/* roulang page: index */
:root {
      --bg-deep: #0B0E14;
      --bg-card: rgba(15, 23, 42, 0.7);
      --accent-cyan: #00E5FF;
      --cyan-dark: #00B8D4;
      --warm-orange: #FF6D00;
      --silver: #B0BEC5;
      --text-primary: #F1F5F9;
      --text-muted: #B0BEC5;
      --border-cyan: rgba(0, 229, 255, 0.2);
      --glass-bg: rgba(15, 23, 42, 0.6);
      --glass-border: rgba(0, 229, 255, 0.12);
      --radius-card: 1rem;
      --radius-btn: 8px;
      --shadow-card: 0 12px 30px rgba(0, 0, 0, 0.45);
      --transition: all 0.28s ease;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
    }

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

    body {
      background-color: var(--bg-deep);
      color: var(--silver);
      font-family: var(--font-sans);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    section {
      padding: 80px 0;
      position: relative;
    }

    /* 背景纹理 */
    body::before {
      content: "";
      position: fixed;
      inset: 0;
      background-image: radial-gradient(circle at 20% 10%, rgba(0, 229, 255, 0.05) 0%, transparent 50%),
                        radial-gradient(circle at 80% 60%, rgba(255, 109, 0, 0.03) 0%, transparent 55%);
      pointer-events: none;
      z-index: 0;
    }

    /* ---------- 导航 ---------- */
    .nav-bar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(11, 14, 20, 0.85);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-cyan);
      z-index: 1000;
      height: 70px;
      display: flex;
      align-items: center;
    }
    .nav-container {
      max-width: 1200px;
      margin: 0 auto;
      width: 100%;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 24px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: 2px;
      color: white;
      text-decoration: none;
    }
    .logo span {
      color: var(--accent-cyan);
    }
    .nav-menu {
      display: flex;
      gap: 2rem;
      list-style: none;
    }
    .nav-menu a {
      text-decoration: none;
      color: var(--text-muted);
      font-weight: 500;
      position: relative;
      padding: 4px 0;
      transition: 0.2s;
    }
    .nav-menu a::after {
      content: "";
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-cyan);
      transition: 0.25s;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--accent-cyan);
    }
    .nav-menu a:hover::after,
    .nav-menu a.active::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      display: block;
      width: 26px;
      height: 2px;
      background: var(--accent-cyan);
      transition: 0.2s;
    }

    /* ---------- Hero 动态背景 ---------- */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      background: radial-gradient(circle at 30% 40%, #0f3460 0%, #0B0E14 80%);
      position: relative;
      overflow: hidden;
      padding-top: 70px;
    }
    .hero::before {
      content: "";
      position: absolute;
      width: 100%;
      height: 100%;
      background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 600"><circle cx="200" cy="180" r="2" fill="%2300E5FF" opacity="0.4"/><circle cx="650" cy="320" r="1.5" fill="%2300E5FF" opacity="0.3"/><circle cx="100" cy="450" r="2.5" fill="%23FF6D00" opacity="0.3"/></svg>');
      background-size: cover;
      animation: floatParticles 20s infinite alternate;
    }
    @keyframes floatParticles {
      0% { transform: translate(0,0); }
      100% { transform: translate(30px, -20px); }
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
    }
    .hero h1 {
      font-size: 3rem;
      font-weight: 700;
      background: linear-gradient(to right, #00E5FF, #00B8D4);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      letter-spacing: 2px;
      margin-bottom: 1.25rem;
    }
    .hero-sub {
      font-size: 1.25rem;
      color: var(--silver);
      margin-bottom: 2.5rem;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: #0B0E14;
      padding: 0.85rem 2.25rem;
      border-radius: 8px;
      font-weight: 700;
      text-decoration: none;
      transition: 0.25s;
      box-shadow: 0 4px 14px rgba(0, 229, 255, 0.3);
    }
    .btn-primary:hover {
      box-shadow: 0 0 28px rgba(0, 229, 255, 0.6);
      background: #33ebff;
    }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 0.85rem 2.25rem;
      border-radius: 8px;
      font-weight: 600;
      text-decoration: none;
      transition: 0.25s;
    }
    .btn-secondary:hover {
      background: rgba(0, 229, 255, 0.1);
    }

    /* ---------- 通用标题 ---------- */
    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      color: white;
      margin-bottom: 0.75rem;
    }
    .section-sub {
      color: var(--text-muted);
      margin-bottom: 3rem;
    }

    /* ---------- 卡片系统 ---------- */
    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(16px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      padding: 2rem;
      transition: var(--transition);
      box-shadow: var(--shadow-card);
    }
    .glass-card:hover {
      border-color: rgba(0, 229, 255, 0.45);
      transform: translateY(-4px);
      box-shadow: 0 20px 35px rgba(0,0,0,0.6);
    }
    .icon-placeholder {
      width: 60px;
      height: 60px;
      background: rgba(0,229,255,0.08);
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.5rem;
      color: var(--accent-cyan);
      font-size: 2rem;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    .data-number {
      font-family: 'Inter', 'Poppins', sans-serif;
      font-size: 2.6rem;
      font-weight: 700;
      color: var(--accent-cyan);
    }
    .orange-number {
      color: var(--warm-orange);
    }

    /* 案例卡片 */
    .case-img {
      width: 100%;
      height: 180px;
      object-fit: cover;
      border-radius: 12px;
      background: #1e293b;
    }
    .tag {
      color: var(--warm-orange);
      font-size: 0.8rem;
      font-weight: 600;
      background: rgba(255,109,0,0.12);
      padding: 2px 12px;
      border-radius: 20px;
    }

    .flow-line {
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .step-num {
      width: 44px;
      height: 44px;
      border: 2px solid var(--accent-cyan);
      border-radius: 50%;
      font-weight: bold;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      margin-bottom: 1rem;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(0,229,255,0.12);
      padding: 1.2rem 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      color: #F1F5F9;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--silver);
      margin-top: 0.5rem;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: #0B0E14;
      background-image: radial-gradient(circle at 30% 45%, rgba(0,229,255,0.08) 0%, transparent 70%);
      text-align: center;
    }
    .btn-glow {
      background: var(--warm-orange);
      color: white;
      padding: 1rem 2.5rem;
      border-radius: 8px;
      font-weight: 700;
      border: none;
      box-shadow: 0 8px 22px rgba(255,109,0,0.4);
      transition: 0.25s;
      display: inline-block;
      text-decoration: none;
    }
    .btn-glow:hover {
      box-shadow: 0 0 35px rgba(255,109,0,0.8);
    }

    footer {
      background: #0A0D13;
      padding: 3rem 0;
    }

    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .grid-4 { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .hamburger { display: flex; }
      .nav-menu {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 70px;
        left:0;
        width:100%;
        background: rgba(11,14,20,0.95);
        backdrop-filter: blur(12px);
        padding: 1.5rem;
        gap: 1.5rem;
      }
      .nav-menu.open { display: flex; }
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero h1 { font-size: 2rem; }
      section { padding: 50px 0; }
    }