diff --git a/4dev/tests/CoreLibsCheckColorsTest.php b/4dev/tests/CoreLibsCheckColorsTest.php
new file mode 100644
index 00000000..7386bf76
--- /dev/null
+++ b/4dev/tests/CoreLibsCheckColorsTest.php
@@ -0,0 +1,329 @@
+<?php
+
+declare(strict_types=1);
+
+namespace tests;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test class for Check\Colors
+ * @coversDefaultClass \CoreLibs\Check\Colors
+ * @testdox \CoreLibs\Check\Colors method tests
+ */
+final class CoreLibsCheckColorsTest extends TestCase
+{
+	public function validateColorProvider(): array
+	{
+		/*
+		0: input color string
+		1: flag (or flags to set)
+		2: expected result (bool)
+		*/
+		return [
+			// * hex
+			'valid hex rgb, flag ALL (default)' => [
+				'#ab12cd',
+				null,
+				true,
+			],
+			'valid hex rgb, flag ALL' => [
+				'#ab12cd',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid hex rgb, flag HEX_RGB' => [
+				'#ab12cd',
+				\CoreLibs\Check\Colors::HEX_RGB,
+				true,
+			],
+			'valid hex rgb, wrong flag' => [
+				'#ab12cd',
+				\CoreLibs\Check\Colors::RGB,
+				false,
+			],
+			// error
+			'invalid hex rgb A' => [
+				'#ab12zz',
+				null,
+				false,
+			],
+			'invalid hex rgb B' => [
+				'#ZyQfo',
+				null,
+				false,
+			],
+			// other valid hex checks
+			'valid hex rgb, alt　A' => [
+				'#AB12cd',
+				null,
+				true,
+			],
+			// * hax alpha
+			'valid hex rgb alpha, flag ALL (default)' => [
+				'#ab12cd12',
+				null,
+				true,
+			],
+			'valid hex rgb alpha, flag ALL' => [
+				'#ab12cd12',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid hex rgb alpha, flag HEX_RGBA' => [
+				'#ab12cd12',
+				\CoreLibs\Check\Colors::HEX_RGBA,
+				true,
+			],
+			'valid hex rgb alpha, wrong flag' => [
+				'#ab12cd12',
+				\CoreLibs\Check\Colors::RGB,
+				false,
+			],
+			// error
+			'invalid hex rgb alpha A' => [
+				'#ab12dd1',
+				null,
+				false,
+			],
+			'invalid hex rgb alpha B' => [
+				'#ab12ddzz',
+				null,
+				false,
+			],
+			'valid hex rgb alpha, alt A' => [
+				'#ab12cdEE',
+				null,
+				true,
+			],
+			// * rgb
+			'valid rgb, flag ALL (default)' => [
+				'rgb(255, 10, 20)',
+				null,
+				true,
+			],
+			'valid rgb, flag ALL' => [
+				'rgb(255, 10, 20)',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid rgb, flag RGB' => [
+				'rgb(255, 10, 20)',
+				\CoreLibs\Check\Colors::RGB,
+				true,
+			],
+			'valid rgb, wrong flag' => [
+				'rgb(255, 10, 20)',
+				\CoreLibs\Check\Colors::HEX_RGB,
+				false,
+			],
+			// error
+			'invalid rgb A' => [
+				'rgb(356, 10, 20)',
+				null,
+				false,
+			],
+			// other valid rgb conbinations
+			'valid rgb, alt A (percent)' => [
+				'rgb(100%, 10%, 20%)',
+				null,
+				true,
+			],
+			// TODO check all % and non percent combinations
+			'valid rgb, alt B (percent, mix)' => [
+				'rgb(100%, 10, 40)',
+				null,
+				true,
+			],
+			// * rgb alpha
+			'valid rgba, flag ALL (default)' => [
+				'rgba(255, 10, 20, 0.5)',
+				null,
+				true,
+			],
+			'valid rgba, flag ALL' => [
+				'rgba(255, 10, 20, 0.5)',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid rgba, flag RGB' => [
+				'rgba(255, 10, 20, 0.5)',
