Answers for "how to insert boostrap into style sheet"

roll back last commit in git

git reset --soft HEAD~1

revert back to a commit git

git reset --hard 4a155e5
Will move the HEAD back to where you want to be

git how to roll back to a commit

//git use a new commit to replace an old commit,commit moves foward not backward
git revert <commit hash>
//Git goes back one spot on the log,undone this commit and go backward one commit:
git reset HEAD~1
//Git looks for and rolls back to a certain file:
git checkout commit-hash-here -- file/location/and/name

bootstrap cdn

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">