* { box-sizing: border-box; margin: 0; padding: 0; }

  body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: #0b0d12;
    color: #e6e8ee;
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
  }

  body::before {
    content: "";
    position: fixed;
    inset: 0;
    background:
      radial-gradient(600px 400px at 15% -5%, rgba(124,108,255,.20), transparent 70%),
      radial-gradient(520px 420px at 90% 15%, rgba(34,211,238,.12), transparent 70%);
    pointer-events: none;
    z-index: 0;
  }

  .wrap {
    position: relative;
    z-index: 1;
    max-width: 760px;
    margin: 0 auto;
    padding: 0 20px 80px;
  }

  .screen { display: none; }
  .screen.active { display: block; animation: fadeIn .35s ease; }

  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: none; }
  }

  /* ============ 开始页 ============ */
  .hero { text-align: center; padding: 72px 0 44px; }

  .badge {
    display: inline-block;
    padding: 6px 14px;
    font-size: 12px;
    letter-spacing: .12em;
    color: #a9a2ff;
    background: rgba(124,108,255,.12);
    border: 1px solid rgba(124,108,255,.28);
    border-radius: 999px;
    margin-bottom: 22px;
  }

  h1 {
    font-size: clamp(26px, 5vw, 38px);
    font-weight: 700;
    letter-spacing: -.02em;
    margin-bottom: 14px;
    background: linear-gradient(120deg, #fff 20%, #b7aaff 90%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
  }

  .sub {
    color: #8b93a5;
    font-size: 14px;
    max-width: 460px;
    margin: 0 auto;
  }

  .size-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
    margin-top: 8px;
  }

  .size-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 26px 10px;
    background: #14181f;
    border: 1px solid rgba(255,255,255,.07);
    border-radius: 18px;
    cursor: pointer;
    color: #e6e8ee;
    font-family: inherit;
    transition: all .2s ease;
  }

  .size-card:hover {
    transform: translateY(-3px);
    border-color: rgba(124,108,255,.55);
    box-shadow: 0 14px 30px -12px rgba(124,108,255,.45);
    background: #171c25;
  }

  .size-num {
    font-size: 34px;
    font-weight: 700;
    line-height: 1.1;
    background: linear-gradient(135deg, #a78bfa, #22d3ee);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
  }

  .size-label { font-size: 14px; font-weight: 600; }
  .size-desc { font-size: 12px; color: #7b8496; }

  .footnote {
    margin-top: 36px;
    text-align: center;
    font-size: 12px;
    color: #5f6779;
    line-height: 1.8;
  }

  /* ============ 答题页 ============ */
  .quiz-bar {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 0;
    background: rgba(11,13,18,.86);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid rgba(255,255,255,.06);
    margin-bottom: 22px;
  }

  .ghost-btn {
    background: none;
    border: 1px solid rgba(255,255,255,.1);
    color: #9aa3b2;
    font-size: 13px;
    font-family: inherit;
    padding: 7px 13px;
    border-radius: 10px;
    cursor: pointer;
    white-space: nowrap;
    transition: all .18s;
  }
  .ghost-btn:hover:not(:disabled) { color: #fff; border-color: rgba(255,255,255,.28); }
  .ghost-btn:disabled { opacity: .32; cursor: not-allowed; }

  .progress-track {
    flex: 1;
    height: 6px;
    background: #1a1f29;
    border-radius: 999px;
    overflow: hidden;
  }

  #progress-fill {
    height: 100%;
    width: 0;
    border-radius: 999px;
    background: linear-gradient(90deg, #7c6cff, #22d3ee);
    transition: width .3s ease;
  }

  .progress-text {
    font-size: 12px;
    color: #8b93a5;
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
    min-width: 48px;
    text-align: right;
  }

  /* 单题卡片 */
  .q-single {
    background: #12161d;
    border: 1px solid rgba(255,255,255,.06);
    border-radius: 20px;
    padding: 28px 24px 24px;
  }

  @keyframes qIn {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  .q-badge {
    display: inline-block;
    font-size: 12px;
    letter-spacing: .06em;
    color: #a9a2ff;
    background: rgba(124,108,255,.12);
    border-radius: 999px;
    padding: 4px 12px;
    margin-bottom: 18px;
  }

  .q-single-text {
    font-size: clamp(17px, 4.6vw, 21px);
    font-weight: 600;
    line-height: 1.55;
    color: #e8ebf2;
    margin-bottom: 24px;
    letter-spacing: -.01em;
  }

  .opt-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }

  .opt-item {
    display: flex;
    align-items: center;
    gap: 14px;
    width: 100%;
    padding: 15px 18px;
    background: #171c25;
    border: 1px solid rgba(255,255,255,.07);
    border-radius: 14px;
    cursor: pointer;
    font-family: inherit;
    font-size: 15px;
    color: #b9c0cf;
    text-align: left;
    transition: all .16s ease;
  }

  .opt-item:hover {
    border-color: rgba(124,108,255,.55);
    background: #1b212b;
    color: #fff;
  }

