If you’re editing a Builder entry with a Builder preview URL (e.g. builder.live, preview.builder.codes, etc) you may have noticed that Builder adds styling to the page, including styling on either a div (#main) or a builder-component that looks like:
These layers aren’t editable directly in the editor, but, you can wrap your content within a section block and remove the max-width via the options tab so your content is full width.