Add buttons (code, demo), make logo clickable

Former-commit-id: a6914da

Author: xhlulu

apps/dash-opioid-epidemic/app.py

@@ -94,7 +94,9 @@
         html.Div(
             id="header",
             children=[
-                html.Img(id="logo", src=app.get_asset_url("dash-logo.png")),
+                html.A(html.Img(id="logo", src=app.get_asset_url("dash-logo.png")), href="https://plotly.com/dash/"),
+                html.A(html.Button("Enterprise Demo", className="link-button"), href="https://plotly.com/get-demo/"),
+                html.A(html.Button("Source Code", className="link-button"), href="https://github.com/plotly/dash-sample-apps/tree/main/apps/dash-opioid-epidemic"),
                 html.H4(children="Rate of US Poison-Induced Deaths"),
                 html.P(
                     id="description",

apps/dash-opioid-epidemic/assets/demo-button.css

@@ -0,0 +1,13 @@
+.link-button {
+    margin-top: 3px;
+    margin-right: 10px;
+    vertical-align: top;
+    color: #7fafdf;
+    float: right;
+    border-color: #7fafdf;
+}
+
+.link-button:hover {
+    color: white;
+    border-color: white;
+}