body {
            font-family: 'Noto Sans SC', sans-serif;
            background-color: #f8fafc;
            color: #334155;
        }
        .hero-gradient {
            background: linear-gradient(135deg, #1e40af 0%, #3b82f6 100%);
        }
        .card-hover {
            transition: all 0.3s ease;
        }
        .card-hover:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px -5px rgba(30, 64, 175, 0.3);
        }
        .nav-link {
            position: relative;
        }
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background-color: #3b82f6;
            transition: width 0.3s ease;
        }
        .nav-link:hover::after {
            width: 100%;
        }
        .mobile-menu {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease;
        }
        .mobile-menu.active {
            max-height: 500px;
        }
        .fade-in {
            animation: fadeIn 0.5s ease forwards;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }


        #submitBtn:hover {
            background-color: #45a049;
            color: #f8fafc;
        }
        #messageDiv {
            margin-top: 10px;
            padding: 10px;
            border-radius: 4px;
            display: none;
        }
        .success {
            background-color: #dff0d8;
            color: #3c763d;
        }
        .error {
            background-color: #f2dede;
            color: #a94442;
        }
    

        .thumbnail:hover {
            border-color: #409EFF;
        }
        .preview-overlay {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.8);
            z-index: 1000;
            justify-content: center;
            align-items: center;
        }
        .preview-image {
            max-width: 80%;
            max-height: 80%;
        }
        .close-btn {
            position: absolute;
            top: 20px;
            right: 20px;
            color: white;
            font-size: 30px;
            cursor: pointer;
        }