/* 默认主题 CSS */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --accent-color: #17a2b8;
    --info-color: #17a2b8;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --text-color: #333;
    --bg-gradient-start: #007bff;
    --bg-gradient-end: #17a2b8;
}

body {
    font-family: 'Roboto', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-color);
    background-color: #ffffff;
}

.hero-section {
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="default-pattern" x="0" y="0" width="20" height="20" patternUnits="userSpaceOnUse"><circle cx="10" cy="10" r="1" fill="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100" height="100" fill="url(%23default-pattern)"/></svg>');
    opacity: 0.3;
}

.hero-section .container {
    position: relative;
    z-index: 2;
}

.navbar {
    background-color: rgba(255, 255, 255, 0.95) !important;
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 123, 255, 0.1);
}

.btn-custom {
    background: linear-gradient(45deg, var(--primary-color), var(--accent-color));
    border: none;
    padding: 12px 30px;
    border-radius: 30px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn-custom::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.5s;
}

.btn-custom:hover::before {
    left: 100%;
}

.btn-custom:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0, 123, 255, 0.3);
}

.card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 123, 255, 0.1);
    transition: all 0.3s ease;
    background: white;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 123, 255, 0.2);
}

.card-body {
    padding: 2rem;
}

.card-title {
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 1rem;
}

.card-text {
    color: #666;
    line-height: 1.6;
}

.section {
    padding: 100px 0;
}

.section h2 {
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 2rem;
    position: relative;
}

.section h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

.bg-light {
    background: linear-gradient(135deg, #f8f9fa, #e3f2fd) !important;
}

.footer {
    background: linear-gradient(135deg, var(--dark-color), #495057);
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.social-links a {
    color: #ccc;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: var(--accent-color);
}

.nav-link {
    font-weight: 500;
    color: var(--text-color) !important;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--primary-color) !important;
}

/* 图标动画 */
.fas, .fab {
    transition: transform 0.3s ease;
}

.card:hover .fas {
    transform: scale(1.1) rotate(5deg);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-section {
        padding: 60px 0;
    }
    
    .section {
        padding: 60px 0;
    }
    
    .display-4 {
        font-size: 2rem;
    }
}

/* 加载动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.8s ease forwards;
}

/* 渐变文字效果 */
.gradient-text {
    background: linear-gradient(45deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}