:root {
            --primary-color: #1a6fb3;
            --secondary-color: #0c4d7a;
            --accent-color: #2ecc71;
            --light-color: #f8f9fa;
            --dark-color: #343a40;
            --text-color: #333;
            --border-radius: 8px;
            --box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Microsoft YaHei', 'Segoe UI', 'PingFang SC', sans-serif;
            color: var(--text-color);
            line-height: 1.7;
            overflow-x: hidden;
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
            color: var(--primary-color) !important;
        }
        .navbar-brand span {
            color: var(--secondary-color);
        }
        .nav-link {
            font-weight: 500;
            padding: 0.5rem 1.2rem !important;
            transition: var(--transition);
            border-radius: var(--border-radius);
        }
        .nav-link:hover, .nav-link.active {
            background-color: rgba(26, 111, 179, 0.1);
            color: var(--primary-color) !important;
        }
        .hero-section {
            background: linear-gradient(rgba(12, 77, 122, 0.85), rgba(26, 111, 179, 0.9)), url('https://images.unsplash.com/photo-1558618666-fcd25c85cd64?ixlib=rb-4.0.3&auto=format&fit=crop&w=2070&q=80') no-repeat center center;
            background-size: cover;
            color: white;
            padding: 8rem 0 6rem;
            position: relative;
        }
        .hero-title {
            font-size: 3.2rem;
            font-weight: 800;
            margin-bottom: 1.5rem;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
        }
        .hero-subtitle {
            font-size: 1.3rem;
            margin-bottom: 2rem;
            opacity: 0.95;
        }
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            padding: 0.8rem 2rem;
            font-weight: 600;
            border-radius: 50px;
            transition: var(--transition);
        }
        .btn-primary:hover {
            background-color: var(--secondary-color);
            border-color: var(--secondary-color);
            transform: translateY(-3px);
            box-shadow: var(--box-shadow);
        }
        .section-title {
            position: relative;
            padding-bottom: 1rem;
            margin-bottom: 3rem;
            text-align: center;
            font-weight: 700;
            color: var(--secondary-color);
        }
        .section-title:after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background-color: var(--accent-color);
            border-radius: 2px;
        }
        .card-hover {
            transition: var(--transition);
            border: none;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            height: 100%;
        }
        .card-hover:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }
        .icon-box {
            width: 70px;
            height: 70px;
            background-color: rgba(26, 111, 179, 0.1);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1.5rem;
        }
        .icon-box i {
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .service-card {
            border-top: 4px solid var(--primary-color);
            overflow: hidden;
        }
        .project-card {
            overflow: hidden;
            position: relative;
        }
        .project-card img {
            transition: transform 0.5s ease;
        }
        .project-card:hover img {
            transform: scale(1.05);
        }
        .project-overlay {
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
            background: linear-gradient(transparent, rgba(12, 77, 122, 0.9));
            color: white;
            padding: 1.5rem;
            transform: translateY(100%);
            transition: var(--transition);
        }
        .project-card:hover .project-overlay {
            transform: translateY(0);
        }
        .timeline {
            position: relative;
            padding-left: 2rem;
        }
        .timeline:before {
            content: '';
            position: absolute;
            left: 0;
            top: 0;
            bottom: 0;
            width: 3px;
            background-color: var(--primary-color);
        }
        .timeline-item {
            position: relative;
            margin-bottom: 2rem;
            padding-left: 2rem;
        }
        .timeline-item:before {
            content: '';
            position: absolute;
            left: -2.5rem;
            top: 0.5rem;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background-color: var(--primary-color);
            border: 3px solid white;
            box-shadow: 0 0 0 3px var(--primary-color);
        }
        .contact-info-box {
            background-color: var(--light-color);
            padding: 2rem;
            border-radius: var(--border-radius);
            height: 100%;
            border-left: 4px solid var(--primary-color);
        }
        .contact-info-box i {
            color: var(--primary-color);
            margin-right: 1rem;
        }
        .footer {
            background-color: var(--secondary-color);
            color: rgba(255,255,255,0.85);
            padding: 4rem 0 2rem;
        }
        .footer a {
            color: rgba(255,255,255,0.85);
            text-decoration: none;
            transition: var(--transition);
        }
        .footer a:hover {
            color: white;
            padding-left: 5px;
        }
        .footer-title {
            color: white;
            font-weight: 600;
            margin-bottom: 1.5rem;
            position: relative;
            padding-bottom: 0.8rem;
        }
        .footer-title:after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 40px;
            height: 2px;
            background-color: var(--accent-color);
        }
        .copyright {
            border-top: 1px solid rgba(255,255,255,0.1);
            padding-top: 1.5rem;
            margin-top: 3rem;
            text-align: center;
            font-size: 0.9rem;
            color: rgba(255,255,255,0.6);
        }
        .flink {
            display: inline-block;
            background-color: rgba(255,255,255,0.1);
            padding: 0.5rem 1.2rem;
            margin: 0.3rem;
            border-radius: 50px;
            transition: var(--transition);
            border: 1px solid rgba(255,255,255,0.2);
        }
        .flink:hover {
            background-color: rgba(255,255,255,0.2);
            transform: translateY(-3px);
        }
        .back-to-top {
            position: fixed;
            bottom: 2rem;
            right: 2rem;
            width: 50px;
            height: 50px;
            background-color: var(--primary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            text-decoration: none;
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
            z-index: 1000;
        }
        .back-to-top.active {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background-color: var(--secondary-color);
            color: white;
        }
        @media (max-width: 768px) {
            .hero-title {
                font-size: 2.5rem;
            }
            .hero-subtitle {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .navbar-nav {
                padding-top: 1rem;
            }
        }