:root{
  --bg:#f4f6fa; --card:#fff; --ink:#0f172a; --muted:#64748b; --line:#e2e8f0;
  --brand:#0f766e; --brand-soft:#ccfbf1; --indigo:#4f46e5;
  --ok:#16a34a; --shaky:#d97706; --weak:#dc2626; --unknown:#94a3b8;
  --radius:14px; --shadow:0 1px 2px rgba(15,23,42,.06),0 8px 24px rgba(15,23,42,.06);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%}
body{
  background:var(--bg); color:var(--ink); font-size:15px; line-height:1.65;
  font-family:"PingFang SC","Microsoft YaHei","Hiragino Sans GB","Source Han Sans SC",system-ui,-apple-system,"Segoe UI",sans-serif;
  -webkit-font-smoothing:antialiased;
  overscroll-behavior-y:none;
}
button,.opt,.subj,#tabbar button{touch-action:manipulation;-webkit-tap-highlight-color:transparent;user-select:none;-webkit-user-select:none}
button{font:inherit;cursor:pointer;border:1px solid var(--line);background:#fff;color:var(--ink);border-radius:10px;padding:7px 13px;transition:.15s}
button:hover{border-color:#cbd5e1;background:#f8fafc}
button.primary{background:var(--brand);border-color:var(--brand);color:#fff}
button.primary:hover{background:#115e56}
button.ghost{background:transparent}
button.danger{color:var(--weak);border-color:#fecaca}
button:disabled{opacity:.5;cursor:not-allowed}
select,input[type=text],input[type=number]{font:inherit;padding:7px 10px;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink);max-width:100%}
h1,h2,h3{margin:0 0 .4em;line-height:1.3}
h1{font-size:26px} h2{font-size:19px} h3{font-size:16px}
p{margin:.4em 0}
a{color:var(--brand)}
.muted{color:var(--muted)}
.small{font-size:13px}
.center{text-align:center}

/* top bar */
.topbar{position:sticky;top:0;z-index:30;display:flex;align-items:center;gap:18px;
  padding:10px 22px;background:rgba(255,255,255,.9);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.brand{font-size:16px;letter-spacing:.3px;white-space:nowrap}
.brand b{color:var(--brand)}
.badge{display:inline-block;margin-left:6px;font-size:11px;padding:1px 6px;border-radius:6px;background:var(--brand-soft);color:#115e56;vertical-align:2px}
#nav{display:flex;gap:4px;flex-wrap:wrap}
#nav button{border:0;background:transparent;padding:6px 12px;border-radius:9px;color:var(--muted)}
#nav button.active{background:#eef2f7;color:var(--ink);font-weight:600}
#nav em{font-style:normal;font-size:11px;background:var(--weak);color:#fff;border-radius:9px;padding:0 5px;margin-left:4px;vertical-align:2px}
#nav em:empty{display:none}
.share-btn{margin-left:auto;border-color:#c7d2fe;color:#4338ca;background:#eef2ff;white-space:nowrap}
.share-btn:hover{background:#e0e7ff}
.qr{display:grid;place-items:center;margin:10px 0}
.qr svg{width:min(260px,70vw);height:auto;border-radius:10px;background:#fff}
pre.code{background:#0f172a;color:#e2e8f0;padding:10px 12px;border-radius:10px;font-size:12px;overflow:auto;white-space:pre-wrap;word-break:break-all}

main{max-width:1360px;margin:0 auto;padding:22px}
.foot{max-width:1360px;margin:10px auto 40px;padding:0 22px;color:var(--muted);font-size:12px}
.loading,.empty{padding:60px 0;text-align:center;color:var(--muted)}

