It is always a great idea to create different versions of your logo with different colors and sizes.
For example, you should probably have a dark and light version of your logo so that it will look great on different background colors. And having a smaller (less vertical and more horizontal) version of the logo for those cramped areas of your website.

One of the best places to use a different version of your logo is on your fixed (or sticky) header.

Read more: https://www.elegantthemes.com/blog/divi-resources/switching-your-logo-on-a-fixed-header-in-divi