update css for theme changer

css/default.scss

@@ -53,10 +53,6 @@ header {
   border-bottom: 0.2rem solid var(--text);
 }
 
-nav {
-  text-align: right;
-}
-
 nav a {
   font-size: 1.8rem;
   font-weight: bold;

templates/default.html

@@ -41,7 +41,7 @@
                 <a href="/gallery.html" title="Photo gallery"><i class="fa-solid fa-image"></i></a>
                 <a href="https://github.com/rostyhn" title="Github"><i class="fa-brands fa-github"></i></a>
                 <a href="https://git.rshyn.site/explore/repos" title="Self-hosted Gitea instance"><i class="fa-brands fa-git-alt"></i></a>
-                <button id="btn-switch" title="Switch light / dark mode"><i class="fa-solid fa-circle-half-stroke"></i></button>
+                <a id="btn-switch" title="Switch light / dark mode"><i class="fa-solid fa-circle-half-stroke"></i></a>
             </nav>
         </header>
         <main role="main">