:root {
  --bg: #f6f5f1; --card: #ffffff; --ink: #1d2320; --muted: #5d665f; --line: #d9d8d0;
  --accent: #1a4fa0; --accent-ink: #ffffff;
  --none-bg: #ecebe4; --none-fg: #5d665f;
  --learn-bg: #f6dcc4; --learn-fg: #9a4d1a;
  --solid-bg: #d6e8d8; --solid-fg: #2c5f36;
  --review-bg: #e2dbf3; --review-fg: #50407f;
  --good-bg: #d6e8d8; --good-fg: #2c5f36; --bad-bg: #f5d5d0; --bad-fg: #8a2a1f;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #151816; --card: #1f2321; --ink: #ecefea; --muted: #a2aaa4; --line: #343a36;
    --accent: #3d85f2; --accent-ink: #ffffff;
    --none-bg: #2b302d; --none-fg: #a2aaa4;
    --learn-bg: #4a3220; --learn-fg: #f1b98a;
    --solid-bg: #1f3d26; --solid-fg: #9fd7a8;
    --review-bg: #32294d; --review-fg: #c5b6ee;
    --good-bg: #1f3d26; --good-fg: #9fd7a8; --bad-bg: #4a2420; --bad-fg: #f2aaa0;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.5 system-ui, -apple-system, Segoe UI, Roboto, sans-serif; }
.wrap { max-width: 780px; margin: 0 auto; padding: calc(12px + env(safe-area-inset-top)) 16px 48px; }
button, a, summary { -webkit-tap-highlight-color: transparent; touch-action: manipulation; }
h1 { font-size: 1.3rem; margin: 6px 0 2px; }
h2 { font-size: 1.15rem; margin: 18px 0 8px; }
h3 { font-size: 1rem; margin: 16px 0 6px; }
a { color: var(--accent); }
.sub { color: var(--muted); font-size: .9rem; margin-bottom: 10px; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }

nav.tabs { display: flex; gap: 4px; overflow-x: auto; margin: 4px 0 14px; border-bottom: 1px solid var(--line); }
nav.tabs a { padding: 10px 14px; text-decoration: none; color: var(--muted); font-weight: 600; white-space: nowrap; border-bottom: 3px solid transparent; }
nav.tabs a.on { color: var(--accent); border-bottom-color: var(--accent); }

.card { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 14px; margin-bottom: 12px; }
.card h2, .card h3 { margin-top: 0; }
.row { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; }
.grow { flex: 1 1 220px; }

button, select, input[type=text], input[type=search], textarea { font: inherit; color: var(--ink); background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; }
button, a.btn { cursor: pointer; min-height: 44px; }
a.btn { display: inline-flex; align-items: center; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 8px 14px; font-weight: 600; }
button:hover, a.btn:hover { border-color: var(--accent); }
.primary { background: var(--accent) !important; color: var(--accent-ink) !important; border-color: var(--accent) !important; font-weight: 600; }
button:disabled { opacity: .45; cursor: default; }
input[type=text] { flex: 1; min-width: 140px; }
.tools { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }

.bar { height: 10px; background: var(--none-bg); border-radius: 6px; overflow: hidden; display: flex; }
.bar span { display: block; height: 100%; }
.b-solid { background: var(--solid-fg); } .b-review { background: var(--review-fg); } .b-learn { background: var(--learn-fg); } .b-acc { background: var(--accent); }
.stats { display: flex; flex-wrap: wrap; gap: 6px 14px; font-size: .85rem; color: var(--muted); margin: 8px 0 4px; }

details.cat { background: var(--card); border: 1px solid var(--line); border-radius: 10px; margin-bottom: 10px; }
details.cat > summary { cursor: pointer; padding: 14px; min-height: 48px; font-weight: 600; list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 10px; }
details.cat > summary span:last-child { flex: none; white-space: nowrap; }
details.cat > summary::-webkit-details-marker { display: none; }
.topic { border-top: 1px solid var(--line); padding: 10px 14px; }
.tname { flex: 1 1 240px; font-weight: 500; }
.tname a { color: var(--ink); text-decoration: none; }
.tname a:hover { text-decoration: underline; }
.lvl { font-size: .85rem; border-radius: 8px; padding: 6px 10px; border: 1px solid transparent; font-weight: 600; min-height: 44px; min-width: 96px; }
.lvl.none { background: var(--none-bg); color: var(--none-fg); }
.lvl.learning { background: var(--learn-bg); color: var(--learn-fg); }
.lvl.solid { background: var(--solid-bg); color: var(--solid-fg); }
.lvl.review { background: var(--review-bg); color: var(--review-fg); }
.note { width: 100%; margin-top: 8px; font-size: .9rem; resize: vertical; min-height: 40px; background: var(--bg); }
.domfoot { border-top: 1px solid var(--line); padding: 10px 14px; }

