:root{
  --red:#a4161a; --red-2:#c1121f; --red-soft:#fdeceb; --gold:#c9a227; --gold-soft:#fdf6e3;
  --ink:#1f1a17; --ink-2:#4a4038; --muted:#8a7f76; --line:#eadfd3; --bg:#faf6ef; --card:#fffdf9;
  --green:#2f7d4f; --green-soft:#e8f4ec; --blue:#2c5f8a; --shadow:0 10px 30px rgba(80,40,20,.08);
  --radius:16px; --max:1080px;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:"PingFang SC","Microsoft YaHei","Noto Sans SC",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  background:var(--bg); color:var(--ink); line-height:1.7; -webkit-font-smoothing:antialiased;
}
a{color:var(--red);text-decoration:none}
a:hover{text-decoration:underline}
button{font-family:inherit}
.app-loading{display:flex;align-items:center;justify-content:center;min-height:100vh}
.boot{text-align:center;color:var(--muted)}
.boot-star{font-size:44px;color:var(--gold);animation:pulse 1.4s infinite}
@keyframes pulse{0%,100%{transform:scale(1);opacity:.8}50%{transform:scale(1.12);opacity:1}}

/* ---------------- layout ---------------- */
.shell{display:flex;min-height:100vh}
.side{
  width:236px;flex:0 0 236px;background:linear-gradient(180deg,#8e1116,#a4161a 45%,#7d0f13);
  color:#fff;display:flex;flex-direction:column;position:sticky;top:0;height:100vh;z-index:20;
}
.brand{display:flex;gap:12px;align-items:center;padding:22px 20px 16px}
.brand-mark{width:42px;height:42px;border-radius:12px;background:linear-gradient(135deg,#f6d365,#e0a800);
  color:#7d0f13;display:grid;place-items:center;font-size:22px;font-weight:800;box-shadow:0 6px 16px rgba(0,0,0,.2)}
.brand h1{font-size:17px;margin:0;letter-spacing:1px}
.brand small{display:block;font-size:10.5px;color:#f3d9d7;font-weight:400;letter-spacing:.2px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:150px}
.nav{padding:8px 12px;display:flex;flex-direction:column;gap:4px}
.nav a{display:flex;align-items:center;gap:10px;color:#fbe9e7;padding:11px 12px;border-radius:11px;font-size:14.5px;transition:.15s}
.nav a:hover{background:rgba(255,255,255,.1);text-decoration:none}
.nav a.active{background:rgba(255,255,255,.16);color:#fff;font-weight:600;box-shadow:inset 3px 0 0 var(--gold)}
.nav .ico{width:20px;text-align:center}
.side-foot{margin-top:auto;padding:16px 18px;font-size:12px;color:#f0cfcd;border-top:1px solid rgba(255,255,255,.12)}
.main{flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:18px 34px;border-bottom:1px solid var(--line);background:rgba(250,246,239,.9);backdrop-filter:blur(8px);position:sticky;top:0;z-index:10}
.crumb{font-size:13px;color:var(--muted)}
.crumb b{color:var(--ink);font-weight:600}
.user-chip{display:flex;align-items:center;gap:10px;font-size:13px;color:var(--ink-2)}
.avatar{width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,#f6d365,#e0a800);color:#7d0f13;display:grid;place-items:center;font-weight:700}
.content{width:100%;max-width:var(--max);margin:0 auto;padding:26px 34px 70px}

