I’m glad to hear that helped with the mobile navigation! 
Usually when I run into an interaction behaving differently on one page compared to another, I’ll try duplicating the parent element and pasting that into the other page to troubleshoot it.
It looks like setting the top-button-wrap class to have a width of 100% should fill that full space. You can also change the text-color in the top-button-wrap interaction or via a hover state. Changing the icon on hover can be done with a display: none, display: inline interaction.
I hope that this helps! Happy designing!