(--info-soft); color: var(--text); border-bottom: 1px solid var(--border);
  padding: 8px 20px; font-size: 13px; display: block;
}
.demo-banner .link-btn { margin-left: 8px; }
.link-btn { background: none; border: 0; padding: 0; color: var(--accent); cursor: pointer; font-weight: 600; }
.link-btn:hover { text-decoration: underline; }

.tabbar { display: none; }

main { outline: none; }
.page { max-width: 1180px; margin: 0 auto; padding: 28px 24px 80px; animation: fadeUp .28s ease both; }
.page-narrow { max-width: 860px; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { * { animation: none !important; transition: none !important; } }

.page-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; margin-bottom: 20px; flex-wrap: wrap; }
.page-head p { color: var(--text-2); margin: 6px 0 0; max-width: 640px; }
.eyebrow { font-size: 12px; font-weight: 650; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); margin-bottom: 6px; }

/* ---------- cards & grid ---------- */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow-1); padding: 20px;
}
.card + .card { margin-top: 16px; }
.card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; flex-wrap: wrap; }
.card-head p { margin: 4px 0 0; color: var(--text-3); font-size: 13px; }
.grid { display: grid; gap: 16px; }
.g2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.g3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.g4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.span2 { grid-column: span 2; }
.stack > * + * { margin-top: 16px; }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }

.tile { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow-1); }
.tile .label { font-size: 12px; color: var(--text-3); font-weight: 600; text-transform: uppercase; letter-spacing: .05em; }
.tile .value { font-size: 28px; font-weight: 700; letter-spacing: -0.02em; margin-top: 4px; font-variant-numeric: tabular-nums; }
.tile .value small { font-size: 14px; color: var(--text-3); font-weight: 500; margin-left: 4px; }
.tile .sub { font-size: 12.5px; color: var(--text-2); margin-top: 2px; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px; height: 40px; padding: 0 16px;
  border-radius: 10px; border: 1px solid var(--border-strong); background: var(--surface); color: var(--text);
  font-weight: 600; font-size: 14px; cursor: pointer; text-decoration: none !important; white-space: nowrap;
  transition: background .15s, border-color .15s, transform .05s, box-shadow .15s;
}
.btn:hover { background: var(--surface-2); }
.btn:active { transform: translateY(1px); }
.btn:focus-visible, .opt:focus-visible, .icon-btn:focus-visible, a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); }
.btn.ghost { border-color: transparent; background: transparent; }
.btn.ghost:hover { background: var(--surface-2); }
.btn.danger { color: var(--bad); }
.btn.lg { height: 48px; padding: 0 22px; font-size: 15px; border-radius: 12px; }
.btn.sm { height: 32px; padding: 0 12px; font-size: 13px; border-radius: 8px; }
.btn[disabled] { opacity: .45; cursor: not-allowed; }
.kbd { font: 600 11px/1 var(--font); border: 1px solid var(--border-strong); border-bottom-width: 2px; border-radius: 5px; padding: 2px 5px; color: var(--text-3); background: var(--surface-2); }

/* ---------- chips/badges ---------- */
.chip { display: inline-flex; align-items: center; gap: 5px; font-size: 12px; font-weight: 600; padding: 3px 9px; border-radius: 99px; background: var(--surface-2); color: var(--text-2); border: 1px solid var(--border); white-space: nowrap; }
.chip.good { background: var(--good-soft); color: var(--good); border-color: transparent; }
.chip.bad { background: var(--bad-soft); color: var(--bad); border-color: transparent; }
.chip.warn { background: var(--warn-soft); color: var(--warn); border-color: transparent; }
.chip.info { background: var(--info-soft); color: var(--info); border-color: transparent; }
.chip.accent { background: var(--accent-soft); color: var(--accent-strong); border-color: transparent; }
.chip svg { width: 13px; height: 13px; }

/* ---------- forms ---------- */
label.field { display: flex; flex-direction: column; gap: 6px; font-size: 13px; font-weight: 600; color: var(--text-2); }
input[type=date], input[type=number], input[type=text], select, textarea {
  font: inherit; color: var(--text); background: var(--surface); border: 1px solid var(--border-strong);
  border-radius: 10px; padding: 9px 12px; min-height: 40px; width: 100%;
}
textarea { resize: vertical; min-height: 70px; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 0; border-color: var(--accent); }
.seg { display: inline-flex; background: var(--surface-2); border: 1px solid var(--border); border-radius: 11px; padding: 3px; gap: 2px; flex-wrap: wrap; }
.seg button { border: 0; background: transparent; padding: 7px 14px; border-radius: 8px; font-weight: 600; font-size: 13.5px; color: var(--text-2); cursor: pointer; }
.seg button.on { background: var(--surface); color: var(--text); box-shadow: var(--shadow-1); }
.checks { display: flex; flex-wrap: wrap; gap: 8px; }
.check-chip { position: relative; }
.check-chip input { position: absolute; opacity: 0; pointer-events: none; }
.check-chip span { display: inline-flex; align-items: center; gap: 6px; padding: 7px 12px; border-radius: 10px; border: 1px solid var(--border-strong); font-size: 13px; font-weight: 500; cursor: pointer; background: var(--surface); transition: all .12s; }
.check-chip input:checked + span { border-color: var(--accent); background: var(--accent-soft); color: var(--accent-strong); font-weight: 600; }
.check-chip input:focus-visible + span { outline: 2px solid var(--accent); }
.check-chip em { font-style: normal; color: var(--text-3); font-size: 12px; }

