fix: page margins

Author: SidonieBouthors

styles/abstracts/_mixins.scss

@@ -34,11 +34,12 @@
 
 @mixin article-content {
   max-width: 38rem;
-  margin: 5rem auto;
-  margin-top: 0;
+  margin: 0 auto;
+  margin-bottom: 5rem;
+
   @media screen and (max-width: 75rem) {
-    margin: 0 auto;
-    padding: 1.5rem;
+    margin-bottom: 3rem;
+    padding: 0 1.5rem;
   }
 }