:root{
    --indigo:#241A55; --indigo2:#2E1F6B; --violet:#6C4DE6; --violet-soft:#8B6FF2;
    --lime:#159B63; --lime-d:#0F7A4B; --lime-bg:#E7F7EF; --coral:#E2574C; --coral-bg:#FCEBEA;
    --ink:#1B1830; --mute:#6F6B89; --line:#E7E3F4; --paper:#F5F3FB; --expl:#EFEBFB; --card:#FFFFFF;
  }
  *{box-sizing:border-box;margin:0;padding:0}
  html,body{background:var(--indigo)}
  body{
    font-family:"Segoe UI",Roboto,system-ui,-apple-system,sans-serif;
    background:radial-gradient(130% 90% at 50% -10%, #3a2a86 0%, #241a55 55%, #190f3d 100%);
    color:var(--ink); min-height:100vh; display:flex; justify-content:center;
    padding:16px 12px 48px; -webkit-font-smoothing:antialiased;
  }
  .app{width:100%;max-width:440px}

  .top{display:flex;align-items:center;justify-content:space-between;color:#fff;margin:4px 4px 16px}
  .brand{font-size:21px;font-weight:800;letter-spacing:-.4px;cursor:pointer}
  .brand span{color:#a78bff}
  .hud{display:flex;gap:7px;font-size:12px;font-weight:700}
  .chip{background:rgba(255,255,255,.13);padding:6px 11px;border-radius:999px;display:flex;gap:5px;align-items:center}
  .chip.streak.hot{background:var(--coral)}
  .chip.timer.warn{background:var(--coral)}

  .card{background:var(--card);border-radius:24px;padding:22px;box-shadow:0 20px 50px rgba(15,8,45,.4)}

  /* home */
  .hero-eyebrow{font-size:11px;font-weight:800;letter-spacing:2px;text-transform:uppercase;color:var(--violet)}
  h1.hero{font-size:25px;line-height:1.2;color:var(--indigo2);margin:6px 0 8px;letter-spacing:-.4px}
  .hero-sub{font-size:14px;color:var(--mute);line-height:1.55;margin-bottom:18px}
  .sections{display:flex;flex-direction:column;gap:12px}
  .sec{display:flex;align-items:center;gap:14px;border:1.5px solid var(--line);border-radius:18px;
    padding:14px 15px;cursor:pointer;transition:.15s;background:#fff;text-align:left;width:100%}
  .sec:hover{border-color:var(--violet-soft);transform:translateY(-1px)}
  .sec:focus-visible{outline:3px solid var(--violet-soft);outline-offset:2px}
  .sec .ic{width:44px;height:44px;border-radius:13px;display:grid;place-items:center;font-size:20px;flex:0 0 auto;color:#fff}
  .sec .ic.l{background:#6C4DE6}.sec .ic.r{background:#159B63}.sec .ic.g{background:#E0823C}.sec .ic.w{background:#C7466B}
  .sec .meta{flex:1;min-width:0}
  .sec .meta h3{font-size:16px;color:var(--ink);margin-bottom:2px}
  .sec .meta p{font-size:12px;color:var(--mute);line-height:1.4}
  .sec .go{font-size:20px;color:var(--violet);font-weight:800}
  .official{font-size:10px;font-weight:800;letter-spacing:.5px;text-transform:uppercase;
    color:var(--lime-d);background:var(--lime-bg);padding:2px 7px;border-radius:6px;margin-left:6px}
  .official.bonus{color:#B5651D;background:#FBEFE2}

  /* study-guide banner card on home */
  .studycard{display:flex;align-items:center;gap:14px;width:100%;text-align:left;cursor:pointer;
    margin-top:14px;border:none;border-radius:18px;padding:16px;color:#fff;transition:.15s;
    background:linear-gradient(120deg,#2E1F6B,#6C4DE6)}
  .studycard:hover{transform:translateY(-1px);box-shadow:0 10px 24px rgba(108,77,230,.4)}
  .studycard .ic{width:44px;height:44px;border-radius:13px;display:grid;place-items:center;
    font-size:20px;background:rgba(255,255,255,.18);flex:0 0 auto}
  .studycard h3{font-size:16px;margin-bottom:2px}
  .studycard p{font-size:12px;color:#e0d8ff;line-height:1.4}
  .studycard .go{font-size:20px;font-weight:800;color:#fff}

  .scoring{margin-top:18px;background:var(--paper);border-radius:16px;padding:14px 16px}
  .scoring h4{font-size:12px;font-weight:800;letter-spacing:1px;text-transform:uppercase;color:var(--violet);margin-bottom:6px}
  .scoring p{font-size:12.5px;color:var(--mute);line-height:1.5}
  .disclaimer{font-size:11px;color:rgba(255,255,255,.55);text-align:center;margin-top:16px;line-height:1.5;padding:0 6px}

