It sounds like the layout or padding settings on your homepage might have been accidentally modified. Here are a few places to check in Magento to adjust the width and restore the white border:
Check the theme settings:
Go to Content > Configuration in the Magento admin panel.
Choose the theme for your store and click Edit.
Look for settings related to the Layout or Page Width. Some themes allow you to adjust the overall width of the page and the padding/margin around the content.
Check the CSS file:
The issue might also be related to the theme’s CSS. Inspect your homepage using a browser developer tool (right-click on the page and click "Inspect").
Look for any changes in the body or .page classes, such as padding, margin, or width. If you see any styles affecting the page width, you can adjust them in your theme’s CSS file.
Check for custom styles:
If you have added custom CSS via the Content > Design > Custom CSS section, it’s possible that some new code was added there which might be affecting the layout.
Magento Page Builder or Widgets:
If you're using Magento's Page Builder or custom widgets, make sure that no new elements were added that are affecting the layout or causing the content to stretch to the edge.
Custom Theme Files:
If you are using a custom theme, check the styles.css or theme.css file (in the /app/design/frontend/[Vendor]/[Theme]/web/css/ directory) to see if there have been changes to container widths or margins.
After checking these areas, adjust the padding, margins, or width settings as needed to restore the white border on your homepage.
I hope that helps!