/* ---------- home ---------- */
.hero {
  position: relative; overflow: hidden; border-radius: 18px; padding: 36px; border: 1px solid var(--border);
  background:
    radial-gradient(900px 300px at 100% 0%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 60%),
    radial-gradient(600px 300px at 0% 100%, color-mix(in srgb, var(--info) 12%, transparent), transparent 60%),
    var(--surface);
  box-shadow: var(--shadow-1);
}
.hero h1 { font-family: var(--serif); font-size: 34px; font-weight: 600; letter-spacing: -0.02em; max-width: 720px; }
.hero p.lead { font-size: 16.5px; color: var(--text-2); max-width: 640px; margin: 12px 0 22px; }
.hero .row { gap: 12px; }
.hero-facts { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; margin-top: 28px; }
.hero-fact { border-top: 1px solid var(--border); padding-top: 12px; }
.hero-fact b { display: block; font-size: 20px; letter-spacing: -0.02em; font-variant-numeric: tabular-nums; }
.hero-fact span { font-size: 12.5px; color: var(--text-3); }
.steps-list { counter-reset: s; list-style: none; padding: 0; margin: 0; display: grid; gap: 12px; }
.steps-list li { counter-increment: s; display: grid; grid-template-columns: 30px 1fr; gap: 12px; align-items: start; }
.steps-list li::before { content: counter(s); width: 26px; height: 26px; border-radius: 50%; background: var(--accent-soft); color: var(--accent-strong); font-weight: 700; font-size: 13px; display: grid; place-items: center; }
.steps-list b { display: block; font-size: 14px; }
.steps-list span { color: var(--text-2); font-size: 13.5px; }
.today-target { display: flex; align-items: center; gap: 18px; }
.ring { --p: 0; width: 84px; height: 84px; border-radius: 50%; display: grid; place-items: center; flex: none;
  background: conic-gradient(var(--accent) calc(var(--p) * 1%), var(--surface-3) 0); }
.ring > div { width: 66px; height: 66px; border-radius: 50%; background: var(--surface); display: grid; place-items: center; font-weight: 700; font-size: 16px; font-variant-numeric: tabular-nums; }

/* ---------- practice builder ---------- */
.builder-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); gap: 16px; align-items: start; }
.opt-group + .opt-group { margin-top: 20px; }
.opt-group > h3 { margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.summary-box { position: sticky; top: calc(var(--topbar-h) + 16px); }
.summary-box .big { font-size: 40px; font-weight: 700; letter-spacing: -0.03em; font-variant-numeric: tabular-nums; }
.blocks-list { display: grid; gap: 8px; }
.block-row { display: grid; grid-template-columns: auto 1fr auto auto; gap: 12px; align-items: center; padding: 10px 12px; border: 1px solid var(--border); border-radius: 10px; background: var(--surface); }
.block-row .score { font-weight: 700; font-variant-numeric: tabular-nums; }

