/* 全局样式 */
body {
    font-family: "Microsoft YaHei", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    color: #333;
    background-color: #f8f9fa;
    line-height: 1.6;
}

/* 全局链接样式 */
a {
    transition: all 0.3s ease;
    text-decoration: none;
}

a:hover {
    text-decoration: none;
}

/* 导航栏样式 */
.navbar {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-weight: bold;
    display: flex;
    align-items: center;
}

.navbar-brand img {
    transition: transform 0.3s ease;
}

.navbar-brand:hover img {
    transform: scale(1.05);
}

.navbar-dark .navbar-nav .nav-link {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    padding: 0.5rem 1rem;
    position: relative;
}

.navbar-dark .navbar-nav .nav-link:before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: #fff;
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.navbar-dark .navbar-nav .nav-link:hover:before,
.navbar-dark .navbar-nav .nav-link.active:before {
    width: 80%;
}

.navbar-dark .navbar-nav .nav-link:hover,
.navbar-dark .navbar-nav .nav-link.active {
    color: #fff;
}

/* 下拉菜单美化 */
.dropdown-menu {
    border: none;
    border-radius: 0.5rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.15);
    padding: 0.7rem 0;
    margin-top: 0.5rem;
    animation: fadeInDown 0.3s ease;
}

.dropdown-item {
    padding: 0.6rem 1.5rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.dropdown-item:hover,
.dropdown-item:focus {
    background-color: rgba(13, 110, 253, 0.07);
    color: #0d6efd;
}

.dropdown-item i {
    transition: transform 0.2s ease;
}

.dropdown-item:hover i {
    transform: translateX(3px);
}

/* 卡片样式 */
.card {
    border: none;
    border-radius: 0.75rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    transition: all 0.4s ease;
    overflow: hidden;
}

.card:hover {
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    transform: translateY(-5px);
}

.card-header {
    background-color: rgba(0, 0, 0, 0.02);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    padding: 1.25rem 1.5rem;
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    background-color: rgba(0, 0, 0, 0.02);
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    padding: 1.25rem 1.5rem;
}

/* 图书推荐卡片 */
.book-card {
    height: 100%;
    position: relative;
}

.book-card .card-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.book-card .card-subtitle {
    font-size: 0.95rem;
    color: #6c757d;
    margin-bottom: 0.75rem;
}

.book-card .card-text {
    font-size: 0.95rem;
    line-height: 1.6;
    color: #495057;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
}

.book-card .book-meta {
    font-size: 0.85rem;
    color: #6c757d;
    display: flex;
    align-items: center;
}

.book-card .book-meta i {
    margin-right: 0.3rem;
}

.book-card .book-status {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    z-index: 10;
}

/* 图书卡片图片效果 */
.book-card .card-img-top {
    height: 200px;
    object-fit: cover;
    transition: all 0.5s ease;
}

.book-card:hover .card-img-top {
    transform: scale(1.05);
}

/* 状态标签样式 */
.status-badge {
    font-size: 0.75rem;
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    font-weight: 500;
    box-shadow: 0 2px 2px rgba(0, 0, 0, 0.1);
}

/* 表单样式 */
.form-label {
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: #495057;
}

.form-control,
.form-select {
    border-radius: 0.5rem;
    padding: 0.5rem 1rem;
    border: 1px solid #dee2e6;
    transition: all 0.3s ease;
}

.form-control:focus,
.form-select:focus {
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
    border-color: #86b7fe;
}

.form-text {
    font-size: 0.85rem;
    color: #6c757d;
    margin-top: 0.3rem;
}

/* 按钮样式 */
.btn {
    border-radius: 0.5rem;
    padding: 0.5rem 1.25rem;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(135deg, #0d6efd 0%, #0a58ca 100%);
    border: none;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #0a58ca 0%, #084298 100%);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(13, 110, 253, 0.3);
}

.btn-outline-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(13, 110, 253, 0.3);
}

.btn-light {
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.btn-light:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.btn i {
    transition: transform 0.3s ease;
}

.btn:hover i {
    transform: translateX(3px);
}

/* 评论样式 */
.comment {
    border-left: 3px solid #dee2e6;
    padding-left: 1.5rem;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
}

.comment:hover {
    border-left-color: #0d6efd;
    background-color: rgba(13, 110, 253, 0.03);
}

.comment-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    align-items: center;
}

.comment-author {
    font-weight: 600;
    color: #343a40;
}

.comment-date {
    font-size: 0.85rem;
    color: #6c757d;
}

.comment-content {
    font-size: 0.95rem;
    color: #495057;
    line-height: 1.6;
}

.comment-actions {
    margin-top: 0.75rem;
    font-size: 0.85rem;
    display: flex;
    gap: 1rem;
}