/* home */
.hero{background:linear-gradient(135deg,#0f766e,#0e7490 55%,#4338ca);color:#fff;border-radius:20px;padding:30px 32px;box-shadow:var(--shadow)}
.hero h1{color:#fff;font-size:28px;margin-bottom:8px}
.hero p{color:#d1fae5;max-width:760px}
.hero .stat{display:flex;gap:26px;margin-top:18px;flex-wrap:wrap}
.hero .stat b{font-size:24px;display:block;line-height:1.2}
.hero .stat span{font-size:12px;color:#a7f3d0}
.subjects{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:12px;margin:22px 0}
.subj{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:14px;cursor:pointer;transition:.15s;box-shadow:var(--shadow)}
.subj:hover{transform:translateY(-2px);border-color:#c7d2fe}
.subj .ico{width:34px;height:34px;border-radius:10px;display:grid;place-items:center;background:var(--brand-soft);color:#115e56;font-weight:700;font-size:13px}
.subj h3{margin:8px 0 2px;font-size:16px}
.subj .n{color:var(--muted);font-size:12px}
.steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:12px;margin-top:8px}
.step{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px}
.step .k{display:inline-grid;place-items:center;width:24px;height:24px;border-radius:50%;background:var(--brand);color:#fff;font-size:13px;margin-right:6px}

/* graph */
.graph-wrap{display:grid;grid-template-columns:280px minmax(0,1fr) 340px;gap:14px;align-items:start}
@media(max-width:1180px){.graph-wrap{grid-template-columns:1fr}}
.panel{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.side{padding:12px;max-height:calc(100vh - 130px);overflow:auto}
.side select,.side input{width:100%;margin-bottom:8px}
.tree{font-size:13px}
.tree details{margin:2px 0}
.tree summary{cursor:pointer;padding:4px 6px;border-radius:8px;color:var(--muted)}
.tree summary:hover{background:#f1f5f9}
.tree .book>summary{font-weight:600;color:var(--ink)}
.tree .item{padding:4px 8px 4px 22px;border-radius:8px;cursor:pointer;color:#334155;display:flex;justify-content:space-between;gap:6px}
.tree .item:hover{background:#f1f5f9}
.tree .item.sel{background:var(--brand-soft);color:#115e56;font-weight:600}
.canvas-wrap{display:flex;flex-direction:column;gap:8px}
.graph-toolbar{display:flex;gap:8px;align-items:center;flex-wrap:wrap;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:8px 10px;box-shadow:var(--shadow)}
.cy{height:calc(100vh - 210px);min-height:420px;background:
  radial-gradient(circle at 1px 1px,#e2e8f0 1px,transparent 0) 0 0/22px 22px,#fff;
  border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);touch-action:none}
.legend{display:flex;gap:12px;font-size:12px;color:var(--muted);flex-wrap:wrap}
.legend i{display:inline-block;width:9px;height:9px;border-radius:3px;margin-right:4px}
.detail{padding:14px;max-height:calc(100vh - 130px);overflow:auto}
.detail h2{font-size:17px}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin:6px 0}
.chip{font-size:12px;padding:2px 8px;border-radius:999px;background:#f1f5f9;color:#475569}
.chip.lv{background:#eef2ff;color:#4338ca}
.chip.fz{background:#fef3c7;color:#92400e}
.chip.ok{background:#dcfce7;color:#166534}
.chip.shaky{background:#fef3c7;color:#92400e}
.chip.weak{background:#fee2e2;color:#991b1b}
ul.tight{margin:.3em 0;padding-left:1.2em}
ul.tight li{margin:.15em 0}
.pre{display:flex;gap:6px;flex-wrap:wrap}
.pre button{font-size:12px;padding:3px 8px;border-radius:8px}

/* diagnose */
.grid2{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);gap:14px}
@media(max-width:980px){.grid2{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.field{display:flex;gap:8px;align-items:center;margin:10px 0;flex-wrap:wrap}
.field label{min-width:74px;color:var(--muted);font-size:13px}
.radio{display:flex;gap:6px;flex-wrap:wrap}
.radio button.on{background:var(--brand);color:#fff;border-color:var(--brand)}
.subject-chips{display:flex;gap:6px;flex-wrap:wrap}