/* ---------- exam player ---------- */
body.in-exam .topbar, body.in-exam .tabbar, body.in-exam .demo-banner { display: none; }
.exam { display: grid; grid-template-rows: auto 1fr auto; height: 100vh; height: 100dvh; background: var(--bg); }
.exam-top {
  display: flex; align-items: center; gap: 10px; padding: 8px 14px; background: var(--surface);
  border-bottom: 1px solid var(--border); min-height: 56px;
}
.exam-top .qpos { font-weight: 700; font-variant-numeric: tabular-nums; }
.exam-top .qpos small { color: var(--text-3); font-weight: 500; }
.exam-top .mode-chip { margin-left: 4px; }
.timer { font: 700 17px/1 var(--font); font-variant-numeric: tabular-nums; padding: 8px 12px; border-radius: 10px; background: var(--surface-2); border: 1px solid var(--border); display: inline-flex; align-items: center; gap: 7px; }
.timer.low { color: var(--bad); border-color: var(--bad); background: var(--bad-soft); animation: pulse 1.6s ease-in-out infinite; }
.timer.paused { opacity: .6; }
@keyframes pulse { 50% { box-shadow: 0 0 0 4px color-mix(in srgb, var(--bad) 18%, transparent); } }
.tool-btn { display: inline-flex; align-items: center; gap: 6px; height: 38px; padding: 0 11px; border-radius: 10px; border: 1px solid var(--border); background: var(--surface); cursor: pointer; font-weight: 600; font-size: 13px; color: var(--text-2); }
.tool-btn:hover { background: var(--surface-2); color: var(--text); }
.tool-btn.on { color: var(--warn); border-color: var(--warn); background: var(--warn-soft); }
.tool-btn svg { width: 17px; height: 17px; }
.exam-body { display: grid; grid-template-columns: 76px minmax(0, 1fr); min-height: 0; }
.navgrid { overflow-y: auto; border-right: 1px solid var(--border); background: var(--surface); padding: 10px 8px; display: flex; flex-direction: column; gap: 4px; }
.navgrid button {
  position: relative; height: 36px; border-radius: 8px; border: 1px solid var(--border); background: var(--surface);
  font-weight: 600; font-size: 13px; cursor: pointer; font-variant-numeric: tabular-nums; color: var(--text-2); flex: none;
}
.navgrid button.answered { background: var(--surface-3); color: var(--text); }
.navgrid button.cur { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); color: var(--accent-strong); }
.navgrid button.correct { background: var(--good-soft); color: var(--good); border-color: transparent; }
.navgrid button.incorrect { background: var(--bad-soft); color: var(--bad); border-color: transparent; }
.navgrid button.marked::after { content: ""; position: absolute; top: 3px; right: 3px; width: 0; height: 0; border-left: 7px solid transparent; border-top: 7px solid var(--warn); }
.exam-main { overflow-y: auto; min-height: 0; scroll-behavior: smooth; }
.exam-content { max-width: 860px; margin: 0 auto; padding: 26px 26px 40px; }
.qmeta { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 14px; }
.stem { font-size: var(--stem-size); line-height: 1.7; color: var(--text); margin-bottom: 16px; user-select: text; }
.stem mark, .hl { background: var(--mark); color: var(--mark-ink); border-radius: 3px; padding: 0 1px; cursor: pointer; }
.leadin { font-size: var(--stem-size); font-weight: 600; margin: 4px 0 18px; line-height: 1.6; }
.opts { display: flex; flex-direction: column; gap: 8px; }
.opt {
  display: grid; grid-template-columns: 30px minmax(0, 1fr) auto; gap: 12px; align-items: center;
  padding: 11px 12px; border-radius: 12px; border: 1px solid var(--border); background: var(--surface);
  cursor: pointer; text-align: left; width: 100%; font-size: var(--stem-size); line-height: 1.45; transition: border-color .12s, background .12s;
  -webkit-touch-callout: none;
}
.opt:hover { border-color: var(--border-strong); }
.opt .letter { width: 28px; height: 28px; border-radius: 50%; border: 1.5px solid var(--border-strong); display: grid; place-items: center; font-weight: 700; font-size: 13px; color: var(--text-2); transition: all .12s; }
.opt.sel { border-color: var(--accent); background: var(--accent-soft); }
.opt.sel .letter { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.opt.struck .otext { text-decoration: line-through; text-decoration-thickness: 1.5px; color: var(--text-3); }
.opt.struck .letter { opacity: .5; }
.opt .strike { opacity: 0; border: 0; background: transparent; color: var(--text-3); cursor: pointer; padding: 4px; border-radius: 6px; display: grid; place-items: center; }
.opt:hover .strike, .opt.struck .strike { opacity: 1; }
.opt .strike:hover { background: var(--surface-2); color: var(--text); }
.opt.locked { cursor: default; }
.opt.is-key { border-color: var(--good); background: var(--good-soft); }
.opt.is-key .letter { background: var(--good); border-color: var(--good); color: #fff; }
.opt.is-wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt.is-wrong .letter { background: var(--bad); border-color: var(--bad); color: #fff; }
.opt .pct { font-size: 12px; font-weight: 600; color: var(--text-3); }
.exam-actions { display: flex; gap: 10px; align-items: center; margin-top: 18px; flex-wrap: wrap; }
.hint-line { font-size: 12px; color: var(--text-3); display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.exam-bottom { display: flex; align-items: center; gap: 8px; padding: 8px 14px; background: var(--surface); border-top: 1px solid var(--border); }

