I haven’t been able to get the mobile logo to resize correctly with the suggested code, unfortunately.
To adjust the logo for larger screens, go to Sections>header.liquid.
Scroll down to line 324 (or thereabouts, depending on whether changes have been made to the original file).
The line you’re looking for is {%- assign image_size = section.settings.logo_width | append: ‘x’ -%}
(right after {%- if section.settings.logo != blank -%})
Replace that line with {%- assign image_size = 450 | append: ‘x’ -%} 450 is the size I went with, but you could choose another size. This number should be the maximum size you want your logo to appear.
If that’s what you already did and it’s not working, then you may have some added code somewhere that’s conflicting with it.
I hope this helps!