  /* quiz */
  .qhead{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
  .qhead .label{font-size:11px;font-weight:800;letter-spacing:1.5px;text-transform:uppercase;color:var(--violet)}
  .qhead .setno{font-size:12px;font-weight:700;color:var(--mute)}
  .progress{height:6px;background:var(--line);border-radius:99px;overflow:hidden;margin-bottom:16px}
  .progress > i{display:block;height:100%;background:var(--violet);width:0;transition:width .3s ease}
  .passage{background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:14px;
    font-size:13.5px;line-height:1.6;color:#34304d;margin-bottom:16px;max-height:200px;overflow:auto}
  .intro-note{font-size:13px;color:var(--coral);font-weight:700;margin-bottom:12px}
  .listen-btn{display:flex;align-items:center;gap:10px;width:100%;justify-content:center;
    background:#efeaff;border:1.5px solid #d9ccff;color:var(--indigo2);
    font-weight:800;font-size:15px;padding:13px;border-radius:14px;cursor:pointer;margin-bottom:16px}
  .listen-btn:active{transform:scale(.99)}.listen-btn.playing{background:#e4dbff}
  .q{font-size:17px;font-weight:700;color:var(--ink);line-height:1.4;margin-bottom:14px}
  .opts{display:flex;flex-direction:column;gap:10px}
  .opt{border:1.5px solid var(--line);background:#fff;border-radius:14px;padding:14px 15px;
    font-size:15px;text-align:left;cursor:pointer;transition:.12s;color:var(--ink);font-weight:600;line-height:1.35}
  .opt:hover{border-color:var(--violet-soft)}
  .opt:focus-visible{outline:3px solid var(--violet-soft);outline-offset:2px}
  .opt.correct{border-color:var(--lime);background:var(--lime-bg);color:#0f5e3c}
  .opt.wrong{border-color:var(--coral);background:var(--coral-bg);color:#9c2f27}
  .opt.dim{opacity:.55}.opts.locked .opt{pointer-events:none}
  .explain{margin-top:13px;font-size:13.5px;line-height:1.5;color:#3a3658;background:var(--paper);
    border-left:3px solid var(--violet);border-radius:8px;padding:11px 13px;display:none}
  .explain.show{display:block}
  .feedback{margin-top:12px;font-size:14px;font-weight:800;min-height:18px}
  .feedback.good{color:var(--lime-d)} .feedback.bad{color:var(--coral)}
  textarea{width:100%;min-height:200px;border:1.5px solid var(--line);border-radius:14px;
    padding:14px;font-size:15px;font-family:inherit;resize:vertical;line-height:1.55;color:var(--ink)}
  textarea:focus{outline:none;border-color:var(--violet)}
  .wcount{font-size:12px;color:var(--mute);margin:8px 2px 0;font-weight:700}
  .btn{display:block;width:100%;border:none;border-radius:14px;padding:15px;font-size:15px;
    font-weight:800;cursor:pointer;margin-top:16px;transition:.12s}
  .btn.primary{background:var(--violet);color:#fff;box-shadow:0 8px 18px rgba(108,77,230,.38)}
  .btn.primary:active{transform:translateY(1px)}
  .btn.ghost{background:var(--paper);color:var(--indigo2)}
  .btn.link{background:none;color:var(--mute);box-shadow:none;font-size:13px;padding:8px;margin-top:8px}
  .btn[disabled]{opacity:.45;cursor:not-allowed;box-shadow:none}
  .row2{display:flex;gap:10px}.row2 .btn{margin-top:16px}

  /* result */
  .band-wrap{text-align:center;padding:4px 0}
  .band-num{font-size:66px;font-weight:800;color:var(--indigo2);line-height:1;letter-spacing:-2px}
  .band-label{font-size:12px;font-weight:800;letter-spacing:2px;text-transform:uppercase;color:var(--violet);margin-top:4px}
  .meter{position:relative;height:16px;border-radius:99px;background:var(--line);margin:20px 0 7px;overflow:hidden}
  .meter > i{position:absolute;inset:0 100% 0 0;border-radius:99px;
    background:linear-gradient(90deg,var(--violet),var(--lime));transition:right 1.1s cubic-bezier(.2,.7,.2,1)}
  .ticks{display:flex;justify-content:space-between;font-size:10px;color:var(--mute);font-weight:700}
  .breakdown{margin-top:18px;display:flex;flex-direction:column;gap:10px}
  .brow{display:flex;align-items:center;justify-content:space-between;background:var(--paper);
    border-radius:12px;padding:12px 14px;font-size:14px;font-weight:700;color:var(--ink)}
  .brow b{color:var(--violet);font-size:15px}
  .note{font-size:12px;color:var(--mute);line-height:1.55;margin-top:14px}

