Walter's Swiper slider isn't working when including Swiper's CSS/JS from a CDN using `require_css` and `require_js` blocks. It works when included directly in <style>/<script> tags.

Twentyninetimes explained that for external CDN links, one should use the function calls `{{ require_css('CDN_URL') }}` and `{{ require_js('CDN_URL', 'footer') }}` OR place the standard `<link>` and `<script>` tags inside `{% require_head %}` / `{% require_footer %}` blocks, rather than using the block syntax `{% require_css %}` / `{% require_js %}`.