CSS stands for Cascading Style Sheets, and it's a type of language used to change the appearance of a webpage. Since Obsidian uses an app-building framework called Electron, CSS can also be used to change the appearance of Obsidian itself. Obsidian [[Themes]] use CSS to change how things look, but you can modify these directly if you're familiar with CSS. You can also add CSS snippets that you use across any theme. Theme settings and their CSS are kept in `vault/.obsidian/themes`. CSS snippets are kept in `vault/snippets`. > [!question]- Can't see .obsidian? > If you don't see a `.obsidian` folder in your vault's root directory, check to make sure that hidden files are enabled. > > On Macs, hit `CMD+SHIFT+.` while in Finder to show hidden files. You don't need to learn or use CSS to use Obsidian-- you'll only need to use it if you want to modify themes.