/* 分页样式 */
.pagination {
    margin-top: 2.5rem;
}

.page-link {
    border: none;
    color: #495057;
    padding: 0.5rem 0.75rem;
    margin: 0 0.2rem;
    border-radius: 0.35rem;
    transition: all 0.3s ease;
}

.page-item.active .page-link {
    background-color: #0d6efd;
    color: white;
    box-shadow: 0 2px 5px rgba(13, 110, 253, 0.3);
}

.page-link:hover {
    background-color: #e9ecef;
    color: #0d6efd;
    transform: translateY(-2px);
}

/* 统计卡片 */
.stat-card {
    text-align: center;
    padding: 2rem 1.5rem;
    background: white;
    border-radius: 0.75rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    transition: all 0.4s ease;
}

.stat-card:hover {
    transform: translateY(-7px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.stat-card .stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    background: linear-gradient(135deg, #0d6efd 0%, #0a58ca 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.stat-card .stat-label {
    font-size: 1.1rem;
    color: #495057;
    font-weight: 500;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .navbar-brand {
        font-size: 1rem;
    }

    .navbar-brand img {
        height: 30px;
    }

    .stat-card {
        margin-bottom: 1rem;
    }

    .book-card {
        margin-bottom: 1.5rem;
    }
}

/* 管理员面板样式 */
.admin-sidebar {
    background-color: white;
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.admin-sidebar .nav-link {
    color: #495057;
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    margin-bottom: 0.5rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.admin-sidebar .nav-link.active {
    color: #0d6efd;
    background-color: rgba(13, 110, 253, 0.1);
    font-weight: 600;
}

.admin-sidebar .nav-link:hover {
    color: #0d6efd;
    background-color: rgba(13, 110, 253, 0.05);
    transform: translateX(5px);
}

.admin-sidebar .nav-link i {
    margin-right: 0.75rem;
    transition: transform 0.3s ease;
}

.admin-sidebar .nav-link:hover i {
    transform: translateX(3px);
}

/* 公告样式 */
.announcement {
    border-left: 4px solid #0dcaf0;
    padding: 1.5rem;
    background-color: #f0f9fc;
    margin-bottom: 1.5rem;
    border-radius: 0.5rem;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.announcement:hover {
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transform: translateY(-3px);
}

.announcement-title {
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: #0c5460;
}

.announcement-date {
    font-size: 0.85rem;
    color: #6c757d;
    margin-bottom: 0.75rem;
}

.announcement-content {
    color: #495057;
    line-height: 1.6;
}

/* 点赞按钮样式 */
.like-btn {
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 20px;
    padding: 0.4rem 1rem;
}

.like-btn:hover,
.like-btn.active {
    color: #dc3545;
    transform: scale(1.05);
}

.like-btn.liked {
    background-color: #dc3545 !important;
    border-color: #dc3545 !important;
    box-shadow: 0 3px 10px rgba(220, 53, 69, 0.3);
}

.like-btn.liked .bi {
    color: white !important;
}

/* 自定义动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-down {
    animation: fadeInDown 0.5s ease;
}

.fade-in-up {
    animation: fadeInUp 0.5s ease;
}

/* 加载动画 */
.loading-spinner {
    display: inline-block;
    width: 1.2rem;
    height: 1.2rem;
    border: 0.2rem solid rgba(0, 0, 0, 0.1);
    border-top-color: #0d6efd;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 页面过渡动画 */
.page-transition {
    animation: fadeIn 0.5s ease;
}

/* 页面标题样式 */
.page-title {
    margin-bottom: 2rem;
    position: relative;
    padding-bottom: 0.75rem;
    font-weight: 600;
    color: #212529;
}

.page-title:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(135deg, #0d6efd 0%, #0a58ca 100%);
    border-radius: 3px;
}

/* 警告框美化 */
.alert {
    border: none;
    border-radius: 0.75rem;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
    padding: 1.25rem 1.5rem;
}

.alert-dismissible .btn-close {
    padding: 1.25rem 1.5rem;
}

/* 页脚样式 */
footer {
    box-shadow: 0 -5px 20px rgba(0, 0, 0, 0.05);
}

footer h5 {
    font-weight: 600;
    margin-bottom: 1.25rem;
    position: relative;
    padding-bottom: 0.5rem;
}

footer h5:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: #0d6efd;
    border-radius: 2px;
}

footer ul li {
    margin-bottom: 0.5rem;
}

footer ul li a {
    color: #495057;
    transition: all 0.3s ease;
}

footer ul li a:hover {
    color: #0d6efd;
    transform: translateX(5px);
}

footer ul li i {
    width: 20px;
    color: #0d6efd;
}

/* 推荐列表页卡片样式优化 */
.recommendations-page .card {
    border: none;
    border-radius: 0.75rem;
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.4s ease;
    background-color: #ffffff;
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.recommendations-page .card:hover {
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.12);
    transform: translateY(-5px);
}

