chore(3000): Dark mode improvements (#18784)

* contrast secondary text from title

* removed unnecessary project home hr in 3000

* fixed dark border color

* Update UI snapshots for `chromium` (1)

---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

frontend/src/lib/components/CompactList/CompactList.scss

@@ -31,4 +31,8 @@
         overflow: auto auto;
         padding: 0 0.5rem 0.5rem;
     }
+
+    .secondary-text {
+        color: var(--text-secondary);
+    }
 }

frontend/src/lib/components/PageHeader.tsx

@@ -5,6 +5,8 @@ import { LemonDivider } from 'lib/lemon-ui/LemonDivider'
 import { createPortal } from 'react-dom'
 import { DraggableToNotebook, DraggableToNotebookProps } from 'scenes/notebooks/AddToNotebook/DraggableToNotebook'
 import { breadcrumbsLogic } from '~/layout/navigation/Breadcrumbs/breadcrumbsLogic'
+import { featureFlagLogic } from 'lib/logic/featureFlagLogic'
+import { FEATURE_FLAGS } from 'lib/constants'
 
 interface PageHeaderProps {
     title: string | JSX.Element
@@ -29,6 +31,9 @@ export function PageHeader({
 }: PageHeaderProps): JSX.Element | null {
     const is3000 = useFeatureFlag('POSTHOG_3000')
     const { actionsContainer } = useValues(breadcrumbsLogic)
+    const { featureFlags } = useValues(featureFlagLogic)
+
+    const has3000 = featureFlags[FEATURE_FLAGS.POSTHOG_3000]
 
     return (
         <>
@@ -52,7 +57,7 @@ export function PageHeader({
             {is3000 && buttons && actionsContainer && createPortal(buttons, actionsContainer)}
 
             {caption && <div className={clsx('page-caption', tabbedPage && 'tabbed')}>{caption}</div>}
-            {delimited && <LemonDivider className="my-4" />}
+            {delimited && <LemonDivider className={has3000 ? 'hidden' : 'my-4'} />}
         </>
     )
 }

frontend/src/scenes/project-homepage/ProjectHomePageCompactListItem.tsx

@@ -23,7 +23,7 @@ export function ProjectHomePageCompactListItem({
 
                 <div className="truncate space-y-1 flex-1">
                     <div className="text-link font-semibold truncate">{title}</div>
-                    <div className="truncate text-default font-normal">{subtitle}</div>
+                    <div className="truncate text-default font-normal secondary-text">{subtitle}</div>
                 </div>
 
                 {suffix ? <span className="shrink-0">{suffix}</span> : null}

frontend/src/styles/vars.scss

@@ -159,7 +159,7 @@ $colors: (
     'secondary-3000-hover-dark': #575d77,
     'accent-3000-dark': #232429,
     'bg-3000-dark': #1d1f27,
-    'border-3000-dark': #2b2c32,
+    'border-3000-dark': #4a4c52,
     'border-bold-3000-dark': #3f4046,
     'glass-bg-3000-dark': #1d1f27b3,
     'glass-border-3000-dark': var(--border-3000-dark),