sass: various tweaks
sass: various tweaks

lowercase heading, and reword some descriptions for clarity and consistency
deekim/tldr,UncommonPleb/tldr,deekim/tldr,katekyan/tldr,zoisom/tldr,UncommonPleb/tldr,zoisom/tldr,Phizho/tldr,felixonmars/tldr,cptdeka10/tldr,slash3b/tldr,slash3b/tldr,katekyan/tldr,felixonmars/tldr,katekyan/tldr,felixonmars/tldr,cptdeka10/tldr,UncommonPleb/tldr,Phizho/tldr,slash3b/tldr,zoisom/tldr,cptdeka10/tldr,deekim/tldr,Phizho/tldr