/* roulang page: index */
:root {
      --deep-blue-black: #0B1A2F;
      --electric-blue: #1E5FBB;
      --warm-gold: #C79A4B;
      --mist-gray-blue: #8EA4C0;
      --light-gray-white: #F4F6FA;
      --deep-blue-gray: #162B44;
      --card-bg: rgba(22, 43, 68, 0.7);
      --card-border-gold: rgba(199, 154, 75, 0.15);
      --shadow-light: 0 8px 24px rgba(0,0,0,0.25);
      --shadow-hover: 0 12px 32px rgba(0,0,0,0.35);
      --radius-card: 12px;
      --radius-btn: 30px;
      --transition-smooth: all 0.25s ease;
      --font-body: 'Noto Sans SC', sans-serif;
      --font-number: 'Inter', sans-serif;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: var(--font-body);
      background-color: var(--deep-blue-black);
      color: #ffffff;
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      font-family: var(--font-body);
      font-weight: 700;
      margin-bottom: 0.5rem;
    }
    h1 {
      font-size: 42px;
      letter-spacing: -0.5px;
      line-height: 1.2;
    }
    h2 {
      font-size: 32px;
      letter-spacing: 0;
      margin-bottom: 1.5rem;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
    }
    p {
      font-size: 16px;
      font-weight: 400;
      color: #D0D9E4;
      line-height: 1.7;
    }
    .section-subtitle {
      font-size: 16px;
      color: var(--mist-gray-blue);
      margin-bottom: 2.5rem;
      max-width: 700px;
      margin-left: auto;
      margin-right: auto;
    }
    a {
      transition: var(--transition-smooth);
      text-decoration: none;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    /* 导航栏 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(11, 26, 47, 0.88);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(199, 154, 75, 0.25);
      z-index: 100;
      padding: 12px 0;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 1.6rem;
      font-weight: 700;
      color: #fff;
      letter-spacing: 1px;
    }
    .logo i {
      color: var(--warm-gold);
      font-size: 2rem;
    }
    .nav-tags {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
    }
    .nav-tag {
      display: inline-block;
      padding: 8px 18px;
      border-radius: 20px;
      background: rgba(22, 43, 68, 0.7);
      color: #D0D9E4;
      font-size: 14px;
      font-weight: 500;
      transition: var(--transition-smooth);
      border: 1px solid transparent;
    }
    .nav-tag:hover, .nav-tag.active {
      background: var(--electric-blue);
      color: #fff;
      border-color: var(--warm-gold);
      box-shadow: 0 0 12px rgba(199,154,75,0.3);
    }
    .header-cta {
      background: var(--electric-blue);
      color: #fff;
      padding: 10px 24px;
      border-radius: 30px;
      font-weight: 600;
      font-size: 15px;
      box-shadow: 0 0 18px rgba(199,154,75,0.5);
      border: none;
      transition: var(--transition-smooth);
      display: inline-block;
    }
    .header-cta:hover {
      background: #174A8A;
      box-shadow: 0 0 24px rgba(199,154,75,0.7);
      transform: translateY(-2px);
      color: #fff;
    }
    .mobile-menu-icon {
      display: none;
      font-size: 1.8rem;
      color: var(--warm-gold);
      cursor: pointer;
    }
    /* Hero */
    #hero {
      padding: 140px 0 90px;
      background: radial-gradient(circle at 30% 40%, #1a314a 0%, #0B1A2F 80%);
      position: relative;
      overflow: hidden;
    }
    .hero-bg-texture {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" opacity="0.08"><path d="M70 40 Q90 20 110 40 T150 60" stroke="%23C79A4B" fill="none" stroke-width="1.2"/><circle cx="160" cy="80" r="8" fill="%23C79A4B" opacity="0.4"/></svg>');
      pointer-events: none;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 40px;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 0 0 60%;
    }
    .hero-visual {
      flex: 0 0 35%;
      display: flex;
      justify-content: center;
    }
    .hero-title {
      color: #fff;
      margin-bottom: 1.2rem;
    }
    .hero-desc {
      font-size: 18px;
      color: #C8D6E5;
      margin-bottom: 2rem;
      max-width: 500px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--electric-blue);
      color: #fff;
      padding: 14px 32px;
      border-radius: 30px;
      font-weight: 600;
      font-size: 15px;
      box-shadow: 0 0 20px rgba(199,154,75,0.45);
      transition: var(--transition-smooth);
      display: inline-block;
      text-align: center;
      border: none;
    }
    .btn-primary:hover {
      background: #174A8A;
      box-shadow: 0 0 28px rgba(199,154,75,0.7);
      transform: translateY(-2px);
      color: #fff;
    }
    .btn-outline-gold {
      background: transparent;
      border: 1.5px solid var(--warm-gold);
      color: var(--warm-gold);
      padding: 14px 32px;
      border-radius: 30px;
      font-weight: 600;
      font-size: 15px;
      transition: var(--transition-smooth);
    }
    .btn-outline-gold:hover {
      background: rgba(199,154,75,0.1);
