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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    display: flex;
    min-height: 100vh;
}

/* 头部样式 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background-color: #2c3e50;
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    z-index: 1000;
}

.header h1 {
    font-size: 1.5rem;
}

.user-info {
    display: flex;
    align-items: center;
}

.dropdown {
    position: relative;
    display: inline-block;
}

.dropbtn {
    background-color: #3498db;
    color: white;
    padding: 8px 16px;
    border: none;
    cursor: pointer;
    border-radius: 4px;
}

.dropdown-content {
    display: none;
    position: absolute;
    right: 0;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.dropdown-content a:hover {
    background-color: #f1f1f1;
}

.dropdown:hover .dropdown-content {
    display: block;
}

/* 侧边栏样式 */
.sidebar {
    position: fixed;
    top: 60px;
    left: 0;
    width: 200px;
    height: calc(100vh - 60px);
    background-color: #34495e;
    padding-top: 20px;
}

.sidebar ul {
    list-style: none;
}

.sidebar li a {
    display: block;
    color: white;
    padding: 12px 20px;
    text-decoration: none;
    transition: background-color 0.3s;
}

.sidebar li a:hover, .sidebar li a.active {
    background-color: #3498db;
}

/* 主内容区样式 */
.main-content {
    margin-left: 200px;
    margin-top: 60px;
    padding: 20px;
    width: calc(100% - 200px);
    min-height: calc(100vh - 60px);
}

.dashboard {
    max-width: 1200px;
    margin: 0 auto;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.stat-card {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

.stat-card h3 {
    color: #7f8c8d;
    font-size: 1rem;
    margin-bottom: 10px;
}

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

.recent-activities {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    margin-top: 30px;
}

.recent-activities h3 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.recent-activities ul {
    list-style: none;
}

.recent-activities li {
    padding: 10px 0;
    border-bottom: 1px solid #eee;
}

.recent-activities li:last-child {
    border-bottom: none;
}

/* 表单样式 */
.form-container {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    max-width: 800px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

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

.btn-primary {
    background-color: #3498db;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

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

.btn-secondary {
    background-color: #95a5a6;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.3s;
}

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

.btn-danger {
    background-color: #e74c3c;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.3s;
}

.btn-danger:hover {
    background-color: #c0392b;
}

/* 表格样式 */
.table-container {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.data-table th {
    background-color: #f8f9fa;
    font-weight: bold;
    color: #2c3e50;
}

.data-table tr:hover {
    background-color: #f5f5f5;
}

/* 卡片列表样式 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.card {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.card h3 {
    margin-bottom: 10px;
    color: #2c3e50;
}

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

.card-actions {
    display: flex;
    justify-content: space-between;
    margin-top: 15px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .sidebar {
        width: 60px;
    }
    
    .sidebar li a span {
        display: none;
    }
    
    .main-content {
        margin-left: 60px;
        width: calc(100% - 60px);
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 0 10px;
    }
    
    .header h1 {
        font-size: 1.2rem;
    }
    
    .main-content {
        padding: 10px;
    }
}
/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 20px;
    border-radius: 8px;
    width: 90%;
    max-width: 500px;
    position: relative;
}

.close {
    position: absolute;
    right: 10px;
    top: 10px;
    font-size: 24px;
    cursor: pointer;
}

/* 标签页样式 */
.tabs {
    display: flex;
    margin-bottom: 20px;
    border-bottom: 1px solid #ddd;
}

.tab-link {
    padding: 10px 20px;
    background-color: #f1f1f1;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s;
    border-bottom: 3px solid transparent;
}

.tab-link.active {
    background-color: white;
    border-bottom-color: #3498db;
    color: #3498db;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* 成员列表样式 */
.member-item {
    padding: 10px;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
}

.member-item:last-child {
    border-bottom: none;
}

/* 白板项目样式 */
.whiteboard-item {
    padding: 15px;
    border: 1px solid #eee;
    border-radius: 4px;
    margin-bottom: 10px;
}

.whiteboard-item h4 {
    margin-bottom: 5px;
}

/* 任务、公告、作业项目样式 */
.task-item,
.announcement-item,
.assignment-item {
    padding: 15px;
    border: 1px solid #eee;
    border-radius: 4px;
    margin-bottom: 15px;
}

.task-meta,
.announcement-meta,
.assignment-meta {
    display: flex;
    gap: 15px;
    margin: 10px 0;
    font-size: 0.9rem;
    color: #7f8c8d;
}

/* 班级元信息样式 */
.class-meta {
    display: flex;
    gap: 20px;
    margin-top: 10px;
}

/* 白板统计信息样式 */
.whiteboard-stats {
    display: flex;
    gap: 15px;
    margin-top: 10px;
}

.whiteboard-stats span {
    background-color: #f8f9fa;
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 0.9rem;
}