diff --git a/lib/Layout/TableBox.php b/lib/Layout/TableBox.php
index 6226d37..0470cae 100644
--- a/lib/Layout/TableBox.php
+++ b/lib/Layout/TableBox.php
@@ -294,36 +294,37 @@ public function setUpWidths(string $availableSpace)
 	{
 		foreach ($this->getChildren() as $rowGroup) {
 			foreach ($rowGroup->getChildren() as $row) {
-				$columns = $row->getChildren();
-				foreach ($columns as $columnIndex => $column) {
-					$cell = $column->getFirstChild();
-					$cellStyle = $cell->getStyle();
-					$columnInnerWidth = $cell->getDimensions()->getMaxWidth();
-					$styleWidth = $column->getStyle()->getRules('width');
-					$this->contentWidths[$columnIndex] = Math::max($this->contentWidths[$columnIndex] ?? '0', $columnInnerWidth);
-					$minColumnWidth = $cell->getDimensions()->getMinWidth();
-					if ($column->getColSpan() > 1) {
-						$minColumnWidth = Math::div($minColumnWidth, (string) $column->getColSpan());
-					}
-					$this->minWidths[$columnIndex] = Math::max($this->minWidths[$columnIndex] ?? '0', $minColumnWidth);
-					if ('auto' !== $styleWidth && false === strpos($styleWidth, '%')) {
+				if ($columns = $row->getChildren()) {
+					foreach ($columns as $columnIndex => $column) {
+						$cell = $column->getFirstChild();
+						$cellStyle = $cell->getStyle();
+						$columnInnerWidth = $cell->getDimensions()->getMaxWidth();
+						$styleWidth = $column->getStyle()->getRules('width');
+						$this->contentWidths[$columnIndex] = Math::max($this->contentWidths[$columnIndex] ?? '0', $columnInnerWidth);
+						$minColumnWidth = $cell->getDimensions()->getMinWidth();
 						if ($column->getColSpan() > 1) {
-							$styleWidth = Math::div($styleWidth, (string) $column->getColSpan());
+							$minColumnWidth = Math::div($minColumnWidth, (string) $column->getColSpan());
 						}
-						$preferred = Math::max($styleWidth, $minColumnWidth);
-						$this->minWidths[$columnIndex] = $preferred;
-					} elseif (strpos($styleWidth, '%') > 0) {
-						$preferred = Math::max($this->preferredWidths[$columnIndex] ?? '0', $columnInnerWidth);
-						$this->percentages[$columnIndex] = Math::max($this->percentages[$columnIndex] ?? '0', trim($styleWidth, '%'));
-					} else {
-						$preferred = Math::max($this->preferredWidths[$columnIndex] ?? '0', $columnInnerWidth);
+						$this->minWidths[$columnIndex] = Math::max($this->minWidths[$columnIndex] ?? '0', $minColumnWidth);
+						if ('auto' !== $styleWidth && false === strpos($styleWidth, '%')) {
+							if ($column->getColSpan() > 1) {
+								$styleWidth = Math::div($styleWidth, (string) $column->getColSpan());
+							}
+							$preferred = Math::max($styleWidth, $minColumnWidth);
+							$this->minWidths[$columnIndex] = $preferred;
+						} elseif (strpos($styleWidth, '%') > 0) {
+							$preferred = Math::max($this->preferredWidths[$columnIndex] ?? '0', $columnInnerWidth);
+							$this->percentages[$columnIndex] = Math::max($this->percentages[$columnIndex] ?? '0', trim($styleWidth, '%'));
+						} else {
+							$preferred = Math::max($this->preferredWidths[$columnIndex] ?? '0', $columnInnerWidth);
+						}
+						$this->preferredWidths[$columnIndex] = $preferred;
 					}
-					$this->preferredWidths[$columnIndex] = $preferred;
+					$this->borderWidth = Math::add($this->borderWidth, $cellStyle->getHorizontalBordersWidth());
+					$this->minWidth = Math::add($this->minWidth, $this->minWidths[$columnIndex]);
+					$this->contentWidth = Math::add($this->contentWidth, $this->contentWidths[$columnIndex]);