/* ---------------- generic ---------------- */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:22px 24px}
.card+.card{margin-top:18px}
.section-title{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:4px 0 14px}
.section-title h2{font-size:19px;margin:0}
.section-title .sub{color:var(--muted);font-size:13px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid transparent;border-radius:11px;
  padding:10px 18px;font-size:14.5px;font-weight:600;cursor:pointer;transition:.15s;background:#fff;color:var(--ink)}
.btn:hover{transform:translateY(-1px)}
.btn.primary{background:linear-gradient(135deg,var(--red-2),var(--red));color:#fff;box-shadow:0 8px 18px rgba(164,22,26,.25)}
.btn.primary:hover{box-shadow:0 10px 22px rgba(164,22,26,.32)}
.btn.ghost{border-color:var(--line);color:var(--ink-2)}
.btn.ghost:hover{border-color:var(--red);color:var(--red)}
.btn.gold{background:linear-gradient(135deg,#f6d365,#e0a800);color:#5c3d00}
.btn.sm{padding:6px 12px;font-size:13px;border-radius:9px}
.btn:disabled{opacity:.5;cursor:not-allowed;transform:none}
.muted{color:var(--muted)}
.pill{display:inline-flex;align-items:center;gap:6px;padding:3px 10px;border-radius:999px;font-size:12px;background:var(--red-soft);color:var(--red)}
.pill.gold{background:var(--gold-soft);color:#8a6a00}
.pill.green{background:var(--green-soft);color:var(--green)}
.pill.gray{background:#f1ece6;color:var(--muted)}
.bar{height:9px;border-radius:999px;background:#f0e6db;overflow:hidden}
.bar>span{display:block;height:100%;border-radius:999px;background:linear-gradient(90deg,var(--gold),var(--red-2));transition:width .4s}
.bar.green>span{background:linear-gradient(90deg,#59b37c,#2f7d4f)}

/* ---------------- login ---------------- */
.login-wrap{min-height:100vh;display:grid;grid-template-columns:1.05fr .95fr}
.login-side{background:radial-gradient(1200px 600px at 10% 0%,#c1121f,#8e1116 55%,#5c0a0d);color:#fff;
  padding:54px 56px;display:flex;flex-direction:column;justify-content:space-between;position:relative;overflow:hidden}
.login-side:after{content:"★";position:absolute;right:-40px;bottom:-60px;font-size:320px;color:rgba(255,255,255,.05)}
.login-side h2{font-size:30px;line-height:1.35;margin:26px 0 12px;letter-spacing:1px}
.login-side p{color:#f3d9d7;font-size:14.5px;max-width:420px}
.login-points{list-style:none;padding:0;margin:26px 0 0;display:grid;gap:12px}
.login-points li{display:flex;gap:10px;align-items:flex-start;color:#fbe9e7;font-size:14px}
.login-points i{color:var(--gold);font-style:normal}
.login-main{display:flex;align-items:center;justify-content:center;padding:40px 24px;background:var(--bg)}
.login-box{width:100%;max-width:400px}
.login-box h3{font-size:23px;margin:0 0 6px}
.tabs{display:flex;gap:6px;background:#f1e9df;padding:4px;border-radius:12px;margin:18px 0 20px}
.tabs button{flex:1;border:0;background:transparent;padding:9px;border-radius:9px;font-size:14px;color:var(--ink-2);cursor:pointer}
.tabs button.on{background:#fff;color:var(--red);font-weight:700;box-shadow:0 2px 8px rgba(0,0,0,.06)}
.field{margin-bottom:14px}
.field label{display:block;font-size:13px;color:var(--ink-2);margin-bottom:6px;font-weight:600}
.field input,.field select{width:100%;padding:11px 13px;border:1px solid var(--line);border-radius:11px;font-size:14.5px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus{outline:none;border-color:var(--red);box-shadow:0 0 0 3px rgba(164,22,26,.1)}
.hint{font-size:12px;color:var(--muted);margin-top:8px}
.alert{background:var(--red-soft);color:#8e1116;border:1px solid #f3c9c6;padding:9px 12px;border-radius:10px;font-size:13px;margin-bottom:12px}

/* ---------------- home ---------------- */
.hero{background:linear-gradient(120deg,#8e1116,#b3181d 60%,#7d0f13);color:#fff;border-radius:20px;padding:26px 28px;
  position:relative;overflow:hidden;box-shadow:0 16px 34px rgba(142,17,22,.22)}
.hero:after{content:"";position:absolute;right:-70px;top:-70px;width:240px;height:240px;border-radius:50%;background:rgba(255,255,255,.06)}
.hero h2{margin:0 0 6px;font-size:24px}
.hero p{margin:0;color:#f6dedd;font-size:14px}
.hero .hero-actions{margin-top:18px;display:flex;gap:10px;flex-wrap:wrap;position:relative;z-index:1}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:18px 0 8px}
.stat{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:15px 16px}
.stat .k{font-size:12px;color:var(--muted)}
.stat .v{font-size:24px;font-weight:800;color:var(--ink);margin-top:2px}
.stat .v small{font-size:12px;font-weight:500;color:var(--muted);margin-left:2px}
.unit{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:18px 20px;margin-top:14px}
.unit-head{display:flex;align-items:center;gap:12px;margin-bottom:10px}
.unit-ico{width:40px;height:40px;border-radius:12px;background:var(--gold-soft);display:grid;place-items:center;font-size:20px}
.unit-head h3{margin:0;font-size:16.5px}
.unit-head .sub{font-size:12.5px;color:var(--muted)}
.unit-head .pct{margin-left:auto;font-size:13px;color:var(--ink-2);font-weight:700}
.lessons{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:9px;margin-top:10px}
.lesson-link{display:flex;gap:9px;align-items:center;padding:9px 11px;border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--ink);font-size:13.5px;transition:.15s}
.lesson-link:hover{border-color:var(--red);text-decoration:none;transform:translateY(-1px)}
.lesson-link .no{font-size:11px;color:var(--muted);min-width:26px}
.lesson-link.done{background:var(--green-soft);border-color:#cfe7d8}
.lesson-link.done .no:after{content:" ✓";color:var(--green);font-weight:800}
.lesson-link .t{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

