this will help you make some changes to the css

base.html

{% extends 'admin/base.html' %}

{% block extrastyle %}{{ block.super }}
<style>
@import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');

:root {
  --primary: #1fc55e;
  --secondary: #4f9b6c;
  --link-fg: #127438;
  --link-selected-fg: #71c792;
}

body {
    font-family: 'Poppins', sans-serif;
}
</style>
{% endblock %}