Reduced a little font-size in toc sidebar (alshedivat#1376)

Signed-off-by: George Araujo <george.gcac@gmail.com>

Author: george-gca

_sass/_base.scss

@@ -865,12 +865,12 @@ nav[data-toggle="toc"] {
   top: 5rem;
 
   .nav .nav>li>a {
-    font-size: .875rem;
+    font-size: .75rem;
   }
 
   .nav>li>a {
     color: var(--global-text-color);
-    font-size: .875rem;
+    font-size: .75rem;
 
     &:hover {
       color: var(--global-hover-color);
@@ -881,7 +881,7 @@ nav[data-toggle="toc"] {
   .nav-link.active {
     color: var(--global-theme-color);
     border-left-color: var(--global-theme-color);
-    font-size: .875rem;
+    font-size: .75rem;
 
     &:hover {
       color: var(--global-hover-color);