/* roulang page: index */
:root {
      --primary: #0F5B3E;
      --primary-deep: #0A4530;
      --accent: #D4A84B;
      --accent-hover: #c0993b;
      --bg-white: #ffffff;
      --bg-light: #F7F8FA;
      --text-primary: #1A1D22;
      --text-secondary: #5A5F66;
      --text-muted: #9BA1AC;
      --border-light: #E8EAED;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Inter", sans-serif;
      --shadow-nav: 0 4px 20px rgba(0, 0, 0, 0.06);
      --shadow-card: none;
      --radius-sm: 6px;
      --radius-md: 8px;
      --radius-lg: 12px;
      --max-width: 1200px;
      --transition-base: 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      color: var(--text-primary);
      background: var(--bg-white);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
      object-fit: cover;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-weight: 600;
      transition: all var(--transition-base);
      border-radius: var(--radius-sm);
      padding: 12px 28px;
      font-size: 16px;
      line-height: 1.2;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover {
      background: var(--primary-deep);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(15, 91, 62, 0.05);
    }
    .btn-accent {
      background: var(--accent);
      color: #1A1D22;
    }
    .btn-accent:hover {
      background: var(--accent-hover);
    }
    h1, h2, h3 {
      font-weight: 600;
      letter-spacing: -0.02em;
    }
    h1 { font-size: 44px; line-height: 1.2; font-weight: 700; }
    h2 { font-size: 32px; line-height: 1.3; }
    h3 { font-size: 20px; line-height: 1.4; }
    .text-muted { color: var(--text-secondary); }
    .text-label { font-size: 14px; font-weight: 600; letter-spacing: 0.5px; color: var(--primary); text-transform: uppercase; }
    .section-spacing { margin: 100px 0; }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 24px; }
      .section-spacing { margin: 60px 0; }
      .btn { padding: 10px 22px; font-size: 15px; }
    }
    /* header / nav */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      height: 64px;
      transition: background 0.25s, box-shadow 0.25s;
      background: transparent;
    }
    .site-header.scrolled {
      background: var(--bg-white);
      box-shadow: var(--shadow-nav);
      color: var(--text-primary);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 64px;
    }
    .logo-area {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 20px;
      color: white;
      transition: color 0.2s;
    }
    .scrolled .logo-area { color: var(--text-primary); }
    .logo-icon {
      width: 36px; height: 36px; background: var(--primary); border-radius: 8px; display: flex; align-items: center; justify-content: center; color: white; font-weight: 700; font-size: 18px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
      font-weight: 500;
      color: white;
      transition: color 0.2s;
    }
    .scrolled .nav-links { color: var(--text-primary); }
    .nav-links a {
      color: inherit;
      font-size: 15px;
      position: relative;
      padding: 4px 0;
      white-space: nowrap;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after { width: 100%; }
    .nav-cta .btn-primary { background: var(--primary); color: white; border: none; }
    .scrolled .nav-cta .btn-primary { background: var(--primary); }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 24px; height: 2px; background: white; transition: 0.2s;
    }
    .scrolled .hamburger span { background: var(--text-primary); }
    .mobile-menu {
      display: none;
      position: fixed; top: 64px; left: 0; width: 100%; height: calc(100vh - 64px);
      background: rgba(255,255,255,0.98); backdrop-filter: blur(8px);
      flex-direction: column; align-items: center; justify-content: center; gap: 28px;
      z-index: 999;
    }
    .mobile-menu a { font-size: 18px; font-weight: 600; color: var(--text-primary); }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .mobile-menu.active { display: flex; }
      .header-inner { height: 56px; }
    }

@keyframes fadeInUp { from { opacity:0; transform:translateY(30px);} to { opacity:1; transform:translateY(0);} }

@media(max-width:768px){.advantage-grid{grid-template-columns:1fr;}}

.product-card:hover{background:#EEF0F4; transform:translateX(4px);} .main-card:hover{transform:translateX(4px);} @media(max-width:768px){.product-grid{flex-direction:column;}}

.scene-card{background:white; border:1px solid var(--border-light); border-radius:8px; overflow:hidden; transition:0.3s;} .scene-card:hover{border-color:var(--primary);} .scene-card:hover img{transform:scale(1.03);} @media(max-width:768px){.scene-grid{grid-template-columns:1fr;}}

.case-card{background:white; border-left:4px solid var(--primary); border-radius:6px; padding:20px; min-width:200px;}

.faq-item{border-bottom:1px solid var(--border-light);} .faq-question{font-weight:600; padding:16px 0; display:flex; justify-content:space-between; cursor:pointer;} .faq-answer{max-height:0; overflow:hidden; transition:max-height 0.35s; color:var(--text-secondary);} .faq-item.active .faq-answer{max-height:200px; padding-bottom:16px;}