:root {
    --blue-deep: #0b3d91;
    --blue-main: #1a73e8;
    --blue-light: #e8f0fe;
    --blue-soft: #f4f8ff;
    --text-main: #1f2a3c;
    --text-sub: #55617a;
    --white: #ffffff;
    --border: #d8e2f3;
    --radius: 14px;
    --shadow: 0 6px 24px rgba(11, 61, 145, 0.08);
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }
  html { scroll-behavior: smooth; }
  body {
    font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: var(--text-main);
    background: var(--blue-soft);
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
  }
  img { max-width: 100%; display: block; }
  a { color: var(--blue-main); text-decoration: none; }

  /* ---------- 头部 ---------- */
  .site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
  }
  .header-inner {
    max-width: 1180px;
    margin: 0 auto;
    padding: 12px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
  }
  .brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    color: var(--blue-deep);
    letter-spacing: 0.5px;
  }
  .brand img {
    height: 34px;
    width: auto;
    border-radius: 8px;
  }
  .nav-links {
    display: flex;
    align-items: center;
    gap: 26px;
    font-size: 15px;
  }
  .nav-links a {
    color: var(--text-sub);
    transition: color 0.2s;
  }
  .nav-links a:hover { color: var(--blue-main); }
  .btn-download {
    display: inline-block;
    background: linear-gradient(135deg, var(--blue-main), var(--blue-deep));
    color: var(--white);
    padding: 10px 24px;
    border-radius: 999px;
    font-weight: 600;
    font-size: 15px;
    box-shadow: 0 4px 14px rgba(26, 115, 232, 0.3);
    transition: transform 0.2s, box-shadow 0.2s;
  }
  .btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(26, 115, 232, 0.38);
  }
  .menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--blue-deep);
    cursor: pointer;
  }

  /* ---------- 首屏 ---------- */
  .hero {
    position: relative;
    overflow: hidden;
    background: linear-gradient(160deg, #eef5ff 0%, #dce9ff 55%, #cfe1ff 100%);
    padding: 72px 20px 88px;
  }
  .hero::after {
    content: "";
    position: absolute;
    width: 520px;
    height: 520px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(26,115,232,0.16), transparent 70%);
    top: -160px;
    right: -140px;
  }
  .hero-inner {
    max-width: 1180px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 52px;
    align-items: center;
    position: relative;
    z-index: 1;
  }
  .hero-tag {
    display: inline-block;
    background: var(--white);
    color: var(--blue-main);
    font-size: 13px;
    font-weight: 600;
    padding: 6px 16px;
    border-radius: 999px;
    border: 1px solid #c3d8f8;
    margin-bottom: 20px;
  }
  .hero h1 {
    font-size: 42px;
    line-height: 1.3;
    color: var(--blue-deep);
    margin-bottom: 18px;
    letter-spacing: 0.5px;
  }
  .hero p.lead {
    font-size: 17px;
    color: var(--text-sub);
    margin-bottom: 30px;
    max-width: 520px;
  }
  .hero-actions {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
  }
  .btn-ghost {
    display: inline-block;
    padding: 10px 24px;
    border-radius: 999px;
    border: 1.5px solid var(--blue-main);
    color: var(--blue-main);
    font-weight: 600;
    font-size: 15px;
    background: transparent;
    transition: background 0.2s, color 0.2s;
  }
  .btn-ghost:hover { background: var(--blue-main); color: var(--white); }
  .hero-note {
    margin-top: 18px;
    font-size: 13px;
    color: #77839a;
  }
  .hero-visual {
    position: relative;
  }
  .hero-visual img {
    border-radius: 20px;
    box-shadow: 0 24px 60px rgba(11, 61, 145, 0.22);
    width: 100%;
    object-fit: cover;
  }

  /* ---------- 通用区块 ---------- */
  .section {
    padding: 76px 20px;
  }
  .section-inner {
    max-width: 1180px;
    margin: 0 auto;
  }
  .section-head {
    max-width: 700px;
    margin-bottom: 44px;
  }
  .section-head h2 {
    font-size: 30px;
    color: var(--blue-deep);
    margin-bottom: 12px;
    line-height: 1.35;
  }
  .section-head p {
    font-size: 16px;
    color: var(--text-sub);
  }
  .alt-bg { background: var(--white); }

  /* ---------- 版块 ---------- */
  .boards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }
  .board-card {
    background: var(--blue-soft);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 24px;
    transition: transform 0.25s, box-shadow 0.25s;
  }
  .board-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
  }
  .board-icon {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--blue-main), var(--blue-deep));
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 18px;
    margin-bottom: 18px;
  }
  .board-card h3 {
    font-size: 19px;
    color: var(--blue-deep);
    margin-bottom: 10px;
  }
  .board-card p {
    font-size: 15px;
    color: var(--text-sub);
  }

  /* ---------- 截图墙 ---------- */
  .gallery-scroll {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
  }
  .gallery-item {
    border-radius: var(--radius);
    overflow: hidden;
    position: relative;
    background: var(--white);
    border: 1px solid var(--border);
    aspect-ratio: 1 / 1;
  }
  .gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s;
  }
  .gallery-item:hover img { transform: scale(1.05); }
  .gallery-item figcaption {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    padding: 20px 14px 10px;
    font-size: 13px;
    color: var(--white);
    background: linear-gradient(to top, rgba(8, 30, 70, 0.78), transparent);
  }

