/* 全局重置 & 深色主题 */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    }

    body {
      background-color: #0d1a26;
      display: flex;
      justify-content: center;
      padding: 1.2rem;
      min-height: 100vh;
    }

    .container {
      max-width: 1024px;
      width: 100%;
      background-color: #13212e;
      border-radius: 36px;
      box-shadow: 0 16px 48px rgba(0, 0, 0, 0.7);
      padding: 2rem 1.8rem 1.8rem;
      transition: all 0.2s;
      margin: 0.5rem 0;
      border: 1px solid #2b3f4f;
    }

    /* ===== 顶部导航 ===== */
    .top-bar {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: space-between;
      padding-bottom: 1.2rem;
      border-bottom: 1px solid #2b3f4f;
      margin-bottom: 1.8rem;
    }

    .brand {
      display: flex;
      flex-wrap: wrap;
      align-items: baseline;
      gap: 0.5rem 0.8rem;
    }

    .brand-title {
      font-size: 1.6rem;
      font-weight: 600;
      color: #e8edf2;
      letter-spacing: -0.02em;
    }

    .brand-address {
      font-size: 0.9rem;
      color: #9ab0c4;
      background: #1e313f;
      padding: 0.2rem 0.8rem;
      border-radius: 20px;
      white-space: nowrap;
      font-weight: 450;
    }

    .actions {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      gap: 0.8rem 1.4rem;
    }

    .actions a {
      text-decoration: none;
      color: #cbdae6;
      font-weight: 500;
      font-size: 0.95rem;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: color 0.15s;
      border-bottom: 2px solid transparent;
      padding-bottom: 2px;
    }

    .actions a:hover {
      color: #7ab7f0;
      border-bottom-color: #7ab7f0;
    }

    .actions .icon {
      font-size: 1.1rem;
      line-height: 1;
    }

    /* ===== 平台下载区 ===== */
    /* 引导标题 */
    .section-head {
      text-align: center;
      margin-bottom: 1.2rem;
    }
    .section-head h2 {
      color: #d6e5f0;
      font-weight: 500;
      font-size: 1.3rem;
      letter-spacing: 0.5px;
      border-bottom: 1px solid #2b3f4f;
      display: inline-block;
      padding-bottom: 0.4rem;
      padding-left: 0.8rem;
      padding-right: 0.8rem;
    }

    .platform-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 1.2rem;
      margin-bottom: 2.6rem;
    }

    .platform-item {
      background: #1a2b38;
      border-radius: 24px;
      padding: 1.2rem 0.6rem 1.2rem;
      border: 1px solid #2f4455;
      display: flex;
      flex-direction: column;
      align-items: center;
      transition: background 0.1s;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
      text-align: center;
    }

    .platform-item:hover {
      background: #1f3140;
      border-color: #3f5a6f;
    }

    .platform-header {
      display: flex;
      flex-direction: column;
      align-items: center;
      width: 100%;
      margin-bottom: 0.2rem;
    }

    .platform-name {
      font-weight: 600;
      font-size: 1.15rem;
      color: #e0eaf2;
      letter-spacing: -0.01em;
    }

    .platform-name small {
      font-weight: 400;
      font-size: 0.7rem;
      color: #86a0b5;
      margin-left: 0.2rem;
    }

    .platform-desc {
      font-size: 0.78rem;
      color: #a8bccf;
      margin-top: 0.15rem;
      opacity: 0.8;
      letter-spacing: 0.2px;
      line-height: 1.4;
      padding: 0 0.2rem;
    }

    .btn-group {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      margin-top: 0.7rem;
    }

    /* 按钮小巧 + 主按钮亮色 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.25rem 0.9rem;
      border-radius: 40px;
      font-weight: 500;
      font-size: 0.75rem;
      text-decoration: none;
      border: 1px solid transparent;
      transition: 0.15s ease;
      cursor: default;
      background: transparent;
      letter-spacing: 0.02em;
      min-height: 28px;
      min-width: 56px;
    }

    /* 主按钮亮色 (明亮蓝/青) */
    .btn-primary {
      background: #4a9eff;
      color: #0b1a26;
      border-color: #4a9eff;
      font-weight: 550;
      box-shadow: 0 2px 6px rgba(74, 158, 255, 0.25);
    }
    .btn-primary:hover {
      background: #6db4ff;
      border-color: #6db4ff;
      box-shadow: 0 4px 10px rgba(74, 158, 255, 0.35);
    }

    /* 安卓主按钮微调 (亮绿) */
    .platform-item:first-child .btn-primary {
      background: #4cdb7c;
      border-color: #4cdb7c;
      color: #0b1a26;
      box-shadow: 0 2px 6px rgba(76, 219, 124, 0.25);
    }
    .platform-item:first-child .btn-primary:hover {
      background: #6eea94;
      border-color: #6eea94;
      box-shadow: 0 4px 10px rgba(76, 219, 124, 0.35);
    }

    .btn-secondary {
      background: transparent;
      color: #c5d6e6;
      border-color: #3d566b;
    }
    .btn-secondary:hover {
      background: #233847;
      border-color: #5f7a92;
    }

    /* ===== 二维码 ===== */
    .qr-section {
      display: flex;
      justify-content: center;
      margin: 1.6rem 0 2.0rem;
    }

