Finale Elegant

Hi there,
i am new at the world of wordpress and now i have my first problems, i hope that anyone can help me.
I am using the Finale Elegant theme from ThemeSmarts: https://themesmarts.com/themes/finale-elegant-wordpress-theme/

My first problem is that i did my website on my macbook and then i opened it on my iphone and saw that the header image and the header logo were not on the right place. The design was not responsive. I tested it on another computer and it was the same, not on the right place.

Second is, i would like to change the color of the footer. How can i do it?

Thank you really much! ??