b38474b73a
Summary: This small PR aims to tweak a bit website appearance and fix small UI issue: * footer background has been changed to reversed splash gradient <img width="1104" alt="Screenshot 2021-03-04 131823" src="https://user-images.githubusercontent.com/719641/109964907-8cba1c80-7cee-11eb-8905-2fa82533cfd7.png"> * GitHub link in the Navbar has been moved to the tight and text was replaced with icon (like on few other Docusaurus sites) <img width="557" alt="Screenshot 2021-03-04 133112" src="https://user-images.githubusercontent.com/719641/109965233-f9351b80-7cee-11eb-84d6-30788f662fbf.png"> * Navbar brand title ("Flipper") hover color issues has been fixed, now hover effect is the same as other navbar links ## Changelog N/A Pull Request resolved: https://github.com/facebook/flipper/pull/1998 Test Plan: Flipper website run on `localhost`. Reviewed By: mweststrate Differential Revision: D26888499 Pulled By: passy fbshipit-source-id: e8abeace8c1d6ae8dcc46c2381009c2bd2500005
