Bulgaria flag tutorial

This is what goes on HTML:

    <div class="horizontalStyle"> 
        <div class="green horizontal"></div>
        <div class="yellow horizontal"></div>
        <div class="blue horizontal"></div>
    </div>
    

This is what goes on CSS:

    .horizontalStyle {
        display: flex;
        flex-direction: column;
    }
    
    .horizontal {
        width: 225px;
        height: 50px;
    }
    
    .white {
        background-color: white;
    }
    .green {
        background-color: green;
    }
    .red {
        background-color: red;
    }