/* roulang page: index */
:root {
      --rb-black: #1A1A1A;
      --rb-red: #C8102E;
      --rb-red-deep: #A00D24;
      --rb-silver: #B0B0B0;
      --rb-warm-bg: #F5F3F0;
      --rb-white: #FFFFFF;
      --rb-gray-dark: #4A4A4A;
      --rb-gray-light: #8A8A8A;
      --rb-border: #E0E0E0;
      --rb-card-shadow: 0 2px 12px rgba(0,0,0,0.04);
      --rb-card-hover-shadow: 0 8px 24px rgba(0,0,0,0.08);
      --rb-btn-shadow: 0 2px 8px rgba(200,16,46,0.25);
      --bs-primary: #C8102E;
      --bs-primary-rgb: 200,16,46;
      --bs-dark: #1A1A1A;
      --bs-body-bg: #F5F3F0;
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, sans-serif;
    }
    * {
      box-sizing: border-box;
    }
    body {
      background-color: var(--rb-warm-bg);
      color: var(--rb-black);
      font-size: 16px;
      line-height: 1.7;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4, .h1, .h2, .h3, .h4 {
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    h1 {
      font-size: clamp(2.25rem, 5vw, 3.5rem);
      line-height: 1.2;
      color: var(--rb-black);
    }
    h2 {
      font-size: clamp(1.75rem, 3.5vw, 2.25rem);
      line-height: 1.3;
      margin-bottom: 1rem;
    }
    h3 {
      font-size: 1.35rem;
      font-weight: 600;
      line-height: 1.4;
    }
    .section-title {
      position: relative;
      display: inline-block;
      margin-bottom: 2.5rem;
      color: var(--rb-black);
    }
    .section-title::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 60%;
      height: 4px;
      background: var(--rb-red);
      border-radius: 2px;
    }
    .text-red {
      color: var(--rb-red);
    }
    .bg-warm {
      background-color: var(--rb-warm-bg);
    }
    .bg-dark-custom {
      background-color: var(--rb-black);
    }
    /* 导航 */
    .navbar-custom {
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(10px);
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      height: 72px;
      transition: all 0.2s;
      z-index: 1030;
    }
    .navbar-brand {
      font-weight: 800;
      font-size: 1.8rem;
      letter-spacing: -0.5px;
      color: var(--rb-black) !important;
    }
    .navbar-brand span {
      color: var(--rb-red);
    }
    .nav-link {
      font-weight: 500;
      color: var(--rb-gray-dark) !important;
      margin: 0 0.25rem;
      padding: 0.5rem 0.9rem !important;
      border-radius: 8px;
      transition: all 0.2s;
      position: relative;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--rb-red) !important;
      background: rgba(200,16,46,0.04);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 4px;
      left: 50%;
      transform: translateX(-50%);
      width: 20px;
      height: 2px;
      background: var(--rb-red);
      border-radius: 2px;
    }
    .navbar-toggler {
      border: none;
      color: var(--rb-black);
      font-size: 1.4rem;
    }
    .offcanvas {
      background: var(--rb-warm-bg);
    }
    .offcanvas .nav-link {
      font-size: 1.2rem;
      margin: 0.5rem 0;
    }
    /* 按钮 */
    .btn-primary-custom {
      background: var(--rb-red);
      border: none;
      color: white;
      font-weight: 600;
      padding: 12px 32px;
      border-radius: 8px;
      box-shadow: var(--rb-btn-shadow);
      transition: all 0.25s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    .btn-primary-custom:hover {
      background: var(--rb-red-deep);
      color: white;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(200,16,46,0.3);
    }
    .btn-outline-custom {
      background: transparent;
      border: 2px solid var(--rb-black);
      color: var(--rb-black);
      font-weight: 600;
      padding: 10px 28px;
      border-radius: 8px;
      transition: all 0.25s;
    }
    .btn-outline-custom:hover {
      background: var(--rb-black);
      color: white;
    }
    .btn-lg-custom {
      padding: 14px 38px;
      font-size: 1.1rem;
    }
    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background-color: var(--rb-warm-bg);
    }
    .hero-left {
      position: relative;
    }
    .hero-line {
      width: 4px;
      height: 60px;
      background: var(--rb-red);
      border-radius: 4px;
      margin-bottom: 1.8rem;
    }
    .hero-subtitle {
      font-size: 1.2rem;
      color: var(--rb-gray-dark);
      max-width: 480px;
