I like Adam Laki’s Quick Tip: CSS Triangles because it covers that ubiquitous fact about front-end techniques: there are always many ways to do the same thing. In this case, drawing a triangle can be done:
with border and a collapsed element
with clip-path: polygon()
with transform: rotate() and overflow: hidden
with glyphs like ?
I’d say that the way I’ve typically done triangles the most over the years is with the border trick, but I think my favorite way now is using clip-path. Code like this is fairly clear, understandable, and maintainable to me: clip-path: polygon(50% 0, 0 100%, 100% 100%); Brain: Middle top! Bottom right! Bottom left! Triangle!
My 2nd Place method goes to an option that didn’t make Adam’s list: inline