:root{
    --bg:#eef1f4;
    --surface:#ffffff;
    --surface-2:#e2e8ef;
    --border:#c7d0da;
    --ink:#16202b;
    --ink-soft:#54636f;
    --ink-faint:#8492a0;
    --accent:#123fb0;
    --accent-strong:#0c2e86;
    --accent-ink:#ffffff;
    --accent-soft:#e2eaff;
    --warn:#a6650a;
    --warn-soft:#fbedd6;
    --good:#187a42;
    --good-soft:#dff3e5;
    --bad:#b3222f;
    --bad-soft:#fbe2e4;
    --shadow: 0 1px 2px rgba(20,30,45,.06), 0 8px 24px -12px rgba(20,30,45,.18);
    --font-display:'Oswald','Arial Narrow',sans-serif;
    --font-body:'Manrope','Segoe UI',sans-serif;
    --font-mono:'JetBrains Mono',ui-monospace,'Consolas',monospace;
    color-scheme: light;
  }
  @media (prefers-color-scheme: dark){
    :root:not([data-theme="light"]){
      --bg:#0a0d12;
      --surface:#1c2531;
      --surface-2:#28323f;
      --border:#42505f;
      --ink:#f0f4f8;
      --ink-soft:#aab8c6;
      --ink-faint:#748393;
      --accent:#7fa0ff;
      --accent-strong:#a3bdff;
      --accent-ink:#0a1224;
      --accent-soft:#233257;
      --warn:#f5bb5c;
      --warn-soft:#40300f;
      --good:#4bdb92;
      --good-soft:#123726;
      --bad:#ff8b8f;
      --bad-soft:#421a1c;
      --shadow: 0 1px 0 rgba(255,255,255,.03) inset, 0 10px 30px -12px rgba(0,0,0,.7);
      color-scheme: dark;
    }
  }
  :root[data-theme="dark"]{
    --bg:#0a0d12;
    --surface:#1c2531;
    --surface-2:#28323f;
    --border:#42505f;
    --ink:#f0f4f8;
    --ink-soft:#aab8c6;
    --ink-faint:#748393;
    --accent:#7fa0ff;
    --accent-strong:#a3bdff;
    --accent-ink:#0a1224;
    --accent-soft:#233257;
    --warn:#f5bb5c;
    --warn-soft:#40300f;
    --good:#4bdb92;
    --good-soft:#123726;
    --bad:#ff8b8f;
    --bad-soft:#421a1c;
    --shadow: 0 1px 0 rgba(255,255,255,.03) inset, 0 10px 30px -12px rgba(0,0,0,.7);
    color-scheme: dark;
  }

  *{box-sizing:border-box;}
  body{
    margin:0;
    background:var(--bg);
    color:var(--ink);
    font-family:var(--font-body);
    font-size:15px;
    line-height:1.5;
    -webkit-font-smoothing:antialiased;
  }
  #app{
    max-width:820px;
    margin:0 auto;
    padding:14px 12px 48px;
    display:flex;
    flex-direction:column;
    gap:16px;
  }
  @media (min-width:600px){
    #app{ padding:20px 18px 64px; gap:18px; }
  }
  a{color:inherit;}
  button{font-family:inherit;}
  ::selection{background:var(--accent-soft);}

  .topbar{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
  }
  .brand{
    display:flex;
    align-items:center;
    gap:10px;
    cursor:pointer;
    user-select:none;
  }
  .brand-mark{
    width:34px;height:34px;border-radius:7px;
    background:var(--accent);
    color:var(--accent-ink);
    display:flex;align-items:center;justify-content:center;
    font-family:var(--font-display);
    font-weight:700;
    font-size:15px;
    letter-spacing:.02em;
    flex-shrink:0;
  }
  .brand-text{
    font-family:var(--font-display);
    font-weight:600;
    font-size:19px;
    letter-spacing:.01em;
    text-transform:uppercase;
  }
  .brand-text small{
    display:block;
    font-family:var(--font-body);
    font-weight:500;
    font-size:11px;
    letter-spacing:.06em;
    text-transform:uppercase;
    color:var(--ink-faint);
    margin-top:1px;
  }
  .icon-btn{
    width:40px;height:40px;
    border-radius:8px;
    border:1px solid var(--border);
    background:var(--surface);
    color:var(--ink-soft);
    display:flex;align-items:center;justify-content:center;
    cursor:pointer;
    transition:border-color .15s, color .15s, background .15s;
  }
  .icon-btn:hover{border-color:var(--accent); color:var(--accent);}
  .icon-btn:focus-visible, button:focus-visible, input:focus-visible, [tabindex]:focus-visible{
    outline:2px solid var(--accent); outline-offset:2px;
  }

