/* roulang page: index */
:root {
      --deep-black: #0A0A0A;
      --near-black: #0F0F0F;
      --pure-white: #FFFFFF;
      --soft-gray: #F8F8F8;
      --mid-gray: #E0E0E0;
      --accent-red: #E63946;
      --hover-red: #C1121F;
      --text-primary: #0A0A0A;
      --text-secondary: #4A4A4A;
      --text-on-dark: #F0F0F0;
      --radius-hard: 4px;
      --shadow-card: 0 20px 40px rgba(0, 0, 0, 0.08);
      --shadow-nav: 0 4px 12px rgba(0, 0, 0, 0.04);
      --transition-fast: 0.2s ease-in-out;
      --transition-smooth: 0.3s ease-out;
      --font-title: "PingFang SC", "Microsoft YaHei", sans-serif;
      --font-body: "PingFang SC", "Microsoft YaHei", sans-serif;
      --font-number: "DIN Alternate", "PingFang SC", sans-serif;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--pure-white);
      color: var(--text-primary);
      line-height: 1.7;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    img {
      max-width: 100%;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-fast);
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      padding: 18px 0;
      background: transparent;
      transition: background 0.25s ease, box-shadow 0.25s ease;
    }

    .nav.scrolled {
      background: rgba(255, 255, 255, 0.98);
      box-shadow: var(--shadow-nav);
    }

    .nav .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .logo {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 26px;
      letter-spacing: 0.5px;
      color: var(--pure-white);
      transition: color 0.25s ease;
    }

    .nav.scrolled .logo {
      color: var(--deep-black);
    }

    .nav-links {
      display: flex;
      gap: 48px;
      align-items: center;
      font-weight: 500;
      font-size: 15px;
      letter-spacing: 0.3px;
      color: var(--pure-white);
      transition: color 0.25s ease;
    }

    .nav.scrolled .nav-links {
      color: var(--text-primary);
    }

    .nav-links a {
      position: relative;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-red);
      transition: width 0.25s ease;
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .nav-cta {
      background: var(--accent-red);
      color: var(--pure-white) !important;
      padding: 10px 24px;
      border-radius: var(--radius-hard);
      font-weight: 700;
    }

    .nav-cta:hover {
      background: var(--hover-red);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--pure-white);
      transition: background 0.25s ease;
    }

    .nav.scrolled .hamburger span {
      background: var(--deep-black);
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--accent-red);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      font-size: 24px;
      font-weight: 700;
      color: var(--pure-white);
      z-index: 999;
    }

    .mobile-menu.active {
      display: flex;
    }

    /* Hero */
    .hero {
      height: 100vh;
      background-color: var(--deep-black);
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }

    .hero-bg {
      position: absolute;
      right: 0;
      top: 0;
      width: 55%;
      height: 100%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      filter: grayscale(100%) brightness(0.7);
      mask-image: radial-gradient(circle at center, black 40%, transparent 85%);
    }

    .hero-bg::after {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(ellipse at center, rgba(230,57,70,0.25) 0%, transparent 70%);
    }

    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 600px;
      color: var(--pure-white);
      animation: fadeUp 1s ease;
    }

    .hero h1 {
      font-family: var(--font-title);
      font-weight: 900;
      font-size: 72px;
      line-height: 1.1;
      margin-bottom: 24px;
      letter-spacing: -0.5px;
    }

    .hero .subtitle {
      font-size: 20px;
      font-weight: 400;
      color: rgba(255,255,255,0.85);
      margin-bottom: 40px;
      border-left: 4px solid var(--accent-red);
      padding-left: 20px;
    }

    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--accent-red);
      color: var(--pure-white);
      font-weight: 700;
      padding: 16px 48px;
      border-radius: var(--radius-hard);
      display: inline-block;
      border: none;
      cursor: pointer;
      font-size: 16px;
      transition: background var(--transition-fast), transform var(--transition-fast);
    }

    .btn-primary:hover {
      background: var(--hover-red);
      transform: translateY(-2px);
    }

    .btn-secondary {
      background: transparent;
      color: var(--pure-white);
      border: 1px solid var(--accent-red);
      font-weight: 700;
      padding: 16px 48px;
      border-radius: var(--radius-hard);
      display: inline-block;
      cursor: pointer;
      font-size: 16px;
      transition: all var(--transition-fast);
    }

    .btn-secondary:hover {
      background: var(--accent-red);
      border-color: var(--accent-red);
      transform: translateY(-2px);
    }

    @keyframes fadeUp {
      0% { opacity: 0; transform: translateY(30px); }
      100% { opacity: 1; transform: translateY(0); }
    }