+				\CoreLibs\Check\Colors::RGBA,
+				true,
+			],
+			'valid rgba, wrong flag' => [
+				'rgba(255, 10, 20, 0.5)',
+				\CoreLibs\Check\Colors::HEX_RGB,
+				false,
+			],
+			// error
+			'invalid rgba A' => [
+				'rgba(356, 10, 20, 0.5)',
+				null,
+				false,
+			],
+			// other valid rgba combinations
+			'valid rgba, alt A (percent)' => [
+				'rgba(100%, 10%, 20%, 0.5)',
+				null,
+				true,
+			],
+			// TODO check all % and non percent combinations
+			'valid rgba, alt B (percent, mix)' => [
+				'rgba(100%, 10, 40, 0.5)',
+				null,
+				true,
+			],
+			// TODO check all % and non percent combinations with percent transparent
+			'valid rgba, alt C (percent transparent)' => [
+				'rgba(100%, 10%, 20%, 50%)',
+				null,
+				true,
+			],
+					/*
+	// hsl
+	'hsl(100, 50%, 60%)',
+	'hsl(100, 50.5%, 60.5%)',
+	'hsla(100, 50%, 60%)',
+	'hsla(100, 50.5%, 60.5%)',
+	'hsla(100, 50%, 60%, 0.5)',
+	'hsla(100, 50.5%, 60.5%, 0.5)',
+	'hsla(100, 50%, 60%, 50%)',
+	'hsla(100, 50.5%, 60.5%, 50%)',
+		*/
+			// * hsl
+			'valid hsl, flag ALL (default)' => [
+				'hsl(100, 50%, 60%)',
+				null,
+				true,
+			],
+			'valid hsl, flag ALL' => [
+				'hsl(100, 50%, 60%)',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid hsl, flag RGB' => [
+				'hsl(100, 50%, 60%)',
+				\CoreLibs\Check\Colors::HSL,
+				true,
+			],
+			'valid hsl, wrong flag' => [
+				'hsl(100, 50%, 60%)',
+				\CoreLibs\Check\Colors::HEX_RGB,
+				false,
+			],
+			'invalid hsl A' => [
+				'hsl(500, 50%, 60%)',
+				null,
+				false,
+			],
+			'valid hsl, alt A' => [
+				'hsl(100, 50.5%, 60.5%)',
+				null,
+				true,
+			],
+			// * hsl alpha
+			'valid hsla, flag ALL (default)' => [
+				'hsla(100, 50%, 60%, 0.5)',
+				null,
+				true,
+			],
+			'valid hsla, flag ALL' => [
+				'hsla(100, 50%, 60%, 0.5)',
+				\CoreLibs\Check\Colors::ALL,
+				true,
+			],
+			'valid hsla, flag RGB' => [
+				'hsla(100, 50%, 60%, 0.5)',
+				\CoreLibs\Check\Colors::HSLA,
+				true,
+			],
+			'valid hsla, wrong flag' => [
+				'hsla(100, 50%, 60%, 0.5)',
+				\CoreLibs\Check\Colors::HEX_RGB,
+				false,
+			],
+			'invalid hsla A' => [
+				'hsla(500, 50%, 60%, 0.5)',
+				null,
+				false,
+			],
+			'valid hsla, alt A (percent alpha' => [
+				'hsla(100, 50%, 60%, 50%)',
+				null,
+				true,
+			],
+			'valid hsla, alt A (percent alpha' => [
+				'hsla(100, 50.5%, 60.5%, 50%)',
+				null,
+				true,
+			],
+			// * combined flag checks
+			'valid rgb, flag RGB|RGBA' => [
+				'rgb(100%, 10%, 20%)',
+				\CoreLibs\Check\Colors::RGB | \CoreLibs\Check\Colors::RGBA,
+				true,
+			],
+			// TODO other combined flag checks all combinations
+			// * invalid string
+			'invalid string A' => [
+				'invalid string',
+				null,
+				false,
+			],
+			'invalid string B' => [
+				'(hsla(100, 100, 100))',
+				null,
+				false,
+			],
+			'invalid string C' => [
+				'hsla(100, 100, 100',
+				null,
+				false,
+			],
+		];
+	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::validateColor
+	 * @dataProvider validateColorProvider
+	 * @testdox validateColor $input with flags $flags be $expected [$_dataName]
+	 *
+	 * @param  string   $input
+	 * @param  int|null $flags
