Add integration tests

src/static/ribbit-core.css

@@ -30,6 +30,11 @@
     font-size: 0.85em;
 }
 
+[data-speculative]::before,
+[data-speculative]::after {
+    content: none !important;
+}
+
 #ribbit.wysiwyg strong.ribbit-editing::before,
 #ribbit.wysiwyg strong.ribbit-editing::after {
     content: "**";

src/static/themes/ribbit-default/theme.css

@@ -4,7 +4,7 @@
  * Replace this file with your own theme to customize the look.
  */
 
-@import "../ribbit-core.css";
+@import "../../ribbit-core.css";
 
 a {
     text-decoration: none;