If you use Tailwind CSS, you have probably seen this annoying warning. When you add @apply lines required by Tailwind to your CSS file, VS Code will throw an "unknown at rule" warning at you. It won't break your program, but it's still annoying.
You can tell VS Code to ignore this issue. Go to Preference, and then Settings in your VS Code, search for unknown. The first one will be the CSS Lint Unknow At Rule, it's set to warning by default, change it to ignore. Problem Solves just like that!