/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部样式 */
header {
    background: linear-gradient(135deg, #1a3a6c 0%, #2c5282 100%);
    color: white;
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 5px;
    text-align: center;
}

.subtitle {
    text-align: center;
    font-size: 1.1em;
    opacity: 0.9;
    margin-bottom: 20px;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    flex-wrap: wrap;
}

nav ul li {
    margin: 0 15px;
}

nav ul li a {
    color: white;
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 4px;
    transition: all 0.3s ease;
}

nav ul li a:hover,
nav ul li a.active {
    background-color: rgba(255,255,255,0.2);
}

/* 主要内容区域 */
main {
    min-height: calc(100vh - 200px);
}

/* 首页英雄区域 */
.hero {
    background: linear-gradient(rgba(0,0,0,0.7), rgba(0,0,0,0.7)), url('https://via.placeholder.com/1200x400/1a3a6c/FFFFFF?text=Singapore+International+Relations') center/cover;
    color: white;
    text-align: center;
    padding: 80px 0;
    margin-bottom: 40px;
}

.hero h2 {
    font-size: 2.5em;
    margin-bottom: 20px;
}

.hero p {
    font-size: 1.2em;
    margin-bottom: 30px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 24px;
    text-decoration: none;
    border-radius: 4px;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1em;
    text-align: center;
}

.btn.primary {
    background-color: #2c5282;
    color: white;
}

.btn.primary:hover {
    background-color: #1a3a6c;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.btn.secondary {
    background-color: transparent;
    color: white;
    border: 2px solid white;
}

.btn.secondary:hover {
    background-color: white;
    color: #2c5282;
}

.btn.small {
    padding: 8px 16px;
    font-size: 0.9em;
}

/* 新闻区域 */
.news {
    padding: 40px 0;
    background-color: white;
}

.news h2 {
    text-align: center;
    margin-bottom: 30px;
    color: #1a3a6c;
}

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.news-item {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.news-item:hover {
    transform: translateY(-5px);
}

.news-item h3 {
    color: #2c5282;
    margin-bottom: 10px;
}

.news-item p {
    margin-bottom: 15px;
    color: #666;
}

.date {
    font-size: 0.9em;
    color: #999;
}

/* 特色服务区域 */
.features {
    padding: 60px 0;
    background-color: #e3f2fd;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-item {
    text-align: center;
    padding: 30px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.feature-item h3 {
    color: #1a3a6c;
    margin-bottom: 15px;
}

/* 页面头部 */
.page-header {
    background: linear-gradient(135deg, #2c5282 0%, #1a3a6c 100%);
    color: white;
    padding: 40px 0;
    text-align: center;
}

.page-header h2 {
    font-size: 2.2em;
}

/* 内容区域 */
.content-section {
    padding: 50px 0;
}

.content-section.light {
    background-color: #f8f9fa;
}

.content-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
}

.content-main h3 {
    color: #1a3a6c;
    margin: 30px 0 15px 0;
}

.content-main p {
    margin-bottom: 15px;
    line-height: 1.8;
}

.content-main ul {
    margin-left: 30px;
    margin-bottom: 20px;
}

.content-main li {
    margin-bottom: 10px;
}

.sidebar-box {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 25px;
}

.sidebar-box h4 {
    color: #1a3a6c;
    margin-bottom: 15px;
}

.sidebar-box ul {
    list-style: none;
    margin-left: 0;
}

.sidebar-box li {
    padding: 8px 0;
    border-bottom: 1px solid #eee;
}

.sidebar-box li:last-child {
    border-bottom: none;
}

/* 时间线样式 */
.timeline {
    position: relative;
    padding-left: 30px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: #2c5282;
}

.timeline-item {
    position: relative;
    margin-bottom: 30px;
}

.timeline-item .year {
    position: absolute;
    left: -30px;
    top: 0;
    background: #2c5282;
    color: white;
    padding: 5px 10px;
    border-radius: 4px;
    font-weight: bold;
}

.timeline-item .content h4 {
    color: #1a3a6c;
    margin-bottom: 5px;
}

/* 研究人员卡片 */
.researchers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.researcher-card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.researcher-card:hover {
    transform: translateY(-5px);
}

.researcher-card img {
    width: 100%;
    height: 250px;
    object-fit: cover;
}

.researcher-info {
    padding: 20px;
}

.researcher-info h3 {
    color: #1a3a6c;
    margin-bottom: 5px;
}

.title {
    color: #666;
    font-weight: bold;
    margin-bottom: 10px;
}

.specialty {
    color: #2c5282;
    font-size: 0.9em;
    margin-bottom: 15px;
}

.bio {
    color: #666;
    margin-bottom: 15px;
    line-height: 1.5;
}

/* 文献资料列表 */
.publications-filter {
    display: flex;
    gap: 20px;
    margin-bottom: 30px;
    flex-wrap: wrap;
    align-items: center;
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.filter-group label {
    font-weight: bold;
    color: #1a3a6c;
}

.filter-group select {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    background: white;
}

.publications-list {
    margin-bottom: 30px;
}

.publication-item {
    display: flex;
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 20px;
    transition: transform 0.3s ease;
}

.publication-item:hover {
    transform: translateX(5px);
}

.pub-icon {
    font-size: 2em;
    margin-right: 20px;
    color: #2c5282;
}

.pub-content {
    flex: 1;
}

.pub-content h3 {
    color: #1a3a6c;
    margin-bottom: 10px;
}

.pub-meta {
    color: #666;
    margin-bottom: 15px;
    font-size: 0.9em;
}

.pub-abstract {
    color: #666;
    margin-bottom: 20px;
    line-height: 1.6;
}

.pub-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
}

.page-numbers a {
    display: inline-block;
    padding: 8px 12px;
    text-decoration: none;
    border-radius: 4px;
    color: #2c5282;
    border: 1px solid #ddd;
}

.page-numbers a.current {
    background-color: #2c5282;
    color: white;
    border-color: #2c5282;
}

/* 联系页面 */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.contact-item {
    margin-bottom: 30px;
}

.contact-item h4 {
    color: #1a3a6c;
    margin-bottom: 10px;
}

.contact-item p {
    line-height: 1.8;
}

.contact-form form {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: #333;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1em;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #2c5282;
    box-shadow: 0 0 0 2px rgba(44, 82, 130, 0.2);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 20px;
}

.faq-item h4 {
    color: #1a3a6c;
    margin-bottom: 10px;
}

/* 页脚 */
footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 50px;
}

footer p {
    margin-bottom: 10px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 2em;
    }
    
    nav ul {
        flex-direction: column;
        align-items: center;
    }
    
    nav ul li {
        margin: 5px 0;
    }
    
    .hero {
        padding: 50px 0;
    }
    
    .hero h2 {
        font-size: 1.8em;
    }
    
    .content-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .researchers-grid {
        grid-template-columns: 1fr;
    }
    
    .publication-item {
        flex-direction: column;
        text-align: center;
    }
    
    .pub-icon {
        margin-right: 0;
        margin-bottom: 15px;
    }
    
    .publications-filter {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero h2 {
        font-size: 1.5em;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
    }
}