/* ===== CSS CUSTOM PROPERTIES (easing system from clay.global) ===== */
    :root {
      --easeOutExpo: cubic-bezier(0.16, 1, 0.3, 1);
      --easeOut: cubic-bezier(0.19, 1, 0.22, 1);
      --easeInExpo: cubic-bezier(0.7, 0, 0.84, 0);
      --color-black: #06070A;
      --color-white: #FFFFFF;
      --color-blue: #2563EB;
      --color-blue-light: #60a5fa;
      --color-gray-50: #F3F4F6;
      --color-gray-100: #E6E8EB;
      --color-gray-300: #B2B8C2;
      --color-gray-400: #989FAB;
      --color-gray-500: #7F8694;
      --color-gray-600: #666C7A;
      --color-gray-700: #4E5361;
      --color-gray-800: #353945;
      --color-dark: #171921;
    }

    /* ===== BASE RESET ===== */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
      color: var(--color-black);
      background: var(--color-white);
      font-size: 1.125rem;
      font-weight: 400;
      line-height: 1.6;
      overflow-x: hidden;
    }

    /* ===== HIDE SCROLLBAR ===== */
    ::-webkit-scrollbar {
      display: none;
      width: 0;
      height: 0;
      background: transparent;
    }
    html, body {
      -ms-overflow-style: none;
      scrollbar-width: none;
    }

    /* ===== TYPOGRAPHY ===== */
    h1, h2, h3, h4 {
      font-weight: 800;
      letter-spacing: -0.04em;
      line-height: 1.05;
    }
    .heading-xl { font-size: clamp(2.5rem, 5vw, 5.5rem); }
    .heading-lg { font-size: clamp(2rem, 4vw, 4rem); }
    .heading-md { font-size: clamp(1.5rem, 3vw, 2.5rem); }

    /* ===== LAYOUT ===== */
    .container-main { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
    .section-padding { padding: 120px 0; }

    /* ===== NAVIGATION ===== */
    .nav {
      position: fixed;
      top: 0; left: 0; right: 0;
      height: 80px;
      z-index: 1000;
      transition: all 0.8s var(--easeOut);
      background: transparent;
    }
    .nav.scrolled {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      box-shadow: 0 1px 0 rgba(0,0,0,0.06);
    }
    .nav-inner {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }
    .nav-logo {
      font-size: 1.25rem;
      font-weight: 800;
      color: var(--color-black);
      text-decoration: none;
      letter-spacing: -0.02em;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    /* 导航链接下划线绘制动效 */
    .nav-links a {
      font-size: 0.9rem;
      font-weight: 500;
      color: var(--color-gray-600);
      text-decoration: none;
      position: relative;
      transition: color 0.3s ease;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px; left: 0; right: 0;
      height: 2px;
      background: var(--color-blue);
      border-radius: 1px;
      transform: scaleX(0);
      transform-origin: left;
      transition: transform 0.5s var(--easeOutExpo);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      transform: scaleX(1);
    }
    .nav-links a:hover,
    .nav-links a.active { color: var(--color-black); }
    .nav-cta {
      display: inline-flex;
      align-items: center;
      padding: 10px 24px;
      background: var(--color-blue);
      color: #fff !important;
      border-radius: 999px;
      font-size: 0.875rem;
      font-weight: 600;
      text-decoration: none;
      transition: all 0.4s var(--easeOutExpo);
    }
    .nav-cta:hover {
      background: #1d4ed8;
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(37,99,235,0.3);
    }

    /* ===== LANGUAGE SWITCH ===== */
    .lang-switch {
      display: inline-flex;
      align-items: center;
      gap: 4px;
      font-size: 0.8rem;
      font-weight: 600;
      margin-left: 8px;
    }
    .lang-switch .lang-btn {
      color: var(--color-gray-400, #9ca3af);
      text-decoration: none;
      padding: 4px 6px;
      border-radius: 4px;
      transition: all 0.3s;
    }
    .lang-switch .lang-btn:hover,
    .lang-switch .lang-btn.active {
      color: var(--color-blue);
      background: rgba(37,99,235,0.08);
    }
    .lang-switch .lang-divider {
      color: var(--color-gray-300, #d1d5db);
      font-size: 0.75rem;
    }

    /* ===== HAMBURGER ===== */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      z-index: 1001;
      background: none;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      display: block;
      width: 24px; height: 2px;
      background: var(--color-black);
      transition: all 0.3s ease;
      border-radius: 1px;
    }
    .hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 6px); }
    .hamburger.open span:nth-child(2) { opacity: 0; }
    .hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -6px); }

    /* ===== MOBILE MENU ===== */
    .mobile-menu {
      display: none;
      position: fixed;
      inset: 0;
      background: #FFFFFF;
      z-index: 999;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      opacity: 0;
      transition: opacity 0.3s ease;
    }
    .mobile-menu.open { display: flex; opacity: 1; }
    .mobile-menu a {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--color-black);
      text-decoration: none;
      transition: color 0.3s ease;
    }
    .mobile-menu a:hover,
    .mobile-menu a.active { color: var(--color-blue); }