      margin: 1.5rem 0 2rem;
    }
    .hero-img {
      width: 100%;
      height: auto;
      max-height: 450px;
      object-fit: cover;
      border-radius: 24px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.08);
    }
    /* 痛点卡片 */
    .pain-card {
      background: #FAFAFA;
      border: 1px solid transparent;
      border-radius: 12px;
      padding: 28px 24px;
      transition: all 0.2s;
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    .pain-card:hover {
      border-color: var(--rb-red);
      background: white;
    }
    .pain-icon {
      font-size: 2rem;
      color: var(--rb-red);
      margin-bottom: 1rem;
    }
    /* 解决方案卡片 */
    .solution-card {
      background: var(--rb-white);
      border-radius: 12px;
      box-shadow: var(--rb-card-shadow);
      overflow: hidden;
      transition: all 0.25s;
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    .solution-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--rb-card-hover-shadow);
    }
    .solution-img {
      height: 180px;
      object-fit: cover;
      width: 100%;
    }
    .solution-body {
      padding: 24px;
      flex: 1;
      display: flex;
      flex-direction: column;
    }
    .feature-list {
      list-style: none;
      padding-left: 0;
      margin-top: 0.8rem;
    }
    .feature-list li {
      padding: 0.2rem 0;
      font-size: 0.95rem;
      color: var(--rb-gray-dark);
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .feature-list i {
      color: var(--rb-red);
      font-size: 0.9rem;
    }
    /* 数据指标 */
    .metric-number {
      font-size: 3.2rem;
      font-weight: 800;
      color: var(--rb-red);
      line-height: 1.1;
    }
    .metric-label {
      font-size: 1rem;
      color: var(--rb-gray-dark);
      font-weight: 500;
    }
    /* 证言卡片 */
    .testimonial-card {
      background: white;
      border-radius: 12px;
      padding: 28px;
      box-shadow: var(--rb-card-shadow);
      position: relative;
      height: 100%;
    }
    .testimonial-quote {
      font-size: 3rem;
      color: var(--rb-red);
      opacity: 0.3;
      position: absolute;
      top: 10px;
      left: 18px;
      line-height: 1;
    }
    .testimonial-text {
      font-style: italic;
      margin-bottom: 1.5rem;
      color: var(--rb-gray-dark);
      position: relative;
      z-index: 1;
    }
    .avatar-placeholder {
      width: 48px;
      height: 48px;
      background: var(--rb-silver);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: white;
      background: var(--rb-black);
    }
    /* FAQ */
    .accordion-custom .accordion-item {
      border: 1px solid var(--rb-border);
      border-radius: 10px !important;
      margin-bottom: 12px;
      background: white;
      overflow: hidden;
    }
    .accordion-custom .accordion-button {
      font-weight: 600;
      font-size: 1.05rem;
      color: var(--rb-black);
      background: white;
      box-shadow: none;
      padding: 18px 22px;
    }
    .accordion-custom .accordion-button:not(.collapsed) {
      background: #FDFCFB;
      color: var(--rb-black);
      border-left: 4px solid var(--rb-red);
    }
    .accordion-custom .accordion-button:focus {
      box-shadow: none;
      border-color: var(--rb-red);
    }
    .accordion-custom .accordion-body {
      padding: 18px 22px;
      color: var(--rb-gray-dark);
    }
    /* CTA 深色区 */
    #cta {
      background: var(--rb-black);
      padding: 90px 0;
      position: relative;
    }
    #cta h2 {
      color: white;
    }
    #cta .btn-primary-custom {
      background: var(--rb-red);
    }
    /* 页脚 */
    footer {
      background: var(--rb-black);
      color: var(--rb-silver);
    }
    footer a {
      color: var(--rb-silver);
      text-decoration: none;
    }
    footer a:hover {
      color: var(--rb-red);
    }
    .footer-brand {
      font-weight: 800;
      font-size: 1.6rem;
      color: white;
    }
    /* 通用间距 */
    .section-padding {
      padding: 90px 0;
    }
    @media (max-width: 768px) {
      .section-padding {
        padding: 60px 0;
      }
      #hero {
        padding: 110px 0 60px;
      }
      .navbar-custom {
        height: 60px;
      }
      .metric-number {
        font-size: 2.5rem;
      }
      .solution-img {
        height: 160px;
      }
    }