/* roulang page: index */
:root {
      --primary-red: #E63946;
      --primary-deep-red: #C1121F;
      --secondary-orange: #F4A261;
      --deep-black: #1D1D1D;
      --warm-white: #F9F6F0;
      --pure-white: #FFFFFF;
      --text-gray: #4A4A4A;
      --light-gray: #B0B0B0;
      --border-light: rgba(0,0,0,0.08);
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 12px 32px rgba(0,0,0,0.12);
      --radius-lg: 16px;
      --radius-md: 8px;
      --font-cn: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-en: "Inter", "Roboto", sans-serif;
      --transition: 0.3s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-cn);
      background-color: var(--warm-white);
      color: var(--deep-black);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.3;
    }
    h1 {
      font-size: clamp(40px, 5vw, 56px);
      font-weight: 800;
      color: var(--pure-white);
      letter-spacing: -0.5px;
    }
    h2 {
      font-size: clamp(32px, 4vw, 40px);
      color: var(--deep-black);
      margin-bottom: 16px;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
      color: var(--deep-black);
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-cn);
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border: none;
      font-weight: 600;
      border-radius: var(--radius-md);
    }
    .btn-primary {
      background: var(--primary-red);
      color: white;
      padding: 14px 32px;
      font-size: 16px;
      box-shadow: 0 4px 12px rgba(230,57,70,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-deep-red);
      transform: scale(1.05);
      box-shadow: 0 8px 20px rgba(230,57,70,0.35);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-red);
      color: var(--primary-red);
      padding: 12px 30px;
      font-size: 16px;
    }
    .btn-outline:hover {
      background: var(--primary-red);
      color: white;
      transform: scale(1.05);
    }
    .btn-white {
      background: var(--pure-white);
      color: var(--deep-black);
      padding: 14px 32px;
      font-weight: 700;
    }
    .btn-white:hover {
      background: var(--secondary-orange);
      color: var(--deep-black);
      transform: scale(1.05);
    }
    /* 导航 */
    .main-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: var(--pure-white);
      height: 64px;
      display: flex;
      align-items: center;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
      transition: box-shadow 0.3s;
    }
    .main-header.scrolled {
      box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-family: var(--font-en);
      font-weight: 800;
      font-size: 28px;
      color: var(--primary-red);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .logo span {
      font-family: var(--font-cn);
      font-weight: 700;
      font-size: 24px;
      color: var(--deep-black);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--deep-black);
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary-red);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary-red);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--deep-black);
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--deep-black);
      flex-direction: column;
      justify-content: center;
      align-items: flex-start;
      padding: 40px;
      z-index: 999;
    }
    .mobile-menu.open {
      display: flex;
    }
    .mobile-menu a {
      color: white;
      font-size: 24px;
      margin-bottom: 24px;
      font-weight: 600;
    }
    .mobile-close {
      position: absolute;
      top: 24px;
      right: 24px;
      font-size: 32px;
      color: white;
      background: none;
      border: none;
    }
    /* Hero */
    #hero {
      background: linear-gradient(135deg, #1D1D1D 0%, #E63946 100%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding: 100px 0 80px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-left {
      color: white;
    }
    .hero-left h1 {
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      opacity: 0.9;
      margin-bottom: 36px;
      max-width: 450px;
    }
    .hero-buttons {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
    .hero-right img {
      border-radius: var(--radius-lg);
      box-shadow: 0 20px 40px rgba(0,0,0,0.3);
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    /* 亮点 */
    #highlights {
      padding: 100px 0;
    }
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .stat-card {
      background: var(--pure-white);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      text-align: center;
      transition: var(--transition);
    }
    .stat-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .stat-number {
      font-family: var(--font-en);
      font-size: clamp(44px, 5vw, 56px);
      font-weight: 900;
      color: var(--primary-red);
      line-height: 1.1;
      margin-bottom: 12px;
    }
    .stat-title {
      font-weight: 700;
      font-size: 18px;
      margin-bottom: 8px;
    }
    .stat-desc {
      color: var(--text-gray);
      font-size: 14px;
    }
    /* 案例 */
    #cases {
      padding: 100px 0;
      background: var(--pure-white);
    }
    .cases-masonry {
      columns: 3 280px;
      column-gap: 24px;
    }
    .case-card {
      break-inside: avoid;
      background: var(--warm-white);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      transition: var(--transition);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      width: 100%;
      display: block;
      background: #e0e0e0;
    }
    .case-content {
      padding: 20px;
    }
    .case-tag {
      background: var(--secondary-orange);
      color: white;
      font-size: 12px;
      padding: 4px 12px;
      border-radius: 20px;
      display: inline-block;
      margin-bottom: 8px;
      font-weight: 600;
    }
    .case-title {
      font-size: 18px;
      font-weight: 700;
      margin-bottom: 8px;
    }
    .case-desc {
      font-size: 14px;
      color: var(--text-gray);
    }
    /* 对比 */
    #compare {
      padding: 100px 0;
    }
    .compare-table {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
      margin-top: 40px;
    }
    .compare-col {
      background: var(--pure-white);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
    }
    .compare-col.highlight {
      background: #FFF0F0;
      border-top: 4px solid var(--primary-red);
    }
    .compare-col h3 {
      margin-bottom: 24px;
      font-size: 22px;
    }
    .compare-item {
      display: flex;
      justify-content: space-between;
      padding: 12px 0;
      border-bottom: 1px solid var(--border-light);
    }
    .check {
      color: var(--primary-red);
      font-weight: bold;
    }
    /* FAQ */
    #faq {
      padding: 100px 0;
      background: var(--pure-white);
    }
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      margin-bottom: 8px;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 700;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--deep-black);
    }
    .faq-question.active {
      color: var(--primary-red);
    }
    .faq-icon {
      font-size: 24px;
      transition: 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-gray);
    }
    .faq-answer.open {
      max-height: 200px;
      padding-bottom: 16px;
    }
    /* CTA */
    #contact {
      background: linear-gradient(135deg, #E63946 0%, #F4A261 100%);
      padding: 100px 0;
      color: white;
    }
    .cta-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .cta-left h2 {
      color: white;
    }
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 14px;
      margin-bottom: 16px;
      background: rgba(255,255,255,0.2);
      border: 1px solid rgba(255,255,255,0.5);
      border-radius: var(--radius-md);
      color: white;
      font-size: 16px;
    }
    .contact-form input::placeholder {
      color: rgba(255,255,255,0.8);
    }
    .contact-form button {
      background: var(--deep-black);
      color: white;
      padding: 16px;
      width: 100%;
      font-weight: 700;
    }
    /* 页脚 */
    footer {
      background: var(--deep-black);
      color: var(--light-gray);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-size: 28px;
      font-weight: 800;
      color: white;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-grid, .cta-grid, .footer-grid { grid-template-columns: 1fr; }
      .highlights-grid { grid-template-columns: 1fr; }
      .cases-masonry { columns: 1; }
      .compare-table { grid-template-columns: 1fr; }
    }