/**
 * 编程题库系统 - 样式表
 */

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

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

/* 导航栏 */
.navbar {
    background-color: #2c3e50;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-menu a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: #3498db;
}

.nav-user {
    color: #ecf0f1;
}

/* 登录框 */
.login-box {
    max-width: 400px;
    margin: 100px auto;
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.login-box h1 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2c3e50;
}

/* 表单 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #555;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #3498db;
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

/* 按钮 */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
}

.btn-primary {
    background-color: #3498db;
    color: white;
}

.btn-primary:hover {
    background-color: #2980b9;
}

.btn-secondary {
    background-color: #95a5a6;
    color: white;
    margin-left: 0.5rem;
}

.btn-secondary:hover {
    background-color: #7f8c8d;
}

.btn-success {
    background-color: #27ae60;
    color: white;
}

.btn-success:hover {
    background-color: #229954;
}

/* 消息提示 */
.message {
    margin-top: 1rem;
    padding: 0.75rem;
    border-radius: 4px;
    text-align: center;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.message.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* 统计卡片 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.stat-card {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

.stat-card h3 {
    color: #7f8c8d;
    font-size: 1rem;
    margin-bottom: 1rem;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: bold;
    color: #2c3e50;
}

/* 筛选器 */
.filters {
    background: white;
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.filters select,
.filters input {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    flex: 1;
    min-width: 150px;
}

/* 题目卡片 */
.question-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.question-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.question-header h3 {
    color: #2c3e50;
    font-size: 1.2rem;
}

.question-meta {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

/* 徽章 */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.875rem;
    background-color: #ecf0f1;
    color: #2c3e50;
}

.badge-easy {
    background-color: #d4edda;
    color: #155724;
}

.badge-medium {
    background-color: #fff3cd;
    color: #856404;
}

.badge-hard {
    background-color: #f8d7da;
    color: #721c24;
}

.badge-tag {
    background-color: #d1ecf1;
    color: #0c5460;
}

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 2rem;
}

.pagination button {
    padding: 0.5rem 1rem;
    border: 1px solid #ddd;
    background: white;
    border-radius: 4px;
    cursor: pointer;
}

.pagination button:hover {
    background-color: #f5f5f5;
}

.pagination button.active {
    background-color: #3498db;
    color: white;
    border-color: #3498db;
}

/* 题目详情 */
.question-detail {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.question-content {
    margin: 1.5rem 0;
    line-height: 1.8;
}

/* 选项 */
.options {
    margin: 1.5rem 0;
}

.option-label {
    display: block;
    padding: 1rem;
    margin-bottom: 0.5rem;
    border: 2px solid #ecf0f1;
    border-radius: 4px;
    cursor: pointer;
    transition: border-color 0.3s;
}

.option-label:hover {
    border-color: #3498db;
}

.option-label input {
    margin-right: 0.5rem;
}

/* 答题区域 */
.answer-section {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

/* 结果显示 */
.result-section {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.result.correct {
    border-left: 4px solid #27ae60;
}

.result.wrong {
    border-left: 4px solid #e74c3c;
}

.explanation {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: 4px;
}

/* 错题卡片 */
.wrong-question-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.error-count {
    color: #e74c3c;
    font-weight: bold;
}

/* 操作按钮组 */
.action-buttons {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
}

.quick-actions {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    margin-top: 2rem;
}

.quick-actions h2 {
    margin-bottom: 1.5rem;
    color: #2c3e50;
}

/* 空状态 */
.empty-message {
    text-align: center;
    padding: 3rem;
    color: #7f8c8d;
    font-size: 1.1rem;
}

.error-message {
    background-color: #f8d7da;
    color: #721c24;
    padding: 1rem;
    border-radius: 4px;
    text-align: center;
}

/* 管理后台样式 */
.admin-sections {
    display: grid;
    gap: 2rem;
    margin-top: 2rem;
}

.admin-section {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.admin-section h2 {
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.admin-section p {
    color: #7f8c8d;
    margin-bottom: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .filters {
        flex-direction: column;
    }

    .action-buttons {
        flex-direction: column;
    }
}