make the form center in all devices

hello.
it can be stupid question but how can I make all contents align as center in all devices?? I used this code but nothing changed.
`<style>
.content {
align-content: center;
margin: auto;
}
</style>

`

[Anonsatyam]

You can use the Materializecss center class to put your division in the center.
You have to put Materializecss script at the bottom of your body.

<script src="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/js/materialize.min.js"></script>

<div class="container center">
 Rest of the code goes here....
</div>

You can check my repo. I already have a projet on Materializecss