Custom header background colour for individual events page

I am hoping someone can help with my individual event page and blog pages.

1) My header is transparent on every other page  (white elements overlay a photo). So currently, my logo is white and sits on a white background on these individual pages. I want the logo and nav items to stay white and add a coloured background.

https://eagle-hen-kkwy.squarespace.com/events-programs/eventone
https://eagle-hen-kkwy.squarespace.com/news/blog-post-title-one-y59z8

2) How do I add a button to the blog posts page instead of an underlined link? I want the button to be similar to the button on the Events page 

https://eagle-hen-kkwy.squarespace.com/events-programs
https://eagle-hen-kkwy.squarespace.com/news
 

#1. Add to Design > Custom CSS

body[class*="type-blog"].view-item header#header, body[class*="type-events"].view-item header#header {
    background-color: #f1f !important;
}

#2. You mean change Back to... to a button?