/* ---------------- lesson ---------------- */
.lesson-head{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:22px 26px;margin-bottom:16px}
.lesson-head h2{margin:6px 0 8px;font-size:24px;line-height:1.4}
.lesson-meta{display:flex;gap:14px;flex-wrap:wrap;color:var(--muted);font-size:12.5px;align-items:center}
.article{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:10px 30px 26px;box-shadow:var(--shadow)}
.article h1{font-size:24px;margin:22px 0 12px}
.article h2{font-size:20px;margin:30px 0 10px;padding-left:12px;border-left:4px solid var(--red)}
.article h3{font-size:16.5px;margin:22px 0 8px;color:var(--red)}
.article h4{font-size:15px;margin:18px 0 6px}
.article p{margin:10px 0;color:#2e2823;font-size:15.5px}
.article li{margin:6px 0;font-size:15.2px}
.article blockquote{margin:14px 0;padding:12px 16px;background:var(--gold-soft);border-left:4px solid var(--gold);border-radius:0 10px 10px 0;color:#5f4a17}
.article blockquote p{margin:4px 0;color:#5f4a17}
.article code{background:#f3ece4;padding:1px 5px;border-radius:5px;font-size:.92em}
.article pre{background:#2a2320;color:#f6eee6;padding:14px 16px;border-radius:11px;overflow:auto;font-size:13px;line-height:1.6}
.article pre code{background:transparent;color:inherit;padding:0}
.article hr{border:0;border-top:1px dashed var(--line);margin:24px 0}
.table-wrap{overflow:auto;margin:14px 0;border:1px solid var(--line);border-radius:11px}
.article table{border-collapse:collapse;width:100%;font-size:13.8px;background:#fff}
.article th,.article td{border-bottom:1px solid var(--line);padding:9px 11px;text-align:left;vertical-align:top}
.article th{background:#faf3ea;color:#6b4a2f;font-weight:700;white-space:nowrap}
.article tr:last-child td{border-bottom:0}
.article a{word-break:break-all}
.lesson-nav{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:18px;flex-wrap:wrap}
.lesson-nav .spacer{flex:1}

