/* roulang page: index */
:root {
      --primary-purple: #7B2FF7;
      --primary-cyan: #00F0FF;
      --deep-black: #0D0D1A;
      --card-bg: rgba(20, 20, 35, 0.7);
      --cta-orange: #FF6B35;
      --cta-orange-light: #FF8C42;
      --text-main: #F0F0F5;
      --text-secondary: #B0B0C0;
      --border-glow: rgba(0, 240, 255, 0.25);
      --shadow-glow: 0 0 20px rgba(123, 47, 247, 0.3);
      --radius-card: 16px;
      --radius-btn: 10px;
      --font-heading: 'Inter', 'Poppins', '思源黑体 Bold', system-ui, -apple-system, sans-serif;
      --font-body: 'Inter', '思源黑体 Regular', system-ui, -apple-system, sans-serif;
      --transition: 0.3s ease;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      background-color: var(--deep-black);
      color: var(--text-main);
      font-family: var(--font-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      background-image: radial-gradient(circle at 30% 10%, rgba(123, 47, 247, 0.08) 0%, transparent 45%),
                        radial-gradient(circle at 80% 70%, rgba(0, 240, 255, 0.06) 0%, transparent 50%);
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    img {
      max-width: 100%;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

    /* 导航栏 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(13, 13, 26, 0.85);
      backdrop-filter: blur(16px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.2);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: -0.3px;
      color: white;
      background: linear-gradient(135deg, #E0D9FF 0%, #FFFFFF 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .logo-icon {
      font-size: 1.8rem;
      filter: drop-shadow(0 0 8px #00F0FF);
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-links a {
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 4px 0;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: white;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary-cyan);
      transition: 0.25s;
    }

    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }

    .btn-nav {
      background: var(--cta-orange);
      color: white;
      border: none;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      box-shadow: 0 4px 14px rgba(255, 107, 53, 0.4);
      transition: 0.25s;
    }

    .btn-nav:hover {
      background: var(--cta-orange-light);
      transform: translateY(-2px);
      box-shadow: 0 8px 22px rgba(255, 107, 53, 0.5);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
    }

    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--primary-cyan);
      transition: 0.3s;
    }

    /* Hero */
    .hero {
      padding: 80px 0 100px;
      display: flex;
      align-items: center;
      position: relative;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      background-blend-mode: overlay;
      background-color: rgba(13, 13, 26, 0.75);
      min-height: 85vh;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 40px;
      flex-wrap: wrap;
    }

    .hero-content {
      flex: 1 1 500px;
    }

    .hero h1 {
      font-size: 3.5rem;
      font-weight: 800;
      font-family: var(--font-heading);
      letter-spacing: -0.8px;
      line-height: 1.2;
      margin-bottom: 24px;
      background: linear-gradient(to right, #FFFFFF, #D9D0FF, #91F0FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-sub {
      font-size: 1.25rem;
      color: #C0C0D0;
      margin-bottom: 32px;
      max-width: 550px;
    }

    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: linear-gradient(135deg, #FF6B35, #FF8C42);
      border: none;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 1.1rem;
      color: white;
      display: flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 8px 22px rgba(255, 107, 53, 0.45);
      transition: 0.3s;
    }

    .btn-primary:hover {
      transform: translateY(-3px);
      box-shadow: 0 14px 30px rgba(255, 107, 53, 0.6);
      background: linear-gradient(135deg, #FF7D4A, #FF9B58);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-cyan);
      color: var(--primary-cyan);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.3s;
    }

    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.08);
      border-color: #7BF0FF;
      color: white;
    }

    .hero-visual {
      flex: 1 1 400px;
      position: relative;
    }

    .hero-visual img {
      border-radius: 24px;
      box-shadow: 0 0 40px rgba(123, 47, 247, 0.45);
      border: 1px solid rgba(0,240,255,0.3);
    }

    /* 通用区块 */
    section {
      padding: 90px 0;
    }

    .section-title {
      font-size: 2.5rem;
      font-weight: 700;
      font-family: var(--font-heading);
      margin-bottom: 16px;
      background: linear-gradient(to right, #F0F0FF, #B5EFFF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .section-sub {
      color: #A0A0B8;
      margin-bottom: 60px;
      font-size: 1.15rem;
    }

    /* 卡片网格 */
    .grid-3, .grid-4 {
      display: grid;
      gap: 28px;
    }
    .grid-3 { grid-template-columns: repeat(3,1fr); }
    .grid-4 { grid-template-columns: repeat(4,1fr); }

    .feature-card {
      background: rgba(20, 20, 40, 0.65);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(0, 240, 255, 0.2);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      transition: 0.3s;
      box-shadow: 0 0 18px rgba(123, 47, 247, 0.15);
    }

    .feature-card:hover {
      border-color: var(--primary-cyan);
      box-shadow: 0 0 28px rgba(0, 240, 255, 0.3);
      transform: translateY(-5px);
    }

    .card-icon {
      font-size: 2.3rem;
      color: var(--primary-cyan);
      margin-bottom: 20px;
    }

    .number-highlight {
      font-size: 3.2rem;
      font-weight: 800;
      background: linear-gradient(180deg, #C084FC 0%, #22D3EE 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.1);
      padding: 20px 0;
      cursor: pointer;
    }

    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      color: #E0E0F0;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.4s;
      color: #B0B0CC;
      margin-top: 8px;
      border-left: 3px solid var(--primary-purple);
      padding-left: 16px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }

    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .grid-4 { grid-template-columns: repeat(2,1fr); }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero h1 { font-size: 2.6rem; }
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .hero-grid { flex-direction: column; }
    }