Edit views/pages/index.ejs
Look for
<!--
For customizing the "body" bg class.
Preview colors at https://tailwindcss.com/docs/background-color/
allowed color values:
red, orange, yellow,
green, teal, blue,
pink
allowed saturation values:
100 to 700
-->
<body class="bg-pink-600">
Change the body class color, e.g.:
<body class="bg-teal-600">
Push the changes to see the update.