/* Workspace-style UI: fixed sidebar, breadcrumb header, one white panel on a grey board. */
:root {
  --ink: #202020;
  --text2: #646464;
  --muted: #838383;
  --faint: #cecece;
  --paper: #f9f9f9;
  --panel: #ffffff;
  --bg2: #f0f0f0;
  --hover: #f7f7f7;
  --line: #e0e0e0;
  --line-soft: #e8e8e8;
  --line-subtle: #f0f0f0;
  --strong: #cecece;
  --good: #218358;
  --good-bg: #e6f6eb;
  --good-line: #8eceaa;
  --bad: #ca244d;
  --bad-bg: #feeaed;
  --bad-line: #efacb8;
  --warn: #ab6400;
  --warn-bg: #fff7c2;
  --warn-line: #e9c162;
  --info: #0d74ce;
  --info-bg: #e6f4fe;
  --mark-bg: #ffefd6;
  --mark: #cc4e00;
  --primary-bg: #202020;
  --primary-fg: #ffffff;
  --side: 244px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #ececec;
    --text2: #b4b4b4;
    --muted: #8f8f8f;
    --faint: #4a4a4a;
    --paper: #111111;
    --panel: #191919;
    --bg2: #232323;
    --hover: #202020;
    --line: #2e2e2e;
    --line-soft: #262626;
    --line-subtle: #222222;
    --strong: #444444;
    --good: #4cc38a;
    --good-bg: #132d21;
    --good-line: #1f5c3c;
    --bad: #ff8fa6;
    --bad-bg: #3b1219;
    --bad-line: #6e2335;
    --warn: #f1c35e;
    --warn-bg: #2e2510;
    --warn-line: #5c4815;
    --info: #70b8ff;
    --info-bg: #0d2847;
    --mark-bg: #3a2410;
    --mark: #ff9d4d;
    --primary-bg: #ececec;
    --primary-fg: #111111;
    color-scheme: dark;
  }
}

/* manual dark choice from the theme switcher (same tokens as above) */
:root[data-theme="dark"] {
  --ink: #ececec; --text2: #b4b4b4; --muted: #8f8f8f; --faint: #4a4a4a;
  --paper: #111111; --panel: #191919; --bg2: #232323; --hover: #202020;
  --line: #2e2e2e; --line-soft: #262626; --line-subtle: #222222; --strong: #444444;
  --good: #4cc38a; --good-bg: #132d21; --good-line: #1f5c3c;
  --bad: #ff8fa6; --bad-bg: #3b1219; --bad-line: #6e2335;
  --warn: #f1c35e; --warn-bg: #2e2510; --warn-line: #5c4815;
  --info: #70b8ff; --info-bg: #0d2847; --mark-bg: #3a2410; --mark: #ff9d4d;
  --primary-bg: #ececec; --primary-fg: #111111;
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 14px/1.55 "FT Polar", "Figtree", Arial, sans-serif;
}
.btn.icon-only { width: 30px; padding: 0; }
.btn.icon-only .icon { color: var(--text2); }
a { color: inherit; }
.icon { width: 16px; height: 16px; flex: 0 0 auto; }
.icon.sm { width: 12px; height: 12px; }

/* ---------- header ---------- */
header {
  height: 64px; margin-left: var(--side); padding: 0 24px 0 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 20px;
}
.breadcrumbs { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: 13px; min-width: 0; }
.breadcrumbs strong { color: var(--ink); font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.header-meta { display: flex; align-items: center; gap: 14px; }
.exam-date, .timer { font-size: 13px; color: var(--text2); font-variant-numeric: tabular-nums; white-space: nowrap; }
.mobile-brand { display: none; }
.sync-ok { color: var(--good); }
.sync-error { color: var(--bad); }

/* ---------- shell ---------- */
.shell { margin-left: var(--side); padding: 0 10px 10px 0; }
.shell > main {
  height: calc(100dvh - 74px); overflow: auto; background: var(--panel);
  border: 1px solid var(--line-soft); border-radius: 16px; scrollbar-width: thin;
  padding: 48px 64px 80px;
}
.shell > main > * { max-width: 720px; margin-left: auto; margin-right: auto; }
.shell > aside {
  position: fixed; inset: 0 auto 0 0; width: var(--side); padding: 18px 12px 12px;
  display: flex; flex-direction: column; overflow: auto; scrollbar-width: thin;
}
.workspace { display: flex; align-items: center; gap: 10px; min-height: 31px; margin: 2px 6px 28px; font-size: 14px; font-weight: 600; }
.workspace-mark { display: inline-flex; align-items: center; justify-content: center; width: 28px; height: 28px; background: var(--mark-bg); border-radius: 8px; }
.workspace-mark .icon { color: var(--mark); width: 18px; height: 18px; }

