Greetings….I’m helping Brian (from Blogging Theme Styles) out here so I wanted to also say thank you for posting here.
It looks like you put WooCommerce into your site, but WooCommerce is using some styling that is in conflict with Bootstrap styles (which this theme uses). However, I won’t bore you with the technical side of this, so here is how you can fix the issue you posted.
It’s a fairly easy one, but go to your customizer in your admin area by going to Appearance >> customize >> and then look for the Additional CSS tab. In the field, copy and paste this CSS code:
@media screen and (min-width: 48em) {
.woocommerce .col2-set .col-1,
.woocommerce-page .col2-set .col-1,
.woocommerce .col2-set .col-2,
.woocommerce-page .col2-set .col-2 {
max-width: initial;
padding: 0;
}
}
That should fix it as I tried this out on your checkout page using my browser webmaster tools.