Don't show links to previous and next chapter

Reasons to not show:
- Highly unlikely to be used (more meaningful when each page is short, and a reader is expected to read one page after another).
- Occupies space that is precious on small screens.
- Current layout breaks when window is so narrow that these links would overlap.

css/MLS-navbar-left.css

@@ -46,9 +46,15 @@ nav > div.ltx_TOC {
 }
 
 .ltx_page_navbar a[rel=start] {
-  display: none; /* Hiding the sidebar title, as it is too long to look good, and seem to lack structure for adequate layout. */
-  margin: 1em;
-  font-weight: bold;
+  display: none; /* Don't show sidebar title, as it is too long to look good, and seem to lack structure for adequate layout. */
+}
+
+.ltx_page_header a[rel=prev] {
+  display: none; /* Don't show link to previous chapter. */
+}
+
+.ltx_page_header a[rel=next] {
+  display: none; /* Don't show link to previous chapter. */
 }
 
 .ltx_TOC {
@@ -91,7 +97,7 @@ nav > div.ltx_TOC {
   position: fixed;
   z-index: 3;
   top: 0px;
-  height: 2.5rem;
+  height: 1.5rem;
   padding: 0.5rem 1rem;
   background: #F6F6F6; /* Same as body. */
   color: black; /* Same as side bar. */
@@ -101,7 +107,7 @@ nav > div.ltx_TOC {
 
 .ltx_page_content {
   padding: 1rem;
-  margin-top: 2.5rem; /* Header height plus padding below, minus a little bit. */
+  margin-top: 1.5rem; /* Header height plus padding below, minus a little bit. */
   background: white;
 }
 
@@ -148,7 +154,7 @@ nav > div.ltx_TOC {
   }
   .ltx_page_navbar {
     width: 500px;
-    height: 3.5rem;
+    height: 2.5rem;
     left: calc(3rem - (500px + 8px));
     transition: 0.3s;
   }