custom.css: Add styling to various elements
custom.css: Add styling to various elements

Closes https://github.com/coala/coala/issues/3792

netman92/coala,MariosPanag/coala,rimacone/testing2,Balaji2198/coala,aptrishu/coala,coala/coala,ayushin78/coala,arush0311/coala,Shade5/coala,arjunsinghy96/coala,Asnelchristian/coala,CruiseDevice/coala,RJ722/coala,Asalle/coala,coala-analyzer/coala,jayvdb/coala,damngamerz/coala,yashLadha/coala,Nosferatul/coala,JohnS-01/coala,MariosPanag/coala,CruiseDevice/coala,MariosPanag/coala,kartikeys98/coala,SanketDG/coala,yashLadha/coala,JohnS-01/coala,Balaji2198/coala,ayushin78/coala,coala-analyzer/coala,refeed/coala,damngamerz/coala,refeed/coala,incorrectusername/coala,rimacone/testing2,netman92/coala,Asalle/coala,arjunsinghy96/coala,kartikeys98/coala,yashLadha/coala,rimacone/testing2,Balaji2198/coala,SanketDG/coala,coala/coala,nemaniarjun/coala,aptrishu/coala,SanketDG/coala,Asnelchristian/coala,jayvdb/coala,Asalle/coala,incorrectusername/coala,coala-analyzer/coala,refeed/coala,shreyans800755/coala,Asnelchristian/coala,shreyans800755/coala,ayushin78/coala,nemaniarjun/coala,Nosferatul/coala,karansingh1559/coala,netman92/coala,arush0311/coala,arush0311/coala,incorrectusername/coala,Shade5/coala,RJ722/coala,damngamerz/coala,karansingh1559/coala,karansingh1559/coala,kartikeys98/coala,shreyans800755/coala,Nosferatul/coala,coala/coala,Shade5/coala,JohnS-01/coala,arjunsinghy96/coala,RJ722/coala,jayvdb/coala,aptrishu/coala,CruiseDevice/coala,nemaniarjun/coala