/* 侧边栏样式 */
.sidebar {
    position: fixed;
    top: 56px;
    bottom: 0;
    left: 0;
    z-index: 100;
    padding: 0;
    box-shadow: inset -1px 0 0 rgba(0, 0, 0, .1);
    overflow-x: hidden;
    overflow-y: auto;
}

.sidebar .nav-link {
    font-weight: 500;
    color: #333;
    padding: 0.75rem 1rem;
}

.sidebar .nav-link:hover {
    color: #007bff;
    background-color: #f8f9fa;
}

.sidebar .nav-link.active {
    color: #007bff;
    background-color: #e7f1ff;
    border-left: 3px solid #007bff;
}

.sidebar .nav-link i {
    margin-right: 0.5rem;
}

/* 主内容区域 */
main {
    margin-top: 56px;
    padding-top: 1rem;
}

/* 图片上传预览 */
.upload-preview {
    width: 100%;
    aspect-ratio: 1;
    border: 2px dashed #dee2e6;
    border-radius: 0.375rem;
    overflow: hidden;
    cursor: pointer;
    position: relative;
    background-color: #f8f9fa;
    transition: all 0.3s;
}

.upload-preview:hover {
    border-color: #0d6efd;
    background-color: #e7f1ff;
}

.upload-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.upload-placeholder {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: #6c757d;
}

.upload-placeholder i {
    font-size: 3rem;
    display: block;
    margin-bottom: 0.5rem;
}

.upload-placeholder p {
    margin: 0;
    font-weight: 500;
}

.upload-placeholder small {
    color: #adb5bd;
}

/* 响应式调整 */
@media (max-width: 767.98px) {
    .sidebar {
        top: 0;
        position: relative;
    }
    
    main {
        margin-top: 0;
    }
}

/* 表格优化 */
.table td {
    vertical-align: middle;
}

/* 卡片统计样式 */
.card {
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15) !important;
}