/* roulang page: index */
:root {
      --primary-deep: #1E2C2A;
      --primary-soft: #2A3A38;
      --accent-gold: #C8A96E;
      --accent-bright: #D4AF6E;
      --bg-warm: #F7F5F2;
      --bg-card: #FFFFFF;
      --text-main: #1E1E1E;
      --text-secondary: #5A5A5A;
      --text-on-dark: #FFFFFF;
      --border-light: #E5E5E5;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, sans-serif;
      --font-number: "Inter", "Segoe UI", "PingFang SC", sans-serif;
      --radius-card: 14px;
      --radius-btn: 8px;
      --transition-base: 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.7;
      display: flex;
      flex-direction: row;
      min-height: 100vh;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      font-weight: 600;
      margin-top: 0;
    }
    a {
      color: inherit;
      text-decoration: none;
    }
    img {
      max-width: 100%;
      display: block;
      object-fit: cover;
    }
    .side-nav {
      width: 260px;
      background-color: var(--primary-deep);
      color: var(--text-on-dark);
      display: flex;
      flex-direction: column;
      position: fixed;
      top: 0;
      left: 0;
      bottom: 0;
      z-index: 1050;
      padding: 2rem 1.5rem;
      box-shadow: 2px 0 15px rgba(0,0,0,0.08);
      transition: transform 0.35s ease;
    }
    .brand-area {
      margin-bottom: 2.5rem;
    }
    .brand-logo {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 0.5rem;
    }
    .brand-logo img {
      width: 40px;
      height: 40px;
      border-radius: 8px;
      background-color: rgba(255,255,255,0.1);
    }
    .brand-name {
      font-size: 1.3rem;
      font-weight: 700;
      letter-spacing: 0.02em;
      color: white;
    }
    .brand-tagline {
      font-size: 0.8rem;
      color: var(--accent-gold);
      opacity: 0.9;
      margin-top: 0.25rem;
      font-weight: 400;
    }
    .nav-menu {
      list-style: none;
      padding: 0;
      margin: 2rem 0 1rem;
      flex: 1;
    }
    .nav-item {
      margin-bottom: 8px;
    }
    .nav-link {
      display: flex;
      align-items: center;
      padding: 0.75rem 1rem;
      border-radius: 8px;
      color: rgba(255,255,255,0.8);
      font-weight: 500;
      font-size: 0.95rem;
      letter-spacing: 0.03em;
      transition: all 0.2s ease;
      position: relative;
      border-left: 3px solid transparent;
    }
    .nav-link i {
      width: 20px;
      margin-right: 12px;
      font-size: 1rem;
      color: var(--accent-gold);
    }
    .nav-link:hover, .nav-link.active {
      background-color: rgba(255,255,255,0.05);
      color: white;
      border-left-color: var(--accent-gold);
      padding-left: 1.2rem;
    }
    .nav-link.active {
      background-color: rgba(200,169,110,0.1);
      font-weight: 600;
    }
    .footer-contact-mini {
      font-size: 0.8rem;
      color: #aaa;
      margin-top: auto;
      border-top: 1px solid rgba(255,255,255,0.15);
      padding-top: 1.2rem;
    }
    .main-content {
      margin-left: 260px;
      width: calc(100% - 260px);
      background-color: var(--bg-warm);
    }
    .mobile-nav {
      display: none;
    }
    section {
      padding: 100px 0;
      scroll-margin-top: 0;
    }
    .container-custom {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 40px;
    }
    h2 {
      font-size: 2.4rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      margin-bottom: 2rem;
      color: var(--primary-deep);
    }
    .section-subtitle {
      color: var(--text-secondary);
      font-size: 1.1rem;
      max-width: 680px;
      margin-bottom: 3rem;
    }
    .btn-primary-custom {
      background-color: var(--accent-gold);
      border: none;
      color: #1E1E1E;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: var(--transition-base);
      letter-spacing: 0.5px;
      box-shadow: 0 4px 12px rgba(200,169,110,0.3);
    }
    .btn-primary-custom:hover {
      background-color: #b8924a;
      color: #1E1E1E;
      box-shadow: 0 6px 18px rgba(200,169,110,0.5);
      transform: translateY(-1px);
    }
    .btn-outline-custom {
      border: 1px solid var(--primary-deep);
      color: var(--primary-deep);
      background: transparent;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: var(--transition-base);
    }
    .btn-outline-custom:hover {
      background-color: rgba(30,44,42,0.05);
      border-color: var(--primary-deep);
      color: var(--primary-deep);
    }
    .card-custom {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      padding: 2rem;
      border: none;
      transition: var(--transition-base);
      height: 100%;
    }
    .card-custom:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .accordion-custom .accordion-button {
      background: white;
      border: 1px solid var(--border-light);
      border-radius: 10px !important;
      font-weight: 600;
      color: var(--primary-deep);
      padding: 1.2rem 1.5rem;
      box-shadow: none;
    }
    .accordion-custom .accordion-button:not(.collapsed) {
      background-color: #F0F4F3;
      border-color: var(--primary-deep);
      color: var(--primary-deep);
    }
    .accordion-custom .accordion-body {
      background: #FAFAFA;
      border-radius: 0 0 10px 10px;
      padding: 1.2rem 1.5rem;
    }
    .form-control-custom {
      border: 1px solid #D1D1D1;
      border-radius: 6px;
      padding: 12px 16px;
      transition: 0.2s;
    }
    .form-control-custom:focus {
      border-color: var(--primary-deep);
      box-shadow: 0 0 0 3px rgba(30,44,42,0.12);
    }
    @media (max-width: 991px) {
      body {
        flex-direction: column;
      }
      .side-nav {
        display: none;
      }
      .mobile-nav {
        display: block;
        background-color: var(--primary-deep);
        position: sticky;
        top: 0;
        z-index: 1040;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .navbar-dark .navbar-toggler {
        border: none;
      }
      .mobile-brand {
        font-weight: 700;
        color: white;
      }
      section {
        padding: 60px 0;
      }
      h2 {
        font-size: 1.8rem;
      }
      .container-custom {
        padding: 0 20px;
      }
    }