fix(theme): style share modal and inputs for dark mode compatibility

frontend/src/lib/theme.ts

@@ -81,6 +81,11 @@ export function setActiveTheme(themeId: ThemeId): void {
   }
   if (typeof document !== 'undefined') {
     document.documentElement.setAttribute('data-theme', themeId);
+    if (themeId !== 'light') {
+      document.documentElement.classList.add('dark');
+    } else {
+      document.documentElement.classList.remove('dark');
+    }
   }
 }
 
@@ -88,6 +93,11 @@ export function initThemeOnBoot(): ThemeId {
   const active = getActiveTheme();
   if (typeof document !== 'undefined') {
     document.documentElement.setAttribute('data-theme', active);
+    if (active !== 'light') {
+      document.documentElement.classList.add('dark');
+    } else {
+      document.documentElement.classList.remove('dark');
+    }
   }
   return active;
 }