+	 * @param  bool     $expected
+	 * @return void
+	 */
+	public function testValidateColor(string $input, ?int $flags, bool $expected)
+	{
+		if ($flags === null) {
+			$result = \CoreLibs\Check\Colors::validateColor($input);
+		} else {
+			$result = \CoreLibs\Check\Colors::validateColor($input, $flags);
+		}
+		$this->assertEquals(
+			$expected,
+			$result
+		);
+	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::validateColor
+	 * @testWith [99]
+	 * @testdox Check Exception throw for $flag
+	 *
+	 * @param  int   $flag
+	 * @return void
+	 */
+	public function testValidateColorException(int $flag): void
+	{
+		$this->expectException(\Exception::class);
+		\CoreLibs\Check\Colors::validateColor('#ffffff', $flag);
+	}
+}
+
+// __END__
diff --git a/4dev/tests/CoreLibsConvertColorsTest.php b/4dev/tests/CoreLibsConvertColorsTest.php
index d58ce903..7b288f0c 100644
--- a/4dev/tests/CoreLibsConvertColorsTest.php
+++ b/4dev/tests/CoreLibsConvertColorsTest.php
@@ -122,6 +122,8 @@ final class CoreLibsConvertColorsTest extends TestCase
 	 */
 	public function rgb2hslAndhsbList(): array
 	{
+		// if hsb_from or hsl_from is set, this will be used in hsb/hsl convert
+		// hsb_rgb is used for adjusted rgb valus due to round error to in
 		return [
 			'valid gray' => [
 				'rgb' => [12, 12, 12],
@@ -137,6 +139,16 @@ final class CoreLibsConvertColorsTest extends TestCase
 				'hsl' => [211.6, 90.5, 41.2],
 				'valid' => true,
 			],
+			// hsg/hsl with 360 which is seen as 0
+			'valid color hue 360' => [
+				'rgb' => [200, 10, 10],
+				'hsb' => [0, 95, 78.0],
+				'hsb_from' => [360, 95, 78.0],
+				'hsb_rgb' => [199, 10, 10], // should be rgb, but rounding error
+				'hsl' => [0.0, 90.5, 41.2],
+				'hsl_from' => [360.0, 90.5, 41.2],
+				'valid' => true,
+			],
 			// invalid values
 			'invalid color' => [
 				'rgb' => [-12, 300, 12],
@@ -176,9 +188,9 @@ final class CoreLibsConvertColorsTest extends TestCase
 		$list = [];
 		foreach ($this->rgb2hslAndhsbList() as $name => $values) {
 			$list[$name . ', hsb to rgb'] = [
-				0 => $values['hsb'][0],
-				1 => $values['hsb'][1],
-				2 => $values['hsb'][2],
+				0 => $values['hsb_from'][0] ?? $values['hsb'][0],
+				1 => $values['hsb_from'][1] ?? $values['hsb'][1],
+				2 => $values['hsb_from'][2] ?? $values['hsb'][2],
 				3 => $values['valid'] ? $values['hsb_rgb'] : false
 			];
 		}
@@ -214,9 +226,9 @@ final class CoreLibsConvertColorsTest extends TestCase
 		$list = [];
 		foreach ($this->rgb2hslAndhsbList() as $name => $values) {
 			$list[$name . ', hsl to rgb'] = [
-				0 => $values['hsl'][0],
-				1 => $values['hsl'][1],
-				2 => $values['hsl'][2],
+				0 => $values['hsl_from'][0] ?? $values['hsl'][0],
+				1 => $values['hsl_from'][1] ?? $values['hsl'][1],
+				2 => $values['hsl_from'][2] ?? $values['hsl'][2],
 				3 => $values['valid'] ? $values['rgb'] : false
 			];
 		}
@@ -382,6 +394,27 @@ final class CoreLibsConvertColorsTest extends TestCase
 			\CoreLibs\Convert\Colors::hsl2rgb($input_h, $input_s, $input_l)
 		);
 	}
+
+	/**
+	 * edge case check hsl/hsb and hue 360 (= 0)
+	 *
+	 * @covers ::hsl2rgb
+	 * @covers ::hsb2rgb
+	 * @testdox hsl2rgb/hsb2rgb hue 360 valid check