  .stat-strip{
    display:grid;
    grid-template-columns:repeat(3,1fr);
    gap:10px;
  }
  .stat-chip{
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:10px;
    padding:10px 12px;
    display:flex;
    flex-direction:column;
    gap:2px;
  }
  .stat-chip .n{
    font-family:var(--font-mono);
    font-weight:700;
    font-size:20px;
    font-variant-numeric:tabular-nums;
  }
  .stat-chip .l{
    font-size:11px;
    color:var(--ink-soft);
    text-transform:uppercase;
    letter-spacing:.05em;
  }
  .stat-chip.new .n{color:var(--accent);}
  .stat-chip.weak .n{color:var(--bad);}
  .stat-chip.mastered .n{color:var(--good);}

  .action-grid{
    display:grid;
    grid-template-columns:1fr;
    gap:10px;
  }
  @media (min-width:600px){ .action-grid{grid-template-columns:1fr 1fr; gap:12px;} }
  .action-card{
    text-align:left;
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:12px;
    padding:16px;
    cursor:pointer;
    display:flex;
    flex-direction:column;
    gap:6px;
    box-shadow:var(--shadow);
    transition:transform .12s ease, border-color .12s ease;
    -webkit-tap-highlight-color:transparent;
  }
  .action-card:hover{transform:translateY(-2px); border-color:var(--accent);}
  .action-card .tag{
    font-family:var(--font-mono);
    font-size:10.5px;
    letter-spacing:.08em;
    text-transform:uppercase;
    color:var(--accent);
    background:var(--accent-soft);
    padding:3px 7px;
    border-radius:4px;
    width:fit-content;
  }
  .action-card h3{
    font-family:var(--font-display);
    font-size:20px;
    margin:2px 0 0;
    text-transform:uppercase;
    letter-spacing:.01em;
  }
  .action-card p{margin:0; color:var(--ink-soft); font-size:13px;}

  .section-label{
    font-family:var(--font-display);
    text-transform:uppercase;
    letter-spacing:.04em;
    font-size:13px;
    color:var(--ink-soft);
    display:flex;
    align-items:center;
    gap:8px;
    margin:4px 0 -6px;
  }
  .section-label::after{
    content:"";
    flex:1;
    height:1px;
    background:var(--border);
  }

  .group-block{display:flex; flex-direction:column; gap:10px;}
  .cat-grid{
    display:grid;
    grid-template-columns:1fr;
    gap:10px;
  }
  @media (min-width:600px){ .cat-grid{grid-template-columns:repeat(2,1fr);} }
  .cat-card{
    background:var(--surface);
    border:1px solid var(--border);
    border-left:4px solid var(--border);
    border-radius:8px;
    padding:13px 14px;
    cursor:pointer;
    display:flex;
    flex-direction:column;
    gap:8px;
    transition:border-color .12s ease;
    -webkit-tap-highlight-color:transparent;
  }
  .cat-card:hover{border-color:var(--accent); border-left-color:var(--accent);}
  .cat-card.done{border-left-color:var(--good);}
  .cat-card .cat-top{display:flex; justify-content:space-between; align-items:baseline; gap:8px;}
  .cat-card .cat-name{font-weight:700; font-size:13.5px;}
  .cat-card .cat-count{font-family:var(--font-mono); font-size:11.5px; color:var(--ink-faint); white-space:nowrap;}
  .bar{height:5px; border-radius:3px; background:var(--surface-2); overflow:hidden;}
  .bar > i{display:block; height:100%; background:var(--accent); border-radius:3px;}
  .cat-card .cat-meta{font-size:11px; color:var(--ink-faint); display:flex; justify-content:space-between;}

