[Yung Lean]

My opinion.
Design is not appealing and looks too old school/outdated. Colors don't match too. That orange border is just murdering all design.
would suggest looking for a nice color combination that would match. Some websites where you can get nice combinations
colorcombos.com
colorhunt.co
Another thing to point out - if you are not experienced with web design/layouts would recommend first maybe reading some basics about design or look at some other MyBB themes and try to make something similar but not publish it as public since you have copied an other websites design for your own use.