fix: Fix HTML validation warnings

layout/page.html

@@ -18,7 +18,7 @@
       <div class="horizontal-center">
 	<div class="vertical header">
 	  <div id="header" class="horizontal">
-	    <img class="avatar" src="{{ page_assets }}/img/avatar.jpg" />
+	    <img class="avatar" src="{{ page_assets }}/img/avatar.jpg" alt="" />
 
 	    <div class="vertical-center">
 	      <span class="name-title">PapaTutuWawa's Blog</span>
@@ -39,12 +39,13 @@
 
 	  <br />
 
-	  <center class="footer">
+	  <div class="horizontal-center footer">
 	    Created by <i>PapaTutuWawa</i> with &lt;3 using
 	    <a href="https://github.com/google/roboto">Roboto</a>,
             <a href="https://github.com/RedHatOfficial/Overpass">Overpass</a> and
 	    <a href="https://github.com/sunainapai/makesite">makesite</a>
-          </center>
+          </div>
 	</div>
+      </div>
     </body>
 </html>