/* quiz */
.quiz{max-width:820px;margin:0 auto}
.qhead{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:10px;color:var(--muted);font-size:13px}
.bar{height:6px;background:#e2e8f0;border-radius:99px;overflow:hidden;margin-bottom:16px}
.bar>i{display:block;height:100%;background:linear-gradient(90deg,#0f766e,#4f46e5);transition:width .25s}
.qcard{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:22px;box-shadow:var(--shadow)}
.qtopic{font-size:12px;color:var(--muted);margin-bottom:6px}
.qtext{font-size:17px;line-height:1.8;margin:6px 0 16px;white-space:pre-wrap}
.opts{display:grid;gap:8px}
.opt{display:flex;gap:10px;align-items:flex-start;text-align:left;padding:11px 13px;border-radius:12px;border:1px solid var(--line);background:#fff}
.opt:hover{border-color:#a5b4fc;background:#f8faff}
.opt.sel{border-color:var(--brand);background:#f0fdfa}
.opt .k{font-weight:700;color:var(--brand);min-width:18px}
.answer-row{display:flex;gap:8px;margin-top:8px}
.answer-row input{flex:1}
.actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:16px}
.feedback{margin-top:16px;border-radius:12px;padding:14px;border:1px solid var(--line);background:#f8fafc}
.feedback.ok{border-color:#bbf7d0;background:#f0fdf4}
.feedback.bad{border-color:#fecaca;background:#fef2f2}
.feedback .ans{font-weight:600;margin-top:4px}
.feedback .exp{color:#475569;margin-top:6px;font-size:14px}
.feedback .self{display:flex;gap:8px;margin-top:10px}

/* result */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:10px;margin:14px 0}
.stat-box{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:12px;text-align:center}
.stat-box b{display:block;font-size:22px}
.stat-box span{font-size:12px;color:var(--muted)}
.stat-box.ok b{color:var(--ok)} .stat-box.shaky b{color:var(--shaky)} .stat-box.weak b{color:var(--weak)}
.roots{display:grid;gap:8px}
.root{display:flex;gap:10px;align-items:center;justify-content:space-between;border:1px solid var(--line);border-radius:12px;padding:10px 12px}
.root .t{min-width:0}
.pathlist{display:flex;flex-direction:column;gap:6px}
.pitem{display:flex;align-items:center;gap:8px;padding:8px 10px;border:1px solid var(--line);border-radius:10px;background:#fff}
.pitem .idx{width:22px;height:22px;border-radius:50%;background:#eef2f7;color:#475569;display:grid;place-items:center;font-size:12px;flex:none}
.pitem .nm{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

/* guide */
.guide-head{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:8px}
.gcard{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:22px;box-shadow:var(--shadow)}
.gcard .teach{background:#f8fafc;border:1px dashed var(--line);border-radius:12px;padding:12px;margin:10px 0}
.pill{font-size:12px;padding:2px 9px;border-radius:999px;background:#eef2ff;color:#4338ca}
.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%) translateY(20px);background:#0f172a;color:#fff;padding:9px 16px;border-radius:10px;font-size:13px;opacity:0;pointer-events:none;transition:.2s;z-index:99}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* wrong book */
.wlist{display:grid;gap:10px}
.witem{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px;box-shadow:var(--shadow)}
.witem .q{font-weight:600}
.witem .row{display:flex;gap:14px;flex-wrap:wrap;font-size:13px;color:var(--muted);margin-top:6px}
.witem .exp{font-size:13px;color:#475569;margin-top:6px}
.tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:12px}
.tabs button.on{background:var(--ink);color:#fff;border-color:var(--ink)}
.kv{display:grid;grid-template-columns:96px 1fr;gap:6px 10px;font-size:14px}
.kv b{color:var(--muted);font-weight:500}

/* capture */
.photo-stage{position:relative;background:#0f172a;border-radius:14px;overflow:hidden;min-height:260px;display:grid;place-items:center;margin:8px 0}
.photo-stage img{max-width:100%;max-height:420px;display:block}
.stage-empty{color:#94a3b8;text-align:center;padding:40px 16px;font-size:15px;line-height:1.9}
textarea{font:inherit;width:100%;padding:10px;border:1px solid var(--line);border-radius:10px;resize:vertical;background:#fff;color:var(--ink)}
.match-list{display:flex;flex-direction:column;gap:6px;margin-top:8px}
.match{display:flex;justify-content:space-between;align-items:center;gap:8px;border:1px solid var(--line);border-radius:10px;padding:8px 10px;background:#fff;text-align:left}
.match:hover{border-color:#a5b4fc;background:#f8faff}
.match.on{border-color:var(--brand);background:#f0fdfa}
.match .sc{font-size:12px;color:var(--muted)}
.bridge{font-size:13px;display:flex;align-items:center;gap:6px}
.dot{width:8px;height:8px;border-radius:50%;background:#cbd5e1;display:inline-block}
.dot.on{background:var(--ok)}
.dot.off{background:var(--weak)}
.photo-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:10px;margin:8px 0}
.pcard{background:var(--card);border:1px solid var(--line);border-radius:14px;overflow:hidden;box-shadow:var(--shadow)}
.pcard .thumb{width:100%;height:150px;object-fit:cover;background:#e2e8f0;display:block}
.pcard .pbody{padding:10px}
.pcard .ptext{font-weight:600;font-size:14px;margin:2px 0 4px}
.pcard .actions{margin-top:6px;gap:6px}
.pcard .actions button{font-size:12px;padding:4px 8px}