/* 行列间距调整 */
.recommendations-page .row.row-cols-1.row-cols-md-2.g-4 {
    margin: 0 -1rem;
}

.recommendations-page .row.row-cols-1.row-cols-md-2.g-4>.col {
    padding: 1rem;
}

/* 推荐列表页面背景 */
.recommendations-page {
    background-color: #f5f7fa;
    padding-top: 1.5rem;
    padding-bottom: 2rem;
    border-radius: 1rem;
}

.recommendations-page .container>.row>.col-lg-12>.card {
    border: none;
    border-radius: 0.75rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    background-color: #ffffff;
}

/* 提高推荐列表页标题的可见度 */
.recommendations-page .card-header.bg-primary {
    background: linear-gradient(135deg, #0d6efd 0%, #0a58ca 100%) !important;
    box-shadow: 0 4px 10px rgba(13, 110, 253, 0.2);
    border: none;
}

.recommendations-page .card-header.bg-primary h1 {
    font-weight: 600;
    letter-spacing: 0.5px;
}

/* 优化列表页筛选按钮组 */
.recommendations-page .btn-group {
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
    border-radius: 0.5rem;
    overflow: hidden;
}

.recommendations-page .btn-group .btn {
    border-radius: 0.5rem;
    margin-right: 0.25rem;
    padding: 0.5rem 1rem;
    font-weight: 500;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .recommendations-page .card {
        margin-bottom: 1rem;
    }

    .recommendations-page .card-header,
    .recommendations-page .card-body,
    .recommendations-page .card-footer {
        padding: 1rem;
    }
}

/* 推荐卡片具体样式 */
.book-recommendation-card {
    position: relative;
    border: 1.5px solid #dee2e6 !important;
    /* 加粗的灰色描边 */
    border-radius: 0.75rem !important;
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.05) !important;
    background-color: #ffffff !important;
    overflow: hidden;
    transition: all 0.3s ease !important;
}

.book-recommendation-card .card-header {
    background: #f8f9fa !important;
    border-bottom: 1px solid #dee2e6 !important;
    padding: 1.25rem 1.5rem !important;
}

.book-recommendation-card .card-title {
    font-weight: 600;
    color: #212529;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.book-recommendation-card .card-body {
    padding: 1.5rem !important;
    background-color: #ffffff !important;
}

.book-recommendation-card .card-footer {
    background-color: #f8f9fa !important;
    border-top: 1px solid #dee2e6 !important;
    padding: 1rem 1.5rem !important;
}

.book-recommendation-card:hover {
    border-color: #adb5bd !important;
    /* 悬停时边框颜色变深 */
    transform: translateY(-5px) !important;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1) !important;
}

.recommendations-page .book-meta {
    font-size: 0.9rem;
    color: #6c757d;
    margin-bottom: 0.5rem;
}

.recommendations-page .book-meta strong {
    color: #495057;
}

.recommendations-page .text-muted {
    color: #6c757d !important;
}

/* 推荐理由样式改进 */
.recommendation-reason {
    background-color: rgba(248, 249, 250, 0.7);
    padding: 1rem;
    border-radius: 0.5rem;
    border-left: 4px solid #dee2e6;
    /* 改为灰色边框，与卡片边框协调 */
    font-size: 0.95rem;
    line-height: 1.6;
    color: #495057 !important;
    position: relative;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
    margin-left: 0.5rem;
}

.recommendation-reason::before {
    content: "\201C";
    position: absolute;
    top: -0.5rem;
    left: 0.5rem;
    font-size: 2rem;
    color: rgba(108, 117, 125, 0.2);
    /* 更改为灰色调 */
    font-family: serif;
}

.recommendation-reason::after {
    content: "\201D";
    position: absolute;
    bottom: -1.5rem;
    right: 0.5rem;
    font-size: 2rem;
    color: rgba(108, 117, 125, 0.2);
    /* 更改为灰色调 */
    font-family: serif;
}

/* 推荐人和时间样式 */
.book-recommendation-card .book-meta {
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
}

.book-recommendation-card .book-meta strong {
    color: #495057;
    width: 80px;
}

/* 按钮样式优化 */
.book-recommendation-card .btn-sm {
    border-radius: 20px;
    padding: 0.25rem 0.75rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.book-recommendation-card .btn-sm:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

/* 管理员操作按钮样式优化 */
.btn-info {
    background-color: #17a2b8 !important;
    border-color: #17a2b8 !important;
    color: #ffffff !important;
    font-weight: 500 !important;
}

.btn-info:hover {
    background-color: #138496 !important;
    border-color: #117a8b !important;
    color: #ffffff !important;
}

/* 更多操作下拉按钮样式 */
.dropdown-toggle-split {
    padding-left: 0.5rem !important;
    padding-right: 0.5rem !important;
}

