Make menu more obvious

It isn't always obvious much is available/how to navigate the horizontally scrolling menu at the bottom of the sidebar content. The arrows for scrolling through the menu sometimes overlay the menu items making them difficult to read: https://smile.d.pr/POy0Wc Suggestions to improve this: * make the arrows more prominent/not overlaid on the menu items (perhaps changing the colour of the arrows or the background behind the arrows) * on desktop, change the ratio between the main video canvas and the sidebar so that the sidebar is wider, allowing text content in the sidebar to have more prominence and giving the menu at the bottom a bit more space.