/* roulang page: index */
:root {
      --primary: #E63946;
      --primary-dark: #C1121F;
      --dark: #1D1D1D;
      --darker: #0B0B0B;
      --accent: #00F5D4;
      --bg-light: #FAFAFA;
      --white: #FFFFFF;
      --text-main: #4A4A4A;
      --text-light: #CCCCCC;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-lg: 0 16px 40px rgba(0,0,0,0.12);
      --radius-md: 12px;
      --radius-btn: 8px;
      --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      margin: 0;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 40px;
    }
    h1, h2, h3, h4 {
      margin: 0;
      font-weight: 600;
    }
    h1 { font-size: 56px; font-weight: 700; letter-spacing: -1px; line-height: 1.2; }
    h2 { font-size: 44px; font-weight: 600; }
    h3 { font-size: 28px; font-weight: 500; }
    h4 { font-size: 20px; font-weight: 500; }
    p { margin: 0; font-size: 16px; font-weight: 400; color: var(--text-main); line-height: 1.8; }
    a { text-decoration: none; color: inherit; }
    img { max-width: 100%; display: block; }
    .section-py { padding: 100px 0; }
    /* 导航 */
    .navbar {
      background: var(--white);
      height: 72px;
      border-bottom: 1px solid rgba(0,0,0,0.05);
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      transition: box-shadow 0.3s;
    }
    .navbar.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--primary), #C1121F);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-right: 10px;
    }
    .logo-icon svg {
      width: 20px;
      height: 20px;
      fill: white;
    }
    .logo-text {
      font-size: 22px;
      font-weight: 700;
      color: var(--dark);
      letter-spacing: 0.5px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 36px;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: #2a2a2a;
      position: relative;
      padding-bottom: 4px;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: background 0.2s, box-shadow 0.2s;
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 0 4px rgba(230, 57, 70, 0.25);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1.5px solid var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      transition: background 0.2s, color 0.2s;
    }
    .btn-outline:hover {
      background: rgba(230, 57, 70, 0.08);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      justify-content: space-between;
      width: 24px;
      height: 18px;
      cursor: pointer;
      position: relative;
      z-index: 150;
    }
    .hamburger span {
      display: block;
      height: 2.5px;
      background: var(--dark);
      border-radius: 4px;
      transition: all 0.3s;
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(13,13,13,0.9);
      backdrop-filter: blur(12px);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      transform: translateY(-100%);
      transition: transform 0.4s ease;
      z-index: 120;
    }
    .mobile-menu.open {
      transform: translateY(0);
    }
    .mobile-menu a {
      color: white;
      font-size: 24px;
      font-weight: 500;
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.3s, transform 0.3s;
    }
    .mobile-menu.open a {
      opacity: 1;
      transform: translateY(0);
    }
    /* Hero 粒子效果 */
    .hero-particles {
      position: absolute;
      right: 0;
      top: 0;
      width: 50%;
      height: 100%;
      background: radial-gradient(circle at 70% 30%, rgba(0,245,212,0.12) 0%, transparent 60%);
      overflow: hidden;
    }
    .particle {
      position: absolute;
      background: var(--accent);
      width: 2px;
      height: 2px;
      border-radius: 50%;
      animation: float 6s infinite ease-in-out;
      opacity: 0.5;
    }
    @keyframes float {
      0% { transform: translateY(100px) scale(0); opacity:0; }
      50% { opacity:0.8; transform: translateY(20px) scale(1.2); }
      100% { transform: translateY(-80px) scale(0); opacity:0; }
    }
    .cursor-blink {
      animation: blink 1s step-end infinite;
    }
    @keyframes blink { 50% { opacity:0; } }
    .card {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s, box-shadow 0.3s;
      padding: 32px;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .price-highlight {
      border: 2px solid var(--primary);
      box-shadow: 0 14px 30px rgba(230,57,70,0.12);
      transform: scale(1.03);
    }
    .accordion-item {
      border-bottom: 1px solid #eee;
    }
    .accordion-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 24px 0;
      cursor: pointer;
      transition: 0.2s;
    }
    .accordion-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    .footer-link:hover { color: var(--primary); }
    @media (max-width: 768px) {
      .container { padding: 0 20px; }
      h1 { font-size: 38px; }
      h2 { font-size: 32px; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .section-py { padding: 60px 0; }
    }