By default, your site background is set to have a transparent overlay. If you wish, you can exclude the homepage from this overlay, meaning the overlay/colour will not display on your homepage. You would do this if you wanted to display a different background like another colour or an image.
To do this, first navigate to Site Settings on the top right of the screen, and click on Background under the 'Look and Feel' section.
Next, click into the Overlay tab.
From here, you can change the website/system pages colour, transparency, whether they're full width, and exclude the overlay on the homepage.
To exclude the overlay on the homepage, tick the Exclude homepage checkbox.
Click Save once you're done.