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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #f5f7fa;
    min-height: 100vh;
    line-height: 1.6;
}

/* 头部导航 */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    font-size: 24px;
}

.nav {
    display: flex;
    gap: 20px;
    align-items: center;
}

.nav a {
    color: white;
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 6px;
    transition: background 0.3s;
}

.nav a:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

/* 卡片 */
.card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    text-decoration: none;
    color: inherit;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

.card-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.card h3 {
    color: #333;
    font-size: 20px;
    margin-bottom: 10px;
}

.card p {
    color: #666;
    font-size: 14px;
}

/* 欢迎卡片 */
.welcome-card {
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    text-align: center;
}

.welcome-card h2 {
    color: #333;
    font-size: 28px;
    margin-bottom: 10px;
}

.welcome-card p {
    color: #666;
    font-size: 16px;
    margin-bottom: 30px;
}

/* 卡片网格 */
.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

/* 按钮 */
.btn {
    padding: 12px 30px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    display: inline-block;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(102, 126, 234, 0.3);
}

.btn-block {
    display: block;
    width: 100%;
}

/* 表单 */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 500;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e1e1e1;
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: #667eea;
}

/* 错误提示 */
.error {
    background: #fee;
    border: 1px solid #fcc;
    color: #c33;
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 14px;
}

/* 成功提示 */
.success {
    background: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 14px;
}

/* 信息框 */
.info-box {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
}

.info-box h3 {
    margin-bottom: 10px;
    color: #333;
}

/* 徽章 */
.badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.badge.admin {
    background: #e3f2fd;
    color: #1976d2;
}

.badge.user {
    background: #e8f5e9;
    color: #388e3c;
}

/* 表格 */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th,
td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid #f0f0f0;
}

th {
    background: #f8f9fa;
    font-weight: 600;
    color: #333;
}

tr:hover {
    background: #f8f9fa;
}

/* 标签页 */
.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.tab {
    padding: 10px 20px;
    background: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.tab.active {
    background: #667eea;
    color: white;
}

.tab:hover:not(.active) {
    background: #e8e8e8;
}

/* 面板 */
.panel {
    display: none;
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.panel.active {
    display: block;
}

/* 响应式 */
@media (max-width: 768px) {
    .header {
        flex-direction: column;
        gap: 15px;
        padding: 20px;
    }
    
    .nav {
        flex-direction: column;
        gap: 10px;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .cards {
        grid-template-columns: 1fr;
    }
}