.tabs { display: flex; flex-direction: column; gap: 3px; }
.side-link {
  display: flex; align-items: center; gap: 10px; height: 36px; padding: 0 10px;
  color: var(--text2); border-radius: 7px; text-decoration: none; white-space: nowrap; font-size: 14px;
}
.side-link .icon { color: var(--muted); }
.side-link:hover { background: var(--hover); }
.side-link.active { background: var(--bg2); color: var(--ink); }
.side-link.active .icon { color: var(--ink); }
.side-link .count { margin-left: auto; font-size: 11px; color: var(--muted); }
.side-link .count.hot { color: var(--bad); font-weight: 600; }

.sidebar-label { font-size: 11px; color: var(--muted); margin: 30px 10px 10px; letter-spacing: .01em; }
.week { display: flex; align-items: center; gap: 10px; width: 100%; padding: 9px 10px; margin-bottom: 2px; border-radius: 8px; color: var(--text2); text-decoration: none; }
.week:hover { background: var(--bg2); }
.week.active { background: var(--bg2); color: var(--ink); }
.week strong { font-size: 12px; font-weight: 500; display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 150px; }
.week small { display: block; font-size: 11px; color: var(--muted); margin-top: 1px; }
.day-icon {
  width: 25px; height: 25px; flex: 0 0 auto; display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--line); border-radius: 7px; background: var(--panel); font-size: 11px; color: var(--muted);
}
.week.mock .day-icon { border-color: var(--warn-line); background: var(--warn-bg); color: var(--warn); }
.side-progress { padding: 14px 10px 12px; border-top: 1px solid var(--line); margin-top: auto; }
.side-progress strong { font-size: 12px; font-weight: 500; }
.side-progress .small { font-size: 11px; line-height: 1.8; color: var(--muted); }

.mobile-view-nav { display: none; }

/* ---------- typography & blocks ---------- */
h1 { font-size: 30px; line-height: 1.2; letter-spacing: -.02em; font-weight: 600; margin: 0 0 14px; }
h2 { font-size: 17px; font-weight: 600; margin: 0 0 16px; }
h3 { font-size: 15px; font-weight: 600; margin: 20px 0 8px; }
p { margin: 0 0 12px; }
.muted { color: var(--muted); }
.small { font-size: 12px; }
.hot { color: var(--bad); font-weight: 600; }
.eyebrow { font-size: 12px; color: var(--muted); margin-bottom: 10px; }
code { background: var(--bg2); padding: 1px 5px; border-radius: 5px; font-size: .92em; }
pre { background: var(--paper); border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; overflow-x: auto; font-size: 13px; line-height: 1.5; }
pre code { background: none; padding: 0; }

.card { padding: 36px 0 32px; border-top: 1px solid var(--line-subtle); }
.card:first-child, .banner + .card, .sessionbar + .card, .sessionbar + .banner + .card { border-top: 0; padding-top: 0; }
.hero p { color: var(--text2); font-size: 15px; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0; }
.chip { border: 1px solid var(--line); border-radius: 999px; padding: 5px 11px; font-size: 12px; color: var(--text2); }
.chip.hot { background: var(--bad-bg); border-color: var(--bad-line); color: var(--bad); }

.actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-top: 28px; }
button, .button {
  font: inherit; border: 1px solid var(--line); border-radius: 999px; min-height: 36px;
  padding: 8px 16px; font-size: 13px; background: var(--panel); display: inline-flex;
  align-items: center; justify-content: center; gap: 7px; color: var(--ink); cursor: pointer;
  text-decoration: none; transition: background .1s ease-out;
}
button:hover, .button:hover { background: var(--hover); border-color: var(--strong); }
button.primary { background: var(--primary-bg); border-color: var(--primary-bg); color: var(--primary-fg); }
button.primary:hover { background: var(--text2); border-color: var(--text2); }
button:disabled { opacity: .45; cursor: default; }
button.link { border: 0; background: none; padding: 0; min-height: 0; color: var(--text2); text-decoration: underline; }
.btn.outline { height: 30px; min-height: 30px; padding: 0 12px; }

.banner { background: var(--info-bg); color: var(--ink); border-radius: 12px; padding: 12px 16px; margin: 0 0 24px; font-size: 13.5px; line-height: 1.6; }
.banner.warn { background: var(--warn-bg); border: 1px solid var(--warn-line); }