/* explanation */
.explain { margin-top: 24px; border-top: 1px solid var(--border); padding-top: 22px; animation: fadeUp .3s ease both; }
.verdict { display: flex; align-items: center; gap: 12px; padding: 14px 16px; border-radius: 12px; margin-bottom: 18px; font-weight: 600; }
.verdict.ok { background: var(--good-soft); color: var(--good); }
.verdict.no { background: var(--bad-soft); color: var(--bad); }
.verdict.skip { background: var(--surface-2); color: var(--text-2); }
.verdict .vsub { font-weight: 500; color: var(--text-2); font-size: 13px; }
.objective { border-left: 3px solid var(--accent); padding: 4px 0 4px 14px; margin-bottom: 18px; }
.objective .eyebrow { margin-bottom: 4px; }
.objective p { margin: 0; font-size: 15px; }
.ex-section h4 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--text-3); margin: 18px 0 8px; }
.ex-opt { display: grid; grid-template-columns: 28px 1fr; gap: 10px; padding: 10px 0; border-bottom: 1px dashed var(--border); }
.ex-opt:last-child { border-bottom: 0; }
.ex-opt .letter { width: 24px; height: 24px; border-radius: 50%; display: grid; place-items: center; font-weight: 700; font-size: 12px; background: var(--surface-2); color: var(--text-2); }
.ex-opt.key .letter { background: var(--good); color: #fff; }
.ex-opt.chosen-wrong .letter { background: var(--bad); color: #fff; }
.ex-opt b { font-weight: 650; }
.ex-opt p { margin: 3px 0 0; color: var(--text-2); font-size: 14.5px; }
.takeaway { margin: 18px 0; padding: 14px 16px; border-radius: 12px; background: var(--info-soft); display: grid; grid-template-columns: 22px 1fr; gap: 10px; }
.takeaway svg { color: var(--info); margin-top: 2px; }
.takeaway b { display: block; font-size: 12px; text-transform: uppercase; letter-spacing: .06em; color: var(--info); margin-bottom: 2px; }
.sources { display: grid; gap: 6px; }
.source { display: flex; gap: 8px; align-items: baseline; font-size: 13.5px; }
.verify-strip { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin-top: 18px; padding: 12px 14px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface-2); }
.verify-strip .vs-title { font-weight: 650; font-size: 13px; margin-right: 4px; display: inline-flex; gap: 6px; align-items: center; }
.why-box { margin-top: 18px; padding: 16px; border-radius: 12px; border: 1px solid var(--border-strong); background: var(--surface); }
.why-box h4 { margin: 0 0 10px; font-size: 14px; text-transform: none; letter-spacing: 0; color: var(--text); }
.why-opts { display: flex; flex-wrap: wrap; gap: 8px; }
.why-opts button { border: 1px solid var(--border-strong); background: var(--surface); border-radius: 99px; padding: 7px 13px; font-size: 13px; font-weight: 600; cursor: pointer; color: var(--text-2); }
.why-opts button:hover { border-color: var(--accent); color: var(--text); }
.why-opts button.on { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.why-box .advice { margin-top: 12px; font-size: 13.5px; color: var(--text-2); }

/* results */
.results-head { display: grid; grid-template-columns: auto 1fr; gap: 24px; align-items: center; }
.big-score { width: 128px; height: 128px; }
.big-score > div { width: 104px; height: 104px; font-size: 28px; flex-direction: column; line-height: 1.1; }
.big-score > div small { font-size: 11px; color: var(--text-3); font-weight: 600; }
.rlist { display: grid; gap: 6px; }
.ritem { display: grid; grid-template-columns: 34px 28px minmax(0, 1fr) auto; gap: 10px; align-items: center; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--border); background: var(--surface); cursor: pointer; text-align: left; width: 100%; }
.ritem:hover { border-color: var(--border-strong); background: var(--surface-2); }
.ritem .n { font-weight: 700; color: var(--text-3); font-variant-numeric: tabular-nums; }
.ritem .st { width: 24px; height: 24px; border-radius: 50%; display: grid; place-items: center; color: #fff; font-size: 13px; font-weight: 800; }
.ritem .st.ok { background: var(--good); }
.ritem .st.no { background: var(--bad); }
.ritem .st.na { background: var(--text-3); }
.ritem .t { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 14px; }

