/* 基础布局 */
body {
    padding-top: 2rem;
    padding-bottom: 3rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.content {
    flex: 1;
}

/* 导航栏样式 */
.navbar {
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

/* 侧边栏样式 */
.sidebar {
    /* 添加圆角 */
    border-radius: 8px;
    /* 添加阴影 */
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    /* 增加内边距让内容不贴边 */
    padding: 1rem 0;
    /* 增加一点外边距避免紧贴 */
    margin: 0 0.5rem;
}

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

.sidebar .nav-link.active {
    /* 加深背景色 */
    background-color: #0a58ca;
    /* 添加左侧高亮边框 */
    border-left: 4px solid #ffffff;
    /* 稍微增大选中项的内边距 */
    padding-left: calc(1rem - 4px); /* 减去左边框宽度 */
    /* 增加文字权重 */
    font-weight: 500;
}

.sidebar .nav-link:hover {
    /* 悬停时也添加轻微阴影 */
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.05);
}

/* 子菜单样式调整 */
.sidebar .nav .nav .nav-link.active {
    background-color: #e7f1ff;
    color: #0a58ca;
    border-left-color: #0a58ca;
}

.sidebar .nav-link:hover:not(.active) {
    background-color: #f8f9fa;
}

.sidebar .nav .nav {
    margin-left: 1rem;
}

.sidebar .nav .nav .nav-link {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

/* 主内容区域 */
main {
    min-height: calc(100vh - 56px - 56px); /* 减去导航栏和页脚高度 */
}

/* 页脚样式 */
.footer {
    margin-top: 3rem;
    padding: 1.5rem 0;
    color: #6c757d;
    background-color: #f8f9fa;
    border-top: 1px solid #e9ecef;
}

/* 卡片和图片样式 */
.card {
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.1);
}

.image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.image-item {
    border-radius: 4px;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.2s;
}

.image-item:hover {
    transform: scale(1.03);
}

.image-item img {
    width: 100%;
    height: 150px;
    object-fit: cover;
}

.image-caption {
    padding: 0.5rem;
    font-size: 0.85rem;
    text-align: center;
    background-color: #f8f9fa;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .sidebar {
        /* 移动端调整圆角和阴影 */
        border-radius: 6px;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
        margin: 0.5rem;
    }
}