PHP HTML - Light Color Detector

<?php

$light = "blue";

?>

<html lang="en">
<head>
    <title>Light Color Detector</title>
    <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-9ndCyUaIbzAi2FUVXJi0CjmCapSmO7SnpJef0486qhLnuZ2cdeRhO02iuK6FUUVM" crossorigin="anonymous">
</head>
<body>

<div class="container">

    <h1>Light Color Detector</h1>

    <?php if($light == "red"):?>

        <h2 class="text-danger">
            <?= "Light color is red"; ?>
        </h2>

    <?php elseif($light == "green"):?>

        <h2 class="text-success">
            <?= "Light color is green"; ?>
        </h2>

    <?php elseif($light == "blue"):?>

        <h2 class="text-primary">
            <?= "Light color is blue"; ?>
        </h2>

    <?php else:?>

        <h2 class="text-secondary">
            <?= "Light color is not detected"; ?>
        </h2>

    <?php endif;?>

</div>

<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-geWF76RCwLtnZ8qwWowPQNguL3RmwHVBC9FhGdlKrxdiJJigb/j/68SIy3Te4Bkz" crossorigin="anonymous"></script>
</body>
</html>