/* 全局样式 */
:root {
    --primary-color: #4e73df;
    --secondary-color: #858796;
    --success-color: #1cc88a;
    --info-color: #36b9cc;
    --warning-color: #f6c23e;
    --danger-color: #e74a3b;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8f9fc;
    min-height: 100vh;
}

/* 前台首页样式 */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-card {
    background: white;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
    padding: 40px;
    max-width: 420px;
    width: 100%;
}

.login-card h1 {
    color: #333;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 10px;
}

.login-card p {
    color: #666;
    margin-bottom: 30px;
}

.login-card .form-control {
    height: 50px;
    border-radius: 10px;
    font-size: 16px;
}

.login-card .btn-primary {
    height: 50px;
    border-radius: 10px;
    font-size: 18px;
    font-weight: 600;
}

/* 课程列表 */
.course-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 0;
    margin-bottom: 30px;
}

.category-card {
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    padding: 30px;
    margin-bottom: 30px;
    transition: transform 0.3s;
}

.category-card:hover {
    transform: translateY(-5px);
}

.category-card h3 {
    color: #333;
    font-weight: 700;
    margin-bottom: 20px;
}

.video-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.video-item {
    display: flex;
    align-items: center;
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 10px;
    background: #f8f9fc;
    transition: background 0.3s;
}

.video-item:hover {
    background: #e8ebf5;
}

.video-item .video-icon {
    font-size: 24px;
    color: var(--primary-color);
    margin-right: 15px;
}

.video-item .video-info {
    flex: 1;
}

.video-item .video-title {
    font-weight: 600;
    color: #333;
    margin-bottom: 3px;
}

.video-item .video-duration {
    font-size: 14px;
    color: #666;
}

.video-item .play-btn {
    padding: 8px 20px;
    border-radius: 20px;
}

/* 视频播放页 */
.video-player-container {
    background: #000;
    border-radius: 15px;
    overflow: hidden;
    margin-bottom: 30px;
}

.video-player-container video {
    width: 100%;
    max-height: 70vh;
}

.video-info-card {
    background: white;
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
}

/* 后台管理样式 */
.admin-wrapper {
    display: flex;
    min-height: 100vh;
}

.admin-sidebar {
    width: 250px;
    background: linear-gradient(180deg, #4e73df 10%, #224abe 100%);
    min-height: 100vh;
    position: fixed;
    left: 0;
    top: 0;
}

.admin-sidebar .brand {
    padding: 20px;
    color: white;
    font-size: 20px;
    font-weight: 700;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.admin-sidebar .nav-link {
    color: rgba(255, 255, 255, 0.8);
    padding: 15px 20px;
    display: flex;
    align-items: center;
    transition: all 0.3s;
}

.admin-sidebar .nav-link:hover,
.admin-sidebar .nav-link.active {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

.admin-sidebar .nav-link i {
    margin-right: 10px;
    font-size: 18px;
}

.admin-content {
    flex: 1;
    margin-left: 250px;
    padding: 30px;
}

.admin-header {
    margin-bottom: 30px;
}

.admin-header h1 {
    color: #333;
    font-weight: 700;
}

/* 统计卡片 */
.stat-card {
    background: white;
    border-radius: 10px;
    padding: 25px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    border-left: 4px solid;
    margin-bottom: 20px;
}

.stat-card.primary {
    border-color: var(--primary-color);
}

.stat-card.success {
    border-color: var(--success-color);
}

.stat-card.info {
    border-color: var(--info-color);
}

.stat-card.warning {
    border-color: var(--warning-color);
}

.stat-card .stat-title {
    color: var(--secondary-color);
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 5px;
}

.stat-card .stat-value {
    font-size: 28px;
    font-weight: 700;
    color: #333;
}

/* 数据表格 */
.data-table {
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    overflow: hidden;
}

.data-table .table-header {
    padding: 20px;
    border-bottom: 1px solid #e3e6f0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.data-table .table-header h5 {
    margin: 0;
    font-weight: 700;
    color: #333;
}

.data-table table {
    margin: 0;
}

.data-table th {
    background: #f8f9fc;
    font-weight: 600;
    color: var(--secondary-color);
    text-transform: uppercase;
    font-size: 12px;
    border-top: none;
}

/* 模态框 */
.modal-header {
    background: var(--primary-color);
    color: white;
}

.modal-header .btn-close {
    filter: invert(1);
}

/* 状态标签 */
.badge-status {
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

/* 响应式 */
@media (max-width: 768px) {
    .admin-sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }

    .admin-content {
        margin-left: 0;
    }

    .login-card {
        margin: 20px;
        padding: 30px;
    }
}