/* 全局样式 */
:root {
    --primary-color: #4A90E2;
    --secondary-color: #50C878;
    --danger-color: #E74C3C;
    --warning-color: #F39C12;
    --dark-color: #2C3E50;
    --light-color: #ECF0F1;
    --border-color: #BDC3C7;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--dark-color);
    line-height: 1.6;
}

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

/* 卡片 */
.card {
    background: white;
    border-radius: 10px;
    padding: 30px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
    transition: var(--transition);
}

.card:hover {
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
    transform: translateY(-2px);
}

/* 登录页面 */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.login-card {
    background: white;
    border-radius: 15px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
    width: 100%;
    max-width: 400px;
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    color: var(--primary-color);
    font-size: 28px;
    margin-bottom: 10px;
}

.login-header p {
    color: #7f8c8d;
    font-size: 14px;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
}

.form-control {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    transition: var(--transition);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

select.form-control {
    cursor: pointer;
}

/* 按钮 */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: #357ABD;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(74, 144, 226, 0.4);
}

.btn-success {
    background: var(--secondary-color);
    color: white;
}

.btn-success:hover:not(:disabled) {
    background: #45B868;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-danger:hover:not(:disabled) {
    background: #C0392B;
}

.btn-warning {
    background: var(--warning-color);
    color: white;
}

.btn-secondary {
    background: #95a5a6;
    color: white;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
}

.btn-outline:hover:not(:disabled) {
    background: var(--primary-color);
    color: white;
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: 8px 16px;
    font-size: 13px;
}

/* 导航栏 */
.navbar {
    background: white;
    box-shadow: var(--shadow);
    padding: 15px 0;
    margin-bottom: 30px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.navbar-brand {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

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

.navbar-user span {
    color: var(--dark-color);
    font-weight: 500;
}

/* 网格布局 */
.grid {
    display: grid;
    gap: 20px;
}

.grid-2 {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
}

/* 科目卡片 */
.subject-card {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    cursor: pointer;
}

.subject-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.subject-card h3 {
    color: var(--primary-color);
    margin-bottom: 10px;
    font-size: 20px;
}

.subject-card p {
    color: #7f8c8d;
    font-size: 14px;
    margin-bottom: 15px;
}

.subject-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--light-color);
}

.subject-stats {
    display: flex;
    gap: 15px;
    font-size: 13px;
    color: #7f8c8d;
}

.subject-actions {
    display: flex;
    gap: 10px;
}

/* 题目卡片 */
.question-card {
    background: white;
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.question-type {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.type-single { background: #E8F5E9; color: #2E7D32; }
.type-multiple { background: #E3F2FD; color: #1565C0; }
.type-blank { background: #FFF3E0; color: #E65100; }
.type-judge { background: #F3E5F5; color: #6A1B9A; }
.type-essay { background: #FBE9E7; color: #BF360C; }

.question-content {
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.question-options {
    margin: 15px 0;
}

.option-item {
    padding: 12px;
    border: 2px solid var(--light-color);
    border-radius: 8px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: var(--transition);
}

.option-item:hover {
    border-color: var(--primary-color);
    background: #f8f9fa;
}

.option-item.selected {
    border-color: var(--primary-color);
    background: rgba(74, 144, 226, 0.1);
}

.option-item.correct {
    border-color: var(--secondary-color);
    background: rgba(80, 200, 120, 0.1);
}

.option-item.wrong {
    border-color: var(--danger-color);
    background: rgba(231, 76, 60, 0.1);
}

.question-answer {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 8px;
    margin-top: 15px;
}

.question-answer strong {
    color: var(--secondary-color);
}

.question-explanation {
    background: #fff9e6;
    padding: 15px;
    border-radius: 8px;
    margin-top: 10px;
    border-left: 4px solid var(--warning-color);
}

.question-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: 15px;
    padding: 30px;
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--light-color);
}

.modal-header h2 {
    color: var(--primary-color);
    font-size: 24px;
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    color: #95a5a6;
    cursor: pointer;
    transition: var(--transition);
}

.close-btn:hover {
    color: var(--danger-color);
}

/* 标签 */
.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.badge-primary { background: var(--primary-color); color: white; }
.badge-success { background: var(--secondary-color); color: white; }
.badge-danger { background: var(--danger-color); color: white; }
.badge-warning { background: var(--warning-color); color: white; }

/* 警告框 */
.alert {
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

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

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

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border: 1px solid #ffeaa7;
}

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

/* 表格 */
.table-container {
    overflow-x: auto;
    margin-top: 20px;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

thead {
    background: var(--light-color);
}

th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    font-weight: 600;
    color: var(--dark-color);
}

tbody tr:hover {
    background: #f8f9fa;
}

.checkbox {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    margin-top: 30px;
}

.pagination button {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    background: white;
    border-radius: 5px;
    cursor: pointer;
    transition: var(--transition);
}

.pagination button:hover:not(:disabled) {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.pagination button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.pagination .page-info {
    color: var(--dark-color);
    font-weight: 500;
}

/* 工具栏 */
.toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 15px;
}

.toolbar-left, .toolbar-right {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.search-box {
    display: flex;
    gap: 10px;
}

.search-box input {
    min-width: 250px;
}

/* 统计卡片 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-card .stat-value {
    font-size: 32px;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.stat-card .stat-label {
    font-size: 14px;
    color: #7f8c8d;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #7f8c8d;
}

.empty-state-icon {
    font-size: 64px;
    margin-bottom: 20px;
    opacity: 0.3;
}

.empty-state h3 {
    margin-bottom: 10px;
    color: var(--dark-color);
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 收藏按钮 */
.favorite-btn {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    transition: var(--transition);
    color: #95a5a6;
}

.favorite-btn.favorited {
    color: var(--danger-color);
}

.favorite-btn:hover {
    transform: scale(1.2);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .card {
        padding: 20px;
    }
    
    .navbar-content {
        flex-direction: column;
        gap: 15px;
    }
    
    .navbar-user {
        flex-direction: column;
        gap: 10px;
        width: 100%;
    }
    
    .toolbar {
        flex-direction: column;
        align-items: stretch;
    }
    
    .toolbar-left, .toolbar-right {
        width: 100%;
        justify-content: space-between;
    }
    
    .search-box {
        flex-direction: column;
    }
    
    .search-box input {
        min-width: 100%;
    }
    
    .grid-2, .grid-3 {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        padding: 20px;
    }
    
    table {
        font-size: 14px;
    }
    
    th, td {
        padding: 8px;
    }
}

@media (max-width: 480px) {
    .login-card {
        padding: 25px;
    }
    
    .btn {
        padding: 10px 16px;
        font-size: 13px;
    }
    
    .subject-info {
        flex-direction: column;
        gap: 15px;
        align-items: flex-start;
    }
    
    .question-header {
        flex-direction: column;
        gap: 10px;
    }
}

/* 打印样式 */
@media print {
    .navbar, .toolbar, .btn, .pagination {
        display: none !important;
    }
    
    .card {
        box-shadow: none;
        break-inside: avoid;
    }
}