[CORD-2514] Added legend for the service graph

Change-Id: I716760a7a61c13ff4d23829db4bd70c74cfc163b
diff --git a/src/app/service-graph/components/graph-legend/graph-legend.component.scss b/src/app/service-graph/components/graph-legend/graph-legend.component.scss
new file mode 100644
index 0000000..56c9804
--- /dev/null
+++ b/src/app/service-graph/components/graph-legend/graph-legend.component.scss
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+@import './../../../style/vars.scss';
+@import '../../../../../node_modules/bootstrap-sass/assets/stylesheets/bootstrap/variables';
+
+xos-service-graph-legend {
+  svg {
+    height: 95%;
+    width: 100%;
+
+    text {
+      fill: #fff;
+    }
+
+    .service path {
+      fill: $color-accent;
+    }
+
+    .serviceinstance path {
+      fill: $serviceinstances-fg;
+    }
+
+    .instance path {
+      fill: $instances-fg;
+    }
+
+    .network path {
+      fill: $networks-fg;
+    }
+  }
+}
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