refactor: Migrate from tailwind.js config to Tailwind CSS config (#451)

* refactor: Migrate from tailwind.js config to Tailwind CSS configuration and improve component styling

- Removed extensive theme and animation configurations from tailwind.config.js, migrating them to index.css for better organization.
- Updated components to utilize CSS variables for grid layouts and animations, enhancing maintainability.
- Adjusted various components to reflect the new CSS structure, ensuring consistent styling across the application.
- Improved accessibility and responsiveness in several UI components, including headers and popovers.
- Fixed minor styling issues and optimized class usage for better performance.

* style: use default tailwindcss/forms options

* refactor(Header): remove unused LuUser icon import

ui/src/components/WebRTCVideo.tsx

@@ -673,7 +673,7 @@ export default function WebRTCVideo() {
   ]);
 
   return (
-    <div className="grid h-full w-full grid-rows-layout">
+    <div className="grid h-full w-full grid-rows-(--grid-layout)">
       <div className="flex min-h-[39.5px] flex-col">
         <div className="flex flex-col">
           <fieldset
@@ -699,7 +699,7 @@ export default function WebRTCVideo() {
           <div className="flex h-full flex-col">
             <div className="relative flex-grow overflow-hidden">
               <div className="flex h-full flex-col">
-                <div className="grid flex-grow grid-rows-bodyFooter overflow-hidden">
+                <div className="grid flex-grow grid-rows-(--grid-bodyFooter) overflow-hidden">
                   <div className="relative mx-4 my-2 flex items-center justify-center overflow-hidden">
                     <div className="relative flex h-full w-full items-center justify-center">
                       <div className="relative inline-block">