style: update css

Author: yanglbme

docs/stylesheets/extra.css

@@ -4,6 +4,15 @@
 .md-typeset h2 {
     margin: 0.5em 0 0em;
 }
+.md-typeset .example-block {
+    overflow-x: auto;
+    padding: 0 .2941176471em;
+    background-color: #f5f5f5;
+    border-radius: .1rem;
+}
+.md-typeset .example-block p {
+    margin: 0;
+}
 .md-content__inner>pre {
     margin: 0;
     overflow-x: auto;