/* modal */
.modal{position:fixed;inset:0;background:rgba(15,23,42,.72);z-index:80;display:grid;place-items:center;padding:16px}
.modal-box{background:#fff;border-radius:16px;padding:14px;max-width:min(760px,96vw);max-height:92vh;overflow:auto;box-shadow:0 20px 60px rgba(0,0,0,.35)}
.modal-box video{width:100%;max-height:64vh;background:#000;border-radius:10px;display:block}
.modal-box img{max-width:100%;max-height:74vh;border-radius:10px;display:block}
.modal-box .actions{justify-content:flex-end}
@media print{.topbar,.foot,#nav,.actions{display:none}main{max-width:none}}

/* ---------- 手机优先 ---------- */
#tabbar{display:none}
#tabbar em{font-style:normal;font-size:10px;background:var(--weak);color:#fff;border-radius:8px;padding:0 4px;margin-left:3px}
#tabbar em:empty{display:none}

@media (max-width:720px){
  :root{--tabh:56px}
  body{padding-bottom:calc(var(--tabh) + env(safe-area-inset-bottom))}
  .topbar{padding:8px 14px;gap:8px}
  #nav{display:none}
  .brand{font-size:15px}
  .share-btn{padding:6px 12px;font-size:13px}
  .foot{display:none}
  main{padding:14px 12px}

  #tabbar{
    display:flex;position:fixed;left:0;right:0;bottom:0;z-index:50;
    background:rgba(255,255,255,.96);backdrop-filter:blur(10px);
    border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);
  }
  #tabbar button{
    flex:1;border:0;background:transparent;border-radius:0;
    padding:7px 2px 8px;font-size:11px;color:var(--muted);
    display:flex;flex-direction:column;align-items:center;gap:3px;min-height:52px;position:relative;
  }
  #tabbar button .ic{font-size:17px;line-height:1;filter:grayscale(.5);opacity:.8}
  #tabbar button.active{color:var(--brand);font-weight:600}
  #tabbar button.active .ic{filter:none;opacity:1}

  .hero{padding:20px 18px;border-radius:16px}
  .hero h1{font-size:22px}
  .hero p{font-size:14px}
  .hero .stat{gap:16px;margin-top:14px}
  .hero .stat b{font-size:20px}

  .subjects{grid-template-columns:repeat(2,1fr);gap:10px;margin:16px 0}
  .subj{padding:12px}
  .subj h3{font-size:15px}

  .steps{grid-template-columns:1fr;gap:10px}

  .graph-wrap{grid-template-columns:1fr;gap:10px}
  .side{order:1;max-height:36vh;overflow:auto}
  .canvas-wrap{order:2}
  .detail{order:3;max-height:none}
  .cy{height:46vh;min-height:280px}
  .tree .item{padding:10px 8px 10px 20px;min-height:42px;align-items:center}
  .tree summary{padding:8px 6px}
  .graph-toolbar{overflow-x:auto;flex-wrap:nowrap;padding:6px 8px}
  .graph-toolbar button{white-space:nowrap}
  .legend{display:none}

