/* roulang page: index */
:root {
      --deep-charcoal: #1E1E1E;
      --deep-navy: #0F172A;
      --electric-orange: #FF5F1F;
      --electric-orange-hover: #E54B0F;
      --bright-yellow: #FFD700;
      --white: #FFFFFF;
      --light-gray: #F8F9FA;
      --text-primary: #1A1A1A;
      --text-secondary: #555555;
      --text-muted: #888888;
      --border-color: #E5E5E5;
      --card-shadow: 0 2px 8px rgba(0,0,0,0.06);
      --card-shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
      --border-radius-card: 12px;
      --border-radius-btn: 8px;
      --border-radius-tag: 6px;
      --font-heading: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-body: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
      --transition-base: 0.25s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-body);
      color: var(--text-primary);
      background-color: var(--white);
      line-height: 1.6;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4, .h1, .h2, .h3 {
      font-family: var(--font-heading);
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    a {
      text-decoration: none;
      transition: color 0.2s ease, background-color 0.2s ease;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    /* 导航覆盖 */
    .navbar {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-color);
      padding: 0.75rem 0;
      transition: var(--transition-base);
    }
    .navbar-brand {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.6rem;
      color: var(--deep-charcoal) !important;
      letter-spacing: -0.5px;
    }
    .navbar-nav .nav-link {
      color: var(--text-secondary) !important;
      font-weight: 500;
      margin: 0 0.25rem;
      padding: 0.5rem 0.75rem !important;
      border-radius: 6px;
      transition: color 0.2s, background-color 0.2s;
    }
    .navbar-nav .nav-link:hover,
    .navbar-nav .nav-link.active {
      color: var(--electric-orange) !important;
      background-color: rgba(255,95,31,0.08);
    }
    .navbar-toggler {
      border: none;
      color: var(--deep-charcoal);
    }
    .navbar-toggler:focus {
      box-shadow: none;
    }
    @media (max-width: 991.98px) {
      .navbar-collapse {
        background: white;
        padding: 1.5rem;
        border-radius: 12px;
        margin-top: 0.75rem;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
      }
    }
    /* 按钮覆盖 */
    .btn-primary {
      background-color: var(--electric-orange);
      border-color: var(--electric-orange);
      border-radius: var(--border-radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      color: white;
      transition: background-color 0.25s, box-shadow 0.25s;
    }
    .btn-primary:hover, .btn-primary:focus {
      background-color: var(--electric-orange-hover);
      border-color: var(--electric-orange-hover);
      box-shadow: 0 4px 10px rgba(255,95,31,0.3);
    }
    .btn-outline-primary {
      border: 2px solid var(--electric-orange);
      color: var(--electric-orange);
      background: transparent;
      border-radius: var(--border-radius-btn);
      padding: 0.65rem 1.8rem;
      font-weight: 600;
      transition: all 0.25s;
    }
    .btn-outline-primary:hover {
      background-color: rgba(255,95,31,0.08);
      border-color: var(--electric-orange);
      color: var(--electric-orange);
    }
    .btn-link {
      color: var(--electric-orange);
      font-weight: 600;
      text-decoration: none;
      border-bottom: 1px solid transparent;
      transition: border 0.2s;
    }
    .btn-link:hover {
      border-bottom: 1px solid var(--electric-orange);
    }
    /* 卡片覆盖 */
    .card {
      border-radius: var(--border-radius-card);
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-color);
      transition: transform 0.25s ease, box-shadow 0.25s ease;
      background: white;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-shadow-hover);
    }
    .feature-icon-circle {
      width: 56px;
      height: 56px;
      background: var(--electric-orange);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.25rem;
    }
    .feature-icon-circle i {
      color: white;
      font-size: 1.8rem;
    }
    /* 手风琴覆盖 */
    .accordion-button {
      font-family: var(--font-heading);
      font-weight: 600;
      color: var(--deep-charcoal);
      background-color: white;
      box-shadow: none;
      border-bottom: 1px solid var(--border-color);
      padding: 1.2rem 1rem;
    }
    .accordion-button:not(.collapsed) {
      background-color: #f9f9f9;
      color: var(--deep-charcoal);
    }
    .accordion-button:focus {
      box-shadow: none;
      border-color: var(--electric-orange);
    }
    .accordion-button::after {
      background-image: none;
      content: "\f107";
      font-family: "Font Awesome 6 Free";
      font-weight: 900;
      color: var(--text-secondary);
      transition: transform 0.2s;
    }
    .accordion-button:not(.collapsed)::after {
      transform: rotate(180deg);
      color: var(--electric-orange);
    }
    .accordion-body {
      color: var(--text-secondary);
      line-height: 1.7;
    }
    /* 版块间距 */
    section {
      padding: 5rem 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 3.5rem 0;
      }
    }
    .bg-light-gray {
      background-color: var(--light-gray);
    }
    .bg-dark {
      background-color: var(--deep-charcoal);
      color: white;
    }
    .text-orange {
      color: var(--electric-orange);
    }
    .decorative-speed {
      background-image: repeating-linear-gradient(45deg, rgba(255,95,31,0.08) 0px, rgba(255,95,31,0.08) 2px, transparent 2px, transparent 8px);
    }
    .hero-min-height {
      min-height: 85vh;
      display: flex;
      align-items: center;
    }
    @media (max-width: 768px) {
      .hero-min-height {
        min-height: 70vh;
      }
    }
    .pricing-card-highlight {
      border-top: 4px solid var(--electric-orange);
      box-shadow: 0 12px 28px rgba(0,0,0,0.1);
    }
    footer a {
      color: #aaa;
      transition: color 0.2s;
    }
    footer a:hover {
      color: var(--electric-orange);
    }