Currently having issues with mobile banner not resizing on debut theme.

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I'm currently having issues with the banner not resizing responsively to mobile, previously found the solution code to input but now it just suddenly stopped working. The image with text overlay won't resize on mobile view, I currently need a solution that will resize it without messing up the desktop view because I previously had to add code to fix the banner since it had a very unseemly whitespace around the banner in desktop view after fixing the mobile view. Can someone help with this please?

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