/* 主题变量 */
:root {
  /* 主题色 */
  --primary-color: #ff2442;
  --primary-color-dark: #b31f35;
  --primary-color-shadow: rgba(254, 40, 67, 0.3);
  /* 文本颜色 */
  --text-color-primary: #333;
  --text-color-secondary: #5c5c5c;
  --text-color-tertiary: #858585;
  --text-color-quaternary: #bbbbbb;
  --text-color-inverse: #fff;
  /* 背景颜色 */
  --bg-color-primary: #fff;
  --bg-color-secondary: #f7f7f7;
  --bg-color-tertiary: #e8e4e4;
  /* 边框颜色 */
  --border-color-primary: #ebebeb;
  --border-color-secondary: #eee;
  /* 阴影颜色 */
  --shadow-color: rgba(0, 0, 0, 0.08);
}

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

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color-secondary);
    color: var(--text-color-primary);
    line-height: 1.6;
}

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

/* 标题样式 */
h1 {
    text-align: center;
    margin-bottom: 40px;
    color: var(--text-color-primary);
    font-size: 36px;
    font-weight: 700;
}

/* 人口计数器样式 */
.population-counter {
    background-color: var(--bg-color-primary);
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    padding: 40px;
    margin-bottom: 40px;
    text-align: center;
    border: 1px solid var(--border-color-primary);
}

.counter {
    margin-bottom: 30px;
}

#population {
    font-size: 64px;
    font-weight: 700;
    color: var(--primary-color);
    font-family: 'Courier New', monospace;
}

.counter-info {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.info-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.info-item .label {
    font-size: 14px;
    color: var(--text-color-tertiary);
    margin-bottom: 5px;
}

.info-item span:not(.label) {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-color-secondary);
}

/* 图表容器样式 */
.population-chart {
    background-color: var(--bg-color-primary);
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    padding: 30px;
    margin-bottom: 40px;
    border: 1px solid var(--border-color-primary);
}

/* 统计卡片样式 */
.population-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 30px;
}

.stat-card {
    background-color: var(--bg-color-primary);
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    padding: 30px;
    border: 1px solid var(--border-color-primary);
}

.stat-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-color-primary);
    margin-bottom: 20px;
    text-align: center;
}

.stat-content {
    height: 300px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 24px;
    }
    
    .population-counter {
        padding: 20px;
    }
    
    #population {
        font-size: 48px;
    }
    
    .counter-info {
        gap: 20px;
    }
    
    .population-chart {
        padding: 20px;
    }
    
    .population-stats {
        grid-template-columns: 1fr;
    }
    
    .stat-card {
        padding: 20px;
    }
    
    .stat-content {
        height: 250px;
    }
}

@media (max-width: 480px) {
    #population {
        font-size: 36px;
    }
    
    .counter-info {
        flex-direction: column;
        gap: 15px;
    }
}

/* 页面链接样式 */
.page-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 40px;
    margin-bottom: 20px;
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s;
    border: 1px solid var(--border-color-primary);
    background-color: var(--bg-color-primary);
    color: var(--text-color-primary);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
    border-color: var(--primary-color);
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--text-color-inverse);
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: var(--primary-color-dark);
    border-color: var(--primary-color-dark);
}