link to index button on home header glows now when hovered over

src/pages/home.astro

···
   <div class="bwcontainer wrapper">
     <header class="bwbox center flex">
       <h1 class="barcodetext">ENTOMOVISCERA.ONLINE</h1>
-      <a href="/">
+      <a href="/" class="glow">
         <img src="/img/icons/poweroff.png" alt="return to landing page" />
       </a>
     </header>
···
   .grid {
     display: grid;
     grid-template-columns: repeat(4, 1fr);
+  }
+
+  .glow {
+    filter: 0;
+  }
+
+  .glow:hover {
+    filter: drop-shadow(0 0 4px var(--white));
   }
 
   @media (max-width: 86ch) {