The documentation shows that the CSS class part is...

# compose-web

[OdenEgg]

The documentation shows that the CSS class part is written in StyleSheet, but how do I implement the CSS id part?
https://github.com/JetBrains/compose-jb/tree/master/tutorials/Web/Style_Dsl
I would appreciate it if you could tell me how the CSS description compares to the Compose-web description.

[Ahmad Daneshvar]

Im not sure I understood. You mean how to select id as selector? Did you try this:

id("body_id").style {
    margin(0.px)
}