feat: able to add more UI theme (#860)

web/default/src/index.css

@@ -0,0 +1,35 @@
+body {
+    margin: 0;
+    padding-top: 55px;
+    overflow-y: scroll;
+    font-family: Lato, 'Helvetica Neue', Arial, Helvetica, "Microsoft YaHei", sans-serif;
+    -webkit-font-smoothing: antialiased;
+    -moz-osx-font-smoothing: grayscale;
+    scrollbar-width: none;
+}
+
+body::-webkit-scrollbar {
+    display: none;
+}
+
+code {
+    font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New', monospace;
+}
+
+.main-content {
+    padding: 4px;
+}
+
+.small-icon .icon {
+    font-size: 1em !important;
+}
+
+.custom-footer {
+    font-size: 1.1em;
+}
+
+@media only screen and (max-width: 600px) {
+    .hide-on-mobile {
+        display: none !important;
+    }
+}