  .opt-item.active {
    background: linear-gradient(135deg, #7c6cff, #5b48d6);
    border-color: transparent;
    color: #fff;
    box-shadow: 0 8px 20px -8px rgba(124,108,255,.9);
  }

  .opt-dot {
    width: 20px;
    height: 20px;
    flex: none;
    border-radius: 50%;
    border: 2px solid #3a4252;
    background: transparent;
    transition: all .16s ease;
  }

  .opt-item:hover .opt-dot { border-color: #7c6cff; }

  .opt-item.active .opt-dot {
    border-color: #fff;
    background: #fff;
    box-shadow: inset 0 0 0 4px #6b5ae0;
  }

  .opt-label { flex: 1; }

  .q-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-top: 24px;
  }

  .primary-btn {
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    color: #fff;
    padding: 13px 34px;
    border: none;
    border-radius: 14px;
    cursor: pointer;
    background: linear-gradient(135deg, #7c6cff, #4f3fd0);
    box-shadow: 0 12px 28px -10px rgba(124,108,255,.9);
    transition: transform .16s, box-shadow .16s;
  }

  .primary-btn:hover { transform: translateY(-2px); box-shadow: 0 16px 34px -10px rgba(124,108,255,1); }
  .primary-btn:active { transform: translateY(0); }

  /* ============ 结果页 ============ */
  .result-card {
    margin-top: 54px;
    padding: 38px 26px;
    text-align: center;
    border-radius: 22px;
    background:
      radial-gradient(420px 200px at 50% 0%, rgba(124,108,255,.20), transparent 70%),
      #12161d;
    border: 1px solid rgba(124,108,255,.22);
  }

  .result-type {
    font-size: clamp(46px, 12vw, 70px);
    font-weight: 800;
    letter-spacing: .06em;
    line-height: 1.05;
    background: linear-gradient(120deg, #ffffff, #a78bfa 55%, #22d3ee);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
  }

  .result-nick {
    margin-top: 8px;
    font-size: 16px;
    font-weight: 600;
    color: #c8c2ff;
  }

  .result-desc {
    margin-top: 14px;
    font-size: 14px;
    color: #8b93a5;
    max-width: 420px;
    margin-left: auto;
    margin-right: auto;
  }

  .dims { margin-top: 34px; }

  .dims-title {
    font-size: 13px;
    color: #6f7789;
    letter-spacing: .1em;
    margin-bottom: 18px;
    text-align: center;
  }

  .dim-row {
    display: grid;
    grid-template-columns: 74px 1fr 74px;
    align-items: center;
    gap: 14px;
    margin-bottom: 20px;
  }

  .dim-side { display: flex; flex-direction: column; line-height: 1.25; }
  .dim-side.right { text-align: right; }

  .dim-code { font-size: 15px; font-weight: 700; color: #d8dce6; }
  .dim-name { font-size: 11px; color: #6f7789; }
  .dim-pct { font-size: 12px; color: #a9a2ff; font-variant-numeric: tabular-nums; }
  .dim-side.right .dim-pct { color: #22d3ee; }

  .dim-track {
    display: flex;
    height: 10px;
    border-radius: 999px;
    overflow: hidden;
    background: #1a1f29;
  }

  .dim-seg.a { background: linear-gradient(90deg, #5b48d6, #7c6cff); transition: width .8s cubic-bezier(.22,1,.36,1); }
  .dim-seg.b { background: linear-gradient(90deg, #22d3ee, #0ea5b7); transition: width .8s cubic-bezier(.22,1,.36,1); }

  .dim-hint {
    text-align: center;
    font-size: 11px;
    color: #5f6779;
    margin-top: 2px;
  }

  .actions { display: flex; gap: 12px; justify-content: center; margin-top: 36px; flex-wrap: wrap; }

  .secondary-btn {
    font-family: inherit;
    font-size: 14px;
    color: #b9c0cf;
    padding: 13px 30px;
    background: #161b24;
    border: 1px solid rgba(255,255,255,.1);
    border-radius: 14px;
    cursor: pointer;
    transition: all .18s;
  }
  .secondary-btn:hover { color: #fff; border-color: rgba(255,255,255,.3); }

  @media (max-width: 520px) {
    .size-grid { gap: 10px; }
    .size-card { padding: 20px 6px; border-radius: 15px; }
    .size-num { font-size: 27px; }
    .size-label { font-size: 13px; }
    .size-desc { font-size: 11px; }
    .q-single { padding: 20px 16px 18px; border-radius: 16px; }
    .q-single-text { margin-bottom: 18px; }
    .opt-item { padding: 13px 15px; font-size: 14px; gap: 12px; }
    .opt-dot { width: 18px; height: 18px; }
    .q-footer { margin-top: 18px; }
    .primary-btn { padding: 12px 26px; font-size: 14px; }
    .dim-row { grid-template-columns: 62px 1fr 62px; gap: 10px; }
    .result-card { margin-top: 34px; padding: 30px 18px; }
  }