fix(frontend): fix white colors (#2614)

# Description

Please include a summary of the changes and the related issue. Please
also include relevant motivation and context.

## Checklist before requesting a review

Please delete options that are not relevant.

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented hard-to-understand areas
- [ ] I have ideally added tests that prove my fix is effective or that
my feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged

## Screenshots (if appropriate):

frontend/app/colors.css

@@ -1,8 +1,7 @@
 :root {
-    /* White */
-    --white-0: #e8e8e8;
-    --white-1: #e4e4e4;
-    --white-2: #e0e0e0;
+    --white-0: #fcfcfc;
+    --white-1: #f8f8f8;
+    --white-2: #f4f4f4;
 
     /* Black */
     --black-0: #1f1f1f;
@@ -15,13 +14,12 @@
     --black-7: #494949;
 
     /* Grey */
-    --grey-0: #808080;
-    --grey-1: #a8a8a8;
-    --grey-2: #ababab;
-    --grey-3: #b8babc;
-    --grey-4: #b8b8b8;
-    --grey-5: #d0d0d0;
-
+    --grey-O: #707070;
+    --grey-1: #c8c8c8;
+    --grey-2: #cbcbcb;
+    --grey-3: #e7e9ec;
+    --grey-4: #d3d3d3;
+    --grey-5: #f5f5f5;
 
     /* Primary */
     --primary-0: #6142d4;
@@ -42,7 +40,7 @@
   
     /* Warning */
     --warning: #c77d33;
-    --warning-lightest: #e9d9c9;
+    --warning-lightest: #f2e9e0;
   
     /* Success */
     --success: #47a455;

frontend/app/globals.css

@@ -111,7 +111,7 @@ body.dark_mode {
   --text-0: var(--black-0);
   --text-1: var(--grey-0);
   --text-2: var(--grey-1);
-  --text-3: var(--white-0);
+  --text-3: var(--white-2);
 
   /* Box Shadow */
   --box-shadow: rgba(255, 255, 255, 0.25);