css_box_model.html

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    <title>Visible Spectrum Wavelengths</title>
    <link rel="stylesheet" href="css/box_model.css">
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    <h1><a href="https://en.wikipedia.org/wiki/Visible_spectrum">Visible Spectrum Wavelengths</a></h1>
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    <div class="box" id="red">620-750 nm</div>
    <div class="box" id="orange"> 590-620 nm</div>
    <div class="box" id="yellow">570-590 nm</div>
    <div class="box" id="green">495-570 nm</div>
    <div class="box" id="blue">450-495 nm</div>
    <div class="box" id="violet">380-450 nm</div>
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