hoping to get some help for a blog!

so,,, i want to try blogging here, and i like making my blogs look super nifty! so i was wondering if there was a css viewer i could use to edit my blogs, and if there was a way i could get a blog theme i really enjoy using that my epic friend made me to work on here! it was made for a napo blog and im a beginner at html and only know the basics....

guh if anybody is kind enough to give me some tips or a helping hand i'd appreciate it!! thank yeww!!!

this site has options to choose themes for your blog, you can hit the <> button and paste your html there. then before you hit publish, hit the preview button and it will show you if your codes worked. hope that helps