You're looking for a UI library. A popular and pretty accessible one is Bootstrap.
NOTE: The number of mentions on this list indicates mentions on common posts plus user suggested alternatives. Hence, a higher number means a more popular project.
UI bug or a QA suggestion?
1 project | reddit.com/r/softwaretesting | 14 Aug 2022
PORTFOLIO CHAT: What platform do these creatives use to design their portfolio // what platform do you use?
1 project | reddit.com/r/graphic_design | 2 Aug 2022
Bootstrap: Introduction to the Modern Front-end Framework
1 project | dev.to | 2 Aug 2022
Is there any awesome UI library for deno?
1 project | reddit.com/r/Deno | 29 Jul 2022
what is a good site for creating a runescape website?
1 project | reddit.com/r/runescape | 28 Jul 2022