:root {
      --bg: #f4f5fa;
      --surface: #ffffff;
      --ink: #1b1f2e;
      --ink-soft: #5a6072;
      --ink-faint: #8a90a4;
      --line: #e4e6f0;
      --primary: #4f46e5;
      --primary-soft: #eef0ff;
      --accent: #7c3aed;
      --good: #059669;
      --bad: #dc2626;
      --radius: 18px;
      --shadow: 0 10px 30px rgba(30, 34, 80, 0.08);
      --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }
    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      min-height: 100vh;
      font-family: var(--font);
      color: var(--ink);
      background:
        radial-gradient(60rem 30rem at 85% -10%, rgba(124, 58, 237, 0.10), transparent 60%),
        radial-gradient(50rem 26rem at -10% 10%, rgba(79, 70, 229, 0.10), transparent 60%),
        var(--bg);
    }
    .wrap { max-width: 42rem; margin: 0 auto; padding: 2.5rem 1.25rem 4rem; }
    header.page { text-align: center; margin-bottom: 1.75rem; }
    .logo { display: inline-flex; align-items: center; gap: 0.55rem; font-weight: 700; font-size: 1.05rem; color: var(--ink); }
    .logo svg { width: 1.5rem; height: 1.5rem; }
    .tagline { margin: 0.4rem 0 0; color: var(--ink-faint); font-size: 0.9rem; }

    .card {
      background: var(--surface);
      border: 1px solid var(--line);
      border-radius: var(--radius);
      box-shadow: var(--shadow);
      padding: 1.75rem;
    }

    /* Step 1: start */
    .start-hero { text-align: center; padding: 1.25rem 0.5rem 0.75rem; }
    .start-hero h1 { font-size: 1.9rem; line-height: 1.25; margin: 0.25rem 0 0.6rem; }
    .start-hero p { color: var(--ink-soft); line-height: 1.8; margin: 0 auto; max-width: 30rem; }
    .meta { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.5rem; margin: 1.1rem 0 1.4rem; }
    .pill { display: inline-flex; align-items: center; gap: 0.35rem; padding: 0.35rem 0.7rem; border-radius: 999px; background: var(--primary-soft); color: var(--primary); font-size: 0.82rem; font-weight: 600; }

    .btn {
      display: inline-flex; align-items: center; justify-content: center; gap: 0.45rem;
      border: 0; cursor: pointer; font-family: inherit; font-weight: 600; font-size: 1rem;
      padding: 0.8rem 2rem; border-radius: 999px; color: #fff; background: linear-gradient(135deg, var(--primary), var(--accent));
      box-shadow: 0 8px 20px rgba(79, 70, 229, 0.28);
      transition: transform 0.15s ease, box-shadow 0.15s ease, opacity 0.15s ease;
    }
    .btn:hover { transform: translateY(-1px); box-shadow: 0 10px 24px rgba(79, 70, 229, 0.34); }
    .btn:active { transform: translateY(0); }
    .btn:focus-visible { outline: 3px solid rgba(79, 70, 229, 0.45); outline-offset: 2px; }
    .btn:disabled { opacity: 0.55; cursor: default; transform: none; }

    /* Progress */
    .progress { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.25rem; }
    .progress .bar { flex: 1; height: 8px; border-radius: 999px; background: #eceef7; overflow: hidden; }
    .progress .bar i { display: block; height: 100%; width: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--primary), var(--accent)); transform-origin: left; transform: scaleX(0); transition: transform 0.35s ease; }
    .progress .num { font-size: 0.82rem; font-weight: 700; color: var(--ink-faint); letter-spacing: 0.02em; }

    .q-head { display: flex; align-items: center; gap: 0.5rem; margin-bottom: 0.5rem; }
    .q-tag { font-size: 0.75rem; font-weight: 700; color: var(--primary); background: var(--primary-soft); padding: 0.2rem 0.55rem; border-radius: 999px; }
    .q-title { font-size: 1.15rem; font-weight: 700; line-height: 1.5; margin: 0 0 1.1rem; }
    .opts { display: grid; gap: 0.65rem; }
    .opt {
      text-align: left; font-family: inherit; font-size: 1rem; color: var(--ink);
      border: 1px solid var(--line); border-radius: 14px; background: #fbfbfe;
      padding: 0.85rem 1rem; cursor: pointer; transition: border-color 0.15s ease, background 0.15s ease, transform 0.15s ease;
    }
    .opt:hover { border-color: var(--primary); background: var(--primary-soft); }
    .opt:focus-visible { outline: 3px solid rgba(79, 70, 229, 0.4); outline-offset: 1px; }
    .opt.selected { border-color: var(--primary); background: var(--primary-soft); font-weight: 600; }
    .q-foot { display: flex; justify-content: flex-end; margin-top: 1.4rem; }

