feature: global view animation

- Updated Header component to adjust title margin and changed subtitle from h3 to h2 for better semantic structure.
- Refined LanguageSwitcher component to enhance language switching functionality and improved accessibility.
- Adjusted Navigation component's margin and link styles for better visual hierarchy.
- Enhanced ThemeToggle component with view transition effects for smoother theme changes.
- Updated global CSS to support new transition styles for theme toggling.
- Bumped rollup version in pnpm-lock.yaml for improved build performance.

src/components/Header.astro

@@ -14,17 +14,17 @@ const marginClass = {
 
 <header>
   <h1
-    class={`${marginClass} mt--3.2 text-12 c-primary font-bold font-title`}
+    class={`${marginClass} mt--5.2 text-12 c-primary font-bold font-title`}
     aria-label="Title Tag"
   >
     <a href="/">
       {title}
     </a>
   </h1>
-  <h3
-    class="text-5.6 c-primary font-navbar opacity-50"
+  <h2
+    class="text-5.6 c-secondary font-navbar"
     aria-label="Meta Description"
   >
     {subtitle}
-  </h3>
+  </h2>
 </header>