:root {
    --primary: #3b82f6;
    --secondary: #8b5cf6;
    --accent: #f97316;
    --dark: #0f172a;
    --gray-800: #1e293b;
    --gray-600: #475569;
    --gray-400: #94a3b8;
    --gray-100: #f1f5f9;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
    --transition: all 0.2s ease;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; line-height: 1.6; color: var(--gray-800); background: white; }
.container { max-width: 1280px; margin: 0 auto; padding: 0 20px; }
.navbar { position: sticky; top: 0; background: rgba(255,255,255,0.98); backdrop-filter: blur(12px); z-index: 1000; border-bottom: 1px solid rgba(0,0,0,0.05); transition: var(--transition); }
.navbar.scrolled { background: rgba(255,255,255,0.92); box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
.navbar .container { display: flex; justify-content: space-between; align-items: center; padding: 1rem 20px; }
.logo { font-size: 1.5rem; font-weight: 800; background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; background-clip: text; color: transparent; text-decoration: none; }
.nav-links { display: flex; gap: 2rem; align-items: center; }
.nav-links a { text-decoration: none; color: var(--gray-600); font-weight: 500; transition: var(--transition); }
.nav-links a:hover, .nav-links a.active { color: var(--primary); }
.dropdown { position: relative; display: inline-block; }
.dropdown-content { display: none; position: absolute; background: white; min-width: 160px; box-shadow: var(--shadow-md); border-radius: 0.5rem; z-index: 1; top: 100%; left: 0; }
.dropdown-content a { color: var(--gray-700); padding: 0.75rem 1rem; display: block; font-size: 0.9rem; }
.dropdown-content a:hover { background: var(--gray-100); color: var(--primary); }
.dropdown:hover .dropdown-content { display: block; }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 1.5rem; color: var(--gray-600); cursor: pointer; }
@media (max-width: 768px) { .mobile-menu-btn { display: block; } .nav-links { position: fixed; top: 70px; left: 0; right: 0; background: white; flex-direction: column; padding: 2rem; gap: 1.5rem; box-shadow: var(--shadow-lg); transform: translateY(-120%); opacity: 0; transition: var(--transition); z-index: 99; } .nav-links.active { transform: translateY(0); opacity: 1; } .dropdown-content { position: static; box-shadow: none; padding-left: 1rem; display: none; } .dropdown.active .dropdown-content { display: block; } }
.hero-sen { position: relative; height: 80vh; min-height: 500px; background: url('https://images.unsplash.com/photo-1506905925346-21bda4d32df4?w=1600') center/cover no-repeat; display: flex; align-items: center; justify-content: center; text-align: center; }
.hero-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); }
.hero-content { position: relative; z-index: 1; color: white; padding: 0 20px; }
.hero-content h1 { font-size: 3rem; font-weight: 800; margin-bottom: 1rem; text-shadow: 0 2px 4px rgba(0,0,0,0.3); }
.hero-content p { font-size: 1.5rem; margin-bottom: 2rem; opacity: 0.9; }
.section { padding: 5rem 0; }
.section-title { font-size: 2rem; font-weight: 700; text-align: center; margin-bottom: 1rem; color: var(--gray-900); }
.section-sub { text-align: center; color: var(--gray-600); max-width: 700px; margin: 0 auto 3rem; }
.cases-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
@media (max-width: 1024px) { .cases-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .cases-grid { grid-template-columns: 1fr; } }
.case-card { background: white; border-radius: 1rem; overflow: hidden; box-shadow: var(--shadow-md); transition: var(--transition); cursor: pointer; }
.case-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.case-cover { position: relative; padding-top: 56.25%; background-size: cover; background-position: center; }
.case-duration { position: absolute; bottom: 8px; right: 8px; background: rgba(0,0,0,0.7); color: white; padding: 2px 6px; border-radius: 4px; font-size: 0.75rem; }
.case-info { padding: 1rem; }
.case-info h3 { font-size: 1.1rem; margin-bottom: 0.25rem; }
.case-info p { color: var(--gray-600); font-size: 0.85rem; }