+					$this->preferredWidth = Math::add($this->preferredWidth, $this->preferredWidths[$columnIndex]);
 				}
-				$this->borderWidth = Math::add($this->borderWidth, $cellStyle->getHorizontalBordersWidth());
-				$this->minWidth = Math::add($this->minWidth, $this->minWidths[$columnIndex]);
-				$this->contentWidth = Math::add($this->contentWidth, $this->contentWidths[$columnIndex]);
-				$this->preferredWidth = Math::add($this->preferredWidth, $this->preferredWidths[$columnIndex]);
 			}
 		}
 		if ('collapse' !== $this->getParent()->getStyle()->getRules('border-collapse')) {
@@ -358,9 +359,9 @@ protected function setUpSizingTypes()
 		foreach ($this->getChildren() as $rowGroup) {
 			foreach ($rowGroup->getChildren() as $row) {
 				foreach ($row->getChildren() as $columnIndex => $column) {
-					if ('percent' === $columnSizingTypes[$columnIndex]) {
+					if (isset($columnSizingTypes[$columnIndex]) && 'percent' === $columnSizingTypes[$columnIndex]) {
 						$this->percentColumns[$columnIndex][] = $column;
-					} elseif ('pixel' === $columnSizingTypes[$columnIndex]) {
+					} elseif (isset($columnSizingTypes[$columnIndex]) && 'pixel' === $columnSizingTypes[$columnIndex]) {
 						$this->pixelColumns[$columnIndex][] = $column;
 					} else {
 						$this->autoColumns[$columnIndex][] = $column;
@@ -1287,7 +1288,7 @@ public function measureHeight(bool $afterPageDividing = false)
 			}
 			// column that is spanned with more than 1 row must have height that is equal to all spanned rows height
 			foreach ($rows as $rowIndex => $row) {
-				$currentRowMax = $maxRowHeights[$rowGroupIndex][$rowIndex];
+				$currentRowMax = $maxRowHeights[$rowGroupIndex][$rowIndex] ?? '0';
 				foreach ($row->getChildren() as $column) {
 					$rowSpan = $column->getRowSpan();
 					if ($rowSpan > 1) {
diff --git a/lib/Style/Color.php b/lib/Style/Color.php
index e66234d..ff47c7e 100644
--- a/lib/Style/Color.php
+++ b/lib/Style/Color.php
@@ -20,11 +20,7 @@
  */
 class Color
 {
-	/**
-	 * Color names hash values.
-	 *
-	 * @var array
-	 */
+	/** @var string[] Color names hash values. */
 	protected static $colorNames = [
 		'aliceblue' => '#f0f8ff',
 		'antiquewhite' => '#faebd7',
@@ -176,6 +172,11 @@ class Color
 		'yellowgreen' => '#9acd32',
 	];
 
+	/** @var array Color names rgba values. */
+	protected static $colorCustomNames = [
+		'transparent' => [0, 0, 0, 0.1]
+	];
+
 	/**
 	 * Get rgba array from color name.
 	 *
@@ -183,7 +184,7 @@ class Color
 	 *
 	 * @return string[]
 	 */
-	public static function fromName(string $colorName)
+	public static function fromName(string $colorName): array
 	{
 		$colorName = strtolower($colorName);
 		if (isset(static::$colorNames[$colorName])) {
@@ -199,7 +200,7 @@ public static function fromName(string $colorName)
 	 *
 	 * @return string[]
 	 */
-	public static function fromHash(string $hashColor)
+	public static function fromHash(string $hashColor): array
 	{
 		$color = substr($hashColor, 1);
 		if (3 === \strlen($color)) {
@@ -233,7 +234,7 @@ public static function fromHash(string $hashColor)
 	 *
 	 * @return string[] rgb/a
 	 */
-	public static function fromRGBA(string $rgbColor)
+	public static function fromRGBA(string $rgbColor): array
 	{
 		$matches = [];
 		preg_match_all('/rgb\(([0-9]+)\s?\,\s?([0-9]+)\s?\,\s?([0-9]+)\s?([0-9]+)?\s?\)/ui', str_replace("\n\t\r ", '', $rgbColor), $matches);
@@ -253,7 +254,7 @@ public static function fromRGBA(string $rgbColor)
 	 *
 	 * @return int[]
 	 */
