Convert HEX Color to RGBA Format

/**
 * Convert a HEX color code to RGBA format.
 *
 * This helper function converts a valid 6-digit HEX
 * color value into an RGBA color string with
 * predefined opacity.
 */
function sj_convert_hex_to_rgba( $hex_color ) {

    // Remove the '#' symbol if present.
    $hex_color = ltrim( $hex_color, '#' );

    // Validate 6-digit HEX color format.
    if ( 6 === strlen( $hex_color ) ) {

        // Convert HEX values to RGB.
        $red   = hexdec( substr( $hex_color, 0, 2 ) );
        $green = hexdec( substr( $hex_color, 2, 2 ) );
        $blue  = hexdec( substr( $hex_color, 4, 2 ) );

        // Return RGBA color with opacity.
        return "rgba($red, $green, $blue, 0.1)";
    }

    return false;
}