* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #f7f5f0; --card: #ffffff; --ink: #2b2b2b; --muted: #8a8578;
  --primary: #d94f30; --primary-soft: #fdeee9; --green: #2e9e5b; --green-soft: #e8f6ee;
  --red: #d93025; --red-soft: #fdecea; --amber: #b8860b; --line: #e8e3d8;
}
body { font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--ink); line-height: 1.7; }

.topbar { background: var(--card); border-bottom: 1px solid var(--line); padding: 10px 20px; display: flex; align-items: center; gap: 24px; flex-wrap: wrap; position: sticky; top: 0; z-index: 10; }
.brand { font-weight: 700; font-size: 18px; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.tab { border: none; background: none; padding: 8px 14px; border-radius: 20px; cursor: pointer; font-size: 14px; color: var(--muted); }
.tab.active { background: var(--primary); color: #fff; font-weight: 600; }
.badge { background: var(--red); color: #fff; border-radius: 10px; padding: 0 6px; font-size: 11px; display: none; }
.badge.show { display: inline-block; }

main { max-width: 860px; margin: 0 auto; padding: 20px 16px 60px; }
.page { display: none; }
.page.active { display: block; }

.hero { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 28px; text-align: center; margin-bottom: 16px; }
.hero h2 { margin-bottom: 6px; }
.hero-stats { display: flex; justify-content: center; gap: 28px; margin: 18px 0; }
.hero-stats .stat b { font-size: 24px; color: var(--primary); display: block; }
.hero-stats .stat span { font-size: 12px; color: var(--muted); }

.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 20px; margin-bottom: 16px; }
.card h3 { margin-bottom: 10px; font-size: 16px; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 700px) { .grid2 { grid-template-columns: 1fr; } }

.btn { border: 1px solid var(--line); background: var(--card); border-radius: 10px; padding: 10px 20px; cursor: pointer; font-size: 15px; }
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }
.btn.big { font-size: 17px; padding: 14px 40px; }
.btn.small { font-size: 13px; padding: 6px 12px; }
.btn.danger { color: var(--red); border-color: var(--red); }
.btn:disabled { opacity: .45; cursor: default; }

.muted { color: var(--muted); }
.small { font-size: 13px; }

/* 科目切换 */
.subj-switch { display: flex; justify-content: center; gap: 10px; margin-bottom: 14px; }
.subj-btn { font-size: 16px; padding: 10px 28px; border-radius: 24px; }
.subj-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); font-weight: 700; }
.small-switch { justify-content: flex-start; margin-bottom: 12px; }
.small-switch .subj-btn { font-size: 13px; padding: 6px 18px; }

/* 练习界面 */
.qcard { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 24px; margin-bottom: 16px; }
.qmeta { font-size: 12px; color: var(--muted); margin-bottom: 12px; display: flex; gap: 8px; flex-wrap: wrap; }
.tag { background: var(--primary-soft); color: var(--primary); border-radius: 6px; padding: 1px 8px; font-size: 12px; }
.tag.gray { background: #f0ede6; color: var(--muted); }
.passage { background: #faf8f3; border-left: 3px solid var(--amber); padding: 14px 16px; border-radius: 8px; margin-bottom: 14px; font-size: 14.5px; white-space: pre-wrap; max-height: 320px; overflow-y: auto; }
.stem { font-size: 17px; font-weight: 600; margin-bottom: 16px; white-space: pre-wrap; }
.opt { display: block; width: 100%; text-align: left; border: 1.5px solid var(--line); background: #fff; border-radius: 10px; padding: 12px 16px; margin-bottom: 10px; cursor: pointer; font-size: 15.5px; }
.opt:hover:not(:disabled) { border-color: var(--primary); }
.opt.correct { border-color: var(--green); background: var(--green-soft); font-weight: 600; }
.opt.wrong { border-color: var(--red); background: var(--red-soft); }
.opt:disabled { cursor: default; }
.verdict { border-radius: 10px; padding: 14px 16px; margin: 14px 0; font-size: 14.5px; white-space: pre-wrap; }
.verdict.ok { background: var(--green-soft); border: 1px solid var(--green); }
.verdict.no { background: var(--red-soft); border: 1px solid var(--red); }
.verdict .ans { font-weight: 700; }
.qfooter { display: flex; gap: 10px; justify-content: flex-end; margin-top: 14px; }
.progress { height: 6px; background: #eee; border-radius: 3px; margin-bottom: 14px; overflow: hidden; }
.progress i { display: block; height: 100%; background: var(--primary); border-radius: 3px; transition: width .3s; }
.session-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; font-size: 14px; color: var(--muted); }