+	 *
+	 * @return void
+	 */
+	public function testHslHsb360hue(): void
+	{
+		$this->assertNotFalse(
+			\CoreLibs\Convert\Colors::hsl2rgb(360.0, 90.5, 41.2),
+			'HSL to RGB with 360 hue'
+		);
+		$this->assertNotFalse(
+			\CoreLibs\Convert\Colors::hsb2rgb(360, 95, 78.0),
+			'HSB to RGB with 360 hue'
+		);
+	}
 }
 
 // __END__
diff --git a/www/admin/class_test.check.colors.php b/www/admin/class_test.check.colors.php
new file mode 100644
index 00000000..9ca898ad
--- /dev/null
+++ b/www/admin/class_test.check.colors.php
@@ -0,0 +1,123 @@
+<?php // phpcs:ignore warning
+
+/**
+ * @phan-file-suppress PhanTypeSuspiciousStringExpression
+ */
+
+declare(strict_types=1);
+
+$DEBUG_ALL_OVERRIDE = 0; // set to 1 to debug on live/remote server locations
+$DEBUG_ALL = 1;
+$PRINT_ALL = 1;
+$DB_DEBUG = 1;
+
+if ($DEBUG_ALL) {
+	error_reporting(E_ALL | E_STRICT | E_ERROR | E_WARNING | E_PARSE | E_COMPILE_ERROR);
+}
+
+ob_start();
+
+// basic class test file
+define('USE_DATABASE', false);
+// sample config
+require 'config.php';
+// define log file id
+$LOG_FILE_ID = 'classTest-check-colors';
+ob_end_flush();
+
+use CoreLibs\Check\Colors;
+// use CoreLibs\Debug\Support as DgS;
+
+$log = new CoreLibs\Debug\Logging([
+	'log_folder' => BASE . LOG,
+	'file_id' => $LOG_FILE_ID,
+	// add file date
+	'print_file_date' => true,
+	// set debug and print flags
+	'debug_all' => $DEBUG_ALL ?? false,
+	'echo_all' => $ECHO_ALL ?? false,
+	'print_all' => $PRINT_ALL ?? false,
+]);
+
+$PAGE_NAME = 'TEST CLASS: CHECK COLORS';
+print "<!DOCTYPE html>";
+print "<html><head><title>" . $PAGE_NAME . "</title><head>";
+print "<body>";
+print '<div><a href="class_test.php">Class Test Master</a></div>';
+print '<div><h1>' . $PAGE_NAME . '</h1></div>';
+
+// list of colors to check
+$css_colors = [
+	// base hex
+	'#ab12cd',
+	'#ab12cd12',
+	// rgb
+	'rgb(255, 10, 20)',
+	'rgb(100%, 10%, 20%)',
+	'rgba(255, 10, 20)',
+	'rgba(100%, 10%, 20%)',
+	'rgba(255, 10, 20, 0.5)',
+	'rgba(100%, 10%, 20%, 0.5)',
+	'rgba(255, 10, 20, 50%)',
+	'rgba(100%, 10%, 20%, 50%)',
+	// hsl
+	'hsl(100, 50%, 60%)',
+	'hsl(100, 50.5%, 60.5%)',
+	'hsla(100, 50%, 60%)',
+	'hsla(100, 50.5%, 60.5%)',
+	'hsla(100, 50%, 60%, 0.5)',
+	'hsla(100, 50.5%, 60.5%, 0.5)',
+	'hsla(100, 50%, 60%, 50%)',
+	'hsla(100, 50.5%, 60.5%, 50%)',
+	// invalid here
+	'invalid string',
+	'(hsla(100, 100, 100))',
+	'hsla(100, 100, 100',
+	// invalid numbers
+	'#zzab99',
+	'#abcdef0',
+	'rgb(255%, 100, 100)',
+	'rgb(255%, 100, -10)',
+	'rgb(100%, 100, -10)',
+	'hsl(370, 100, 10)',
+	'hsl(200, 100%, 160%)',
+];
+
+foreach ($css_colors as $color) {
+	$check = Colors::validateColor($color);
+	print "Color check: $color with (" . Colors::ALL . "): ";
+	if ($check) {
+		print '<span style="color: green;">OK</span>';
+	} else {
+		print '<span style="color: red;">ERROR</span>';
+	}
+	print "<br>";
+}
+
+echo "<hr>";
+
+// valid rgb/hsl checks
+$color = 'hsla(360, 100%, 60%, 0.556)';
+$check = Colors::validateColor($color);
+print "Color check: $color with (" . Colors::ALL . "): ";
+if ($check) {
+	print '<span style="color: green;">OK</span>';
+} else {
+	print '<span style="color: red;">ERROR</span>';
+}
+