/* ---------- performance ---------- */
.heat-wrap { overflow-x: auto; margin: 0 -4px; padding: 0 4px 4px; }
table.heat { border-collapse: separate; border-spacing: 3px; font-size: 12px; min-width: 860px; width: 100%; }
table.heat th { font-weight: 600; color: var(--text-2); text-align: left; padding: 4px 6px; }
table.heat thead th { writing-mode: vertical-rl; transform: rotate(180deg); text-align: left; vertical-align: bottom; height: 128px; white-space: nowrap; padding: 6px 2px; font-size: 11.5px; }
table.heat tbody th { white-space: nowrap; max-width: 210px; overflow: hidden; text-overflow: ellipsis; }
table.heat td { height: 40px; min-width: 52px; border-radius: 6px; text-align: center; font-weight: 650; font-variant-numeric: tabular-nums; cursor: pointer; position: relative; transition: transform .1s, box-shadow .1s; }
table.heat td:hover { transform: scale(1.06); box-shadow: 0 0 0 2px var(--text); z-index: 2; }
table.heat td.empty { background: repeating-linear-gradient(135deg, var(--surface-2), var(--surface-2) 4px, var(--surface) 4px, var(--surface) 8px); color: var(--text-3); font-weight: 500; }
table.heat td small { display: block; font-size: 10px; font-weight: 500; opacity: .85; }
table.heat td.sel { box-shadow: 0 0 0 2px var(--accent); }
.legend { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--text-3); flex-wrap: wrap; }
.legend .ramp { width: 160px; height: 10px; border-radius: 99px; background: linear-gradient(90deg, var(--div-lo), var(--div-mid), var(--div-hi)); }
.drill-panel { margin-top: 14px; padding: 14px 16px; border-radius: 12px; background: var(--surface-2); display: flex; align-items: center; gap: 12px; flex-wrap: wrap; animation: fadeUp .2s ease both; }
.chart { width: 100%; height: auto; display: block; overflow: visible; }
.chart text { fill: var(--text-3); font-size: 11px; font-family: var(--font); }
.chart .grid line { stroke: var(--border); stroke-width: 1; }
.chart .series { stroke: var(--series-1); stroke-width: 2; fill: none; }
.chart .area { fill: color-mix(in srgb, var(--series-1) 12%, transparent); }
.chart .pt { fill: var(--series-1); stroke: var(--surface); stroke-width: 2; }
.chart .target { stroke: var(--text-3); stroke-dasharray: 4 4; stroke-width: 1.2; }
.chart-tip { position: fixed; pointer-events: none; z-index: 90; background: var(--text); color: var(--bg); font-size: 12px; padding: 6px 9px; border-radius: 8px; box-shadow: var(--shadow-2); opacity: 0; transition: opacity .1s; white-space: nowrap; }
.bars { display: grid; gap: 10px; }
.bar-row { display: grid; grid-template-columns: minmax(120px, 210px) minmax(0, 1fr) 64px; gap: 12px; align-items: center; font-size: 13px; }
.bar-row .name { color: var(--text-2); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.bar-track { position: relative; height: 12px; border-radius: 99px; background: var(--surface-2); }
.bar-fill { position: absolute; left: 0; top: 0; bottom: 0; border-radius: 99px; background: var(--series-1); transition: width .6s cubic-bezier(.2, .8, .2, 1); }
.bar-band { position: absolute; top: -3px; bottom: -3px; border: 1.5px dashed var(--text-3); border-radius: 4px; }
.bar-row .v { text-align: right; font-weight: 650; font-variant-numeric: tabular-nums; }
.signal { display: grid; grid-template-columns: 26px 1fr auto; gap: 10px; align-items: start; padding: 10px 0; border-bottom: 1px solid var(--border); }
.signal:last-child { border-bottom: 0; }
.signal .ico { width: 24px; height: 24px; border-radius: 50%; display: grid; place-items: center; font-size: 13px; font-weight: 800; }
.signal .ico.good { background: var(--good-soft); color: var(--good); }
.signal .ico.warn { background: var(--warn-soft); color: var(--warn); }
.signal .ico.bad { background: var(--bad-soft); color: var(--bad); }
.signal b { font-size: 14px; }
.signal p { margin: 2px 0 0; font-size: 13px; color: var(--text-2); }
.readiness-badge { display: inline-flex; align-items: center; gap: 8px; padding: 6px 12px; border-radius: 99px; font-weight: 700; font-size: 13px; }
.err-row { display: grid; grid-template-columns: minmax(130px, 190px) minmax(0, 1fr) 40px; gap: 12px; align-items: center; padding: 6px 0; font-size: 13.5px; }
.advice-card { border: 1px solid var(--border); border-radius: 12px; padding: 14px 16px; background: var(--surface); }
.advice-card h3 { display: flex; align-items: center; gap: 8px; margin-bottom: 6px; }
.advice-card p, .advice-card li { font-size: 13.5px; color: var(--text-2); }
.advice-card ul { margin: 6px 0 0; padding-left: 18px; }
.timeline { display: grid; gap: 0; }
.tl-item { display: grid; grid-template-columns: 96px 18px 1fr; gap: 10px; align-items: start; padding-bottom: 14px; position: relative; }
.tl-item .date { font-size: 12.5px; color: var(--text-3); font-weight: 600; padding-top: 1px; font-variant-numeric: tabular-nums; }
.tl-item .dot { width: 12px; height: 12px; border-radius: 50%; border: 2px solid var(--accent); background: var(--surface); margin-top: 4px; position: relative; z-index: 1; }
.tl-item.done .dot { background: var(--accent); }
.tl-item::before { content: ""; position: absolute; left: 111px; top: 14px; bottom: 0; width: 2px; background: var(--border); }
.tl-item:last-child::before { display: none; }
.tl-item b { font-size: 14px; }
.tl-item p { margin: 2px 0 0; font-size: 13px; color: var(--text-2); }

