HTML example:

<!-- START: Page Border -->
<div class="nk-page-border">
    <div class="nk-page-border-t"></div>
    <div class="nk-page-border-r"></div>
    <div class="nk-page-border-b"></div>
    <div class="nk-page-border-l"></div>
</div>
<!-- END: Page Border -->