.lesson p { margin: 0 0 12px; }
.lesson ul { margin: 0 0 12px; padding-left: 22px; }
.lesson li { margin-bottom: 4px; }
.lesson .formula { font-family: ui-monospace, Menlo, Consolas, monospace; background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin: 0 0 12px; overflow-x: auto; white-space: pre-wrap; }
.lesson .callout { border-left: 4px solid var(--accent); background: var(--bg); padding: 10px 12px; margin: 0 0 12px; border-radius: 0 8px 8px 0; }
dl.terms { margin: 0; }
dl.terms dt { font-weight: 700; margin-top: 8px; }
dl.terms dd { margin: 2px 0 0; }

.qmeta { display: flex; justify-content: space-between; color: var(--muted); font-size: .9rem; margin-bottom: 8px; }
.qtext { font-size: 1.1rem; font-weight: 600; margin: 0 0 14px; }
.choice { display: block; width: 100%; text-align: left; margin-bottom: 10px; padding: 14px; min-height: 52px; line-height: 1.35; }
.choice.sel { border-color: var(--accent); outline: 2px solid var(--accent); }
.choice:disabled { opacity: 1; cursor: default; }
.choice:disabled:not(.right):not(.wrong) { opacity: .6; }
.choice.right { background: var(--good-bg); color: var(--good-fg); border-color: var(--good-fg); }
.choice.wrong { background: var(--bad-bg); color: var(--bad-fg); border-color: var(--bad-fg); }
.explain { background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin: 10px 0; }
.badge { display: inline-block; border-radius: 6px; padding: 2px 8px; font-size: .8rem; font-weight: 700; }
.badge.pass { background: var(--good-bg); color: var(--good-fg); }
.badge.fail { background: var(--bad-bg); color: var(--bad-fg); }
.score { font-size: 2rem; font-weight: 800; margin: 4px 0; }
.missed { border-top: 1px solid var(--line); padding: 10px 0; }
.missed:first-of-type { border-top: 0; }
table { width: 100%; border-collapse: collapse; font-size: .9rem; }
th, td { text-align: left; padding: 6px 8px; border-bottom: 1px solid var(--line); }
th { color: var(--muted); font-weight: 600; }
#msg { font-size: .85rem; color: var(--accent); min-height: 1.2em; }
.hint { font-size: .8rem; color: var(--muted); margin-top: 16px; }

.code { font-family: ui-monospace, Menlo, Consolas, monospace; background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin: 0 0 12px; white-space: pre-wrap; word-break: break-word; font-size: .95rem; }

.link { padding: 8px 0; border-top: 1px solid var(--line); }
.link:first-of-type { border-top: 0; }
.link a { font-weight: 600; }

.srcs { margin: 4px 0 8px; padding-left: 20px; font-size: .9rem; }
.unver { border-left: 4px solid var(--learn-fg); background: var(--bg); padding: 8px 12px; border-radius: 0 8px 8px 0; font-size: .9rem; }