+// invalid flag
+echo "<hr>";
+try {
+	$check = Colors::validateColor('#ab12cd', 99);
+	print "No Exception";
+} catch (\Exception $e) {
+	print "ERROR: " . $e->getCode() . ": " . $e->getMessage() . "<br>";
+}
+
+// error message
+print $log->printErrorMsg();
+
+print "</body></html>";
+
+// __END__
diff --git a/www/admin/class_test.colors.php b/www/admin/class_test.convert.colors.php
similarity index 97%
rename from www/admin/class_test.colors.php
rename to www/admin/class_test.convert.colors.php
index a66a0783..9c0312a4 100644
--- a/www/admin/class_test.colors.php
+++ b/www/admin/class_test.convert.colors.php
@@ -22,7 +22,7 @@ define('USE_DATABASE', false);
 // sample config
 require 'config.php';
 // define log file id
-$LOG_FILE_ID = 'classTest-colors';
+$LOG_FILE_ID = 'classTest-convert-colors';
 ob_end_flush();
 
 use CoreLibs\Convert\Colors;
@@ -40,7 +40,7 @@ $log = new CoreLibs\Debug\Logging([
 ]);
 $color_class = 'CoreLibs\Convert\Colors';
 
-$PAGE_NAME = 'TEST CLASS: COLORS';
+$PAGE_NAME = 'TEST CLASS: CONVERT COLORS';
 print "<!DOCTYPE html>";
 print "<html><head><title>" . $PAGE_NAME . "</title><head>";
 print "<body>";
diff --git a/www/admin/class_test.php b/www/admin/class_test.php
index bb17fbd6..54ea5dd6 100644
--- a/www/admin/class_test.php
+++ b/www/admin/class_test.php
@@ -55,7 +55,8 @@ print "<body>";
 
 print '<div><a href="class_test.db.php">Class Test: DB</a></div>';
 print '<div><a href="class_test.db.dbReturn.php">Class Test: DB dbReturn</a></div>';
-print '<div><a href="class_test.colors.php">Class Test: COLORS</a></div>';
+print '<div><a href="class_test.convert.colors.php">Class Test: CONVERT COLORS</a></div>';
+print '<div><a href="class_test.check.colors.php">Class Test: CHECK COLORS</a></div>';
 print '<div><a href="class_test.mime.php">Class Test: MIME</a></div>';
 print '<div><a href="class_test.json.php">Class Test: JSON</a></div>';
 print '<div><a href="class_test.token.php">Class Test: FORM TOKEN</a></div>';
diff --git a/www/lib/CoreLibs/ACL/Login.php b/www/lib/CoreLibs/ACL/Login.php
index c46671d2..7e4ccf79 100644
--- a/www/lib/CoreLibs/ACL/Login.php
+++ b/www/lib/CoreLibs/ACL/Login.php
@@ -690,6 +690,7 @@ class Login
 				// rgb(), rgba(), hsl(), hsla()
 				// rgb: nnn.n for each
 				// hsl: nnn.n for first, nnn.n% for 2nd, 3rd
+				// Check\Colors::validateColor()
 				$_SESSION['LANG'] = $res['locale'] ?? 'en';
 				$_SESSION['DEFAULT_CHARSET'] = $res['encoding'] ?? 'UTF-8';
 				$_SESSION['DEFAULT_LOCALE'] = $_SESSION['LANG']
diff --git a/www/lib/CoreLibs/Check/Colors.php b/www/lib/CoreLibs/Check/Colors.php
new file mode 100644
index 00000000..2d1d3ae3
--- /dev/null
+++ b/www/lib/CoreLibs/Check/Colors.php
@@ -0,0 +1,187 @@
+<?php
+
+/*
+ * valid checks for css/html based colors
+ * # hex
+ * # hex + alpha
+ * rgb
+ * rgba
+ * hsl
+ * hsla
+ */
+
+declare(strict_types=1);
+
+namespace CoreLibs\Check;
+
+use Exception;
+
+class Colors
+{
+	/** @var int 1 for HEX rgb */
+	public const HEX_RGB = 1;
+	/** @var int 2 for HEX rgb with alpha */
+	public const HEX_RGBA = 2;
+	/** @var int 4 for rgb() */
+	public const RGB = 4;
+	/** @var int 8 for rgba() */
+	public const RGBA = 8;
