Add a shortcode for folding rows of a table on small screens

assets/scss/style.scss

@@ -149,22 +149,24 @@ table {
     padding: 0.5rem;
 }
 
-tr {
+.fold-table + table {
+    tr {
         @include below-container-width {
             display: flex;
             flex-direction: column;
         }
+    }
 }
 
 td {
     @include below-container-width {
         overflow-x: auto;
     }
-    padding: 0.5rem;
 }
 
-th {
+td, th {
     padding: 0.5rem;
+    vertical-align: top;
 }
 
 div.highlight tr {

layouts/shortcodes/foldtable.html

@@ -0,0 +1 @@
+<span class="fold-table"></span>