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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

.header {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    color: #333;
    font-size: 24px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.user-badge {
    background: #667eea;
    color: white;
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 14px;
}

.btn {
    padding: 8px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5568d3;
}

.btn-danger {
    background: #dc3545;
    color: white;
}

.btn-danger:hover {
    background: #c82333;
}

.btn-warning {
    background: #ffc107;
    color: #333;
}

.btn-warning:hover {
    background: #e0a800;
}

.btn-info {
    background: #17a2b8;
    color: white;
}

.btn-info:hover {
    background: #138496;
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

/* 登录页面 */
.login-container {
    max-width: 400px;
    margin: 100px auto;
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.login-container h2 {
    text-align: center;
    margin-bottom: 30px;
    color: #333;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 14px;
    transition: border-color 0.3s;
}

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

/* 主内容区 */
.main-content {
    display: none;
}

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

.menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.menu-card {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    cursor: pointer;
    transition: all 0.3s;
    text-align: center;
}

.menu-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}

.menu-card h3 {
    color: #333;
    margin-bottom: 10px;
}

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

/* 功能页面 */
.function-page {
    display: none;
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.function-page.active {
    display: block;
}

.function-page h2 {
    color: #333;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #667eea;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 15px;
    margin-bottom: 15px;
}

.form-group-full {
    grid-column: 1 / -1;
}

.alert {
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
}

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

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

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

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

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

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

th {
    background: #667eea;
    color: white;
    font-weight: 500;
}

tr:hover {
    background: #f5f5f5;
}

.action-buttons {
    display: flex;
    gap: 10px;
}

.btn-sm {
    padding: 5px 12px;
    font-size: 12px;
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 40px;
    color: #666;
}

.spinner {
    border: 3px solid #f3f3f3;
    border-top: 3px solid #667eea;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 返回按钮 */
.back-btn {
    margin-bottom: 20px;
}

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

.stat-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
}

.stat-card h3 {
    font-size: 32px;
    margin-bottom: 10px;
}

.stat-card p {
    opacity: 0.9;
}

/* 群组选择复选框样式 */
.group-checkbox {
    cursor: pointer;
    margin-right: 10px;
}

#groupListContainer label {
    display: flex;
    align-items: center;
    cursor: pointer;
    padding: 8px;
    border-bottom: 1px solid #eee;
    transition: background-color 0.2s;
}

#groupListContainer label:hover {
    background: #f0f0f0;
}

#groupListContainer label:last-child {
    border-bottom: none;
}