Implement a modern layout to my website that was built with php and bootstrap Open

I need to implement a modern layout to my website that was built with php and bootstrap, it's about 16 pages, they are already created with php / bootstrap some php and js/jquery, so this skills are necessary. I'm talking about making it a pretty layout, professional, and keep it responsive as it already is. The website needs things like fonts, colors, images all in harmony. I'll analyze each interested person, I'm only working with experient people.