Update file footer.html

wiki/footer.html

-<footer class="pb-2 pt-2 mt-5 footer" style="background-color: #ffe4e1;border-radius: 50px; place-items: center;">
-  <div class="container ">
-    <div class="row place-items: center;">
+<footer class="pb-2 pt-2 mt-5 footer text-center" style="background-color: #ffe4e1; border-radius: 50px; display: flex; flex-direction: column; align-items: center;">
+  <div class="container">
+    <div class="row justify-content-center">
       <div class="col-lg-6 col-xs-12">
           <h4 class="mt-lg-0 mt-sm-3">Follow us on social media</h4>
-          <div class="row">
+          <div class="row justify-content-center">
               <div class="col-lg-6 col-xs-12">
                   <div class="m-1 p-1">
                       <p><a href="https://www.instagram.com/" style="color: black;">Instagram</a></p>
@@ -23,21 +23,21 @@
 
       <div class="col-lg-6 col-xs-12">
           <h4>Contact</h4>
-          <p>Tsinghua University,Hai Dian, Beijing</p>
+          <p>Tsinghua University, Hai Dian, Beijing</p>
           <p>+86 12345678900</p>
           <p>xxx@mails.tsinghua.edu.cn</p>
       </div>
-  </div>
+    </div>
  
     <hr>
-    <!-- The following MUST be on every page: license information and link to the repository on gitlab.igem.org -->
-    <div class="row mt-4 place-items: center;">
+    <div class="row justify-content-center mt-4">
       <div class="col">
-        <p class="mb-0 place-items: center;"><small>© 2024 - Content on this site is licensed under a <a class="subfoot" href= "https://creativecommons.org/licenses/by/4.0/" style="color: black;" rel="license">Creative Commons Attribution 4.0 International license</a>.</small></p>
-	      <p><small>The repository used to create this website is available at <a href="https://gitlab.igem.org/2024/tsinghua" style="color: black;" >gitlab.igem.org/2024/tsinghua</a>.</small></p>
+        <p class="mb-0 text-center"><small>© 2024 - Content on this site is licensed under a <a class="subfoot" href="https://creativecommons.org/licenses/by/4.0/" style="color: black;" rel="license">Creative Commons Attribution 4.0 International license</a>.</small></p>
+        <p class="text-center"><small>The repository used to create this website is available at <a href="https://gitlab.igem.org/2024/tsinghua" style="color: black;" >gitlab.igem.org/2024/tsinghua</a>.</small></p>
       </div>
     </div>
 
   </div>
 </footer>
 
+