Browsing/scrolling not working in WP 6.02

It seems your site has some problems with the CSS. The arrow buttons are not the only problem but literally all UI elements are damaged by the CSS rules.

I don’t have the time to analyze the whole stylesheets in detail, but just as an example this rule from the “dt-the7” theme:

button, input, select, textarea {
    font-size: 100%;
    margin: 0;
    vertical-align: baseline;
}

This is a global rule to modify all button, input, select and textarea elements – this should not be done, because you never know, if a plugin might want to add its own button elements with its own specific style.

There are also tons of other things here, as for example for #the7-body there are more than 30 custom settings defined.

You need to fix the CSS or ask the guys who provide the “The7” theme. The existing CSS rules from the theme seem to affect the lightbox as well and there is not much I can do to fix this.