Prettify frontend with a CSS template

code/app/templates/data.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+
+{% block content %}
+    <h1>Hey, {{ current_user.username }}!</h1>
+    Wanna check out some cool data?
+    <li><a href="{{ url_for('tables') }}"></a></li>
+    <li><a href="{{ url_for('plots') }}"></a></li>
+{% endblock %}