  /* ---------- 特色双栏 ---------- */
  .feature-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
  }
  .feature-row.reverse .feature-text { order: 2; }
  .feature-row.reverse .feature-media { order: 1; }
  .feature-media img {
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
    object-fit: cover;
  }
  .feature-text h2 {
    font-size: 27px;
    color: var(--blue-deep);
    margin-bottom: 16px;
    line-height: 1.4;
  }
  .feature-text p {
    font-size: 16px;
    color: var(--text-sub);
    margin-bottom: 16px;
  }
  .feature-list {
    list-style: none;
    margin-top: 8px;
  }
  .feature-list li {
    position: relative;
    padding-left: 26px;
    font-size: 15px;
    color: var(--text-main);
    margin-bottom: 10px;
  }
  .feature-list li::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 9px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--blue-main);
  }

  /* ---------- 今日看点 ---------- */
  .today-grid {
    display: grid;
    grid-template-columns: 1.4fr 1fr;
    gap: 24px;
  }
  .today-main {
    position: relative;
    border-radius: var(--radius);
    overflow: hidden;
    min-height: 320px;
  }
  .today-main img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    position: absolute;
    inset: 0;
  }
  .today-main-text {
    position: relative;
    z-index: 2;
    padding: 34px 28px;
    color: var(--white);
    background: linear-gradient(100deg, rgba(8, 30, 70, 0.82) 0%, rgba(8, 30, 70, 0.32) 70%, transparent 100%);
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
  }
  .today-main-text h3 {
    font-size: 23px;
    margin-bottom: 10px;
  }
  .today-main-text p { font-size: 15px; opacity: 0.92; }
  .today-side {
    display: grid;
    grid-template-rows: 1fr 1fr;
    gap: 24px;
  }
  .today-small {
    display: flex;
    gap: 16px;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px;
    align-items: center;
  }
  .today-small img {
    width: 96px;
    height: 84px;
    object-fit: cover;
    border-radius: 10px;
    flex-shrink: 0;
  }
  .today-small h3 {
    font-size: 16px;
    color: var(--blue-deep);
    margin-bottom: 6px;
  }
  .today-small p {
    font-size: 13.5px;
    color: var(--text-sub);
    line-height: 1.6;
  }

  /* ---------- 下载区 ---------- */
  .download-section {
    background: linear-gradient(150deg, var(--blue-deep), #102c66 60%, #071a40);
    color: var(--white);
    text-align: center;
  }
  .download-section h2 {
    font-size: 31px;
    margin-bottom: 16px;
    color: var(--white);
  }
  .download-section p {
    font-size: 16px;
    color: #c4d4f0;
    max-width: 620px;
    margin: 0 auto 32px;
  }
  .download-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 22px;
    max-width: 860px;
    margin: 0 auto 40px;
    text-align: left;
  }
  .step-item {
    background: rgba(255, 255, 255, 0.07);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: var(--radius);
    padding: 22px 20px;
  }
  .step-num {
    font-size: 13px;
    font-weight: 700;
    color: #93b6f5;
    margin-bottom: 8px;
    letter-spacing: 1px;
  }
  .step-item h3 {
    font-size: 17px;
    color: var(--white);
    margin-bottom: 6px;
  }
  .step-item p {
    font-size: 14px;
    color: #b9cbea;
    margin: 0;
  }
  .btn-download-lg {
    display: inline-block;
    background: var(--white);
    color: var(--blue-deep);
    padding: 15px 46px;
    border-radius: 999px;
    font-weight: 700;
    font-size: 17px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
    transition: transform 0.2s;
  }
  .btn-download-lg:hover { transform: translateY(-3px); }

  /* ---------- 页脚 ---------- */
  .site-footer {
    background: #071a40;
    color: #8fa4c6;
    padding: 34px 20px 30px;
    font-size: 13px;
    line-height: 1.9;
  }
  .footer-inner {
    max-width: 1180px;
    margin: 0 auto;
    text-align: center;
  }
  .footer-inner p { margin-bottom: 6px; }
  .site-footer a { color: #a8c0e8; }
  .site-footer time { color: #7d92b3; }

  /* ---------- 响应式 ---------- */
  @media (max-width: 1024px) {
    .hero h1 { font-size: 36px; }
    .hero-inner { grid-template-columns: 1fr; gap: 36px; }
    .hero-visual { max-width: 560px; }
    .boards-grid { grid-template-columns: repeat(2, 1fr); }
    .gallery-scroll { grid-template-columns: repeat(3, 1fr); }
    .today-grid { grid-template-columns: 1fr; }
    .today-main { min-height: 280px; }
  }
  @media (max-width: 768px) {
    .header-inner { padding: 10px 16px; }
    .nav-links {
      display: none;
      position: absolute;
      top: 100%;
      left: 0;
      right: 0;
      background: var(--white);
      flex-direction: column;
      align-items: flex-start;
      gap: 0;
      padding: 8px 20px 16px;
      border-bottom: 1px solid var(--border);
    }
    .nav-links.open { display: flex; }
    .nav-links a { padding: 10px 0; width: 100%; }
    .menu-toggle { display: block; }
    .header-download { display: none; }
    .hero { padding: 48px 16px 60px; }
    .hero h1 { font-size: 29px; }
    .hero p.lead { font-size: 15.5px; }
    .section { padding: 54px 16px; }
    .section-head h2 { font-size: 24px; }
    .boards-grid { grid-template-columns: 1fr; }
    .gallery-scroll { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .feature-row { grid-template-columns: 1fr; gap: 26px; }
    .feature-row.reverse .feature-text { order: 1; }
    .feature-row.reverse .feature-media { order: 2; }
    .feature-text h2 { font-size: 23px; }
    .download-section h2 { font-size: 25px; }
    .download-steps { grid-template-columns: 1fr; gap: 14px; }
    .today-small img { width: 84px; height: 76px; }
    .today-small h3 { font-size: 15px; }
  }