/* roulang page: index */
:root {
      --primary-burn: #E94E1B;
      --primary-deep: #C43D14;
      --secondary-dark: #1E1E1E;
      --surface-white: #FFFFFF;
      --bg-light: #F5F5F7;
      --accent-neon: #C7FF38;
      --text-body: #6B6B6B;
      --text-light: #9A9A9A;
      --border-light: #E0E0E0;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-md: 0 12px 32px rgba(233,78,27,0.15);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: 0.25s ease-out;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-number: "Inter", "Roboto", sans-serif;
      --container-max: 1280px;
      --nav-height: 64px;
      --section-gap: 100px;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.8;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    h1, h2, h3, .stat-number {
      font-weight: 700;
      color: var(--secondary-dark);
    }
    
    h1 {
      font-size: 48px;
      font-weight: 800;
      letter-spacing: -0.5px;
      line-height: 1.2;
    }
    
    h2 {
      font-size: 36px;
      font-weight: 700;
      display: flex;
      align-items: center;
      gap: 16px;
      margin-bottom: 2rem;
    }
    
    h2::before {
      content: '';
      display: inline-block;
      width: 4px;
      height: 32px;
      background-color: var(--primary-burn);
      border-radius: 2px;
    }
    
    h3 {
      font-size: 20px;
      font-weight: 600;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      font-weight: 700;
      border: none;
      background: none;
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border-radius: var(--radius-btn);
    }
    
    /* 导航 */
    .nav {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(8px);
      height: var(--nav-height);
      display: flex;
      align-items: center;
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.3s;
    }
    
    .nav.scrolled {
      box-shadow: 0 4px 20px rgba(0,0,0,0.05);
      border-bottom: 1px solid var(--border-light);
    }
    
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .logo {
      font-size: 24px;
      font-weight: 800;
      color: var(--secondary-dark);
      letter-spacing: 1px;
    }
    
    .logo span {
      color: var(--primary-burn);
    }
    
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    
    .nav-links a {
      font-weight: 500;
      color: var(--secondary-dark);
      position: relative;
      padding: 4px 0;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary-burn);
      transition: width 0.2s;
    }
    
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    
    .btn-primary {
      background: var(--primary-burn);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      box-shadow: 0 4px 12px rgba(233,78,27,0.3);
    }
    
    .btn-primary:hover {
      background: var(--primary-deep);
      box-shadow: 0 0 18px rgba(233,78,27,0.5);
    }
    
    .btn-outline {
      border: 2px solid var(--secondary-dark);
      color: var(--secondary-dark);
      background: transparent;
      padding: 12px 28px;
      font-weight: 700;
    }
    
    .btn-outline:hover {
      border-color: var(--primary-burn);
      color: var(--primary-burn);
    }
    
    .btn-ghost {
      border: 2px solid white;
      color: white;
      padding: 12px 28px;
      background: transparent;
    }
    
    .btn-ghost:hover {
      background: white;
      color: var(--secondary-dark);
    }
    
    .hamburger {
      display: none;
      font-size: 24px;
      background: none;
      border: none;
      color: var(--secondary-dark);
    }
    
    /* Hero */
    .hero {
      background: linear-gradient(135deg, #1E1E1E 0%, #3A2C24 100%);
      position: relative;
      overflow: hidden;
      display: flex;
      align-items: center;
      min-height: 85vh;
      color: white;
    }
    
    .hero::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: radial-gradient(circle at 20% 30%, rgba(233,78,27,0.25) 0%, transparent 50%);
      pointer-events: none;
    }
    
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 40px;
      position: relative;
      z-index: 2;
    }
    
    .hero-text {
      flex: 1 1 55%;
    }
    
    .hero-text h1 {
      color: white;
      margin-bottom: 20px;
    }
    
    .hero-sub {
      font-size: 18px;
      color: rgba(255,255,255,0.8);
      margin-bottom: 32px;
      max-width: 480px;
    }
    
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    
    .hero-visual {
      flex: 1 1 45%;
      position: relative;
      min-height: 400px;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
      overflow: hidden;
    }
    
    .hero-visual::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(45deg, rgba(233,78,27,0.2) 0%, transparent 60%);
      mix-blend-mode: overlay;
    }
    
    .section {
      padding: var(--section-gap) 0;
    }
    
    .bg-dark {
      background: var(--secondary-dark);
      color: white;
    }
    
    .bg-dark h2, .bg-dark h3 {
      color: white;
    }
    
    .bg-gray {
      background: #EAEAEC;
    }
    
    .card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s, box-shadow 0.25s;
    }
    
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    
    .pain-card {
      background: transparent;
      box-shadow: none;
      border-bottom: 2px solid var(--border-light);
      padding: 24px 0;
      border-radius: 0;
    }
    
    .pain-card:hover {
      border-bottom-color: var(--primary-burn);
      transform: none;
      box-shadow: none;
    }
    
    .stat-large {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 900;
      color: var(--primary-burn);
      line-height: 1.1;
    }
    
    .accent-number {
      color: var(--accent-neon);
    }
    
    .testimonial-card {
      background: white;
      border-radius: 16px;
      padding: 28px;
      font-style: italic;
    }
    
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 20px 0;
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: transparent;
      border: none;
      color: var(--secondary-dark);
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      padding: 0 0;
    }
    
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    
    .footer {
      background: var(--secondary-dark);
      color: #B0B0B0;
      padding: 60px 0 30px;
    }
    
    .footer a {
      color: #D0D0D0;
    }
    
    .footer a:hover {
      color: var(--primary-burn);
    }
    
    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
    }
    
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 26px; }
      .nav-links { display: none; }
      .hamburger { display: block; }
      .hero-grid { flex-direction: column; }
      .grid-3, .grid-2 { grid-template-columns: 1fr; }
      .section { padding: 60px 0; }
    }