style: add style for <hr>

Author: int64ago

_sass/_basscss.scss

@@ -53,6 +53,14 @@ p, .p, .f4, h4, h5, h6, dl, ol, ul {
   line-height: 1.5rem;
 }
 
+hr {
+  height: 0.25em;
+  padding: 0;
+  margin: 24px 0;
+  background-color: #e1e4e8;
+  border: 0;
+}
+
 small, .small, .f5 {
   font-size: .875rem;
   line-height: 1.5rem;