This section uses alternating challenge styles to show how to use CSS to position elements in a flexible way. First, a challenge will explain theory, then a practical challenge using a simple tweet component will apply the flexbox concept.
Placing the CSS property <code>display: flex;</code> on an element allows you to use other flex properties to build a responsive page.
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## Instructions
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Add the CSS property <code>display</code> to <code>#box-container</code> and set its value to flex.
testString: 'assert($("#box-container").css("display") == "flex", "<code>#box-container</code> should have the <code>display</code> property set to a value of flex.");'