    /* Analyzing animation */
    .analyzing { text-align: center; padding: 1.5rem 0.5rem; }
    .brain { width: 3.25rem; height: 3.25rem; margin: 0 auto 1rem; color: var(--primary); }
    .brain circle.ring { animation: pulse 1.4s ease-in-out infinite; transform-origin: center; }
    .analyzing p { color: var(--ink-soft); margin: 0.3rem 0 0; font-size: 0.95rem; }
    .steps { display: grid; gap: 0.5rem; max-width: 24rem; margin: 1.1rem auto 0; text-align: left; }
    .steps li { list-style: none; display: flex; align-items: center; gap: 0.55rem; color: var(--ink-faint); font-size: 0.88rem; opacity: 0.35; transition: opacity 0.4s ease; }
    .steps li.done { opacity: 1; color: var(--ink-soft); }
    .steps li.done::before { content: "\2713"; color: var(--good); font-weight: 700; }
    .steps li:not(.done)::before { content: "\00b7"; font-weight: 700; }
    @keyframes pulse { 0%, 100% { opacity: 0.35; transform: scale(0.92); } 50% { opacity: 1; transform: scale(1); } }

    /* Result */
    .result { text-align: center; }
    .score-ring { position: relative; width: 9.5rem; height: 9.5rem; margin: 0.5rem auto 0.25rem; }
    .score-ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
    .score-ring .track { fill: none; stroke: #eceef7; stroke-width: 10; }
    .score-ring .value { fill: none; stroke: url(#grad); stroke-width: 10; stroke-linecap: round; transition: stroke-dashoffset 1s ease; }
    .score-num { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
    .score-num b { font-size: 2.3rem; line-height: 1; }
    .score-num span { font-size: 0.78rem; color: var(--ink-faint); margin-top: 0.25rem; }
    .band { display: inline-block; margin-top: 0.35rem; padding: 0.35rem 1rem; border-radius: 999px; font-weight: 700; font-size: 0.95rem; }
    .band.high { background: #ecfdf5; color: var(--good); }
    .band.mid { background: #eef0ff; color: var(--primary); }
    .band.low { background: #fff7ed; color: #c2410c; }
    .insight { margin: 1.4rem auto 0; max-width: 30rem; text-align: left; }
    .insight h3 { font-size: 0.95rem; margin: 0 0 0.75rem; display: flex; align-items: center; gap: 0.4rem; color: var(--primary); }
    .insight .lines { display: grid; gap: 0.6rem; }
    .insight .line { border-left: 3px solid var(--line); padding: 0.55rem 0.9rem; background: #fafafe; border-radius: 0 10px 10px 0; color: var(--ink-soft); line-height: 1.65; font-size: 0.94rem; opacity: 0; transform: translateY(6px); transition: opacity 0.5s ease, transform 0.5s ease; }
    .insight .line.show { opacity: 1; transform: none; }
    .result-actions { margin-top: 1.6rem; display: flex; flex-wrap: wrap; justify-content: center; gap: 0.75rem; }
    .btn.ghost { background: transparent; color: var(--primary); border: 1px solid var(--line); box-shadow: none; }
    .btn.ghost:hover { border-color: var(--primary); background: var(--primary-soft); box-shadow: none; }

    .note { margin-top: 1.25rem; color: var(--ink-faint); font-size: 0.78rem; line-height: 1.6; text-align: center; }
    footer.page { text-align: center; color: var(--ink-faint); font-size: 0.78rem; margin-top: 1.75rem; }

    .hidden { display: none !important; }

    @media (max-width: 480px) {
      .wrap { padding-top: 1.5rem; }
      .card { padding: 1.35rem; }
      .start-hero h1 { font-size: 1.6rem; }
    }
    @media print {
      body { background: #fff; }
      .wrap { padding: 0; }
      .card { box-shadow: none; }
      .btn, .result-actions, footer.page { display: none; }
    }
    @media (prefers-reduced-motion: reduce) {
      *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
    }