/* 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;
}

/* 全球应用概况样式 */
.overview-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.application-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.stat-item {
    background: linear-gradient(135deg, #3498db 0%, #2c3e50 100%);
    color: white;
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.9;
}

/* 国内应用进展样式 */
.project-cards {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

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

.project-card h4 {
    color: #2c3e50;
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.project-details p {
    margin-bottom: 0.8rem;
}

/* 应用领域样式 */
.area-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.area-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-top: 4px solid #e74c3c;
    transition: transform 0.3s;
}

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

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

.area-details ul {
    padding-left: 1.5rem;
}

.area-details li {
    margin-bottom: 0.5rem;
}

/* 工艺形式与工程案例样式 */
.process-type-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.process-type-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #9b59b6;
}

.process-type-card h4 {
    color: #2c3e50;
    margin-bottom: 1rem;
}

.process-description ul {
    padding-left: 1.5rem;
}

.process-description li {
    margin-bottom: 0.5rem;
}

.case-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.case-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-top: 4px solid #f39c12;
}

.case-card h4 {
    color: #2c3e50;
    margin-bottom: 1rem;
}

.case-details p {
    margin-bottom: 0.8rem;
}

/* 挑战与解决方案样式 */
.challenges-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

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

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

.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;
}

/* 未来发展趋势样式 */
.trend-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.trend-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-top: 4px solid #3498db;
    transition: transform 0.3s;
}

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

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

.trend-card ul {
    padding-left: 1.5rem;
}

.trend-card li {
    margin-bottom: 0.5rem;
}

.conclusion {
    background: #f1f8ff;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #3498db;
    margin-top: 1.5rem;
}

/* 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) {
    .application-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .area-cards, .process-type-cards, .case-cards, .trend-cards {
        grid-template-columns: 1fr;
    }
    
    .nav-container {
        flex-direction: column;
    }
    
    .nav-menu {
        margin-top: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-item {
        margin: 0.5rem;
    }
}

@media (max-width: 480px) {
    .application-stats {
        grid-template-columns: 1fr;
    }
    
    .page-header h1 {
        font-size: 2rem;
    }
    
    .content-section {
        padding: 1.5rem;
    }
}