+	/** @var int 16 for hsl() */
+	public const HSL = 16;
+	/** @var int 32 for hsla() */
+	public const HSLA = 32;
+	/** @var int 63 for all bits set (sum of above) */
+	public const ALL = 63;
+
+	/**
+	 * check rgb/hsl content values in detail
+	 * will abort and return false on first error found
+	 *
+	 * @param  string    $color    html/css tring to check
+	 * @param  int|false $rgb_flag flag to check for rgb
+	 * @param  int|false $hsl_flag flag to check for hsl type
+	 * @return bool                True if no error, False if error
+	 */
+	private static function rgbHslContentCheck(string $color, $rgb_flag, $hsl_flag): bool
+	{
+		// extract string between () and split into elements
+		preg_match("/\((.*)\)/", $color, $matches);
+		if (
+			!is_array($color_list = preg_split("/,\s*/", $matches[1] ?? ''))
+		) {
+			throw new \Exception("Could not extract color list from rgg/hsl", 3);
+		}
+		// based on rgb/hsl settings check that entries are valid
+		// rgb: either 0-255 OR 0-100%
+		// hsl: first: 0-360
+		foreach ($color_list as $pos => $color_check) {
+			if (empty($color_check)) {
+				return false;
+			}
+			$percent_check = false;
+			if (strrpos($color_check, '%', -1) !== false) {
+				$percent_check = true;
+				$color_check = str_replace('%', '', $color_check);
+			}
+			// first three normal percent or valid number
+			if ($rgb_flag !== false) {
+				if ($percent_check === true) {
+					// for ALL pos
+					if ($color_check  < 0  || $color_check > 100) {
+						return false;
+					}
+				} elseif (
+					$pos < 3 &&
+					($color_check < 0 || $color_check > 255)
+				) {
+						return false;
+				} elseif (
+					// RGBA set pos 3 if not percent
+					$pos == 3 &&
+					($color_check < 0 || $color_check > 1)
+				) {
+					return false;
+				}
+			} elseif ($hsl_flag !== false) {
+				// pos 0: 0-360
+				// pos 1,2: %
+				// pos 3: % or 0-1 (float)
+				if (
+					$pos == 0 &&
+					($color_check < 0 || $color_check > 360)
+				) {
+					return false;
+				} elseif (
+					// if pos 1/2 are not percent
+					($pos == 1 || $pos == 2) &&
+					($percent_check != true ||
+					($color_check  < 0  || $color_check > 100))
+				) {
+					return false;
+				} elseif (
+					// 3 is either percent or 0~1
+					$pos == 3 &&
+					(
+						($percent_check == false &&
+						($color_check < 0 || $color_check > 1)) ||
+						($percent_check === true  &&
+						($color_check  < 0  || $color_check > 100))
+					)
+				) {
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * check if html/css color string is valid
+	 * @param string $color A color string of any format
+	 * @param int $flags    defaults to ALL, else use | to combined from
+	 *                      HEX_RGB, HEX_RGBA, RGB, RGBA, HSL, HSLA
+	 * @return bool         True if valid, False if not
+	 * @throws Exception    1: no valid flag set
+	 */
+	public static function validateColor(string $color, int $flags = self::ALL): bool
+	{
+		// blocks for each check
+		$regex_blocks = [];
+		// set what to check
+		if ($flags & self::HEX_RGB) {
+			$regex_blocks[] = '#[\dA-Fa-f]{6}';
+		}
+		if ($flags & self::HEX_RGBA) {
+			$regex_blocks[] = '#[\dA-Fa-f]{8}';
+		}
+		if ($flags & self::RGB) {