/* ---------------- quiz ---------------- */
.mode-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px}
.mode{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:18px;display:flex;flex-direction:column;gap:8px}
.mode h3{margin:0;font-size:16px}
.mode p{margin:0;color:var(--muted);font-size:12.8px;min-height:38px}
.mode .ico{font-size:24px}
.quiz-top{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:14px;flex-wrap:wrap}
.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:18px;color:var(--red);background:var(--red-soft);padding:6px 14px;border-radius:10px}
.timer.warn{animation:blink 1s infinite}
@keyframes blink{50%{opacity:.45}}
.q-card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:22px 24px;box-shadow:var(--shadow)}
.q-num{color:var(--muted);font-size:12.5px;margin-bottom:6px}
.q-stem{font-size:17px;font-weight:600;line-height:1.7;margin-bottom:16px}
.opts{display:grid;gap:10px}
.opt{display:flex;gap:12px;align-items:flex-start;border:1.5px solid var(--line);border-radius:12px;padding:12px 14px;cursor:pointer;background:#fff;transition:.15s;font-size:15px}
.opt:hover{border-color:#d9b9b2}
.opt.on{border-color:var(--red);background:var(--red-soft)}
.opt .k{width:25px;height:25px;flex:0 0 25px;border-radius:50%;border:1.5px solid #d8c9ba;display:grid;place-items:center;font-size:12.5px;font-weight:700;color:var(--ink-2);background:#fff}
.opt.on .k{background:var(--red);border-color:var(--red);color:#fff}
.opt.correct{border-color:var(--green);background:var(--green-soft)}
.opt.correct .k{background:var(--green);border-color:var(--green);color:#fff}
.opt.wrong{border-color:var(--red-2);background:#fdeceb}
.opt.wrong .k{background:var(--red-2);border-color:var(--red-2);color:#fff}
.palette{display:grid;grid-template-columns:repeat(auto-fill,minmax(34px,1fr));gap:8px;margin-top:14px}
.palette button{aspect-ratio:1;border:1px solid var(--line);background:#fff;border-radius:8px;font-size:12px;cursor:pointer;color:var(--ink-2)}
.palette button.done{background:var(--green-soft);border-color:#bfe0ca;color:var(--green);font-weight:700}
.palette button.cur{outline:2px solid var(--red);outline-offset:1px}
.quiz-actions{display:flex;gap:10px;justify-content:space-between;margin-top:16px;flex-wrap:wrap}
.result-hero{display:flex;gap:24px;align-items:center;flex-wrap:wrap}
.ring{width:132px;height:132px;border-radius:50%;display:grid;place-items:center;position:relative;flex:0 0 132px}
.ring:before{content:"";position:absolute;inset:10px;background:var(--card);border-radius:50%}
.ring .val{position:relative;text-align:center}
.ring .val b{font-size:32px;display:block;line-height:1}
.ring .val span{font-size:11px;color:var(--muted)}
.review{margin-top:14px;border:1px solid var(--line);border-radius:14px;padding:16px 18px;background:var(--card)}
.review.correct{border-left:5px solid var(--green)}
.review.wrong{border-left:5px solid var(--red-2)}
.review .stem{font-weight:600;margin:4px 0 10px}
.tag{font-size:11px;padding:2px 8px;border-radius:999px;background:#f1ece6;color:var(--muted);margin-left:6px}
.explain{background:var(--gold-soft);border-radius:10px;padding:9px 12px;font-size:13px;color:#6a5216;margin-top:8px}

/* ---------------- table / me / teacher ---------------- */
table.simple{width:100%;border-collapse:collapse;font-size:13.6px}
table.simple th,table.simple td{padding:9px 10px;border-bottom:1px solid var(--line);text-align:left}
table.simple th{color:var(--muted);font-weight:600;font-size:12.5px;background:#faf5ee}
table.simple tr:last-child td{border-bottom:0}
.profile-head{display:flex;gap:16px;align-items:center;flex-wrap:wrap}
.profile-head .avatar{width:58px;height:58px;font-size:22px}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.empty{text-align:center;color:var(--muted);padding:28px;font-size:13.5px}
.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%);background:#2a2320;color:#fff;padding:10px 18px;border-radius:999px;font-size:13.5px;z-index:99;box-shadow:0 10px 26px rgba(0,0,0,.25);opacity:0;pointer-events:none;transition:.25s}
.toast.on{opacity:1;bottom:36px}

/* ---------------- mobile ---------------- */
.mobile-nav{display:none}
@media (max-width:900px){
  .login-wrap{grid-template-columns:1fr}
  .login-side{display:none}
  .stats{grid-template-columns:1fr 1fr}
  .grid-2{grid-template-columns:1fr}
  .side{display:none}
  .topbar{padding:14px 18px}
  .content{padding:18px 16px 96px}
  .article{padding:6px 18px 22px}
  .mobile-nav{display:flex;position:fixed;left:0;right:0;bottom:0;background:#fff;border-top:1px solid var(--line);
    padding:8px 6px calc(8px + env(safe-area-inset-bottom));justify-content:space-around;z-index:30}
  .mobile-nav a{display:flex;flex-direction:column;align-items:center;gap:2px;font-size:11px;color:var(--muted);flex:1}
  .mobile-nav a.active{color:var(--red);font-weight:700}
  .mobile-nav .ico{font-size:18px}
  .lesson-head h2{font-size:20px}
  .q-stem{font-size:16px}
}