Get Two Columns with different background colours that extend to screen edge [duplicate]

Bootstrap 5 beta

The concept is still the same in Bootstrap 5. Use a absolute position pseudo element on the column(s) to create the appearance of a container inside a container-fluid…

Bootstrap 5 example

Or, use container-fluid and nest smaller grid columns inside the outer columns with background color…

<div class="container-fluid">
    <div class="row">
        <div class="col-6 bg-info">
            <div class="row justify-content-end">
                <div class="col-9"> ... </div>
            </div>
        </div>
        <div class="col-6 bg-danger">
            <div class="row justify-content-start">
                <div class="col-9"> ... </div>
            </div>
        </div>
    </div>
</div>

Bootstrap 5 nesting example

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Bootstrap 4

The concept is still the same in Bootstrap 4, but the -xs- infix no longer exists.

Bootstrap 4 example

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Bootstrap 3 (original answer)

Use another wrapper DIV around a 2nd container…

<div class="container" style="background: bisque;">
    <div class="row">
        <div class="col-xs-12">
            <h1>Normal Boxed Width</h1>
        </div>
    </div>
</div>
<div style="background-color: aquamarine; padding: 0">
    <div class="container">
        <div class="row">
            <div>
                <div class="col-sm-9">
                    <h1>Left Panel</h1>
                    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Recusandae doloribus unde, distinctio a autem, soluta nulla similique. Vero natus deleniti, culpa consequuntur eveniet beatae laudantium in fuga mollitia sapiente! Assumenda!</p>
                </div>
                <div class="col-sm-3 gray-background" style="background-color: rebeccapurple;padding: 10px;color:#fff">
                    <h1>Right Panel</h1>
                    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ducimus, beatae amet est repellendus optio, exercitationem distinctio quasi ut, sapiente, nihil sed libero facere fugiat eaque numquam nulla mollitia suscipit nobis.</p>
                </div>
            </div>
        </div>
        <!--  .row -->
    </div>
    <!--  .container-fluid -->
</div>

EDIT

Use a psuedo element such as..

.right:before {
    right: -999em;
    background: rebeccapurple;
    content: '';
    display: block;
    position: absolute;
    width: 999em;
    top: 0;
    bottom: 0;
}

Bootstrap 3 example

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