  .quiz{max-width:none}
  .qcard{padding:16px;border-radius:14px}
  .qtext{font-size:16px;margin:4px 0 14px}
  .opt{min-height:48px;padding:12px 13px;font-size:15px}
  .answer-row input{font-size:16px;min-height:46px}
  .actions{gap:8px}
  .actions button{min-height:42px}
  .qcard .actions{position:sticky;bottom:calc(var(--tabh) + env(safe-area-inset-bottom) + 4px);
    background:linear-gradient(rgba(255,255,255,0),#fff 30%);padding-top:8px;margin-top:12px}
  .qhead{font-size:12px}

  .stats{grid-template-columns:repeat(2,1fr);gap:8px}
  .stat-box b{font-size:20px}

  .modal{align-items:flex-end;padding:0}
  .modal-box{width:100%;max-width:100%;border-radius:16px 16px 0 0;max-height:90vh;padding:16px 16px calc(16px + env(safe-area-inset-bottom))}

  .photo-grid{grid-template-columns:repeat(2,1fr);gap:8px}
  .pcard .thumb{height:112px}
  .pcard .actions button{font-size:11px;padding:5px 6px}
  .photo-stage{min-height:200px}
  .photo-stage img{max-height:320px}

  textarea,input[type=text],input[type=number],select{font-size:16px} /* 防 iOS 自动放大 */

  .kv{grid-template-columns:84px 1fr;font-size:13px}
  .pitem .nm{max-width:60vw}
}


/* ---------- iOS / 安全区 / 键盘 / 动态视口 加固 ---------- */
@supports not (position: sticky){
  .qcard .actions{position:static !important;background:none !important;padding-top:0 !important}
}
@media (display-mode: standalone){
  .topbar{padding-top:calc(8px + env(safe-area-inset-top,0px))}
}
@media (max-width:720px){
  body{
    padding-left:env(safe-area-inset-left,0px);
    padding-right:env(safe-area-inset-right,0px);
  }
  .topbar{padding-top:calc(8px + env(safe-area-inset-top,0px))}
  #tabbar{
    padding-left:env(safe-area-inset-left,0px);
    padding-right:env(safe-area-inset-right,0px);
  }
  /* 动态视口：iOS 地址栏收起/展开时 vh 会跳，dvh 更稳；不支持的浏览器自动忽略 */
  .cy{height:46dvh}
  .side{max-height:36dvh}
  .modal-box{max-height:90dvh}

  .tree .item > span:first-child{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .pcard .ptext{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

  /* 键盘弹出：隐藏底部栏，取消吸底，把输入框让出来 */
  body.kb-open{padding-bottom:0}
  body.kb-open #tabbar{display:none}
  body.kb-open .qcard .actions{position:static;background:none;padding-top:0}
  body.kb-open .cy{height:40dvh}
}
@media (max-width:360px){
  .subjects{grid-template-columns:1fr}
  .hero h1{font-size:20px}
  .hero .stat b{font-size:18px}
  .qcard{padding:14px}
  .qtext{font-size:15px}
}
@media (max-height:520px) and (orientation:landscape){
  .cy{height:64dvh}
  .side{max-height:44dvh}
  #tabbar button{min-height:44px;font-size:10px}
  .topbar{padding-top:6px}
}

/* ---------- 邀请码门禁 ---------- */
.gate{position:fixed;inset:0;z-index:300;display:grid;place-items:center;padding:24px;
  background:linear-gradient(160deg,#0f766e,#0e7490 55%,#4338ca);
  padding-top:calc(24px + env(safe-area-inset-top,0px));
  padding-bottom:calc(24px + env(safe-area-inset-bottom,0px))}
.gate-card{background:#fff;border-radius:20px;padding:26px 22px;width:100%;max-width:360px;text-align:center;
  box-shadow:0 24px 70px rgba(0,0,0,.35)}
.gate-mark{width:54px;height:54px;border-radius:16px;background:var(--brand-soft);color:#115e56;
  display:grid;place-items:center;font-size:24px;font-weight:700;margin:0 auto 10px}
.gate-card h1{font-size:20px;margin:0 0 4px}
.gate-card input{width:100%;margin:16px 0 10px;text-align:center;font-size:18px;letter-spacing:1.5px;
  text-transform:uppercase;font-family:ui-monospace,Menlo,Consolas,monospace}
.gate-card button{width:100%;min-height:46px}
.gate-err{color:var(--weak)}
body.gated{overflow:hidden}