/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

body {
    color: #333;
    line-height: 1.6;
    background-color: #f8f9fa;
}

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

/* 导航栏样式 */
.navbar {
    background-color: #2c3e50;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
}

.nav-item {
    margin-left: 1.5rem;
}

.nav-link {
    color: #ecf0f1;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
    padding: 0.5rem 0;
}

.nav-link:hover, .nav-link.active {
    color: #3498db;
    border-bottom: 2px solid #3498db;
}

/* 页面头部样式 */
.page-header {
    background: linear-gradient(135deg, #1a2980 0%, #26d0ce 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
    margin-bottom: 2rem;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.page-header p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* 主要内容区域样式 */
.main-content {
    padding: 2rem 0;
}

.content-section {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.content-section h2 {
    color: #2c3e50;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #3498db;
}

/* 技术定义部分样式 */
.definition-content {
    display: flex;
    gap: 2rem;
    align-items: flex-start;
}

.text-content {
    flex: 2;
}

.text-content p {
    margin-bottom: 1rem;
}

.chemical-formula {
    background-color: #f1f8ff;
    border-left: 4px solid #3498db;
    padding: 1rem;
    margin: 1.5rem 0;
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
    border-radius: 0 4px 4px 0;
}

.image-content {
    flex: 1;
}

.image-container {
    text-align: center;
}

.image-container img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.image-container img:hover {
    transform: scale(1.02);
}

.image-caption {
    margin-top: 0.5rem;
    font-style: italic;
    color: #666;
    font-size: 0.9rem;
}

/* 时间轴样式 */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: #3498db;
    transform: translateX(-50%);
}

.timeline-item {
    display: flex;
    margin-bottom: 2rem;
    position: relative;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-year {
    flex: 1;
    padding: 0 1rem;
    text-align: center;
    font-weight: bold;
    color: #3498db;
    font-size: 1.2rem;
}

.timeline-content {
    flex: 2;
    padding: 1rem;
    background: #f8f9fa;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.timeline-content h3 {
    margin-bottom: 0.5rem;
    color: #2c3e50;
}

/* 表格样式 */
.comparison-table-container {
    overflow-x: auto;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
}

.comparison-table th, .comparison-table td {
    padding: 0.75rem;
    text-align: center;
    border: 1px solid #dee2e6;
}

.comparison-table th {
    background-color: #3498db;
    color: white;
    font-weight: 600;
}

.comparison-table tr:nth-child(even) {
    background-color: #f8f9fa;
}

.comparison-table tr:hover {
    background-color: #e9f7fe;
}

/* 工艺卡片样式 */
.process-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.process-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #3498db;
}

.process-card h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.process-types {
    margin-top: 1rem;
}

.process-type {
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #dee2e6;
}

.process-type:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.process-type h4 {
    color: #3498db;
    margin-bottom: 0.5rem;
}

/* 应用领域样式 */
.application-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.application-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #2ecc71;
}

.application-card h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

/* 挑战与解决方案样式 */
.challenges-container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.challenge {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #e74c3c;
}

.challenge h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.solutions {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px dashed #dee2e6;
}

.solutions h4 {
    margin-bottom: 0.5rem;
    color: #27ae60;
}

.solutions ul {
    padding-left: 1.5rem;
}

.solutions li {
    margin-bottom: 0.5rem;
}

/* 研究方向样式 */
.research-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.research-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-top: 4px solid #9b59b6;
    transition: transform 0.3s;
}

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

.research-card h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

/* 应用前景样式 */
.prospects-content p {
    margin-bottom: 1.5rem;
}

.quote {
    background: #f1f8ff;
    border-left: 4px solid #3498db;
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    font-style: italic;
}

/* 页脚样式 */
.footer {
    background-color: #2c3e50;
    color: #ecf0f1;
    padding: 2rem 0;
    text-align: center;
    margin-top: 2rem;
}

.footer p {
    margin-bottom: 0.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .definition-content {
        flex-direction: column;
    }
    
    .process-cards, .application-cards {
        grid-template-columns: 1fr;
    }
    
    .research-cards {
        grid-template-columns: 1fr;
    }
    
    .timeline::before {
        left: 20px;
    }
    
    .timeline-item {
        flex-direction: row !important;
        padding-left: 50px;
    }
    
    .timeline-year {
        position: absolute;
        left: 0;
        top: 0;
        width: 40px;
        text-align: center;
    }
    
    .nav-container {
        flex-direction: column;
    }
    
    .nav-menu {
        margin-top: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-item {
        margin: 0.5rem;
    }
}