    /* ===== BUTTONS ===== */
    .btn-primary {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 16px 32px;
      background: var(--color-blue);
      color: #fff;
      border-radius: 999px;
      font-size: 1rem;
      font-weight: 600;
      text-decoration: none;
      border: none;
      cursor: pointer;
      transition: all 0.4s var(--easeOutExpo);
    }
    .btn-primary:hover {
      background: #1d4ed8;
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(37,99,235,0.3);
    }
    /* 按钮箭头滑动动效 */
    .btn-primary .btn-arrow {
      transition: transform 0.55s var(--easeOutExpo);
    }
    .btn-primary:hover .btn-arrow {
      transform: translateX(4px);
    }
    .btn-outline {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 16px 32px;
      background: transparent;
      color: var(--color-black);
      border: 2px solid var(--color-black);
      border-radius: 999px;
      font-size: 1rem;
      font-weight: 600;
      text-decoration: none;
      cursor: pointer;
      transition: all 0.4s var(--easeOutExpo);
    }
    .btn-outline:hover {
      background: var(--color-black);
      color: #fff;
      transform: translateY(-2px);
    }

    /* ===== SCROLL REVEAL ANIMATIONS ===== */
    .reveal {
      opacity: 0;
      transform: translateY(30px);
      transition: opacity 0.9s var(--easeOutExpo),
                  transform 1.2s var(--easeOutExpo);
    }
    .reveal.visible {
      opacity: 1;
      transform: translateY(0);
    }
    .reveal-delay-1 { transition-delay: 0.1s; }
    .reveal-delay-2 { transition-delay: 0.2s; }
    .reveal-delay-3 { transition-delay: 0.3s; }
    .reveal-delay-4 { transition-delay: 0.4s; }
    .reveal-delay-5 { transition-delay: 0.5s; }

    /* ===== HERO TEXT SPLIT ANIMATION (逐词显现) ===== */
    .split-line {
      display: block;
      overflow: hidden;
    }
    .split-word {
      display: inline-block;
      opacity: 0;
      transform: translateY(100%);
      transition: opacity 0.9s var(--easeOutExpo),
                  transform 1.2s var(--easeOutExpo);
    }
    .split-triggered .split-word {
      opacity: 1;
      transform: translateY(0);
    }

    /* ===== HERO SECTION ===== */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      background: #f8f9fc;
    }
    #hero-canvas {
      position: absolute;
      top: 0; left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
      z-index: 0;
    }
    .hero-content {
      position: relative;
      z-index: 1;
    }

    /* ===== VIDEO SECTION ===== */
    .video-section {
      position: relative;
      width: 100%;
      height: 70vh;
      overflow: hidden;
      background: var(--color-dark);
    }
    .video-section video {
      width: 100%;
      height: 100%;
      object-fit: cover;
      opacity: 0.7;
    }
    .video-overlay {
      position: absolute;
      inset: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      background: linear-gradient(180deg, rgba(23,25,33,0.3) 0%, rgba(23,25,33,0.7) 100%);
    }
    .video-overlay h2 {
      color: #fff;
      text-align: center;
      font-size: clamp(1.5rem, 3.5vw, 3.5rem);
      font-weight: 800;
      letter-spacing: -0.03em;
      line-height: 1.2;
      max-width: 700px;
      padding: 0 24px;
    }

    /* ===== SERVICE CARDS ===== */
    .service-card {
      padding: 40px 32px;
      border: 1px solid var(--color-gray-100);
      transition: all 0.5s var(--easeOutExpo);
      position: relative;
      overflow: hidden;
    }
    .service-card::before {
      content: '';
      position: absolute;
      top: 0; left: 0;
      width: 100%; height: 3px;
      background: var(--color-blue);
      transform: scaleX(0);
      transform-origin: left;
      transition: transform 0.6s var(--easeOutExpo);
    }
    .service-card:hover::before {
      transform: scaleX(1);
    }
    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
      border-color: transparent;
    }
    .service-card.dark {
      background: var(--color-dark);
      border-color: rgba(255,255,255,0.06);
    }
    .service-card.dark::before {
      background: var(--color-blue-light);
    }
    .service-card.dark:hover {
      box-shadow: 0 20px 40px rgba(0,0,0,0.4);
      border-color: rgba(37,99,235,0.3);
    }
    .service-card.dark h3 { color: #fff; }
    .service-card.dark p { color: var(--color-gray-400); }
    .service-card.dark .service-icon { color: var(--color-blue-light); }
    .service-icon {
      width: 48px; height: 48px;
      color: var(--color-blue);
      margin-bottom: 24px;
    }

