There are multiple ways to install this style.
apiVersion: v1
kind: ConfigMap
metadata:
...
name: argocd-cm
data:
ui.cssurl: "https://raw.githubusercontent.com/DaanV2/argocd-scifi-style/main/styles.css"
server:
...
config:
...
ui.cssurl: "https://raw.githubusercontent.com/DaanV2/argocd-scifi-style/main/styles.css"