/* roulang page: index */
:root {
      --primary: #1A1A1A;
      --accent: #E85D04;
      --accent-hover: #C94A00;
      --bg-page: #F9F9F6;
      --bg-card: #FFFFFF;
      --bg-dark: #2B2B2B;
      --text-primary: #1A1A1A;
      --text-body: #4A4A4A;
      --text-muted: #8C8C8C;
      --text-on-dark: #F0F0F0;
      --border-light: rgba(0,0,0,0.06);
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --transition: 0.3s ease;
      --nav-width: 240px;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      margin: 0;
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.6;
      font-weight: 400;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container-main {
      margin-left: var(--nav-width);
      transition: margin-left 0.3s;
      position: relative;
      min-height: 100vh;
    }
    /* 左侧竖向导航 */
    .side-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: var(--nav-width);
      height: 100vh;
      background-color: var(--primary);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      z-index: 1000;
      box-shadow: 2px 0 12px rgba(0,0,0,0.06);
      transition: transform 0.3s ease;
    }
    .nav-brand {
      padding: 2.5rem 1.5rem 1.5rem;
      text-align: center;
    }
    .nav-brand .logo-text {
      font-size: 2rem;
      font-weight: 700;
      color: white;
      letter-spacing: 1px;
    }
    .nav-brand .logo-sub {
      font-size: 0.8rem;
      color: #aaa;
      letter-spacing: 2px;
      margin-top: 0.2rem;
    }
    .nav-menu {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
      padding: 1rem 0.8rem;
    }
    .nav-item {
      display: block;
      padding: 0.8rem 1.2rem;
      color: #D0D0D0;
      border-radius: 6px;
      font-weight: 500;
      transition: all 0.25s ease;
      position: relative;
      border-left: 3px solid transparent;
    }
    .nav-item:hover {
      background-color: rgba(255,255,255,0.05);
      color: white;
      border-left-color: var(--accent);
    }
    .nav-item.active {
      color: var(--accent);
      background-color: rgba(232,93,4,0.08);
      border-left-color: var(--accent);
    }
    .nav-footer {
      padding: 1.5rem;
      color: #777;
      font-size: 0.8rem;
      text-align: center;
    }
    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--primary);
      padding: 0.8rem 1.2rem;
      z-index: 1001;
      justify-content: space-between;
      align-items: center;
      box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    }
    .mobile-logo {
      font-weight: 700;
      font-size: 1.6rem;
      color: white;
    }
    .hamburger {
      font-size: 1.6rem;
      color: white;
      background: none;
      border: none;
      cursor: pointer;
    }
    .mobile-menu {
      position: fixed;
      top: 60px;
      left: 0;
      width: 100%;
      background: rgba(26,26,26,0.96);
      backdrop-filter: blur(12px);
      flex-direction: column;
      padding: 1rem;
      display: none;
      z-index: 999;
    }
    .mobile-menu.active {
      display: flex;
    }
    .mobile-menu a {
      padding: 0.9rem 1rem;
      color: #D0D0D0;
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    /* 内容区块通用 */
    .section {
      padding: 80px 2rem;
    }
    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--text-primary);
      margin-bottom: 1rem;
      position: relative;
      display: inline-block;
    }
    .section-title::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 0;
      width: 48px;
      height: 4px;
      background: var(--accent);
      border-radius: 2px;
    }
    .section-title.center::after {
      left: 50%;
      transform: translateX(-50%);
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      font-weight: 600;
      padding: 0.8rem 2rem;
      border-radius: 50px;
      border: none;
      cursor: pointer;
      transition: all 0.3s;
      display: inline-block;
      text-align: center;
      box-shadow: 0 6px 16px rgba(232,93,4,0.25);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      box-shadow: 0 10px 22px rgba(201,74,0,0.3);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 0.8rem 2rem;
      border-radius: 50px;
      cursor: pointer;
      transition: all 0.3s;
      display: inline-block;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .text-accent {
      color: var(--accent);
    }
    @media (max-width: 768px) {
      .side-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .container-main {
        margin-left: 0;
        padding-top: 70px;
      }
      .section {
        padding: 48px 1.2rem;
      }
      .section-title {
        font-size: 28px;
      }
      .hero-left h1 {
        font-size: 36px !important;
        line-height: 1.3;
      }
    }
    /* 动态旋转动画 */
    .hero-visual-wrapper {
      position: relative;
      width: 100%;
      height: 100%;
      min-height: 320px;
    }
    .rotating-geo {
      position: absolute;
      top: 20%;
      left: 20%;
      width: 200px;
      height: 200px;
      border: 2px solid rgba(232,93,4,0.35);
      border-radius: 42% 58% 38% 62% / 58% 42% 62% 38%;
      animation: rotateGeo 20s infinite linear;
      opacity: 0.5;
    }
    .rotating-geo2 {
      width: 160px;
      height: 160px;
      top: 45%;
      left: 50%;
      border-color: rgba(255,255,255,0.2);
      animation-duration: 25s;
      animation-direction: reverse;
    }
    @keyframes rotateGeo {
      from { transform: rotate(0deg); }
      to { transform: rotate(360deg); }
    }
    .glow-dot {
      position: absolute;
      width: 8px;
      height: 8px;
      background: var(--accent);
      border-radius: 50%;
      box-shadow: 0 0 20px var(--accent);
    }