add css extension

tools/chromium_extension/css/app.css

@@ -1,10 +1,13 @@
 tr:hover {
   border: 8px solid #ddd !important;
-  border-radius: 1rem !important;
+  border-radius: 8px !important;
   box-shadow: 5px 5px 15px #daf5fe !important;
 
   color: #fff !important;
   background-color: #3ec487 !important;
+  /*
   font-weight: 200;
   font-size: 1.1rem;
+  */
+
 }