Why did I can't put cancel and confirm buttons in one line.

[Caballarii]

I did't import css/less. Should I just import it in jsx instead of in html?

[chentsulin]

You should import sweetalert.css from cdn, file, node_modules(sweetalert/dist/sweetalert.css) or wherever can find the css code. Import it In jsx or html doesn't matter.

Checkout full examples here.