:root {
    --primary-color: #2c5282;
    --secondary-color: #3182ce;
    --light-color: #f7fafc;
    --dark-color: #2d3748;
    --transition-speed: 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #333;
    overflow-x: hidden;
}

/* 导航栏 */
.navbar {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-link {
    font-weight: 500;
    color: var(--dark-color);
    transition: color var(--transition-speed);
    padding: 1rem 1.5rem;
}

.nav-link:hover, .nav-link.active {
    color: var(--secondary-color);
}

.dropdown-menu {
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.dropdown-item {
    font-weight: 400;
    padding: 0.5rem 1.5rem;
}

.dropdown-item:hover {
    background-color: rgba(44, 82, 130, 0.1);
}

/* 主要内容区 */
.section-title {
    font-weight: 700;
    color: var(--primary-color);
}

/* 时间线样式 */
.timeline {
    position: relative;
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 4px;
    background-color: var(--secondary-color);
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
}

.timeline-point {
    position: absolute;
    left: -8px;
    top: 15px;
    width: 20px;
    height: 20px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    z-index: 1;
}

.timeline-content {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    padding: 25px;
    margin-left: 40px;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.timeline-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.timeline-date {
    color: var(--secondary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: block;
}

.timeline-title {
    color: var(--dark-color);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.timeline-text {
    color: #4a5568;
    line-height: 1.7;
}

/* 版权信息栏 */
.footer {
    background-color: var(--dark-color);
    color: white;
    padding: 3rem 0;
    margin-top: 3rem;
}

.footer-logo {
    margin-top: 1rem;
}

.footer h5 {
    font-weight: 600;
    margin-bottom: 1.2rem;
    color: white;
}

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.8rem;
}

.footer-links a {
    color: #cbd5e0;
    text-decoration: none;
    transition: color var(--transition-speed);
}

.footer-links a:hover {
    color: white;
}

.copyright {
    margin-bottom: 0.8rem;
    color: #cbd5e0;
}

.copyright a {
    color: #cbd5e0;
    text-decoration: none;
}

.copyright a:hover {
    text-decoration: underline;
    color: white;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .timeline-content {
        margin-left: 20px;
        padding: 20px;
    }
    
    .timeline::before {
        left: 15px;
    }
    
    .timeline-point {
        left: 7px;
    }
}