  .card{
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:12px;
    padding:20px;
    box-shadow:var(--shadow);
  }
  .field{display:flex; flex-direction:column; gap:6px; margin-bottom:16px;}
  .field label{font-size:12.5px; font-weight:700; text-transform:uppercase; letter-spacing:.04em; color:var(--ink-soft);}
  .field .hint{font-size:12px; color:var(--ink-faint);}
  input[type=number]{
    font-family:var(--font-mono);
    font-size:16px;
    padding:8px 10px;
    border-radius:8px;
    border:1px solid var(--border);
    background:var(--bg);
    color:var(--ink);
    width:110px;
  }
  input[type=range]{width:100%; accent-color:var(--accent);}
  .toggle-row{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
    padding:12px 0;
    border-top:1px solid var(--border);
  }
  .toggle-row:first-of-type{border-top:none;}
  .toggle-row .t-title{font-weight:700; font-size:13.5px;}
  .toggle-row .t-desc{font-size:12px; color:var(--ink-soft); margin-top:2px;}
  .switch{
    position:relative; width:42px; height:24px; flex-shrink:0;
    border-radius:12px; background:var(--surface-2); border:1px solid var(--border);
    cursor:pointer; transition:background .15s;
  }
  .switch.on{background:var(--accent); border-color:var(--accent);}
  .switch i{
    position:absolute; top:2px; left:2px; width:18px; height:18px; border-radius:50%;
    background:var(--surface); transition:left .15s; box-shadow:0 1px 2px rgba(0,0,0,.3);
  }
  .switch.on i{left:20px; background:#fff;}

  .chk-list{display:flex; flex-direction:column; gap:2px; max-height:280px; overflow-y:auto; padding-right:4px;}
  .chk-item{
    display:flex; align-items:center; gap:10px;
    padding:10px 6px; border-radius:6px; cursor:pointer;
    min-height:26px;
  }
  .chk-item:hover{background:var(--surface-2);}
  .chk-box{
    width:18px; height:18px; border-radius:5px; border:1.5px solid var(--border);
    display:flex; align-items:center; justify-content:center; flex-shrink:0;
    color:var(--accent-ink); font-size:12px;
  }
  .chk-item.checked .chk-box{background:var(--accent); border-color:var(--accent);}
  .chk-group-row{border-top:1px solid var(--border); margin-top:6px; padding-top:10px !important;}
  .chk-group-row:first-child{border-top:none; margin-top:0;}
  .chk-group-row .chk-label{font-family:var(--font-display); text-transform:uppercase; font-size:12px; letter-spacing:.05em; color:var(--ink-soft); font-weight:600;}
  .chk-sub-disabled{opacity:.4;}
  .chk-item .chk-label{flex:1; font-size:13.5px;}
  .chk-item .chk-n{font-family:var(--font-mono); font-size:11px; color:var(--ink-faint);}

  .btn{
    display:inline-flex; align-items:center; justify-content:center; gap:8px;
    border-radius:9px; border:1px solid transparent; cursor:pointer;
    font-weight:700; font-size:14.5px; padding:12px 20px;
    font-family:var(--font-body);
    transition:transform .1s ease, filter .12s ease, background .12s ease;
  }
  .btn:active{transform:scale(.98);}
  .btn-primary{background:var(--accent); color:var(--accent-ink);}
  .btn-primary:hover{filter:brightness(1.08);}
  .btn-primary:disabled{opacity:.45; cursor:not-allowed;}
  .btn-ghost{background:transparent; color:var(--ink-soft); border-color:var(--border);}
  .btn-ghost:hover{border-color:var(--accent); color:var(--accent);}
  .btn-block{width:100%;}
  .btn-danger{background:transparent; color:var(--bad); border-color:var(--bad);}
  .btn-danger:hover{background:var(--bad-soft);}

  .progress-row{display:flex; align-items:center; gap:10px;}
  .progress-row .bar{flex:1;}
  .progress-row .pos{font-family:var(--font-mono); font-size:12.5px; color:var(--ink-soft); white-space:nowrap;}