/* ---------- review / flashcards ---------- */
.fc-stage { perspective: 1400px; max-width: 680px; margin: 0 auto; }
.fc { position: relative; min-height: 300px; transform-style: preserve-3d; transition: transform .5s cubic-bezier(.2, .8, .2, 1); cursor: pointer; }
.fc.flipped { transform: rotateY(180deg); }
.fc-face { position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden; border-radius: 18px; padding: 30px; background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow-2); display: flex; flex-direction: column; }
.fc-face.back { transform: rotateY(180deg); }
.fc-face .fc-label { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .08em; color: var(--accent); }
.fc-face .fc-text { font-family: var(--serif); font-size: 22px; line-height: 1.45; margin: auto 0; padding: 12px 0; }
.fc-face .fc-foot { font-size: 12px; color: var(--text-3); display: flex; justify-content: space-between; gap: 10px; flex-wrap: wrap; }
.grade-row { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; max-width: 680px; margin: 18px auto 0; }
.grade-row button { border: 1px solid var(--border-strong); background: var(--surface); border-radius: 12px; padding: 10px 6px; cursor: pointer; font-weight: 650; font-size: 14px; display: flex; flex-direction: column; align-items: center; gap: 2px; }
.grade-row button small { font-weight: 500; color: var(--text-3); font-size: 11.5px; }
.grade-row button:hover { border-color: var(--accent); }
.grade-row button.again { color: var(--bad); }
.grade-row button.good { color: var(--accent-strong); }
.deck-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.deck-table th, .deck-table td { text-align: left; padding: 9px 8px; border-bottom: 1px solid var(--border); vertical-align: top; }
.deck-table th { font-size: 12px; color: var(--text-3); font-weight: 600; text-transform: uppercase; letter-spacing: .04em; }

/* ---------- plan ---------- */
.plan-weeks { display: grid; gap: 10px; }
.week { border: 1px solid var(--border); border-radius: 12px; background: var(--surface); overflow: hidden; }
.week summary { list-style: none; display: grid; grid-template-columns: 90px minmax(0, 1fr) auto; gap: 12px; align-items: center; padding: 12px 14px; cursor: pointer; }
.week summary::-webkit-details-marker { display: none; }
.week summary .wk { font-weight: 700; font-size: 14px; }
.week summary .wk small { display: block; font-weight: 500; color: var(--text-3); font-size: 11.5px; }
.week.current { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.week .wk-body { padding: 0 14px 14px; }
.focus-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.days { display: grid; grid-template-columns: repeat(7, minmax(0, 1fr)); gap: 6px; }
.day { border: 1px solid var(--border); border-radius: 10px; padding: 8px; font-size: 12px; min-height: 76px; background: var(--surface-2); }
.day b { display: block; font-size: 12px; }
.day .q { font-size: 15px; font-weight: 700; font-variant-numeric: tabular-nums; }
.day.today { border-color: var(--accent); background: var(--accent-soft); }
.day.past { opacity: .6; }
.day.off { background: repeating-linear-gradient(135deg, var(--surface-2), var(--surface-2) 4px, var(--surface) 4px, var(--surface) 8px); }
.day.nbme { border-color: var(--info); }
.phase { font-size: 11px; font-weight: 700; padding: 3px 8px; border-radius: 99px; text-transform: uppercase; letter-spacing: .05em; }
.phase.p1 { background: var(--info-soft); color: var(--info); }
.phase.p2 { background: var(--accent-soft); color: var(--accent-strong); }
.phase.p3 { background: var(--warn-soft); color: var(--warn); }