  /* ---------- STUDY GUIDE (sg- prefixed to avoid clashes) ---------- */
  .sg-head{display:flex;align-items:center;gap:10px;margin-bottom:14px}
  .sg-back{background:var(--paper);border:none;border-radius:10px;width:38px;height:38px;font-size:18px;
    color:var(--indigo2);cursor:pointer;flex:0 0 auto}
  .sg-head h2{font-size:18px;color:var(--indigo2);letter-spacing:-.3px}
  .sg-head p{font-size:11px;color:var(--mute)}
  .sg-tabs{display:flex;gap:5px;overflow-x:auto;padding-bottom:10px;margin-bottom:6px;border-bottom:1px solid var(--line)}
  .sg-tab{flex:0 0 auto;border:none;background:none;font-size:13px;font-weight:700;color:var(--mute);
    padding:8px 12px;border-radius:999px;cursor:pointer;white-space:nowrap}
  .sg-tab.active{background:var(--violet);color:#fff}
  .sg-toggle{display:flex;justify-content:flex-end;align-items:center;gap:8px;font-size:12px;
    color:var(--mute);font-weight:700;margin:10px 0 14px}
  .sg-switch{position:relative;width:42px;height:24px;background:var(--line);border-radius:99px;cursor:pointer;transition:.2s}
  .sg-switch.on{background:var(--lime)}
  .sg-switch i{position:absolute;top:3px;left:3px;width:18px;height:18px;background:#fff;border-radius:50%;transition:.2s}
  .sg-switch.on i{left:21px}
  .sg-pane{display:none}.sg-pane.active{display:block}
  .sg-panel{background:var(--paper);border-radius:14px;padding:15px 16px;margin-bottom:12px}
  .sg-panel h3{font-size:14px;color:var(--indigo2);margin-bottom:9px}
  .sg-panel ul{list-style:none}
  .sg-panel li{position:relative;padding-left:18px;margin-bottom:8px;font-size:13px;color:#2c2945;line-height:1.5}
  .sg-panel li::before{content:"";position:absolute;left:0;top:7px;width:7px;height:7px;border-radius:50%;background:var(--violet)}
  .sg-set{border:1px solid var(--line);border-radius:14px;padding:15px;margin-bottom:13px}
  .sg-setname{font-size:14px;font-weight:800;color:var(--indigo2);margin-bottom:9px}
  .sg-source{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:11px 12px;
    font-size:12.5px;line-height:1.6;color:#34304d;margin-bottom:12px}
  .sg-source b{color:var(--violet);text-transform:uppercase;font-size:10px;letter-spacing:1px}
  .sg-q{margin-bottom:14px}.sg-q:last-child{margin-bottom:0}
  .sg-qtext{font-size:13.5px;font-weight:700;color:var(--ink);margin-bottom:7px;line-height:1.4}
  .sg-opt{font-size:13px;padding:6px 11px;border:1.5px solid var(--line);border-radius:9px;margin-bottom:5px;color:var(--ink)}
  .sg-reveal .sg-opt.correct{border-color:var(--lime);background:var(--lime-bg);color:var(--lime-d);font-weight:700}
  .sg-opt .lt{font-weight:800;color:var(--mute);margin-right:6px}
  .sg-reveal .sg-opt.correct .lt{color:var(--lime-d)}
  .sg-why{font-size:12.5px;line-height:1.55;color:#34304f;background:var(--expl);border-left:3px solid var(--violet);
    border-radius:8px;padding:9px 11px;margin-top:7px;display:none}
  .sg-reveal .sg-why{display:block}
  .sg-why b{color:var(--violet)}
  .sg-pnum{font-size:11px;font-weight:800;color:var(--violet);letter-spacing:.5px}
  .sg-prompt{font-size:13.5px;color:var(--ink);margin:3px 0 7px;font-weight:600;line-height:1.45}

  .hidden{display:none}
  @media (prefers-reduced-motion: reduce){*{transition:none!important}}

  /* ---------- study-guide password gate ---------- */
  .sg-gate{text-align:center;padding:22px 8px}
  .sg-lock{font-size:42px;margin-bottom:10px}
  .sg-gate h3{font-size:18px;color:var(--indigo2);margin-bottom:6px}
  .sg-gate p{font-size:13px;color:var(--mute);margin-bottom:16px;line-height:1.5}
  .sg-gate input{width:100%;border:1.5px solid var(--line);border-radius:12px;padding:13px 14px;
    font-size:15px;text-align:center;letter-spacing:1px;color:var(--ink)}
  .sg-gate input:focus{outline:none;border-color:var(--violet)}
  .sg-err{display:none;color:var(--coral);font-size:13px;font-weight:700;margin-top:10px}
  .sg-err.show{display:block}