+			$regex_blocks[] = 'rgb\(\d{1,3}%?,\s*\d{1,3}%?,\s*\d{1,3}%?\)';
+		}
+		if ($flags & self::RGBA) {
+			$regex_blocks[] = 'rgba\(\d{1,3}%?,\s*\d{1,3}%?,\s*\d{1,3}%?(,\s*(0\.\d{1,2}|1(\.0)?|\d{1,3}%))?\)';
+		}
+		if ($flags & self::HSL) {
+			$regex_blocks[] = 'hsl\(\d{1,3},\s*\d{1,3}(\.\d{1})?%,\s*\d{1,3}(\.\d{1})?%\)';
+		}
+		if ($flags & self::HSLA) {
+			$regex_blocks[] = 'hsla\(\d{1,3},\s*\d{1,3}(\.\d{1})?%,\s*\d{1,3}'
+				. '(\.\d{1})?%(,\s*(0\.\d{1,2}|1(\.0)?|\d{1,3}%))?\)';
+		}
+		// wrong flag set
+		if ($flags > self::ALL) {
+			throw new \Exception("Invalid flags parameter: $flags", 1);
+		}
+		if (!count($regex_blocks)) {
+			throw new \Exception("No regex blocks set: $flags", 2);
+		}
+
+		// build regex
+		$regex = '^('
+			. join('|', $regex_blocks)
+			// close regex
+			. ')$';
+		// print "C: $color, F: $flags, R: $regex\n";
+
+		if (preg_match("/$regex/", $color)) {
+			// if valid regex, we now need to check if the content is actually valid
+			// only for rgb/hsl type
+			/** @var int|false */
+			$rgb_flag = strpos($color, 'rgb');
+			/** @var int|false */
+			$hsl_flag = strpos($color, 'hsl');
+			// if both not match, return true
+			if (
+				$rgb_flag === false &&
+				$hsl_flag === false
+			) {
+				return true;
+			}
+			// run detaul rgb/hsl content check
+			return self::rgbHslContentCheck($color, $rgb_flag, $hsl_flag);
+		} else {
+			return false;
+		}
+	}
+}
+
+// __END__
diff --git a/www/vendor/composer/autoload_classmap.php b/www/vendor/composer/autoload_classmap.php
index 7a5b8e8e..ad05dece 100644
--- a/www/vendor/composer/autoload_classmap.php
+++ b/www/vendor/composer/autoload_classmap.php
@@ -12,6 +12,7 @@ return array(
     'CoreLibs\\Admin\\Backend' => $baseDir . '/lib/CoreLibs/Admin/Backend.php',
     'CoreLibs\\Admin\\EditBase' => $baseDir . '/lib/CoreLibs/Admin/EditBase.php',
     'CoreLibs\\Basic' => $baseDir . '/lib/CoreLibs/Basic.php',
+    'CoreLibs\\Check\\Colors' => $baseDir . '/lib/CoreLibs/Check/Colors.php',
     'CoreLibs\\Check\\Email' => $baseDir . '/lib/CoreLibs/Check/Email.php',
     'CoreLibs\\Check\\Encoding' => $baseDir . '/lib/CoreLibs/Check/Encoding.php',
     'CoreLibs\\Check\\File' => $baseDir . '/lib/CoreLibs/Check/File.php',
diff --git a/www/vendor/composer/autoload_static.php b/www/vendor/composer/autoload_static.php
index 5a00df1a..5a5ae608 100644
--- a/www/vendor/composer/autoload_static.php
+++ b/www/vendor/composer/autoload_static.php
@@ -45,6 +45,7 @@ class ComposerStaticInit10fe8fe2ec4017b8644d2b64bcf398b9
         'CoreLibs\\Admin\\Backend' => __DIR__ . '/../..' . '/lib/CoreLibs/Admin/Backend.php',
         'CoreLibs\\Admin\\EditBase' => __DIR__ . '/../..' . '/lib/CoreLibs/Admin/EditBase.php',
         'CoreLibs\\Basic' => __DIR__ . '/../..' . '/lib/CoreLibs/Basic.php',
+        'CoreLibs\\Check\\Colors' => __DIR__ . '/../..' . '/lib/CoreLibs/Check/Colors.php',
         'CoreLibs\\Check\\Email' => __DIR__ . '/../..' . '/lib/CoreLibs/Check/Email.php',
         'CoreLibs\\Check\\Encoding' => __DIR__ . '/../..' . '/lib/CoreLibs/Check/Encoding.php',
         'CoreLibs\\Check\\File' => __DIR__ . '/../..' . '/lib/CoreLibs/Check/File.php',