/* ---- Verification badge ---- */
.vbadge { display: block; width: 100%; text-align: left; margin: 4px 0 10px; padding: 10px 12px; border-radius: 8px; border: 1px solid var(--line); font-size: .9rem; line-height: 1.35; }
.vbadge.vok { background: var(--good-bg); color: var(--good-fg); border-color: var(--good-fg); }
.vbadge.vpart { background: var(--review-bg); color: var(--review-fg); border-color: var(--review-fg); }
.vbadge.vsingle { background: var(--learn-bg); color: var(--learn-fg); border-color: var(--learn-fg); }
.vbadge.vnone { background: var(--bad-bg); color: var(--bad-fg); border-color: var(--bad-fg); }
.vchip { display: inline-block; font-size: .72rem; font-weight: 700; border-radius: 5px; padding: 1px 6px; vertical-align: middle; white-space: nowrap; }
.vchip.vok { background: var(--good-bg); color: var(--good-fg); }
.vchip.vpart { background: var(--review-bg); color: var(--review-fg); }
.vchip.vsingle { background: var(--learn-bg); color: var(--learn-fg); }
.vchip.vnone { background: var(--bad-bg); color: var(--bad-fg); }

/* ---- Search ---- */
.searchbar { display: flex; gap: 8px; margin: 0 0 12px; }
.searchbar input { flex: 1; min-width: 0; min-height: 44px; font-size: 16px; }
.hit { padding: 10px 0; border-top: 1px solid var(--line); }
.card .hit:first-of-type { border-top: 0; }
.hq { font-weight: 700; margin-bottom: 2px; }
mark { background: var(--learn-bg); color: var(--learn-fg); border-radius: 3px; padding: 0 2px; }

/* ---- Dashboard ---- */
a.dom { display: block; text-decoration: none; color: var(--ink); padding: 10px 0; border-top: 1px solid var(--line); }
.card h2 + a.dom { border-top: 0; }
.dom-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 10px; margin-bottom: 6px; }
.dom-name { font-weight: 600; }
.dom-acc { flex: none; font-weight: 700; font-size: .9rem; border-radius: 6px; padding: 1px 8px; background: var(--none-bg); color: var(--none-fg); }
.dom-acc.ok { background: var(--good-bg); color: var(--good-fg); }
.dom-acc.mid { background: var(--learn-bg); color: var(--learn-fg); }
.dom-acc.low { background: var(--bad-bg); color: var(--bad-fg); }
.dom-meta { display: flex; flex-wrap: wrap; gap: 2px 14px; font-size: .8rem; color: var(--muted); margin-top: 6px; }

/* ---- Responsive: phone bottom bar, desktop topic sidebar ---- */
.split { display: block; }
.toc { display: none; }
.dot { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 8px; flex: none; background: var(--none-fg); opacity: .45; }
.dot.learning { background: var(--learn-fg); opacity: 1; }
.dot.solid { background: var(--solid-fg); opacity: 1; }
.dot.review { background: var(--review-fg); opacity: 1; }

@media (max-width: 640px) {
  .wrap { padding-bottom: calc(92px + env(safe-area-inset-bottom)); }
  .actions .btn, .actions button { flex: 1 1 140px; justify-content: center; }
  nav.tabs { position: fixed; left: 0; right: 0; bottom: 0; margin: 0; gap: 0; overflow: visible; justify-content: space-around;
    background: var(--card); border-top: 1px solid var(--line); border-bottom: none; z-index: 20; padding-bottom: env(safe-area-inset-bottom); }
  nav.tabs a { flex: 1 1 0; text-align: center; padding: 16px 2px; font-size: .8rem; border-bottom: none; border-top: 3px solid transparent; }
  nav.tabs a.on { border-top-color: var(--accent); }
}

@media (min-width: 1000px) {
  .wrap.wide { max-width: 1180px; }
  .wrap.wide .split { display: grid; grid-template-columns: 290px minmax(0, 1fr); gap: 28px; align-items: start; }
  .wrap.wide .main { max-width: 780px; }
  .toc { display: block; position: sticky; top: 12px; max-height: calc(100vh - 24px); overflow-y: auto; font-size: .88rem;
    background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 6px 4px; }
  .toc details { border-bottom: 1px solid var(--line); }
  .toc details:last-child { border-bottom: none; }
  .toc summary { cursor: pointer; padding: 8px 10px; font-weight: 600; }
  .toc a { display: flex; align-items: center; padding: 5px 10px 5px 14px; text-decoration: none; color: var(--ink); border-radius: 6px; }
  .toc a:hover { background: var(--none-bg); }
  .toc a.cur { background: var(--accent); color: var(--accent-ink); font-weight: 600; }
  .toc a.cur .dot { background: var(--accent-ink); opacity: 1; }
}