/* roulang page: index */
:root {
      --primary: #FF4D2E;
      --primary-hover: #FF6B4A;
      --secondary-bg: #1A1A2E;
      --accent: #00E5FF;
      --bg-deep: #0D0D1A;
      --bg-card: rgba(19, 19, 43, 0.7);
      --text-white: #FFFFFF;
      --text-body: #B0B0CC;
      --text-highlight: #FF4D2E;
      --border-glow: rgba(255, 77, 46, 0.25);
      --border-subtle: rgba(255, 255, 255, 0.08);
      --glass-blur: blur(18px);
      --radius-card: 20px;
      --radius-btn: 50px;
      --radius-input: 12px;
      --shadow-card: 0 8px 32px rgba(0,0,0,0.4);
      --shadow-glow: 0 0 20px rgba(255,77,46,0.6);
      --font-cn: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-en: 'Inter', 'SF Pro Display', sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-cn);
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.7;
      overflow-x: hidden;
    }
    .container {
      max-width: 1320px;
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3 {
      font-weight: 700;
      color: var(--text-white);
    }
    h2 {
      font-size: 2.6rem;
      margin-bottom: 1rem;
      letter-spacing: -0.5px;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 600;
    }
    p {
      color: var(--text-body);
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
    }
    .section {
      padding: 100px 0;
    }
    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.3s ease;
      cursor: pointer;
      border: none;
      background: transparent;
      letter-spacing: 0.3px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      box-shadow: var(--shadow-glow);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 0 35px rgba(255,77,46,0.8);
      transform: translateY(-2px);
    }
    .btn-ghost {
      border: 2px solid var(--primary);
      color: var(--primary);
      background: transparent;
    }
    .btn-ghost:hover {
      background: var(--primary);
      color: white;
      box-shadow: 0 0 25px rgba(255,77,46,0.5);
    }
    .btn-sm {
      padding: 0.6rem 1.6rem;
      font-size: 0.9rem;
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 32px;
      z-index: 999;
      transition: background 0.3s ease, backdrop-filter 0.3s;
      background: transparent;
    }
    .navbar.scrolled {
      background: rgba(13, 13, 26, 0.85);
      backdrop-filter: blur(20px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    .logo {
      font-size: 1.6rem;
      font-weight: 700;
      background: linear-gradient(135deg, #FF4D2E, #FF8C5A);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: 1px;
    }
    .nav-links {
      display: flex;
      gap: 2.5rem;
      align-items: center;
    }
    .nav-links a {
      color: #B0B0CC;
      font-weight: 500;
      position: relative;
      padding: 0.3rem 0;
      transition: color 0.2s;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      box-shadow: 0 0 8px var(--primary);
      transition: width 0.25s ease;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .menu-toggle {
      display: none;
      font-size: 1.8rem;
      color: white;
      cursor: pointer;
    }
    /* 移动端导航抽屉 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        height: 100vh;
        background: rgba(10, 10, 22, 0.95);
        backdrop-filter: blur(25px);
        flex-direction: column;
        justify-content: center;
        gap: 2.5rem;
        transition: right 0.4s ease;
        border-left: 1px solid rgba(255,77,46,0.3);
      }
      .nav-links.open {
        right: 0;
      }
      .nav-links a {
        font-size: 1.4rem;
        margin-left: 2rem;
        border-left: 3px solid transparent;
        padding-left: 1rem;
      }
      .nav-links a.active {
        border-left-color: var(--primary);
      }
      .menu-toggle {
        display: block;
      }
      .navbar {
        padding: 0 20px;
      }
    }
    /* Hero */
    #hero {
      height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-attachment: fixed;
    }
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: rgba(0,0,0,0.55);
      z-index: 1;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      text-align: center;
      max-width: 900px;
      padding: 0 20px;
    }
    .hero-content h1 {
      font-size: 3.5rem;
      line-height: 1.2;
      text-shadow: 0 0 40px rgba(255,77,46,0.8);
      margin-bottom: 1.5rem;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: #B0B0CC;
      margin-bottom: 2.5rem;
    }
    .hero-btns {
      display: flex;
      gap: 1.5rem;
      justify-content: center;
      flex-wrap: wrap;
    }
    .scroll-indicator {
      position: absolute;
      bottom: 30px;
      left: 50%;
      transform: translateX(-50%);
      color: white;
      font-size: 1.8rem;
      animation: bounce 2s infinite;
      z-index: 2;
    }
    @keyframes bounce {
      0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
      40% { transform: translateX(-50%) translateY(-10px); }
      60% { transform: translateX(-50%) translateY(-5px); }
    }
    /* 核心优势不对称栅格 */
    .value-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr;
      gap: 32px;
      margin-top: 3rem;
    }
    .value-card {
      background: var(--bg-card);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-glow);
      border-radius: var(--radius-card);
      padding: 2.5rem;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .value-card:hover {
      border-color: var(--accent);
      transform: translateY(-6px);
      box-shadow: 0 12px 40px rgba(255,77,46,0.3);
    }
    .value-card.wide {
      grid-column: span 1;
    }
    .value-icon {
      font-size: 2.5rem;
      color: var(--primary);
      margin-bottom: 1.2rem;
    }
    /* 功能卡片网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 32px;
      margin-top: 3rem;
    }
    .feature-card {
      background: var(--bg-card);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-glow);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: 0.3s;
    }
    .feature-card:hover {
      border-color: var(--accent);
      transform: translateY(-6px);
    }
    .feature-img {
      height: 200px;
      background-size: cover;
      background-position: center;
    }
    .feature-body {
      padding: 1.8rem;
    }
    .tag {
      display: inline-block;
      background: rgba(255,77,46,0.2);
      color: var(--primary);
      padding: 0.3rem 1rem;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      margin-top: 0.8rem;
    }
    /* 案例卡片 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 32px;
      margin-top: 3rem;
    }
    .case-card {
      background: var(--bg-card);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-glow);
      border-radius: var(--radius-card);
      padding: 2rem;
    }
    .case-number {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--accent);
    }
    /* 价格方案 */
    .pricing-grid {
      display: flex;
      gap: 24px;
      justify-content: center;
      flex-wrap: wrap;
      margin-top: 3rem;
    }
    .pricing-card {
      background: var(--bg-card);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-glow);
      border-radius: var(--radius-card);
      padding: 2.5rem;
      flex: 1 1 280px;
      max-width: 350px;
      position: relative;
    }
    .pricing-card.recommended {
      border-color: var(--primary);
      box-shadow: 0 0 30px rgba(255,77,46,0.4);
    }
    .badge {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--primary);
      color: white;
      padding: 0.3rem 1.2rem;
      border-radius: 20px;
      font-size: 0.8rem;
    }
    /* FAQ */
    .faq-item {
      background: rgba(19,19,43,0.6);
      border: 1px solid var(--border-subtle);
      border-radius: 16px;
      margin-bottom: 12px;
      padding: 20px;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      font-size: 1.1rem;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      color: #B0B0CC;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 2rem;
      padding: 60px 0;
    }
    @media (max-width: 768px) {
      .section { padding: 60px 0; }
      h2 { font-size: 2rem; }
      .hero-content h1 { font-size: 2.2rem; }
      .value-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .footer-grid { grid-template-columns: 1fr; }
    }