diff --git a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyGetParser.ts b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyGetParser.ts
index 1ed544904..482cc627f 100644
--- a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyGetParser.ts
+++ b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyGetParser.ts
@@ -16,6 +16,26 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['margin-top']?.value) {
 			return null;
 		}
+		const values = [properties['margin-top'].value];
+		if (
+			properties['margin-right']?.value &&
+			(properties['margin-right'].value !== properties['margin-top'].value ||
+				(properties['margin-bottom']?.value &&
+					properties['margin-bottom'].value !== properties['margin-top'].value))
+		) {
+			values.push(properties['margin-right'].value);
+		}
+		if (
+			properties['margin-bottom']?.value &&
+			(properties['margin-bottom'].value !== properties['margin-top'].value ||
+				(properties['margin-left']?.value &&
+					properties['margin-left'].value !== properties['margin-right'].value))
+		) {
+			values.push(properties['margin-bottom'].value);
+		}
+		if (properties['margin-left']?.value) {
+			values.push(properties['margin-left'].value);
+		}
 		return {
 			important: ![
 				properties['margin-top']?.important,
@@ -23,21 +43,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['margin-left']?.important,
 				properties['margin-right']?.important
 			].some((important) => important === false),
-			value: `${properties['margin-top'].value} ${
-				properties['margin-top'].value !== properties['margin-right']?.value
-					? properties['margin-right']?.value || ''
-					: ''
-			} ${
-				properties['margin-top'].value !== properties['margin-bottom']?.value
-					? properties['margin-bottom']?.value || ''
-					: ''
-			} ${
-				properties['margin-right']?.value !== properties['margin-left']?.value
-					? properties['margin-left']?.value || ''
-					: ''
-			}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -53,6 +59,16 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['padding-top']?.value) {
 			return null;
 		}
+		const values = [properties['padding-top'].value];
+		if (properties['padding-right']?.value) {
+			values.push(properties['padding-right'].value);
+		}
+		if (properties['padding-bottom']?.value) {
+			values.push(properties['padding-bottom'].value);
+		}
+		if (properties['padding-left']?.value) {
+			values.push(properties['padding-left'].value);
+		}
 		return {
 			important: ![
 				properties['padding-top']?.important,
@@ -60,21 +76,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['padding-left']?.important,
 				properties['padding-right']?.important
 			].some((important) => important === false),
-			value: `${properties['padding-top'].value} ${
-				properties['padding-top'].value !== properties['padding-right']?.value
-					? properties['padding-right']?.value || ''
-					: ''
-			} ${
-				properties['padding-top'].value !== properties['padding-bottom']?.value
-					? properties['padding-bottom']?.value || ''
-					: ''
-			} ${
-				properties['padding-right']?.value !== properties['padding-left']?.value
-					? properties['padding-left']?.value || ''
-					: ''
-			}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -89,18 +91,34 @@ export default class CSSStyleDeclarationPropertyGetParser {
 	}): ICSSStyleDeclarationPropertyValue {
 		if (
 			!properties['border-top-width']?.value ||
-			properties['border-right-width']?.value !== properties['border-top-width']?.value ||
-			properties['border-right-style']?.value !== properties['border-top-style']?.value ||
-			properties['border-right-color']?.value !== properties['border-top-color']?.value ||
-			properties['border-bottom-width']?.value !== properties['border-top-width']?.value ||
-			properties['border-bottom-style']?.value !== properties['border-top-style']?.value ||
-			properties['border-bottom-color']?.value !== properties['border-top-color']?.value ||
-			properties['border-left-width']?.value !== properties['border-top-width']?.value ||
-			properties['border-left-style']?.value !== properties['border-top-style']?.value ||
-			properties['border-left-color']?.value !== properties['border-top-color']?.value
+			properties['border-top-width']?.value !== properties['border-right-width']?.value ||
+			properties['border-top-width']?.value !== properties['border-bottom-width']?.value ||
+			properties['border-top-width']?.value !== properties['border-left-width']?.value
 		) {
 			return null;
