Style modal buttons

popup.html

@@ -43,6 +43,10 @@
       transition: all .2s ease-out;
       border-radius: .25em;
     }
+    button {
+      padding: 0.25em 1em;
+      width: auto;
+    }
     button.secondary {
       background: #aaa;
       border: 1px solid #aaa;