.flow { margin: 0; padding-left: 22px; color: var(--text2); font-size: 14.5px; line-height: 1.6; }
.flow li { margin: 10px 0; padding-left: 4px; }
.flow b { color: var(--ink); font-weight: 500; }

/* ---------- question ---------- */
.sessionbar {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 32px;
}
.sessionbar span { border: 1px solid var(--line); border-radius: 999px; padding: 5px 11px; font-size: 12px; color: var(--text2); }
.sessionbar .link { margin-left: auto; font-size: 12px; }
.q .meta {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center; justify-content: space-between;
  font-size: 12px; color: var(--muted); margin: 4px 0 26px;
}
.stem { font-size: 16px; line-height: 1.7; }
.stem p:first-child { margin-top: 0; }
.stem table, .prose table { border-collapse: collapse; margin: 10px 0; font-size: 13px; display: block; overflow-x: auto; }
.stem th, .stem td, .prose th, .prose td { border: 1px solid var(--line); padding: 5px 10px; text-align: left; }
.figure { margin: 22px 0; color: var(--ink); }
.figure svg { display: block; width: 100%; max-width: 360px; max-height: 280px; height: auto; }
.otext svg { display: block; width: 100%; max-width: 140px; max-height: 120px; height: auto; }

.opts { margin: 26px 0 10px; }
.opt {
  display: flex; align-items: center; gap: 14px; width: 100%; min-height: 57px; padding: 14px 17px;
  border: 1px solid var(--line); border-radius: 12px; background: var(--panel); margin: 12px 0;
  font-size: 15px; line-height: 1.65; cursor: pointer; transition: background .12s, border-color .12s;
}
.opt:hover { background: var(--hover); border-color: var(--strong); }
.opt input { position: absolute; opacity: 0; pointer-events: none; }
.opt .key {
  display: flex; align-items: center; justify-content: center; flex: 0 0 auto; width: 25px; height: 25px;
  border: 1px solid var(--line); border-radius: 7px; font-size: 11px; color: var(--muted); background: var(--panel);
}
.opt.msq .key { border-radius: 7px; }
.opt:has(input:checked) { border-color: var(--text2); background: var(--hover); }
.opt:has(input:checked) .key { background: var(--ink); color: var(--panel); border-color: var(--ink); }
.opt .otext { flex: 1; min-width: 0; overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.opt.right, .opt.right:has(input:checked) { border-color: var(--good-line); background: var(--good-bg); }
.opt.wrong, .opt.wrong:has(input:checked) { border-color: var(--bad-line); background: var(--bad-bg); }
.opt.right .key, .opt.right:has(input:checked) .key { background: var(--good); border-color: var(--good); color: #fff; }
.opt.wrong .key, .opt.wrong:has(input:checked) .key { background: var(--bad); border-color: var(--bad); color: #fff; }
.opt.plain { opacity: .7; }
.otext .katex, .stem .katex { font-size: 1.12em; }

.nat { display: flex; align-items: center; gap: 12px; font-size: 14px; margin: 26px 0 10px; }
.nat input {
  font: inherit; font-size: 15px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 11px;
  width: 240px; max-width: 100%; background: var(--panel); color: var(--ink);
}
.hint { font-size: 12px; color: var(--muted); margin: 4px 0; }
.conf { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 26px 0 10px; font-size: 12.5px; color: var(--muted); }
.conf label { display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 999px; padding: 7px 14px; cursor: pointer; color: var(--text2); margin: 0; }
.conf label input { display: none; }
.conf label:has(input:checked) { background: var(--primary-bg); color: var(--primary-fg); border-color: var(--primary-bg); }
.err { color: var(--bad); font-size: 12px; min-height: 1.3em; margin: 6px 0; }

.verdict { font-weight: 600; font-size: 17px; margin: 32px 0 14px; padding-top: 24px; border-top: 1px solid var(--line-subtle); }
.verdict.ok { color: var(--good); }
.verdict.no { color: var(--bad); }
.why { padding: 12px 16px; border-radius: 12px; margin: 10px 0; font-size: 14px; line-height: 1.6; border: 1px solid var(--line); }
.why.good { background: var(--good-bg); border-color: var(--good-line); }
.why.bad { background: var(--bad-bg); border-color: var(--bad-line); }
details { margin: 18px 0; }
summary { cursor: pointer; font-weight: 500; font-size: 14px; padding: 4px 0; }
.sol { padding: 10px 0 0; font-size: 15px; line-height: 1.65; }

