How to use lightning base components

Question

I'm trying to use lightning base components in some components but I only got basic html component in my page. For example I add this button :

<lightning:button variant="brand" label="Précédent" onclick="{!c.previousPage}"/>

It is the only lightning base element in my component, maybe I have to insert it into a special element, like a container ?

My Salesforce org is in spring 17.

Here is the kind of button I got : instead of button with slds design.

Edit : I try differents browsers but I always get the same result.

Answer 1

If you are testing in an app container then you will need to extend with force:slds

<aura:application extends="force:slds">
    <lightning:button variant="brand" label="Précédent" onclick="{!c.previousPage}"/>
</aura:application>

And if you are using in community builder or app builder or lightning out the styling is automatically taken care