docs style update

src/assets/style/docs.scss

@@ -10,8 +10,16 @@
 }
 
 .documents-block {
-  margin: 3em 0 0;
+  margin: 3em auto 0;
 
+  width: 80%;
+
+  h2{
+    margin: 0 0 2em;
+  }
+}
+
+.documents-container {
   display: flex;
   flex-wrap: wrap;
   justify-content: space-around;