    .qr-box {
      background: #1c2d3b;
      padding: 1.2rem 1.8rem 1.0rem;
      border-radius: 40px;
      border: 1px solid #314b5e;
      display: inline-flex;
      flex-direction: column;
      align-items: center;
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    }

    .qr-svg {
      width: 140px;
      height: 140px;
      display: block;
      background: #f0f6fc;
      border-radius: 16px;
      padding: 6px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.3);
    }

    .qr-label {
      margin-top: 0.6rem;
      font-size: 0.85rem;
      color: #b6cddf;
      font-weight: 450;
      letter-spacing: 0.3px;
    }

    /* ===== 折叠 FAQ ===== */
    .faq-section {
      margin: 2.0rem 0 2.2rem;
      border-top: 1px solid #2b3f4f;
      padding-top: 1.6rem;
    }

    .faq-heading {
      color: #d6e5f0;
      font-weight: 500;
      font-size: 1.2rem;
      letter-spacing: 0.4px;
      margin-bottom: 1.2rem;
      text-align: center;
    }
    .faq-heading span {
      border-bottom: 1px solid #2b3f4f;
      padding-bottom: 0.3rem;
      padding-left: 1rem;
      padding-right: 1rem;
      display: inline-block;
    }

    details {
      background: #172733;
      border-radius: 18px;
      padding: 0.2rem 0.6rem 0.2rem 1.0rem;
      margin-bottom: 0.6rem;
      border: 1px solid #2f4455;
      transition: 0.1s;
    }

    details[open] {
      background: #1b2f3d;
      border-color: #40617a;
    }

    summary {
      font-weight: 550;
      color: #dae6f0;
      padding: 0.7rem 0.2rem;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: space-between;
      list-style: none;
      font-size: 1rem;
    }

    summary::-webkit-details-marker {
      display: none;
    }

    summary::after {
      content: "▶";
      font-size: 0.7rem;
      color: #7f9bb3;
      margin-left: 1rem;
      transition: transform 0.15s;
    }

    details[open] summary::after {
      transform: rotate(90deg);
    }

    .faq-answer {
      padding: 0.1rem 0.2rem 0.8rem 0.2rem;
      color: #c9dcec;
      line-height: 1.5;
      font-size: 0.95rem;
      border-top: 1px dashed #2c4457;
      margin-top: 0.2rem;
      padding-top: 0.8rem;
    }

    .faq-answer a {
      color: #78b5e6;
      text-decoration: none;
    }
    .faq-answer a:hover {
      text-decoration: underline;
    }

    /* ===== 底部 ===== */
    .footer {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: space-between;
      border-top: 1px solid #2b3f4f;
      padding-top: 1.5rem;
      margin-top: 0.4rem;
      font-size: 0.9rem;
      color: #b0c9dd;
      gap: 0.8rem;
    }

    .footer-links {
      display: flex;
      flex-wrap: wrap;
      gap: 1.2rem 1.6rem;
    }

    .footer-links a {
      text-decoration: none;
      color: #c5d8ea;
      font-weight: 470;
      border-bottom: 1px dotted transparent;
      transition: 0.1s;
    }
    .footer-links a:hover {
      color: #7ab7f0;
      border-bottom-color: #7ab7f0;
    }

    .footer-download {
      background: #1f3343;
      padding: 0.2rem 1.2rem;
      border-radius: 40px;
      font-weight: 470;
      color: #d4e3f0;
      border: 1px solid #3a576e;
      white-space: nowrap;
    }
    .footer-download a {
      text-decoration: none;
      color: inherit;
    }
    .footer-download a:hover {
      color: #9ac6ee;
    }

    /* ===== 响应式 ===== */
    @media (max-width: 820px) {
      .platform-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
      }
      .container {
        padding: 1.5rem 1.2rem;
      }
    }

    @media (max-width: 480px) {
      .platform-grid {
        grid-template-columns: 1fr 1fr;
        gap: 0.8rem;
      }
      .platform-item {
        padding: 0.9rem 0.4rem;
      }
      .platform-name {
        font-size: 1rem;
      }
      .platform-desc {
        font-size: 0.7rem;
      }
      .btn {
        font-size: 0.65rem;
        padding: 0.15rem 0.6rem;
        min-height: 24px;
        min-width: 44px;
      }
      .container {
        padding: 1rem 0.6rem;
        border-radius: 24px;
      }
      .top-bar {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
      }
      .actions {
        width: 100%;
        justify-content: flex-start;
        gap: 0.6rem 1rem;
        flex-wrap: wrap;
      }
      .actions a {
        font-size: 0.8rem;
      }
      .brand-title {
        font-size: 1.3rem;
      }
      .qr-svg {
        width: 100px;
        height: 100px;
      }
      .qr-box {
        padding: 0.8rem 1rem 0.6rem;
      }
      .footer {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.6rem;
      }
      .footer-links {
        gap: 0.6rem 1rem;
      }
      .section-head h2 {
        font-size: 1.1rem;
      }
      .faq-heading {
        font-size: 1rem;
      }
    }

    @media (max-width: 380px) {
      .platform-grid {
        grid-template-columns: 1fr;
        gap: 0.8rem;
      }
      .platform-item {
        max-width: 280px;
        margin: 0 auto;
        width: 100%;
      }
      .btn-group {
        flex-wrap: wrap;
      }
    }