Update shimmer effect styles in ModernCertifications, ModernEducation, and ModernWorkExperience components for improved dark mode support

- Changed shimmer effect gradient from white to black for better visibility in light mode.
- Ensured consistent styling across all three components to enhance user experience and visual appeal.

src/components/widgets/ModernEducation.astro

@@ -89,7 +89,7 @@ const getEducationStyle = (title: string) => {
           </div>
           
           <!-- Shimmer effect -->
-          <div class="absolute inset-0 bg-gradient-to-r from-transparent via-white/10 to-transparent -translate-x-full group-hover:translate-x-full transition-transform duration-700 ease-out"></div>
+          <div class="absolute inset-0 bg-gradient-to-r from-transparent via-black/10 to-transparent dark:via-white/10 -translate-x-full group-hover:translate-x-full transition-transform duration-700 ease-out"></div>
         </div>
       );
     })}