      color: #fff;
      border-color: #fff;
    }
    .abstract-bb {
      width: 220px;
      height: 220px;
      background: radial-gradient(circle at 30% 30%, #C79A4B, #1E5FBB);
      border-radius: 42% 58% 35% 65% / 56% 34% 66% 44%;
      filter: blur(18px);
      opacity: 0.8;
    }
    /* 通用section */
    section {
      padding: 80px 0;
    }
    .section-header {
      text-align: center;
      margin-bottom: 3rem;
    }
    .bg-light {
      background-color: var(--light-gray-white);
      color: #1E2B3C;
    }
    .bg-light h2, .bg-light h3, .bg-light .section-subtitle {
      color: #1E2B3C;
    }
    /* 卡片网格 */
    .card-grid {
      display: flex;
      flex-wrap: wrap;
      gap: 24px;
      justify-content: center;
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-light);
      border-left: 4px solid var(--warm-gold);
      transition: var(--transition-smooth);
      flex: 1 1 280px;
      max-width: 350px;
      backdrop-filter: blur(4px);
      color: #fff;
    }
    .bg-light .card {
      background: #ffffff;
      box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      border-left-color: var(--electric-blue);
      color: #1E2B3C;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .card-icon {
      font-size: 2.4rem;
      color: var(--warm-gold);
      margin-bottom: 16px;
    }
    .card h3 {
      margin-bottom: 12px;
    }
    .card-link {
      color: var(--warm-gold);
      font-weight: 500;
      margin-top: 14px;
      display: inline-block;
      border-bottom: 1px solid transparent;
    }
    .card-link:hover {
      border-bottom-color: var(--warm-gold);
    }
    /* 数据优势 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 28px;
    }
    .stat-item {
      text-align: center;
      flex: 1 1 160px;
    }
    .stat-number {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 700;
      color: var(--warm-gold);
      line-height: 1.1;
    }
    .stat-label {
      color: #AAB9CE;
      font-size: 15px;
      margin-top: 6px;
    }
    /* 案例卡片 */
    .case-card {
      background-size: cover;
      background-position: center;
      border-radius: var(--radius-card);
      height: 260px;
      position: relative;
      overflow: hidden;
      transition: var(--transition-smooth);
      display: flex;
      align-items: flex-end;
      box-shadow: var(--shadow-light);
    }
    .case-overlay {
      background: linear-gradient(0deg, rgba(11,26,47,0.85) 0%, transparent 70%);
      padding: 24px;
      width: 100%;
      color: #fff;
    }
    .case-card:hover {
      transform: scale(1.02);
    }
    /* 解决方案步骤 */
    .solution-step {
      display: flex;
      gap: 24px;
      margin-bottom: 32px;
      align-items: flex-start;
    }
    .step-number {
      font-family: var(--font-number);
      font-size: 40px;
      font-weight: 700;
      color: var(--warm-gold);
      min-width: 60px;
      border-right: 3px solid var(--warm-gold);
      padding-right: 20px;
    }
    /* FAQ */
    .accordion-item {
      background: rgba(22,43,68,0.5);
      border-radius: 10px;
      margin-bottom: 12px;
      border-left: 3px solid transparent;
      transition: 0.2s;
    }
    .accordion-title {
      padding: 18px 24px;
      font-weight: 600;
      font-size: 18px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .accordion-content {
      padding: 0 24px 20px;
      display: none;
      color: #D0D9E4;
    }
    .accordion-item.active {
      background: #F4F6FA;
      border-left-color: var(--electric-blue);
    }
    .accordion-item.active .accordion-title,
    .accordion-item.active .accordion-content {
      color: #0B1A2F;
    }
    /* CTA */
    #cta {
      background: radial-gradient(ellipse at center, #1E334D 0%, #0B1A2F 70%);
      text-align: center;
    }
    .cta-large-btn {
      padding: 18px 40px;
      font-size: 18px;
    }
    /* 页脚 */
    .site-footer {
      background: #0B1A2F;
      padding: 50px 0 20px;
      color: var(--mist-gray-blue);
    }
    .footer-grid {
      display: flex;
      flex-wrap: wrap;
      gap: 30px;
      justify-content: space-between;
    }
    .footer-col a {
      color: #B0C4DE;
      display: block;
      margin-bottom: 8px;
    }
    .footer-col a:hover {
      color: var(--warm-gold);
    }
    .copyright {
      text-align: center;
      margin-top: 30px;
      border-top: 1px solid rgba(142,164,192,0.2);
      padding-top: 20px;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid { flex-direction: column; text-align: center; }
      .hero-text, .hero-visual { flex: 1; }
      .btn-group { justify-content: center; }
    }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 24px; }
      .nav-tags, .header-cta { display: none; }
      .mobile-menu-icon { display: block; }
      .card { max-width: 100%; }
    }
    @media (max-width: 640px) {
      .stats-grid { flex-direction: column; align-items: center; }
    }