/* roulang page: index */
:root {
      --bg-deep: #0A0E17;
      --bg-card: #2D2F3A;
      --accent-cyan: #00F0FF;
      --accent-pink: #FF3366;
      --text-primary: #F0F2F5;
      --text-secondary: #8A8F99;
      --gradient-main: linear-gradient(135deg, #00F0FF 0%, #007BFF 100%);
      --radius-md: 8px;
      --radius-lg: 12px;
      --shadow-cyan: 0 8px 30px rgba(0, 240, 255, 0.2);
      --font-raj: 'Rajdhani', 'Inter', sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.7;
      overflow-x: hidden;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background 0.2s;
    }
    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    /* 装饰性背景光晕 */
    body::before {
      content: "";
      position: fixed;
      top: -20%;
      right: -15%;
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(0,240,255,0.08) 0%, transparent 70%);
      z-index: -1;
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 999;
      background: rgba(10, 14, 23, 0.8);
      backdrop-filter: blur(18px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.2);
      transition: background 0.3s;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand {
      font-family: var(--font-raj);
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      background: linear-gradient(to right, #00F0FF, #5ee4ff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-links a {
      font-weight: 600;
      font-size: 0.95rem;
      color: var(--text-secondary);
      transition: color 0.2s;
      position: relative;
      padding-bottom: 4px;
    }
    .nav-links a:hover,
    .nav-links a:focus-visible {
      color: var(--accent-cyan);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: 0;
      height: 2px;
      width: 0;
      background: var(--accent-cyan);
      transition: width 0.25s ease;
    }
    .nav-links a:hover::after,
    .nav-links a:focus-visible::after {
      width: 100%;
    }
    .btn-primary-sm {
      background: var(--accent-cyan);
      color: #0A0E17;
      padding: 10px 22px;
      border-radius: var(--radius-md);
      font-weight: 700;
      font-size: 0.9rem;
      border: none;
      cursor: pointer;
      transition: 0.2s;
      letter-spacing: 0.3px;
    }
    .btn-primary-sm:hover {
      background: #33F4FF;
      box-shadow: 0 0 20px rgba(0,240,255,0.55);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 28px;
      height: 2px;
      background: var(--accent-cyan);
      display: block;
      border-radius: 4px;
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(10, 14, 23, 0.98);
        flex-direction: column;
        justify-content: center;
        gap: 3rem;
        transform: translateX(100%);
        transition: transform 0.35s ease;
        font-size: 2rem;
      }
      .nav-links.active {
        transform: translateX(0);
      }
      .hamburger {
        display: flex;
        z-index: 1001;
      }
      .btn-primary-sm.nav-cta {
        display: none;
      }
    }

    section {
      padding: 5.5rem 0 5rem;
    }

    h2 {
      font-family: var(--font-raj);
      font-size: clamp(2rem, 5vw, 2.8rem);
      font-weight: 700;
      margin-bottom: 1rem;
      letter-spacing: -0.02em;
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -12px;
      width: 65px;
      height: 4px;
      background: var(--accent-cyan);
      border-radius: 2px;
    }
    .section-title-center h2::after {
      left: 50%;
      transform: translateX(-50%);
    }
    .section-title-center {
      text-align: center;
      margin-bottom: 3rem;
    }
    /* Hero */
    .hero {
      padding-top: 10rem;
      padding-bottom: 7rem;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 2rem;
      background: radial-gradient(circle at 20% 20%, rgba(0,240,255,0.04) 0%, transparent 50%);
    }
    .hero-text {
      flex: 1 1 50%;
    }
    .hero-text h1 {
      font-family: var(--font-raj);
      font-size: clamp(2.9rem, 7vw, 4.4rem);
      font-weight: 800;
      line-height: 1.1;
      letter-spacing: -0.025em;
      color: white;
      text-transform: uppercase;
    }
    .highlight {
      background: linear-gradient(to right, #00F0FF, #FF3366);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-sub {
      margin: 1.8rem 0 2.2rem;
      font-size: 1.25rem;
      color: var(--text-secondary);
      max-width: 450px;
    }
    .btn-group {
      display: flex;
      flex-wrap: wrap;
      gap: 1.3rem;
    }
    .btn-gradient {
      background: var(--gradient-main);
      color: #0A0E17;
      border: none;
      padding: 14px 34px;
      border-radius: var(--radius-md);
      font-weight: 700;
      font-size: 1.1rem;
      transition: 0.25s;
    }
    .btn-gradient:hover {
      box-shadow: 0 0 28px rgba(0,240,255,0.7);
      background: linear-gradient(135deg, #4df0ff, #2f7fff);
    }
    .btn-outline {
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
      background: transparent;
      padding: 14px 34px;
      border-radius: var(--radius-md);
      font-weight: 700;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
    }
    .hero-image {
      flex: 1 1 45%;
      position: relative;
    }
    .hero-image img {
      border-radius: 20px;
      border: 1px solid rgba(0,240,255,0.25);
      box-shadow: 0 20px 40px rgba(0,15,25,0.8);
    }
    /* 版块通用 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 30px;
      margin-top: 2rem;
    }
    .card-feature {
      background: var(--bg-card);
      border: 1px solid rgba(0,240,255,0.12);
      border-radius: var(--radius-lg);
      padding: 2rem 1.7rem;
      transition: 0.3s ease;
    }
    .card-feature:hover {
      border-color: var(--accent-cyan);
      box-shadow: var(--shadow-cyan);
      transform: translateY(-6px);
    }
    .icon-cyan {
      font-size: 2.5rem;
      color: var(--accent-cyan);
      margin-bottom: 1.3rem;
    }
    /* 图文交替 */
    .alt-row {
      display: flex;
      align-items: center;
      gap: 3rem;
      margin: 4rem 0;
      flex-wrap: wrap;
    }
    .alt-row.reverse {
      flex-direction: row-reverse;
    }
    .alt-img {
      flex: 1 1 45%;
    }
    .alt-img img {
      border-radius: 18px;
      border: 1px solid rgba(255,255,255,0.05);
    }
    /* FAQ */
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
    }
    .faq-item {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      padding: 1.2rem;
      border-left: 3px solid var(--accent-cyan);
      transition: 0.2s;
      cursor: pointer;
    }
    .faq-item.active {
      border-left-color: var(--accent-pink);
    }
    .price-card {
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      padding: 2.3rem;
      text-align: center;
      border: 1px solid rgba(255,255,255,0.07);
    }
    .price-card.popular {
      border: 2px solid var(--accent-cyan);
      position: relative;
    }
    .badge-hot {
      background: var(--accent-pink);
      padding: 0.2rem 1rem;
      border-radius: 20px;
    }
    footer {
      background: #06090F;
      padding: 4rem 0 1.5rem;
    }
    @media (max-width: 900px) {
      .cards-grid, .faq-grid {
        grid-template-columns: 1fr;
      }
      .hero {
        flex-direction: column;
        text-align: center;
      }
      .btn-group {
        justify-content: center;
      }
  境    }