aces from let and right)-->
<!--container-fluid (full parent space without allocating spaces from left and right)-->

<main class="container-fluid"> <!--use a container before using the grid system-->

    <section class="row">
        <div class="col bg-primary"></div>
        <div class="col bg-danger"></div>
        <div class="col bg-warning"></div>
    </section>

    <section class="row">
        <div class="col bg-info"></div>
    </section>

    <section class="row"> <!--col spaces 12-->
        <di