feat: Update Docusaurus configuration and theme styles to support Light Theme

- Updated color mode settings to respect user preferences and changed default mode.
- Switched logo source based on theme (light/dark) in the home page component.
- Enhanced banner section styles with CSS variables for better theme support.
- Copied logo asset for dark theme.
- Introduced CSS variables for light and dark theme backgrounds and gradients.

Signed-off-by: Gervais, Raymond <raymond.gervais@rbc.com>

microsite/docusaurus.config.ts

@@ -101,23 +101,23 @@ const config: Config = {
           sidebarPath: 'sidebars.ts',
           ...(useVersionedDocs
             ? {
-                includeCurrentVersion: true,
-                lastVersion: 'stable',
-                versions: {
-                  stable: {
-                    label: 'Stable',
-                    path: '/',
-                    banner: 'none',
-                    badge: false,
-                  },
-                  current: {
-                    label: 'Next',
-                    path: '/next',
-                    banner: 'unreleased',
-                    badge: true,
-                  },
+              includeCurrentVersion: true,
+              lastVersion: 'stable',
+              versions: {
+                stable: {
+                  label: 'Stable',
+                  path: '/',
+                  banner: 'none',
+                  badge: false,
                 },
-              }
+                current: {
+                  label: 'Next',
+                  path: '/next',
+                  banner: 'unreleased',
+                  badge: true,
+                },
+              },
+            }
             : undefined),
           docItemComponent: '@theme/ApiItem',
         },
@@ -343,13 +343,14 @@ const config: Config = {
     ],
 
     colorMode: {
-      defaultMode: 'dark',
-      disableSwitch: true,
+      disableSwitch: false,
+      respectPrefersColorScheme: true
     },
     navbar: {
       logo: {
         alt: 'Backstage Software Catalog and Developer Platform',
-        src: 'img/logo.svg',
+        src: 'img/logo-black.svg',
+        srcDark: 'img/logo.svg'
       },
       items: [
         {
@@ -394,11 +395,11 @@ const config: Config = {
         },
         ...(useVersionedDocs
           ? [
-              {
-                type: 'docsVersionDropdown',
-                position: 'right' as const,
-              },
-            ]
+            {
+              type: 'docsVersionDropdown',
+              position: 'right' as const,
+            },
+          ]
           : []),
       ],
     },