justify-content isn't workin - flexbox problem : I am working on the following code:

html:

    
   
    
    <div class="positiones">
    <div class="mainheading">
    <h1>The biggest startup event of the year!</h1><br>
    </div><br>
    </div>
    <div class="linebreak"></div><br>
    
    <div class="Button">
    	<button type="button" class="btn btn-primary btn-lg">Get more info</button><br>
    </div>
    </div>
 

  

css:

    .positiones {
    
    	display: flex;
    	height: 100vh;
    	align-items: center;
    	justify-content: center;
    }

as you can see, the justify-content property isn't working.

well, I need some help, thank you:)




