tools: visualize RIB dataset in nfd-status

refs #1749

Change-Id: Ia11b88187635ffa4eda4b829afd6a20120765d58
diff --git a/tools/nfd-status-http-server-files/style.css b/tools/nfd-status-http-server-files/style.css
index f2b99d5..176da83 100644
--- a/tools/nfd-status-http-server-files/style.css
+++ b/tools/nfd-status-http-server-files/style.css
@@ -114,6 +114,43 @@
     border-top: 1px solid transparent;
 }
 
+.item-sublist
+{
+    border-collapse:collapse;
+    border:1px solid gray;
+
+    padding: 4px;
+    font-family: sans-serif;
+    text-align: center;
+    margin-bottom: 0;
+}
+
+.item-sublist th
+{
+    background-color: transparent;
+    font-weight: bold;
+    padding: 4px;
+    text-align: center;
+
+    border-collapse:collapse;
+    border:1px solid gray;
+}
+
+.item-sublist th.border-left {
+}
+
+.item-sublist td
+{
+    border-collapse:collapse;
+    border:1px solid gray;
+
+    padding: 2px;
+    color: #000;
+    text-align: center;
+    min-width: 20px;
+}
+
+
 tr.center td
 {
     text-align: center;