Description: adding a back to top text between Blog Post Pagination

You can use this code to Blog Page Header Injection
<style>
section.item-pagination.item-pagination--prev-next {
position: relative;
}
.item-pagination-backtotop {
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
text-decoration: none;
font-size: 16px;
font-weight: 400;
color: #000;
white-space: nowrap;
cursor: pointer;
opacity: 0.85;
transition: opacity 0.2s ease;
}
.item-pagination-backtotop:hover {
opacity: 1;
}
</style>
<script>
document.addEventListener('DOMContentLoaded', function () {
const pagination = document.querySelector('section.item-pagination.item-pagination--prev-next');
if (!pagination) return;
if (pagination.querySelector('.item-pagination-backtotop')) return;
const backToTop = document.createElement('a');
backToTop.className = 'item-pagination-backtotop';
backToTop.href = '#';
backToTop.textContent = 'Back to Top';
pagination.appendChild(backToTop);
backToTop.addEventListener('click', function (e) {
e.preventDefault();
window.scrollTo({ top: 0, behavior: 'smooth' });
});
});
</script>

You can change text here.