  .q-meta{display:flex; align-items:center; gap:8px; margin-bottom:10px; flex-wrap:wrap;}
  .q-tag{
    font-family:var(--font-mono); font-size:10.5px; text-transform:uppercase; letter-spacing:.06em;
    background:var(--surface-2); color:var(--ink-soft); padding:3px 8px; border-radius:4px;
  }
  .q-tag.multi{background:var(--accent-soft); color:var(--accent);}
  .q-tag.warn{background:var(--warn-soft); color:var(--warn);}
  .q-text{
    font-size:18px; font-weight:700; line-height:1.4; margin:0 0 16px;
    text-wrap:balance;
  }
  .q-image{margin:0 0 16px; border-radius:9px; overflow:hidden; border:1px solid var(--border); background:var(--surface-2);}
  .q-image img{display:block; width:100%; height:auto; max-height:360px; object-fit:contain;}
  .opt-list{display:flex; flex-direction:column; gap:8px;}
  .opt{
    display:flex; align-items:flex-start; gap:11px;
    border:1.5px solid var(--border); border-radius:9px;
    padding:11px 13px; cursor:pointer; font-size:14.5px; line-height:1.45;
    transition:border-color .12s, background .12s;
  }
  .opt:hover{border-color:var(--accent);}
  .opt .mark{
    width:20px; height:20px; border-radius:50%; border:1.5px solid var(--border);
    flex-shrink:0; margin-top:1px; display:flex; align-items:center; justify-content:center;
    font-size:12px; color:#fff;
  }
  .opt.multi .mark{border-radius:5px;}
  .opt.checked .mark{background:var(--accent); border-color:var(--accent);}
  .opt.locked{cursor:default;}
  .opt.locked:hover{border-color:var(--border);}
  .opt.correct{border-color:var(--good); background:var(--good-soft);}
  .opt.correct .mark{background:var(--good); border-color:var(--good);}
  .opt.wrong{border-color:var(--bad); background:var(--bad-soft);}
  .opt.wrong .mark{background:var(--bad); border-color:var(--bad);}

  .order-list{display:flex; flex-direction:column; gap:8px;}
  .order-item{
    display:flex; align-items:center; gap:10px;
    border:1.5px solid var(--border); border-radius:9px; padding:10px 12px; font-size:14px;
  }
  .order-item .idx{
    font-family:var(--font-mono); font-weight:700; color:var(--accent);
    width:20px; text-align:center; flex-shrink:0;
  }
  .order-item .txt{flex:1;}
  .order-item .mv{display:flex; gap:4px;}
  .order-item .mv button{
    width:26px; height:26px; border-radius:6px; border:1px solid var(--border);
    background:var(--surface); color:var(--ink-soft); cursor:pointer;
  }
  .order-item .mv button:hover{border-color:var(--accent); color:var(--accent);}
  .order-item .mv button:disabled{opacity:.3; cursor:default;}
  .order-item.correct{border-color:var(--good); background:var(--good-soft);}
  .order-item.wrong{border-color:var(--bad); background:var(--bad-soft);}

  .note-box{
    font-size:12.5px; color:var(--warn); background:var(--warn-soft);
    border-radius:8px; padding:9px 11px; margin-top:12px; display:flex; gap:8px;
  }

  .feedback-banner{
    display:flex; align-items:center; gap:10px; padding:12px 14px; border-radius:9px;
    font-weight:700; font-size:14px; margin-bottom:14px;
  }
  .feedback-banner.good{background:var(--good-soft); color:var(--good);}
  .feedback-banner.bad{background:var(--bad-soft); color:var(--bad);}

  .actions-row{display:flex; gap:10px; margin-top:18px;}
  .actions-row .btn{flex:1;}

  .center-col{display:flex; flex-direction:column; align-items:center; text-align:center; gap:8px; padding:20px 6px;}
  .big-score{font-family:var(--font-display); font-size:56px; font-weight:700; line-height:1;}
  .big-score small{display:block; font-family:var(--font-body); font-size:13px; font-weight:600; color:var(--ink-soft); text-transform:uppercase; letter-spacing:.05em; margin-top:6px;}

  .mistake-list{display:flex; flex-direction:column; gap:10px; margin-top:10px;}
  .mistake-item{border:1px solid var(--border); border-radius:9px; padding:11px 13px;}
  .mistake-item .mq{font-weight:700; font-size:13.5px; margin-bottom:6px;}
  .mistake-item .ma{font-size:12.5px; color:var(--ink-soft);}
  .mistake-item .ma b{color:var(--good);}

  .flagged-item{border:1px solid var(--border); border-radius:9px; padding:12px; display:flex; flex-direction:column; gap:6px;}
  .flagged-item .fq{font-weight:700; font-size:13.5px;}
  .flagged-item .fn{font-size:12px; color:var(--warn);}

  .empty{color:var(--ink-faint); font-size:13.5px; text-align:center; padding:30px 10px;}

  .kbd-hint{font-size:11.5px; color:var(--ink-faint); text-align:center; margin-top:6px;}