add footer notice on green hosting

src/components/Footer.astro

@@ -3,10 +3,30 @@ const today = new Date();
 ---
 
 <footer>
-  &copy; {today.getFullYear()} Nicola Zambello. <em data-tooltip="😉">No rights reserved</em>.
+  <p>
+    &copy; {today.getFullYear()} Nicola Zambello. <em data-tooltip="😉"
+      >No rights reserved</em
+    >.
+  </p>
+  <p class="subfooter">
+    Hosted on <a
+      href="https://www.hetzner.com/unternehmen/umweltschutz/"
+      target="_blank"
+      rel="noopener noreferrer">green energy</a
+    > in Europe.
+  </p>
 </footer>
 <style>
   footer {
     text-align: center;
   }
+
+  footer p {
+    margin: 0 0 0.5em;
+  }
+
+  footer p.subfooter {
+    font-size: 0.75em;
+    margin-bottom: 0;
+  }
 </style>