.clients-grid { display: flex; flex-wrap: wrap; justify-content: center; gap: 2rem; align-items: center; }
.client-logo { max-width: 120px; max-height: 60px; opacity: 0.7; transition: var(--transition); filter: grayscale(100%); }
.client-logo:hover { opacity: 1; filter: grayscale(0); }
.gallery-container { position: relative; overflow: hidden; margin: 0 auto; }
.gallery-track { display: flex; gap: 1rem; overflow-x: auto; scroll-behavior: smooth; scrollbar-width: none; -webkit-overflow-scrolling: touch; padding: 0.5rem 0; }
.gallery-track::-webkit-scrollbar { display: none; }
.gallery-item { flex: 0 0 calc(25% - 0.75rem); aspect-ratio: 4/3; border-radius: 0.75rem; overflow: hidden; cursor: pointer; }
.gallery-item img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.3s; }
.gallery-item img:hover { transform: scale(1.03); }
.gallery-arrow { position: absolute; top: 50%; transform: translateY(-50%); background: rgba(0,0,0,0.5); color: white; border: none; width: 40px; height: 40px; border-radius: 50%; cursor: pointer; z-index: 2; transition: var(--transition); }
.gallery-arrow:hover { background: var(--primary); }
.gallery-arrow.prev { left: 10px; }
.gallery-arrow.next { right: 10px; }
.gallery-dots { display: flex; justify-content: center; gap: 8px; margin-top: 1rem; }
.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--gray-400); cursor: pointer; }
.dot.active { background: var(--primary); width: 24px; border-radius: 4px; }
@media (max-width: 768px) { .gallery-item { flex: 0 0 calc(50% - 0.5rem); } }
@media (max-width: 480px) { .gallery-item { flex: 0 0 100%; } }
.philosophy-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; }
.philosophy-card { background: var(--gray-100); padding: 2rem; border-radius: 1rem; text-align: center; transition: var(--transition); }
.philosophy-card i { font-size: 2.5rem; color: var(--primary); margin-bottom: 1rem; }
.philosophy-card h3 { margin-bottom: 1rem; font-size: 1.3rem; }
.philosophy-card p { color: var(--gray-600); line-height: 1.7; }
.contact-sen { background: var(--gray-100); text-align: center; }
.contact-methods { display: flex; justify-content: center; gap: 2rem; margin-top: 2rem; flex-wrap: wrap; }
.contact-methods div { font-size: 1rem; color: var(--gray-700); }
.contact-methods i { margin-right: 0.5rem; color: var(--primary); }
.btn-large { padding: 0.75rem 2rem; font-size: 1.1rem; }
.btn-primary { display: inline-block; background: linear-gradient(135deg, var(--primary), var(--secondary)); color: white; padding: 0.75rem 1.5rem; border-radius: 9999px; text-decoration: none; font-weight: 600; border: none; cursor: pointer; transition: var(--transition); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(59,130,246,0.4); }
.modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.6); z-index: 2000; justify-content: center; align-items: center; }
.modal.active { display: flex; }
.modal-content { background: white; border-radius: 1rem; padding: 2rem; max-width: 400px; width: 90%; text-align: center; position: relative; }
.modal-close { position: absolute; top: 10px; right: 15px; font-size: 1.5rem; cursor: pointer; color: var(--gray-600); }
.footer { background: #f8fafc; color: var(--gray-600); padding: 3rem 0; text-align: center; border-top: 1px solid var(--gray-200); }
/* 修复视频弹窗中的video标签显示不全 */
.modal .modal-content video {
    width: 100%;
    height: auto;
    max-height: 80vh;
    object-fit: contain;  /* 保持比例，不裁剪 */
}
/* 修复合作客户 logo 显示 */
.clients-grid .client-logo {
    filter: none !important;
    max-width: 140px;
    max-height: 80px;
    width: auto;
    height: auto;
    margin: 0 15px;
    transition: transform 0.2s;
}
.clients-grid .client-logo:hover {
    transform: scale(1.05);
}
/* 彻底去掉合作客户 logo 的所有蒙版效果 */
.clients-grid .client-logo {
    filter: none !important;
    opacity: 1 !important;
    background: transparent !important;
    box-shadow: none !important;
    border: none !important;
    transition: none !important;
}
.clients-grid .client-logo:hover {
    transform: scale(1.02);
    filter: none !important;
}