/* roulang page: index */
:root {
      --primary-black: #0A0E17;
      --action-red: #E53E3E;
      --red-dark: #C53030;
      --ice-white: #F5F6FA;
      --charcoal: #1A202C;
      --speed-cyan: #38B2AC;
      --text-body: #2D3748;
      --text-muted: #718096;
      --border-light: rgba(10, 14, 23, 0.08);
      --border-dark: rgba(255, 255, 255, 0.08);
      --shadow-card: 0 2px 12px rgba(10,14,23,0.06);
      --shadow-hover: 0 8px 30px rgba(229,62,62,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --radius-container: 16px;
      --font-title: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-number: "DIN Alternate", "PingFang SC", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      background-color: var(--ice-white);
      color: var(--text-body);
      line-height: 1.8;
      font-weight: 400;
      font-size: 16px;
      scroll-behavior: smooth;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: transparent;
      transition: background 0.3s ease, backdrop-filter 0.3s ease;
      padding: 16px 0;
    }
    .main-header.scrolled {
      background: rgba(10, 14, 23, 0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 24px;
      letter-spacing: -0.02em;
      color: white;
      text-shadow: 0 2px 8px rgba(0,0,0,0.3);
    }
    .logo-icon {
      width: 10px;
      height: 24px;
      background: var(--action-red);
      border-radius: 20px;
      margin-right: 2px;
      transform: skewX(-12deg);
    }
    .desktop-nav {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .desktop-nav a {
      color: rgba(255,255,255,0.85);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      transition: color 0.2s;
    }
    .desktop-nav a:hover {
      color: white;
    }
    .desktop-nav a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--action-red);
      transition: width 0.3s ease;
    }
    .desktop-nav a:hover::after {
      width: 100%;
    }
    .btn-nav {
      background: var(--action-red);
      color: white !important;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background 0.2s, transform 0.1s;
      box-shadow: 0 4px 12px rgba(229,62,62,0.4);
    }
    .btn-nav:hover {
      background: var(--red-dark);
      transform: translateY(-1px);
    }
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: var(--primary-black);
      backdrop-filter: blur(20px);
      border-top: 1px solid rgba(255,255,255,0.08);
      padding: 8px 16px;
      justify-content: space-around;
      align-items: center;
      z-index: 100;
    }
    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .mobile-bottom-nav {
        display: flex;
      }
    }
    /* 按钮通用 */
    .btn-primary {
      background: var(--action-red);
      color: white;
      border: none;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: background 0.25s, transform 0.15s, box-shadow 0.25s;
      display: inline-block;
      box-shadow: 0 6px 18px rgba(229,62,62,0.3);
    }
    .btn-primary:hover {
      background: var(--red-dark);
      transform: translateY(-2px);
      box-shadow: 0 12px 28px rgba(229,62,62,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--action-red);
      color: var(--action-red);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.25s;
      cursor: pointer;
    }
    .btn-outline:hover {
      background: var(--action-red);
      color: white;
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.25s;
    }
    .btn-ghost:hover {
      border-color: var(--action-red);
      background: var(--action-red);
      color: white;
    }
    /* Hero */
    .hero {
      background-color: var(--primary-black);
      background-image: radial-gradient(circle at 30% 40%, rgba(229,62,62,0.15) 0%, transparent 40%),
                        linear-gradient(135deg, #0A0E17 5%, #1A202C 85%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    .hero-svg-lines {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
      opacity: 0.25;
    }
    .line-animated {
      stroke: var(--speed-cyan);
      stroke-width: 2;
      fill: none;
    }
    .hero-content {
      display: flex;
      align-items: center;
      gap: 3rem;
      position: relative;
      z-index: 2;
      padding: 80px 0;
    }
    .hero-left {
      flex: 1 1 50%;
      color: white;
    }
    .hero-right {
      flex: 1 1 50%;
      display: flex;
      justify-content: center;
    }
    .hero-right img {
      max-height: 500px;
      border-radius: 20px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