    /* 板块 */
    section {
      padding: 120px 0;
    }

    .section-tag {
      font-weight: 700;
      color: var(--accent-red);
      letter-spacing: 1px;
      text-transform: uppercase;
      font-size: 14px;
      margin-bottom: 12px;
    }

    .section-title {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 48px;
      line-height: 1.2;
      margin-bottom: 20px;
      display: flex;
      align-items: center;
    }

    .section-title .red-line {
      width: 4px;
      height: 32px;
      background: var(--accent-red);
      display: inline-block;
      margin-right: 16px;
      border-radius: 2px;
    }

    /* 优势非对称 */
    .advantage-row {
      display: flex;
      align-items: center;
      gap: 80px;
      margin-bottom: 100px;
    }

    .advantage-row.reverse {
      flex-direction: row-reverse;
    }

    .adv-text {
      flex: 1;
    }

    .adv-image {
      flex: 1;
      border-radius: var(--radius-hard);
      overflow: hidden;
      transition: transform 0.4s ease;
    }

    .adv-image img {
      width: 100%;
      height: 380px;
      object-fit: cover;
      filter: grayscale(40%);
      transition: transform 0.4s ease;
    }

    .adv-image:hover img {
      transform: scale(1.03);
      filter: grayscale(0%);
    }

    .adv-text h3 {
      font-size: 32px;
      font-weight: 700;
      margin-bottom: 16px;
    }

    /* 功能标签页 */
    .tabs-nav {
      display: flex;
      gap: 48px;
      border-bottom: 1px solid var(--mid-gray);
      margin-bottom: 48px;
      flex-wrap: wrap;
    }

    .tab-btn {
      background: none;
      border: none;
      font-weight: 700;
      font-size: 18px;
      padding-bottom: 12px;
      cursor: pointer;
      position: relative;
      color: var(--text-secondary);
      transition: color 0.2s;
    }

    .tab-btn.active {
      color: var(--text-primary);
    }

    .tab-btn.active::after {
      content: '';
      position: absolute;
      bottom: -1px;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--accent-red);
    }

    .tab-panel {
      display: none;
      animation: fadeUp 0.4s ease;
    }

    .tab-panel.active {
      display: block;
    }

    .capability-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    .cap-card {
      background: var(--pure-white);
      padding: 32px;
      border-radius: var(--radius-hard);
      border: 1px solid var(--mid-gray);
      transition: box-shadow 0.3s ease, transform 0.3s ease;
    }

    .cap-card:hover {
      box-shadow: var(--shadow-card);
      transform: translateY(-4px);
    }

    /* 场景 */
    .scenario-band {
      background: var(--near-black);
      color: var(--pure-white);
      padding: 100px 0;
      position: relative;
      background-image: url('/assets/images/backpic/back-2.webp');
      background-size: cover;
      background-attachment: fixed;
      filter: grayscale(30%);
    }

    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 40px;
      margin-top: 48px;
    }

    .scenario-item {
      background: rgba(10,10,10,0.75);
      backdrop-filter: blur(8px);
      padding: 32px;
      border-radius: var(--radius-hard);
      border-left: 4px solid var(--accent-red);
    }

    /* 数据 */
    .stats-row {
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
      gap: 40px;
    }

    .stat-number {
      font-family: var(--font-number);
      font-size: 80px;
      font-weight: 700;
      color: var(--accent-red);
      line-height: 1;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid var(--mid-gray);
      padding: 24px 0;
      cursor: pointer;
    }

    .faq-question {
      font-weight: 700;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-secondary);
      margin-top: 8px;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--accent-red);
      color: var(--pure-white);
      padding: 80px 0;
      text-align: center;
    }

    .cta-banner .btn-secondary {
      border-color: var(--pure-white);
      color: var(--pure-white);
    }

    /* 页脚 */
    .footer {
      background: var(--deep-black);
      color: var(--text-on-dark);
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 32px;
    }

    .footer a {
      color: var(--text-on-dark);
      opacity: 0.8;
    }

    .copyright {
      margin-top: 40px;
      opacity: 0.6;
      font-size: 14px;
    }

    @media (max-width: 1024px) {
      .hero h1 { font-size: 52px; }
      .section-title { font-size: 36px; }
    }

    @media (max-width: 768px) {
      .nav-links, .nav-cta { display: none; }
      .hamburger { display: flex; }
      .hero { flex-direction: column; height: auto; padding: 120px 0 60px; }
      .hero-bg { width: 100%; height: 50%; top: auto; bottom: 0; }
      .advantage-row, .advantage-row.reverse { flex-direction: column; gap: 32px; }
      .capability-grid { grid-template-columns: 1fr; }
      .scenario-grid { grid-template-columns: 1fr; }
      .hero h1 { font-size: 40px; }
      section { padding: 80px 0; }
    }