function adjustBrightness($hex, $steps) {
    // Steps should be between -255 and 255. Negative = darker, positive = lighter
    $steps = max(-255, min(255, $steps));

    // Normalize into a six character long hex string
    $hex = str_replace('#', '', $hex);
    if (strlen($hex) == 3) {
        $hex = str_repeat(substr($hex, 0, 1), 2) . str_repeat(substr($hex, 1, 1), 2) . str_repeat(substr($hex, 2, 1), 2);
    }

    // Split into three parts: R, G and B
    $color_parts = str_split($hex, 2);
    $return = '#';

    foreach ($color_parts as $color) {
        $color = hexdec($color); // Convert to decimal
        $color = max(0, min(255, $color + $steps)); // Adjust color
        $return .= str_pad(dechex($color), 2, '0', STR_PAD_LEFT); // Make two char hex code
    }

    return $return;

}

// Is device a mobile?
function isMobile() {
    return preg_match("/(android|avantgo|blackberry|bolt|boost|cricket|docomo|fone|hiptop|mini|mobi|palm|phone|pie|tablet|up\.browser|up\.link|webos|wos)/i", $_SERVER["HTTP_USER_AGENT"]);
}

// Get our colors for use in the content
$theme_half = hex2rgba($theme_color, 0.5);
$theme_part = hex2rgba($theme_color, 0.75);
$theme_full = hex2rgba($theme_color, 1);

$hex = $theme_color; //Bg color in hex, without any prefixing #!

//break up the color in its RGB components
$r = hexdec(substr($hex, 0, 2));
$g = hexdec(substr($hex, 2, 2));
$b = hexdec(substr($hex, 4, 2));

//do simple weighted avarage
//
//(This might be overly simplistic as different colors are perceived
// differently. That is a green of 128 might be brighter than a red of 128.
// But as long as it's just about picking a white or black text color...)
$header_shade = "";

if ($r + $g + $b > 382) {
    //bright color, use dark font
    $header_shade = adjustBrightness($theme_colorr, 150);
    echo "bright color";
} else {
    //dark color, use bright font
    $header_shade = adjustBrightness($theme_colorr, 150);
    echo "dark color";
    echo $header_shade;
}