-	public static function toRGBA($colorInput, bool $inPDFColorSpace = false)
+	public static function toRGBA($colorInput, bool $inPDFColorSpace = false): array
 	{
 		$colorInput = trim(strtolower($colorInput));
 		if ($colorInput) {
@@ -263,6 +264,8 @@ public static function toRGBA($colorInput, bool $inPDFColorSpace = false)
 				$color = static::fromRGBA($colorInput);
 			} elseif (\array_key_exists($colorInput, static::$colorNames)) {
 				$color = static::fromName($colorInput);
+			} elseif (isset(static::$colorCustomNames[$colorInput])) {
+				return static::$colorCustomNames[$colorInput];
 			}
 			$r = $inPDFColorSpace ? Math::div($color[0], '255') : $color[0];
 			$g = $inPDFColorSpace ? Math::div($color[1], '255') : $color[1];
@@ -280,7 +283,7 @@ public static function toRGBA($colorInput, bool $inPDFColorSpace = false)
 	 *
 	 * @return string
 	 */
-	public static function toPdfString(string $colorInput)
+	public static function toPdfString(string $colorInput): string
 	{
 		$color = static::toRGBA($colorInput);
 		return "{$color[0]} {$color[1]} {$color[2]} RG";
diff --git a/lib/Style/Normalizer/MarginLeft.php b/lib/Style/Normalizer/MarginLeft.php
index 80db914..a2d27a4 100644
--- a/lib/Style/Normalizer/MarginLeft.php
+++ b/lib/Style/Normalizer/MarginLeft.php
@@ -21,7 +21,11 @@ class MarginLeft extends Normalizer
 	public function normalize($ruleValue, string $ruleName = ''): array
 	{
 		if (null === $this->normalized) {
-			return $this->normalized = ['margin-left' => $this->getNumberValues($ruleValue)[0]];
+			$css = [];
+			if ($number = $this->getNumberValues($ruleValue)) {
+				$css = ['margin-left' => $number[0]];
+			}
+			$this->normalized = $css;
 		}
 		return $this->normalized;
 	}
diff --git a/lib/Style/Normalizer/Normalizer.php b/lib/Style/Normalizer/Normalizer.php
index 4cf3876..22f3427 100644
--- a/lib/Style/Normalizer/Normalizer.php
+++ b/lib/Style/Normalizer/Normalizer.php
@@ -79,8 +79,10 @@ public function getNumberValues($ruleValue, bool $isFont = false)
 		if ($ruleValue instanceof NumericValue) {
 			return $ruleValue;
 		}
-		$matches = [];
 		preg_match_all(static::$numericRegex, $ruleValue, $matches, PREG_SET_ORDER);
+		if (!$matches) {
+			$matches = [['0', '0', '0']];
+		}
 		$originalSize = $matches[0][2];
 		$originalUnit = 'em';
 		if (isset($matches[0][3])) {
@@ -97,25 +99,25 @@ public function getNumberValues($ruleValue, bool $isFont = false)
 		$matchesCount = \count($matches);
 		if ($matchesCount >= 2) {
 			$multi[] = (new NumericValue())
-				->setUnit($matches[1][3])
+				->setUnit($matches[1][3] ?? $originalUnit)
 				->setValue($matches[1][2])
-				->setOriginal($matches[1][2] . $matches[1][3])
+				->setOriginal($matches[1][2] . ($matches[1][3] ?? $originalUnit))
 				->setIsFont($isFont)
 				->convert($this->style);
 		}
 		if ($matchesCount >= 3) {
 			$multi[] = (new NumericValue())
-				->setUnit($matches[2][3])
+				->setUnit($matches[2][3] ?? $originalUnit)
 				->setValue($matches[2][2])
-				->setOriginal($matches[2][2] . $matches[2][3])
+				->setOriginal($matches[2][2] . ($matches[2][3] ?? $originalUnit))
 				->setIsFont($isFont)
 				->convert($this->style);
 		}
 		if (4 === $matchesCount) {
 			$multi[] = (new NumericValue())
-				->setUnit($matches[3][3])
+				->setUnit($matches[3][3] ?? $originalUnit)
 				->setValue($matches[3][2])
-				->setOriginal($matches[3][2] . $matches[3][3])
+				->setOriginal($matches[3][2] . ($matches[3][3] ?? $originalUnit))
 				->setIsFont($isFont)
 				->convert($this->style);
 		}