.subj-box { background: #faf8f3; border: 1px dashed var(--amber); border-radius: 10px; padding: 14px; margin: 12px 0; font-size: 14px; }

/* 错题本 */
.witem { border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin-bottom: 10px; background: #fff; }
.witem .top { display: flex; justify-content: space-between; align-items: center; gap: 8px; flex-wrap: wrap; }
.pill { border-radius: 12px; padding: 2px 10px; font-size: 12px; font-weight: 600; }
.pill.due { background: var(--red-soft); color: var(--red); }
.pill.wait { background: #f0ede6; color: var(--muted); }
.pill.nail { background: #fff3d6; color: var(--amber); }
.pill.grad { background: var(--green-soft); color: var(--green); }

/* 知识库 */
.kbcat { display: inline-block; margin: 0 6px 10px 0; }
.kbitem { border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin-bottom: 10px; background: #fff; cursor: pointer; }
.kbitem:hover { border-color: var(--primary); }
.kbitem h4 { font-size: 15px; }
.kb-detail-body { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 24px; }
.kb-detail-body h2 { margin: 16px 0 10px; font-size: 17px; }
.kb-detail-body table { border-collapse: collapse; width: 100%; margin: 10px 0; font-size: 14px; }
.kb-detail-body th, .kb-detail-body td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; }
.kb-detail-body th { background: #faf8f3; }
.kb-detail-body ul, .kb-detail-body ol { padding-left: 22px; margin: 8px 0; }
.kb-detail-body p { margin: 8px 0; }
.kb-detail-body strong { color: var(--primary); }

/* 看板 */
.stat-row { display: flex; justify-content: space-between; padding: 6px 0; border-bottom: 1px dashed var(--line); font-size: 14.5px; }
.kpbar { margin-bottom: 10px; font-size: 13.5px; }
.kpbar .bar { height: 8px; background: #f0ede6; border-radius: 4px; margin-top: 3px; overflow: hidden; }
.kpbar .bar i { display: block; height: 100%; background: var(--red); border-radius: 4px; }
select { padding: 8px 12px; border-radius: 8px; border: 1px solid var(--line); font-size: 14px; width: 100%; }
.footer { text-align: center; padding: 20px; }

.result-emoji { font-size: 40px; text-align: center; }

/* ---------- 云同步 ---------- */
.sync-dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; flex: 0 0 auto; margin-left: auto; background: #dcd8cc; }
.sync-dot.s-idle { background: #c9c4b8; }
.sync-dot.s-syncing { background: var(--amber); animation: syncPulse 1s ease-in-out infinite; }
.sync-dot.s-ok { background: var(--green); }
.sync-dot.s-offline { background: var(--red); }
.sync-dot.s-disabled { background: #dedad0; }
@keyframes syncPulse { 0%, 100% { opacity: .3; } 50% { opacity: 1; } }

.sync-pill { border-radius: 10px; padding: 1px 8px; font-size: 12px; font-weight: 500; }
.sync-pill.ok, .sync-pill.idle { background: var(--green-soft); color: var(--green); }
.sync-pill.syncing { background: #fdf3dc; color: var(--amber); }
.sync-pill.offline { background: var(--red-soft); color: var(--red); }
.sync-pill.disabled { background: #f0ede6; color: var(--muted); }
#syncInfo code { background: #f3f0e9; border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px; font-size: 13px; }