Minor stylesheet tweaks and improvements

themes/mnemosyne/assets/style/main.sass

@@ -34,7 +34,7 @@ $link: $turquoise
 @import '_code.scss'
 
 body
-  font-size: 14px
+  font-size: 16px
 
 h1, h2, h3, h4, h5, h6
   font-family: $family-sans-serif
@@ -54,11 +54,14 @@ h1
 
 h2, .content h2
   font-size: $size-medium
+  margin: 2em 0 1em;
 
   &:before
     content: "## "
 
 h3, .content h3
+  margin: 2em 0 1em;
+
   &:before
     content: "### "
 
@@ -82,7 +85,9 @@ h6, .content h6
     text-decoration: underline
 
   ul
-    *:marker
+    margin-left: 2ex
+
+    *::marker
       font-weight: bold
 
     list-style-type: "* "
@@ -101,6 +106,12 @@ h6, .content h6
       &.taxonomy-list.tags-list
         column-count: 4
 
+  dt
+    font-weight: bold
+    font-style: italic
+  dd
+    margin-left: 2ex
+
 .summary
   @extend .hero
   @extend .my-5