 		}
+
+		const values = [properties['border-top-width'].value];
+
+		if (
+			properties['border-top-style']?.value &&
+			properties['border-top-style'].value === properties['border-right-style'].value &&
+			properties['border-top-color'].value === properties['border-right-color'].value &&
+			properties['border-top-color'].value === properties['border-bottom-color'].value &&
+			properties['border-top-color'].value === properties['border-left-color'].value
+		) {
+			values.push(properties['border-top-style'].value);
+		}
+
+		if (
+			properties['border-top-color']?.value &&
+			properties['border-top-color'].value === properties['border-right-color'].value &&
+			properties['border-top-color'].value === properties['border-bottom-color'].value &&
+			properties['border-top-color'].value === properties['border-left-color'].value
+		) {
+			values.push(properties['border-top-color'].value);
+		}
+
 		return {
 			important: ![
 				properties['border-top-width']?.important,
@@ -116,11 +134,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['border-bottom-color']?.important,
 				properties['border-left-color']?.important
 			].some((important) => important === false),
-			value: `${properties['border-top-width'].value} ${
-				properties['border-top-style']?.value || ''
-			} ${properties['border-top-color']?.value || ''}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -136,17 +150,20 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['border-top-width']?.value) {
 			return null;
 		}
+		const values = [properties['border-top-width'].value];
+		if (properties['border-top-style']?.value) {
+			values.push(properties['border-top-style'].value);
+		}
+		if (properties['border-top-color']?.value) {
+			values.push(properties['border-top-color'].value);
+		}
 		return {
 			important: ![
 				properties['border-top-width']?.important,
 				properties['border-top-style']?.important,
 				properties['border-top-color']?.important
 			].some((important) => important === false),
-			value: `${properties['border-top-width'].value} ${
-				properties['border-top-style']?.value || ''
-			} ${properties['border-top-color']?.value || ''}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -162,17 +179,20 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['border-right-width']?.value) {
 			return null;
 		}
+		const values = [properties['border-right-width'].value];
+		if (properties['border-right-style']?.value) {
+			values.push(properties['border-right-style'].value);
+		}
+		if (properties['border-right-color']?.value) {
+			values.push(properties['border-right-color'].value);
+		}
 		return {
 			important: ![
 				properties['border-right-width']?.important,
 				properties['border-right-style']?.important,
 				properties['border-right-color']?.important
 			].some((important) => important === false),
-			value: `${properties['border-right-width'].value} ${
-				properties['border-right-style']?.value || ''
-			} ${properties['border-right-color']?.value || ''}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -188,17 +208,20 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['border-bottom-width']?.value) {
 			return null;
 		}
+		const values = [properties['border-bottom-width'].value];
+		if (properties['border-bottom-style']?.value) {
+			values.push(properties['border-bottom-style'].value);
+		}
+		if (properties['border-bottom-color']?.value) {
+			values.push(properties['border-bottom-color'].value);
+		}
 		return {
 			important: ![
 				properties['border-bottom-width']?.important,
 				properties['border-bottom-style']?.important,
 				properties['border-bottom-color']?.important
 			].some((important) => important === false),
-			value: `${properties['border-bottom-width'].value} ${
-				properties['border-bottom-style']?.value || ''
-			} ${properties['border-bottom-color']?.value || ''}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -214,17 +237,20 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['border-left-width']?.value) {
 			return null;
 		}
+		const values = [properties['border-left-width'].value];
+		if (properties['border-left-style']?.value) {
+			values.push(properties['border-bottom-style'].value);
+		}
+		if (properties['border-left-color']?.value) {
+			values.push(properties['border-left-color'].value);
+		}
 		return {
 			important: ![
 				properties['border-left-width']?.important,
 				properties['border-left-style']?.important,
 				properties['border-left-color']?.important