/* "标记为已采购"按钮组样式 */
.btn-group .btn-info {
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1) !important;
}

.btn-group .btn-info.dropdown-toggle-split {
    background-color: #138496 !important;
    border-color: #117a8b !important;
}

.btn-group .btn-info.dropdown-toggle-split:hover {
    background-color: #0f6674 !important;
    border-color: #0e5e6a !important;
}

/* 下拉菜单样式 */
.dropdown-menu {
    border: none !important;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.15) !important;
    padding: 0.5rem 0 !important;
}

.dropdown-item {
    padding: 0.5rem 1.25rem !important;
    font-weight: 500 !important;
}

.dropdown-item:hover {
    background-color: rgba(23, 162, 184, 0.1) !important;
    color: #17a2b8 !important;
}

/* 强化已采购按钮的视觉效果 */
.btn-info .bi-bag-check {
    color: #ffffff !important;
}

/* 确保更多操作文本不会被隐藏 */
.btn-info.dropdown-toggle-split .visually-hidden {
    position: static !important;
    width: auto !important;
    height: auto !important;
    padding: 0 !important;
    margin: 0 !important;
    overflow: visible !important;
    clip: auto !important;
    white-space: normal !important;
    border: 0 !important;
}

/* 替换掉原始的下拉图标，使用更明显的图标 */
.btn-info.dropdown-toggle-split::after {
    display: inline-block;
    margin-left: 0.255em;
    vertical-align: 0.255em;
    content: "";
    border-top: 0.3em solid;
    border-right: 0.3em solid transparent;
    border-bottom: 0;
    border-left: 0.3em solid transparent;
    color: #ffffff !important;
}

/* 管理员成功按钮样式优化 */
.btn-success {
    background-color: #28a745 !important;
    border-color: #28a745 !important;
    color: #ffffff !important;
    font-weight: 500 !important;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1) !important;
}

.btn-success:hover {
    background-color: #218838 !important;
    border-color: #1e7e34 !important;
    color: #ffffff !important;
}

.btn-group .btn-success.dropdown-toggle-split {
    background-color: #218838 !important;
    border-color: #1e7e34 !important;
}

.btn-group .btn-success.dropdown-toggle-split:hover {
    background-color: #1a692c !important;
    border-color: #175c27 !important;
}

/* 确保按钮组中的按钮排列紧凑 */
.btn-group>.btn:not(:last-child):not(.dropdown-toggle) {
    border-top-right-radius: 0 !important;
    border-bottom-right-radius: 0 !important;
}

.btn-group>.btn:not(:first-child) {
    border-top-left-radius: 0 !important;
    border-bottom-left-radius: 0 !important;
    margin-left: -1px !important;
}

/* 按钮图标样式增强 */
.btn i.bi {
    margin-right: 0.25rem;
    font-size: 1rem;
    vertical-align: -0.125em;
}

.btn-info i.bi,
.btn-success i.bi,
.btn-warning i.bi,
.btn-secondary i.bi {
    font-size: 1.1rem;
}

/* 美化下拉按钮中的文本 */
.dropdown-toggle-split span {
    margin-left: 0.25rem;
    margin-right: 0.25rem;
    font-size: 0.875rem;
}

/* 高亮显示管理员操作按钮 */
.btn-info,
.btn-success,
.btn-warning,
.btn-secondary {
    position: relative;
    overflow: hidden;
}

.btn-info::before,
.btn-success::before,
.btn-warning::before,
.btn-secondary::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.1);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
}

.btn-info:hover::before,
.btn-success:hover::before,
.btn-warning:hover::before,
.btn-secondary:hover::before {
    transform: translateX(0);
}

/* 返回顶部按钮样式 */
.back-to-top-container {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 99;
}

.back-to-top-btn {
    width: 45px;
    height: 45px;
    border-radius: 8px;
    background-color: #0d6efd;
    color: white;
    border: none;
    box-shadow: 0 4px 10px rgba(13, 110, 253, 0.3);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.back-to-top-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 0;
    background-color: rgba(255, 255, 255, 0.2);
    transition: height 0.3s ease;
}

.back-to-top-btn:hover::before {
    height: 100%;
}

.back-to-top-btn i {
    font-size: 1.5rem;
    transition: transform 0.3s ease;
}

.back-to-top-btn:hover i {
    transform: translateY(-3px);
}

.back-to-top-btn.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* 移动设备上的样式调整 */
@media (max-width: 768px) {
    .back-to-top-container {
        bottom: 20px;
        right: 20px;
    }

    .back-to-top-btn {
        width: 40px;
        height: 40px;
    }
}

/* 滑入动画 */
@keyframes slideInUp {
    from {
        transform: translateY(40px);
        opacity: 0;
    }

    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.back-to-top-btn.show {
    animation: slideInUp 0.3s ease forwards;
}