/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
    overflow-x: hidden;
}

/* 容器样式 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 15px;
    min-height: 100vh;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
}

/* 头部样式 */
.header {
    background: linear-gradient(135deg, #1a73e8, #0d47a1);
    color: white;
    text-align: center;
    padding: 30px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.header h1 {
    font-size: 1.8em;
    margin-bottom: 8px;
    font-weight: 600;
}

.header p {
    font-size: 1em;
    opacity: 0.9;
    margin-bottom: 5px;
}

/* 内容区域样式 */
.content {
    background: white;
    border-radius: 8px;
    padding: 25px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
    flex: 1;
}

/* 年份选择区域 */
.year-section {
    text-align: center;
    margin-bottom: 20px;
}

.year-section h2 {
    font-size: 1.5em;
    margin-bottom: 15px;
    color: #333;
}

/* 年份卡片容器 */
.year-cards {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

/* 年份卡片 */
.year-card {
    background: #f8f9fa;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    padding: 20px;
    width: 260px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.year-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
    border-color: #1a73e8;
}

.year-card h3 {
    font-size: 1.3em;
    margin-bottom: 10px;
    color: #333;
}

.year-card p {
    margin-bottom: 15px;
    color: #666;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 10px 20px;
    background: #1a73e8;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 500;
    transition: background 0.3s ease;
    font-size: 0.9em;
}

.btn:hover {
    background: #1557b0;
}

.btn-disabled {
    background: #ccc;
    cursor: not-allowed;
}

.btn-disabled:hover {
    background: #ccc;
}

/* 页脚样式 */
.footer {
    text-align: center;
    margin-top: 20px;
    padding: 25px 20px;
    background: linear-gradient(135deg, #1e3a8a, #3b82f6);
    color: white;
    font-size: 0.8em;
    line-height: 1.6;
    border-radius: 8px;
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.1);
}

.footer p {
    margin-bottom: 6px;
    opacity: 0.9;
}

.footer a {
    color: #bfdbfe;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* 响应式设计 */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.6em;
    }
    
    .header p {
        font-size: 0.9em;
    }
    
    .content {
        padding: 20px;
        margin-bottom: 20px;
    }
    
    .year-cards {
        flex-direction: column;
        align-items: center;
        gap: 15px;
    }
    
    .year-card {
        width: 100%;
        max-width: 280px;
        padding: 15px;
    }
    
    .footer {
        padding: 20px 15px;
        margin-top: 20px;
    }
    
    .container {
        padding: 10px;
    }
}