    /* ===== WORK CARDS (clay.global 风格 hover) ===== */
    .work-card {
      display: block;
      text-decoration: none;
      color: inherit;
      position: relative;
    }
    .work-card-media {
      overflow: hidden;
      position: relative;
    }
    .work-card-img {
      width: 100%;
      aspect-ratio: 16 / 10;
      object-fit: cover;
      transform: scale(0.92);
      transition: transform 1.3s var(--easeOutExpo);
    }
    .work-card:hover .work-card-img {
      transform: scale(1);
    }
    .work-card-media-inner {
      transform: translateY(20px);
      transition: transform 0.7s var(--easeOutExpo);
    }
    .work-card:hover .work-card-media-inner {
      transform: translateY(0);
    }
    /* 下划线绘制动效 */
    .work-card-line {
      display: block;
      height: 1px;
      background: var(--color-gray-100);
      margin-top: 20px;
      transform: scaleX(0);
      transform-origin: left;
      transition: transform 0.7s var(--easeOutExpo);
    }
    .work-card:hover .work-card-line {
      transform: scaleX(1);
    }
    .work-card-title {
      padding: 20px 0 0;
      transition: color 0.3s ease;
    }
    .work-card:hover .work-card-title {
      color: var(--color-blue);
    }

    /* ===== STATS 数字滚动 ===== */
    .stat-number {
      font-size: clamp(2rem, 4vw, 3.5rem);
      font-weight: 800;
      color: var(--color-blue);
      letter-spacing: -0.04em;
      line-height: 1;
    }
    .stat-label {
      font-size: 0.875rem;
      color: var(--color-gray-500);
      margin-top: 8px;
      font-weight: 500;
    }

    /* ===== NEWS CARDS ===== */
    .news-card {
      transition: all 0.5s var(--easeOutExpo);
    }
    .news-card:hover {
      transform: translateY(-8px);
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
    }
    .news-card-img-wrap {
      overflow: hidden;
      margin-bottom: 20px;
    }
    .news-card-img {
      width: 100%;
      aspect-ratio: 16 / 9;
      object-fit: cover;
      transition: transform 0.8s var(--easeOutExpo);
    }
    .news-card:hover .news-card-img {
      transform: scale(1.05);
    }

    /* ===== CLIENT LOGOS 交错淡入 ===== */
    .logo-item {
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 24px 32px;
      filter: grayscale(100%);
      opacity: 0.3;
      transition: all 0.8s var(--easeOut);
      font-size: 0.875rem;
      font-weight: 700;
      color: var(--color-gray-600);
      letter-spacing: 0.1em;
      border: 1px solid var(--color-gray-100);
    }
    .logo-item.triggered {
      opacity: 1;
      filter: grayscale(0%);
    }
    .logo-item:hover { opacity: 1; filter: grayscale(0%); }

    /* ===== LINK ARROW 滑动动效 ===== */
    .link-arrow {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      color: var(--color-black);
      font-size: 0.95rem;
      font-weight: 500;
      text-decoration: none;
      position: relative;
    }
    .link-arrow::after {
      content: '';
      position: absolute;
      bottom: -2px; left: 0; right: 0;
      height: 1px;
      background: var(--color-black);
      transform: scaleX(0);
      transform-origin: left;
      transition: transform 0.5s var(--easeOutExpo);
    }
    .link-arrow:hover::after {
      transform: scaleX(1);
    }
    .link-arrow svg {
      transition: transform 0.55s var(--easeOutExpo);
    }
    .link-arrow:hover svg {
      transform: translateX(4px);
    }

    /* ===== FOOTER ===== */
    .footer {
      background: var(--color-dark);
      color: #FFFFFF;
      padding: 80px 0 40px;
    }
    .footer a {
      color: var(--color-gray-400);
      text-decoration: none;
      transition: color 0.3s ease;
      font-size: 0.9rem;
    }
    .footer a:hover { color: #FFFFFF; }

    /* ===== SCROLL INDICATOR ===== */
    .scroll-indicator {
      position: absolute;
      bottom: 40px;
      left: 50%;
      transform: translateX(-50%);
      animation: scrollBounce 2s infinite;
    }
    @keyframes scrollBounce {
      0%, 100% { transform: translateX(-50%) translateY(0); opacity: 1; }
      50% { transform: translateX(-50%) translateY(12px); opacity: 0.5; }
    }

    /* ===== PARALLAX IMAGES ===== */
    .parallax-img {
      will-change: transform;
    }

    /* ===== RESPONSIVE ===== */
    @media (max-width: 1024px) {
      .services-grid { grid-template-columns: repeat(2, 1fr) !important; }
      .works-grid { grid-template-columns: repeat(2, 1fr) !important; }
      #hero-canvas { opacity: 0.6; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .section-padding { padding: 80px 0; }
      .hero { min-height: 90vh; }
      #hero-canvas { opacity: 0.4; }
      .services-grid { grid-template-columns: 1fr !important; }
      .works-grid { grid-template-columns: 1fr !important; }
      .stats-row { flex-direction: column; gap: 32px !important; }
      .news-grid { grid-template-columns: 1fr !important; }
      .footer-cols { grid-template-columns: 1fr !important; gap: 48px !important; }
      .client-logos { grid-template-columns: repeat(2, 1fr) !important; }
      .video-section { height: 50vh; }
      .about-grid, .ai-grid { grid-template-columns: 1fr !important; gap: 40px !important; }
    }