      filter: drop-shadow(0 0 20px rgba(229,62,62,0.25));
      object-fit: cover;
      width: 100%;
      border: 1px solid rgba(255,255,255,0.1);
    }
    .hero h1 {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 56px;
      line-height: 1.2;
      letter-spacing: -0.02em;
      margin-bottom: 1.5rem;
      color: white;
    }
    .hero-sub {
      font-size: 18px;
      font-weight: 400;
      color: rgba(255,255,255,0.8);
      margin-bottom: 2rem;
      max-width: 480px;
    }
    .trust-badges {
      display: flex;
      gap: 2rem;
      margin-top: 2rem;
      color: rgba(255,255,255,0.7);
      font-size: 0.9rem;
    }
    @media (max-width: 768px) {
      .hero-content {
        flex-direction: column;
        gap: 2rem;
      }
      .hero h1 {
        font-size: 36px;
      }
      .trust-badges {
        flex-wrap: wrap;
        gap: 1rem;
      }
    }
    /* 板块通用 */
    section {
      padding: 90px 0;
    }
    .section-title {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 40px;
      letter-spacing: -0.02em;
      color: var(--primary-black);
      margin-bottom: 1.8rem;
    }
    @media (max-width: 768px) {
      .section-title {
        font-size: 28px;
      }
    }
    /* Solutions 对比式 */
    .contrast-row {
      display: flex;
      gap: 2rem;
      margin-bottom: 40px;
      align-items: center;
      border-bottom: 1px solid rgba(10,14,23,0.06);
      padding-bottom: 36px;
    }
    .contrast-left {
      flex: 1;
      color: var(--text-muted);
      text-decoration: line-through;
      font-size: 17px;
      background: #f1f2f6;
      padding: 24px;
      border-radius: var(--radius-card);
    }
    .contrast-right {
      flex: 1;
      background: white;
      border-left: 5px solid var(--action-red);
      padding: 24px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      font-weight: 500;
    }
    @media (max-width: 768px) {
      .contrast-row {
        flex-direction: column;
      }
    }
    /* 时间轴 */
    .timeline {
      display: flex;
      justify-content: space-between;
      position: relative;
      margin: 50px 0;
    }
    .timeline::before {
      content: '';
      position: absolute;
      top: 18px;
      left: 5%;
      width: 90%;
      height: 3px;
      background: var(--speed-cyan);
    }
    .timeline-node {
      display: flex;
      flex-direction: column;
      align-items: center;
      width: 22%;
      position: relative;
    }
    .node-dot {
      width: 24px;
      height: 24px;
      background: var(--action-red);
      border-radius: 50%;
      margin-bottom: 16px;
      z-index: 2;
      box-shadow: 0 0 15px rgba(229,62,62,0.5);
    }
    @media (max-width: 768px) {
      .timeline {
        flex-direction: column;
        align-items: flex-start;
      }
      .timeline::before {
        display: none;
      }
      .timeline-node {
        flex-direction: row;
        width: 100%;
        gap: 16px;
        margin-bottom: 24px;
      }
    }
    /* 数据大数字 */
    .metric-grid {
      display: flex;
      gap: 2rem;
      justify-content: center;
      margin: 50px 0;
    }
    .metric-item {
      text-align: center;
    }
    .metric-number {
      font-family: var(--font-number);
      font-weight: 700;
      font-size: 52px;
      color: var(--action-red);
    }
    /* 卡片案例 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 24px;
      margin-top: 30px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      overflow: hidden;
      transition: all 0.25s;
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .case-card img {
      height: 200px;
      object-fit: cover;
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      font-weight: 700;
      font-size: 18px;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      color: var(--primary-black);
    }
    .faq-answer {
      padding: 0 0 20px;
      color: var(--text-muted);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    /* CTA 红色区 */
    .cta-ultimate {
      background: var(--action-red);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    .footer {
      background: var(--primary-black);
      color: rgba(255,255,255,0.7);
      padding: 60px 0 20px;
    }
    input, textarea {
      width: 100%;
      padding: 12px 16px;
      border-radius: var(--radius-input);
      border: 1px solid var(--border-light);
      margin-bottom: 12px;
      font-family: inherit;
    }