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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

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

/* 头部样式 */
.header {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    color: white;
    padding: 2rem 0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.back-btn {
    display: inline-flex;
    align-items: center;
    color: white;
    text-decoration: none;
    font-size: 1rem;
    margin-bottom: 1rem;
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateX(-5px);
}

.title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* 主内容区域 */
.main-container {
    padding: 2rem 0;
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 100%;
    background: linear-gradient(to bottom, #3498db, #2c3e50);
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.6s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.timeline-content {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    position: relative;
    transition: all 0.3s ease;
    border-left: 4px solid #3498db;
}

.timeline-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.timeline-content::before {
    content: '';
    position: absolute;
    top: 20px;
    width: 0;
    height: 0;
    border-style: solid;
}

.timeline-item:nth-child(odd) .timeline-content {
    margin-left: 0;
    margin-right: 50%;
}

.timeline-item:nth-child(odd) .timeline-content::before {
    right: -10px;
    border-width: 10px 0 10px 10px;
    border-color: transparent transparent transparent white;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: 50%;
}

.timeline-item:nth-child(even) .timeline-content::before {
    left: -10px;
    border-width: 10px 10px 10px 0;
    border-color: transparent white transparent transparent;
}

.timeline-date {
    position: absolute;
    top: 10px;
    background: #3498db;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    box-shadow: 0 3px 10px rgba(52, 152, 219, 0.3);
}

.timeline-item:nth-child(odd) .timeline-date {
    right: -120px;
}

.timeline-item:nth-child(even) .timeline-date {
    left: -120px;
}

.timeline-title {
    font-size: 1.3rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.timeline-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: #7f8c8d;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid #ecf0f1;
}

.timeline-content-text {
    color: #2c3e50;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.timeline-analysis {
    background: #f8f9fa;
    border-left: 3px solid #e74c3c;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
}

.analysis-header {
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
    color: #e74c3c;
    font-weight: 600;
}

.analysis-header i {
    margin-right: 0.5rem;
}

.analysis-content {
    color: #2c3e50;
    line-height: 1.6;
}

.analysis-content p {
    margin-bottom: 0.5rem;
}

/* 加载指示器 */
.loading {
    text-align: center;
    padding: 2rem;
    display: none;
}

.spinner {
    border: 3px solid #f3f3f3;
    border-top: 3px solid #3498db;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.no-more {
    text-align: center;
    padding: 2rem;
    color: #7f8c8d;
    display: none;
}

.no-more i {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: #2ecc71;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
    transition: all 0.3s ease;
    display: none;
    z-index: 99;
}

.back-to-top:hover {
    background: #2980b9;
    transform: translateY(-3px);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .timeline::before {
        left: 30px;
    }
    
    .timeline-item:nth-child(odd) .timeline-content,
    .timeline-item:nth-child(even) .timeline-content {
        margin-left: 60px;
        margin-right: 0;
    }
    
    .timeline-item:nth-child(odd) .timeline-content::before,
    .timeline-item:nth-child(even) .timeline-content::before {
        left: -10px;
        border-width: 10px 10px 10px 0;
        border-color: transparent white transparent transparent;
    }
    
    .timeline-item:nth-child(odd) .timeline-date,
    .timeline-item:nth-child(even) .timeline-date {
        left: -90px;
        right: auto;
    }
    
    .title {
        font-size: 2rem;
    }
    
    .container {
        padding: 0 15px;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 1.5rem 0;
    }
    
    .title {
        font-size: 1.8rem;
    }
    
    .timeline-content {
        padding: 1rem;
    }
    
    .timeline-item:nth-child(odd) .timeline-content,
    .timeline-item:nth-child(even) .timeline-content {
        margin-left: 40px;
    }
    
    .timeline-item:nth-child(odd) .timeline-date,
    .timeline-item:nth-child(even) .timeline-date {
        left: -70px;
        font-size: 0.8rem;
    }
}