How can I make my background image full screen on both desktop and mobile?

Topic summary

A user is attempting to create a full-screen background image/GIF with a centered email box that displays correctly on both desktop and mobile devices. They also want to remove a gray bar appearing at the bottom of the page.

Solutions Proposed:

Two support teams offered CSS-based fixes:

  • EBOOST’s approach: Modify the section-image-banner.css file by adding specific CSS code to set the banner position to absolute and height to 100%, with media queries for responsive behavior.

  • GemPages’ approach: Edit the theme’s liquid file and paste custom markup code before the </head> tag.

Both solutions involve accessing the theme editor through Online Store > Theme > Edit code. Screenshots were provided to guide the implementation process, though the specific code snippets appear partially corrupted in the conversation text.

Summarized with AI on November 23. AI used: claude-sonnet-4-5-20250929.

Hello, I would like to make sure my page is correct on both desktop and mobile. I am trying to make the background gif or image that i have full screen with the email box in the center and I can’t find a way to remove the grey bar at the bottom. Help is very appreciated.

My URL is :

https://homecentreshop.myshopify.com/password

password is:ohtootles

Hi @jpborja1020

May I suggest to update code these steps:

  1. Go to Store Online-> theme → edit code

  1. Assets/section-image-banner.css

  1. Add code below to bottom of file
.password .banner--medium:not(.banner--adapt) {
	min-height: 100vh;
}
.password  .banner--medium.banner--mobile-bottom:not(.banner--adapt) .banner__media, 
.password .banner--medium.banner--stacked:not(.banner--mobile-bottom):not(.banner--adapt) > .banner__media {
	height: 100%!imprtant;
	position: absolute!important;
}

Hello @jpborja1020 ,

It’s GemPages support team and glad to support you today.

I would like to give you a recommendation to support you so kindly follow steps below:

  1. Go to Online Store > Theme > Edit code of your current theme

  1. Open your theme.liquid theme file

  2. Paste the below code before


If you require any further information, feel free to contact me.

Best regards,
GemPages Support Team