/* ---------- quality lab ---------- */
.pipeline { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 0; position: relative; }
.pstep { position: relative; padding: 14px 12px; text-align: left; }
.pstep:not(:last-child)::after { content: ""; position: absolute; right: -7px; top: 34px; width: 14px; height: 14px; border-top: 2px solid var(--border-strong); border-right: 2px solid var(--border-strong); transform: rotate(45deg); z-index: 1; }
.pstep .pico { width: 40px; height: 40px; border-radius: 12px; background: var(--accent-soft); color: var(--accent-strong); display: grid; place-items: center; margin-bottom: 10px; }
.pstep .pico svg { width: 22px; height: 22px; }
.pstep b { display: block; font-size: 14px; margin-bottom: 4px; }
.pstep p { font-size: 12.5px; color: var(--text-2); margin: 0; }
.pstep .who { margin-top: 8px; display: flex; flex-wrap: wrap; gap: 4px; }
.qtable { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.qtable th, .qtable td { padding: 10px 8px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: middle; }
.qtable th { font-size: 11.5px; text-transform: uppercase; letter-spacing: .05em; color: var(--text-3); font-weight: 650; }
.qtable tr.clickable { cursor: pointer; }
.qtable tr.clickable:hover td { background: var(--surface-2); }
.badges { display: flex; gap: 4px; flex-wrap: wrap; }
.reject-card { border: 1px solid var(--border); border-left: 4px solid var(--bad); border-radius: 12px; padding: 16px; background: var(--surface); }
.reject-card + .reject-card { margin-top: 12px; }
.reject-card .stem-x { font-size: 14px; color: var(--text-2); margin: 8px 0; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.reject-card.open .stem-x { -webkit-line-clamp: unset; display: block; }
.reason { display: grid; grid-template-columns: auto 1fr; gap: 8px; align-items: start; font-size: 13.5px; padding: 6px 0; }
.mini-opts { display: grid; gap: 4px; margin: 8px 0; font-size: 13.5px; }
.mini-opts div { padding: 5px 10px; border-radius: 8px; background: var(--surface-2); }
.mini-opts div.k { background: var(--good-soft); color: var(--good); font-weight: 600; }
.mini-opts div.alt { background: var(--warn-soft); color: var(--warn); font-weight: 600; }
.audit { display: grid; gap: 14px; }
.audit-pass { border: 1px solid var(--border); border-radius: 12px; padding: 14px; }
.audit-pass h4 { font-size: 13.5px; margin-bottom: 8px; display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.checkgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 4px; }
.ck { font-size: 12px; padding: 4px 8px; border-radius: 6px; background: var(--surface-2); display: flex; gap: 6px; align-items: center; }
.ck.fail { background: var(--bad-soft); color: var(--bad); font-weight: 600; }
.ck.warn { background: var(--warn-soft); color: var(--warn); }
.ck.pass::before { content: "✓"; color: var(--good); font-weight: 800; }
.ck.fail::before { content: "✕"; font-weight: 800; }
.ck.warn::before { content: "!"; font-weight: 800; }
.solver-row { display: grid; grid-template-columns: 1fr auto; gap: 8px; font-size: 13px; padding: 6px 0; border-bottom: 1px dashed var(--border); }
.solver-row:last-child { border-bottom: 0; }
.vendor-bars .bar-fill { background: var(--good); }
.evidence { font-size: 13px; color: var(--text-2); }
.evidence li { margin-bottom: 6px; }

/* ---------- drawer / modal / toast ---------- */
.drawer { position: fixed; top: 0; right: 0; bottom: 0; width: min(440px, 100vw); background: var(--surface); border-left: 1px solid var(--border); box-shadow: var(--shadow-2); z-index: 70; transform: translateX(105%); transition: transform .28s cubic-bezier(.2, .8, .2, 1); display: flex; flex-direction: column; }
.drawer.open { transform: none; }
.drawer-head { display: flex; align-items: center; gap: 10px; padding: 14px 16px; border-bottom: 1px solid var(--border); }
.drawer-body { overflow-y: auto; padding: 8px 16px 24px; flex: 1; }
.lab-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.lab-table td { padding: 7px 4px; border-bottom: 1px solid var(--border); }
.lab-table td:last-child { text-align: right; font-variant-numeric: tabular-nums; color: var(--text-2); white-space: nowrap; }
.lab-table tr.grp td { font-weight: 700; color: var(--accent-strong); padding-top: 16px; border-bottom: 2px solid var(--border); font-size: 12px; text-transform: uppercase; letter-spacing: .05em; }
.modal-back { position: fixed; inset: 0; background: rgba(5, 10, 18, .5); z-index: 80; display: grid; place-items: center; padding: 16px; animation: fade .15s ease both; }
@keyframes fade { from { opacity: 0; } }
.modal { background: var(--surface); border-radius: 16px; border: 1px solid var(--border); box-shadow: var(--shadow-2); width: min(560px, 100%); max-height: 88vh; overflow: auto; padding: 22px; animation: fadeUp .2s ease both; }
.modal.wide { width: min(940px, 100%); }
.modal h2 { margin-bottom: 8px; }
.modal-actions { display: flex; gap: 8px; justify-content: flex-end; margin-top: 18px; flex-wrap: wrap; }
.radio-list { display: grid; gap: 6px; margin: 12px 0; }
.radio-list label { display: flex; gap: 10px; align-items: center; padding: 10px 12px; border: 1px solid var(--border); border-radius: 10px; cursor: pointer; font-size: 14px; }
.radio-list label:has(input:checked) { border-color: var(--accent); background: var(--accent-soft); }
.toast { position: fixed; left: 50%; bottom: 24px; transform: translate(-50%, 20px); background: var(--text); color: var(--bg); padding: 10px 16px; border-radius: 10px; font-size: 14px; font-weight: 500; opacity: 0; pointer-events: none; transition: all .2s; z-index: 100; box-shadow: var(--shadow-2); max-width: calc(100vw - 32px); }
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.empty-state { text-align: center; padding: 40px 20px; color: var(--text-2); }
.empty-state svg { width: 48px; height: 48px; color: var(--text-3); margin-bottom: 10px; }
.empty-state h3 { margin-bottom: 6px; }

