Feat: Replace color variables according to design draft #3221 (#9305)

### What problem does this PR solve?

Feat: Replace color variables according to design draft #3221

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/dataset/dataset-title.tsx

@@ -9,7 +9,7 @@ export function TopTitle({ title, description }: TopTitleProps) {
   return (
     <div className="pb-5">
       <div className="text-2xl font-semibold">{title}</div>
-      <p className="text-text-sub-title pt-2">{description}</p>
+      <p className="text-text-secondary pt-2">{description}</p>
     </div>
   );
 }

web/src/pages/dataset/sidebar/index.tsx

@@ -62,8 +62,8 @@ export function SideBar({ refreshCount }: PropType) {
           name={data.name}
           className="size-16"
         ></RAGFlowAvatar>
-        <div className=" text-text-sub-title text-xs space-y-1">
-          <h3 className="text-lg font-semibold line-clamp-1 text-text-title">
+        <div className=" text-text-secondary text-xs space-y-1">
+          <h3 className="text-lg font-semibold line-clamp-1 text-text-primary">
             {data.name}
           </h3>
           <div className="flex justify-between">
@@ -85,7 +85,7 @@ export function SideBar({ refreshCount }: PropType) {
                 'w-full justify-start gap-2.5 px-3 relative h-10 text-text-sub-title-invert',
                 {
                   'bg-bg-card': active,
-                  'text-text-title': active,
+                  'text-text-primary': active,
                 },
               )}
               onClick={handleMenuClick(item.key)}

web/src/pages/dataset/testing/index.tsx

@@ -44,7 +44,7 @@ export default function RetrievalTesting() {
         <section className="flex divide-x h-full">
           <div className="p-4 flex-1">
             <div className="flex justify-between pb-2.5">
-              <span className="text-text-title font-semibold text-2xl">
+              <span className="text-text-primary font-semibold text-2xl">
                 Test setting
               </span>
               {/* <Button variant={'outline'} onClick={addCount}>

web/src/pages/dataset/testing/testing-result.tsx

@@ -65,7 +65,7 @@ export function TestingResult({
   return (
     <div className="p-4 flex-1">
       <div className="flex justify-between pb-2.5">
-        <span className="text-text-title font-semibold text-2xl">
+        <span className="text-text-primary font-semibold text-2xl">
           Test results
         </span>
         <FilterPopover