PHP Random Color - array and function

<style>
div {
    padding:20px;
    margin: 5px 0;
    color:#333;
}
hr {
    border:none;
    height: 1px;
    background-color:#222;
    margin: 25px 0;
}
</style>

<h1 style="color:Tomato;">Random Color > array</h1>

<?php
$rgbColor = array();

//Create a loop.
foreach(array('r', 'g', 'b') as $color){
    //Generate a random number between 0 and 255.
    $rgbColor[$color] = mt_rand(0, 255);
}
echo "<pre>\n";
var_dump($rgbColor);
echo "</pre>";
?>

<div style="background-color: rgb(<?= implode(",", $rgbColor); ?>);">
    Random Color!
</div>

<hr/>

<h1 style="color:Tomato;">Random Color > function</h1>

<?php
function randomColor() {
    $str = '#';
    for($i = 0 ; $i < 6 ; $i++) {
        $randNum = rand(0 , 15);
        switch ($randNum) {
            case 10: $randNum = 'A'; break;
            case 11: $randNum = 'B'; break;
            case 12: $randNum = 'C'; break;
            case 13: $randNum = 'D'; break;
            case 14: $randNum = 'E'; break;
            case 15: $randNum = 'F'; break;
        }
        $str .= $randNum;
    }
    return $str;
}
$color = randomColor();
?>

<h3><?php echo $color;?></h3>

<div style="background-color: <?php echo $color;?>;">
    <?php echo $color;?>
</div>

<hr/>

<h1 style="color:Tomato;">Random Color > function > for</h1>

<?php
for ($x = 1; $x <= 25; $x++) {
    $color = randomColor();
    echo '<div style="background-color:'. $color .'">'. $x .' '.$color .'</div>'."\n";
}
?>