/* ---------- responsive ---------- */
@media (max-width: 980px) {
  .mainnav { display: none; }
  .tabbar {
    display: grid; grid-template-columns: repeat(6, 1fr); position: fixed; left: 0; right: 0; bottom: 0; z-index: 45;
    background: color-mix(in srgb, var(--surface) 94%, transparent); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
    border-top: 1px solid var(--border); padding: 4px 4px calc(4px + env(safe-area-inset-bottom));
  }
  .tabbar a { position: relative; display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 6px 0; color: var(--text-3); font-size: 10.5px; font-weight: 600; text-decoration: none; border-radius: 10px; }
  .tabbar a svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
  .tabbar a.active { color: var(--accent); }
  .tabbar .dot { position: absolute; top: 4px; right: calc(50% - 16px); width: 8px; height: 8px; border-radius: 50%; background: var(--bad); }
  .page { padding: 20px 16px 110px; }
  .builder-grid { grid-template-columns: 1fr; }
  .summary-box { position: static; }
  .g4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .g3 { grid-template-columns: 1fr; }
  .pipeline { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pstep:not(:last-child)::after { display: none; }
}
@media (max-width: 720px) {
  .topbar { padding: 0 12px; gap: 10px; }
  h1 { font-size: 22px; }
  .hero { padding: 24px 18px; border-radius: 16px; }
  .hero h1 { font-size: 26px; }
  .hero p.lead { font-size: 15px; }
  .hero-facts { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .g2 { grid-template-columns: 1fr; }
  .span2 { grid-column: auto; }
  .card { padding: 16px; }
  .exam-body { grid-template-columns: 1fr; }
  .navgrid { display: none; }
  .navgrid.mobile-open { display: grid; grid-template-columns: repeat(auto-fill, minmax(46px, 1fr)); position: fixed; inset: 56px 0 auto 0; max-height: 50vh; z-index: 30; border-bottom: 1px solid var(--border); box-shadow: var(--shadow-2); padding: 12px; }
  .exam-content { padding: 18px 16px 30px; }
  .exam-top { gap: 6px; padding: 6px 10px; }
  .tool-btn .lbl { display: none; }
  .tool-btn { padding: 0 9px; }
  .opt .strike { opacity: 1; }
  .results-head { grid-template-columns: 1fr; justify-items: start; }
  .days { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .bar-row { grid-template-columns: minmax(90px, 120px) minmax(0, 1fr) 52px; }
  .err-row { grid-template-columns: minmax(100px, 130px) minmax(0, 1fr) 34px; }
  .pipeline { grid-template-columns: 1fr; }
  .fc-face .fc-text { font-size: 19px; }
  .week summary { grid-template-columns: 70px minmax(0, 1fr); }
  .week summary > :last-child { grid-column: 1 / -1; }
  .ritem { grid-template-columns: 26px 24px minmax(0, 1fr); }
  .ritem > :last-child { display: none; }
  .qtable .hide-sm { display: none; }
  .tl-item { grid-template-columns: 74px 18px 1fr; }
  .tl-item::before { left: 89px; }
}
.mobile-only { display: none; }
@media (max-width: 720px) { .mobile-only { display: inline-flex; } .desktop-only { display: none !important; } }
[hidden] { display: none !important; }
.grid > .card + .card { margin-top: 0; }
.lab-table tr.grp td { text-align: left; }
.stem p { margin: 0 0 12px; }
.stem p:last-child { margin-bottom: 0; }
.stem-labs { border-collapse: collapse; margin: 4px 0 14px; font-size: calc(var(--stem-size) - 1px); min-width: min(420px, 100%); }
.stem-labs td { padding: 4px 18px 4px 0; border-bottom: 1px solid var(--border); vertical-align: top; }
.stem-labs td:first-child { color: var(--text-2); }
.stem-labs td:last-child { font-variant-numeric: tabular-nums; font-weight: 500; }
.deck-table td.num { white-space: nowrap; }
.qtable td.num { white-space: nowrap; }
.exam, .exam-body, .exam-main { max-width: 100vw; }
.exam-main { overflow-x: hidden; }
.qpos { white-space: nowrap; }
@media (max-width: 720px) {
  .exam-top .mode-chip { display: none; }
  .exam-top { gap: 5px; }
  .exam-top .qpos { font-size: 14px; }
  .timer { font-size: 15px; padding: 7px 9px; gap: 5px; }
  .tool-btn { height: 36px; padding: 0 8px; }
  .exam-top .btn.sm { padding: 0 10px; }
  .stem-labs { min-width: 0; width: 100%; }
}
table.heat tbody th { position: sticky; left: 0; background: var(--surface); z-index: 3; }
@media (max-width: 720px) {
  .signal { grid-template-columns: 26px 1fr; }
  .signal > :last-child { grid-column: 2; text-align: left !important; }
  .reason { grid-template-columns: 1fr; gap: 4px; }
  .reason .chip { justify-self: start; }
  table.heat tbody th { max-width: 120px; font-size: 11px; }
}
.pstep .chip { white-space: normal; }