/* roulang page: index */
:root {
      --primary: #00E676;
      --primary-dark: #00C853;
      --secondary: #1E1E1E;
      --accent: #FF6D00;
      --gray-light: #F5F5F5;
      --gray-mid: #9E9E9E;
      --gray-dark: #333333;
      --white: #FFFFFF;
      --border-light: #E0E0E0;
      --border-lighter: #EEEEEE;
      --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.05);
      --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.06);
      --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
      --shadow-glow: 0 4px 12px rgba(0, 230, 118, 0.4);
      --radius-md: 12px;
      --radius-btn: 8px;
      --radius-full: 50px;
      --transition: 0.3s ease;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--gray-dark);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.2;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
      font-weight: 700;
      letter-spacing: 0.5px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      background: transparent;
      padding: 16px 0;
    }
    .header.scrolled {
      background: var(--white);
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
      padding: 12px 0;
    }
    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--white);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
      transition: color 0.3s;
    }
    .header.scrolled .logo {
      color: var(--secondary);
    }
    .logo svg {
      width: 36px;
      height: 36px;
      fill: currentColor;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      color: rgba(255,255,255,0.85);
      font-weight: 500;
      font-size: 1rem;
      transition: color 0.2s;
      position: relative;
    }
    .header.scrolled .nav-links a {
      color: var(--secondary);
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .header.scrolled .nav-links a:hover {
      color: var(--primary-dark);
    }
    .cta-btn {
      background: var(--primary);
      color: var(--secondary) !important;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      letter-spacing: 0.8px;
      background: var(--primary);
      border: none;
    }
    .header.scrolled .cta-btn {
      background: var(--primary);
      color: var(--secondary) !important;
    }
    .cta-btn:hover {
      background: var(--primary-dark);
      box-shadow: var(--shadow-glow);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
      background: transparent;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 28px;
      height: 3px;
      background: var(--white);
      transition: 0.3s;
      border-radius: 4px;
    }
    .header.scrolled .hamburger span {
      background: var(--secondary);
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--secondary);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 40px;
      z-index: 999;
      transform: translateY(-100%);
      transition: transform 0.4s ease;
    }
    .mobile-menu.open {
      transform: translateY(0);
      display: flex;
    }
    .mobile-menu a {
      color: white;
      font-size: 2rem;
      font-weight: 600;
    }
    /* Hero */
    .hero {
      height: 100vh;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
    }
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(30,30,30,0.4) 0%, rgba(0,0,0,0.8) 90%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 900px;
      padding: 0 24px;
    }
    .hero h1 {
      font-size: 56px;
      font-weight: 800;
      color: white;
      text-shadow: 0 4px 20px rgba(0,0,0,0.5);
      margin-bottom: 24px;
    }
    .hero p {
      font-size: 1.3rem;
      color: rgba(255,255,255,0.9);
      margin-bottom: 40px;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: #1E1E1E;
      padding: 16px 36px;
      border-radius: var(--radius-btn);
      font-size: 1.1rem;
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 16px 36px;
      border-radius: var(--radius-btn);
    }
    .audio-wave {
      margin: 30px auto 0;
      display: flex;
      justify-content: center;
      gap: 6px;
      height: 40px;
    }
    .wave-bar {
      width: 6px;
      background: var(--primary);
      border-radius: 3px;
      animation: wave 1.2s infinite ease-in-out alternate;
    }
    @keyframes wave {
      0% { height: 10px; opacity: 0.6; }
      100% { height: 100%; opacity: 1; }
    }
    /* 通用section */
    section {
      padding: 100px 0;
    }
    .section-title {
      font-size: 40px;
      font-weight: 700;
      margin-bottom: 16px;
      padding-left: 20px;
      border-left: 4px solid var(--primary);
    }
    .text-center {
      text-align: center;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 32px;
    }
    .card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .footer {
      background: var(--secondary);
      color: #ccc;
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
    }
    .footer a {
      color: #aaa;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero h1 { font-size: 36px; }
      .section-title { font-size: 32px; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }