/* roulang page: index */
:root {
      --asphalt: #1A1A1A;
      --track-white: #F7F7F2;
      --racing-orange: #E8553D;
      --racing-orange-deep: #D1442F;
      --warm-gray-bg: #FAFAF8;
      --light-gray: #F0F0EA;
      --card-border: #E5E5DF;
      --card-border-hover: #D1D1C8;
      --text-primary: #1A1A1A;
      --text-secondary: #666666;
      --text-muted: #999999;
      --white: #FFFFFF;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-pill: 24px;
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.04);
      --transition-smooth: 300ms ease;
      --transition-fast: 200ms ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      margin: 0;
      padding: 0;
      background-color: var(--warm-gray-bg);
      color: var(--text-primary);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    a {
      color: inherit;
      text-decoration: none;
    }

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

    button, input, textarea {
      font-family: inherit;
    }

    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 768px) {
      .container-custom {
        padding-left: 2.5rem;
        padding-right: 2.5rem;
      }
    }

    /* 导航 */
    .nav-blur {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .search-box {
      background: var(--light-gray);
      border: 1px solid var(--card-border);
      border-radius: 24px;
      transition: border var(--transition-fast), background var(--transition-fast);
    }
    .search-box:focus-within {
      border-color: var(--asphalt);
      background: var(--white);
    }
    .hamburger-line {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--asphalt);
      margin: 5px 0;
      transition: var(--transition-smooth);
    }
    .mobile-menu-open .hamburger-line:nth-child(1) {
      transform: rotate(45deg) translate(5px, 5px);
    }
    .mobile-menu-open .hamburger-line:nth-child(2) {
      opacity: 0;
    }
    .mobile-menu-open .hamburger-line:nth-child(3) {
      transform: rotate(-45deg) translate(5px, -5px);
    }

    /* 按钮 */
    .btn-primary {
      background-color: var(--racing-orange);
      color: white;
      border-radius: var(--radius-btn);
      padding: 0.75rem 1.75rem;
      font-weight: 600;
      transition: background var(--transition-fast), transform var(--transition-fast);
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background-color: var(--racing-orange-deep);
      transform: scale(1.03);
    }
    .btn-outline {
      background: transparent;
      color: var(--asphalt);
      border: 1px solid var(--asphalt);
      border-radius: var(--radius-btn);
      padding: 0.75rem 1.75rem;
      font-weight: 600;
      transition: background var(--transition-fast), color var(--transition-fast);
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: var(--asphalt);
      color: white;
    }

    /* 卡片 */
    .card-service {
      background: var(--white);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      padding: 2rem;
      transition: transform var(--transition-smooth), box-shadow var(--transition-smooth), border-color var(--transition-smooth);
    }
    .card-service:hover {
      transform: translateY(-4px);
      border-color: var(--card-border-hover);
      box-shadow: var(--shadow-card-hover);
    }
    .case-card {
      background: var(--white);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      overflow: hidden;
      transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-img {
      aspect-ratio: 4/3;
      object-fit: cover;
      transition: transform 0.4s ease;
    }
    .case-card:hover .case-img {
      transform: scale(1.03);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--card-border);
    }
    .faq-question {
      cursor: pointer;
      padding: 1.25rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 500;
      font-size: 1.1rem;
    }
    .faq-icon {
      font-size: 1.5rem;
      color: var(--racing-orange);
      transition: transform 0.3s ease;
      line-height: 1;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
      color: var(--text-secondary);
      padding: 0 0 0 0;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding: 0 0 1.25rem 0;
    }

    /* 浮动图形 */
    .floating-shape {
      position: absolute;
      background: var(--asphalt);
      opacity: 0.04;
      border-radius: 50%;
      animation: floatAnim 8s infinite alternate ease-in-out;
    }
    @keyframes floatAnim {
      0% { transform: translate(0, 0) rotate(0deg); }
      100% { transform: translate(15px, -25px) rotate(10deg); }
    }
    .diagonal-line {
      position: absolute;
      width: 120px;
      height: 2px;
      background: var(--asphalt);
      opacity: 0.06;
      transform: rotate(-30deg);
    }

    /* 联系表单深色区 */
    .dark-input {
      background: transparent;
      border: none;
      border-bottom: 1px solid #555;
      color: white;
      padding: 0.75rem 0;
      width: 100%;
      transition: border-color var(--transition-fast);
    }
    .dark-input:focus {
      outline: none;
      border-bottom-color: var(--racing-orange);
    }
    .dark-input::placeholder {
      color: #aaa;
    }

    /* 页脚链接 */
    .footer-link:hover {
      color: white;
      transition: color var(--transition-fast);
    }