Fix: Switch the default theme from light mode to dark mode and improve some styles #9869 (#10552)

### What problem does this PR solve?

Fix: Switch the default theme from light mode to dark mode and improve
some styles #9869
-Update UI component styles such as input boxes, tables, and prompt
boxes
-Optimize login page layout and style details
-Revise some of the wording, such as uniformly changing "data flow" to
"pipeline"
-Adjust the parser to support the markdown type

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/login-next/card.tsx

@@ -23,12 +23,12 @@ const FlipCard3D = (props: IProps) => {
         className={`relative w-full h-full transition-transform transform-style-3d ${isFlipped ? 'rotate-y-180' : ''}`}
       >
         {/* Front Face */}
-        <div className="absolute inset-0 flex items-center justify-center bg-blue-500 text-white rounded-xl backface-hidden">
+        <div className="absolute inset-0 flex items-center justify-center backface-hidden">
           {children}
         </div>
 
         {/* Back Face */}
-        <div className="absolute inset-0 flex items-center justify-center bg-green-500 text-white rounded-xl backface-hidden rotate-y-180">
+        <div className="absolute inset-0 flex items-center justify-center backface-hidden rotate-y-180">
           {children}
         </div>
       </div>