Fix slide preview styles might overwrite code block styles
Fix slide preview styles might overwrite code block styles

Yukaii/hackmd,PeterDaveHello/hackmd,Rwing/hackmd,ironhack/hackmd,jackycute/HackMD,ironhack/hackmd,jccrofty30/hackmd,aswathyjacob8/newtest,hackmdio/hackmd,jccrofty30/hackmd,jackycute/HackMD,PeterDaveHello/hackmd,jackycute/HackMD,PeterDaveHello/hackmd,Rwing/hackmd,Rwing/hackmd,aswathyjacob8/newtest,Yukaii/hackmd,ironhack/hackmd,aswathyjacob8/newtest,hackmdio/hackmd,Yukaii/hackmd,jccrofty30/hackmd,hackmdio/hackmd