/* ---------- stats, tables, forms ---------- */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 12px; margin: 20px 0 24px; }
.stats div { border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; }
.stats b { display: block; font-size: 24px; font-weight: 600; letter-spacing: -.01em; margin-bottom: 2px; }
.stats span { font-size: 11px; color: var(--muted); }

form label { display: block; font-size: 12.5px; color: var(--text2); margin: 14px 0; }
form input:not([type=radio]):not([type=checkbox]), form select, form textarea {
  display: block; width: 100%; margin-top: 6px; font: inherit; font-size: 14px; padding: 10px 12px;
  border: 1px solid var(--line); border-radius: 9px; background: var(--panel); color: var(--ink);
}
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 18px; }
.span2 { grid-column: 1 / -1; }

.tbl { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.tbl th, .tbl td { text-align: left; padding: 12px 10px; border-bottom: 1px solid var(--line-subtle); vertical-align: top; }
.tbl th { font-size: 11px; color: var(--muted); font-weight: 500; }
.tbl tr.due td:first-child { box-shadow: inset 2px 0 0 var(--bad); padding-left: 10px; }
section.card { overflow-x: auto; }

.minibar { display: inline-block; width: 80px; height: 6px; background: var(--bg2); border-radius: 4px; overflow: hidden; vertical-align: middle; margin-right: 6px; }
.minibar div { height: 100%; background: var(--ink); }
.bar { height: 6px; background: var(--bg2); border-radius: 4px; overflow: hidden; margin: 14px 0; }
.bar div { height: 100%; background: var(--ink); }
.countdown { margin-bottom: 18px; }
.countdown b { font-size: 44px; font-weight: 600; line-height: 1; letter-spacing: -.03em; margin-right: 10px; }
.countdown span { color: var(--muted); font-size: 14px; }

.t72.ok { color: var(--good); }
.t72.near { color: var(--warn); }
.t72.far { color: var(--bad); }
.t72bar, .t72mini { position: relative; overflow: visible; }
.t72bar i, .t72mini i { position: absolute; top: -4px; bottom: -4px; width: 2px; background: var(--bad); border-radius: 1px; }
.chart { width: 100%; height: auto; }
.cbar { fill: var(--faint); }
.cline { fill: none; stroke: var(--ink); stroke-width: 2; }
.cdot { fill: var(--ink); }
.cgrid { stroke: var(--line); stroke-dasharray: 3 3; }
.clabel { font-size: 10px; fill: var(--muted); }

.links { padding-left: 20px; font-size: 14.5px; }
.links li { margin: 10px 0; line-height: 1.5; }
.links a { text-decoration: none; font-weight: 500; }
.links a:hover { text-decoration: underline; }
.prose { font-size: 15px; line-height: 1.7; }
.prose h1 { font-size: 26px; }
.prose h2 { margin-top: 34px; }
.prose li { margin: 6px 0; }
.recall { border-top: 1px solid var(--line-subtle); padding-top: 2px; }
.recall h3 a { text-decoration: none; }
.recall { padding: 4px 0 6px; }
.recall ul { margin: 6px 0 14px; padding-left: 22px; font-size: 14px; }
.recall li { margin: 5px 0; }
.katex-display { overflow-x: auto; overflow-y: hidden; }

/* ---------- mobile ---------- */
@media (max-width: 860px) {
  header { margin-left: 0; height: 54px; padding: 0 16px; }
  .breadcrumbs { display: none; }
  .mobile-brand { display: flex; align-items: center; gap: 8px; font-weight: 600; font-size: 14px; }
  .mobile-brand .workspace-mark { width: 26px; height: 26px; }
  .shell { margin-left: 0; padding: 0 0 64px; }
  .shell > aside { display: none; }
  .shell > main { height: auto; min-height: calc(100dvh - 118px); border-radius: 16px 16px 0 0; border-bottom: 0; padding: 24px 16px 40px; }
  .exam-date { display: none; }
  h1 { font-size: 24px; }
  .grid2 { grid-template-columns: 1fr; }
  .mobile-view-nav {
    display: flex; position: fixed; left: 0; right: 0; bottom: 0; z-index: 10; height: 60px;
    background: var(--panel); border-top: 1px solid var(--line); justify-content: space-around; align-items: center;
    padding-bottom: env(safe-area-inset-bottom);
  }
  .mobile-view-nav a { display: flex; flex-direction: column; align-items: center; gap: 2px; font-size: 10px; color: var(--muted); text-decoration: none; padding: 6px 4px; }
  .mobile-view-nav a.active { color: var(--ink); }
  .mobile-view-nav .icon { width: 20px; height: 20px; }
  .opt { padding: 12px 13px; gap: 11px; }
}