 			].some((important) => important === false),
-			value: `${properties['border-left-width'].value} ${
-				properties['border-left-style']?.value || ''
-			} ${properties['border-left-color']?.value || ''}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -324,6 +350,16 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['border-top-left-radius']?.value) {
 			return null;
 		}
+		const values = [properties['border-top-left-radius'].value];
+		if (properties['border-top-right-radius']?.value) {
+			values.push(properties['border-top-right-radius'].value);
+		}
+		if (properties['border-bottom-right-radius']?.value) {
+			values.push(properties['border-bottom-right-radius'].value);
+		}
+		if (properties['border-bottom-left-radius']?.value) {
+			values.push(properties['border-bottom-left-radius'].value);
+		}
 		return {
 			important: ![
 				properties['border-top-left-radius']?.important,
@@ -331,23 +367,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['border-bottom-right-radius']?.important,
 				properties['border-bottom-left-radius']?.important
 			].some((important) => important === false),
-			value: `${properties['border-top-left-radius'].value} ${
-				properties['border-top-left-radius'].value !== properties['border-top-right-radius']?.value
-					? properties['border-top-right-radius']?.value || ''
-					: ''
-			} ${
-				properties['border-top-left-radius'].value !==
-				properties['border-bottom-right-radius']?.value
-					? properties['border-bottom-right-radius']?.value || ''
-					: ''
-			} ${
-				properties['border-top-right-radius']?.value !==
-				properties['border-bottom-left-radius']?.value
-					? properties['border-bottom-left-radius']?.value || ''
-					: ''
-			}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -363,6 +383,22 @@ export default class CSSStyleDeclarationPropertyGetParser {
 		if (!properties['background-color']?.value && !properties['background-image']?.value) {
 			return null;
 		}
+		const values = [];
+		if (properties['background-color']?.value) {
+			values.push(properties['background-color'].value);
+		}
+		if (properties['background-image']?.value) {
+			values.push(properties['background-image'].value);
+		}
+		if (properties['background-repeat']?.value) {
+			values.push(properties['background-repeat'].value);
+		}
+		if (properties['background-attachment']?.value) {
+			values.push(properties['background-attachment'].value);
+		}
+		if (properties['background-position']?.value) {
+			values.push(properties['background-position'].value);
+		}
 		return {
 			important: ![
 				properties['background-color']?.important,
@@ -371,19 +407,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['background-attachment']?.important,
 				properties['background-position']?.important
 			].some((important) => important === false),
-			value: `${properties['background-color']?.value || ''} ${
-				properties['background-image']?.value || ''
-			} ${properties['background-repeat']?.value || ''} ${
-				properties['background-repeat']?.value
-					? properties['background-attachment']?.value || ''
-					: ''
-			} ${
-				properties['background-repeat']?.value && properties['background-attachment']?.value
-					? properties['background-position']?.value || ''
-					: ''
-			}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 
@@ -431,6 +455,26 @@ export default class CSSStyleDeclarationPropertyGetParser {
 			sizeAndLineHeight.push(properties['line-height'].value);
 		}
 
+		const values = [];
+		if (properties['font-style']?.value) {
+			values.push(properties['font-style'].value);
+		}
+		if (properties['font-variant']?.value) {
+			values.push(properties['font-variant'].value);
+		}
+		if (properties['font-weight']?.value) {
+			values.push(properties['font-weight'].value);
+		}
+		if (properties['font-stretch']?.value) {
+			values.push(properties['font-stretch'].value);
+		}
+
+		values.push(sizeAndLineHeight.join('/'));
+
+		if (properties['font-family']?.value) {
+			values.push(properties['font-family'].value);
+		}
+
 		return {
 			important: ![
 				properties['font-style']?.important,
@@ -441,13 +485,7 @@ export default class CSSStyleDeclarationPropertyGetParser {
 				properties['line-height']?.important,
 				properties['font-family']?.important
 			].some((important) => important === false),
-			value: `${properties['font-style']?.value || ''} ${properties['font-variant']?.value || ''} ${
-				properties['font-weight']?.value || ''
-			} ${properties['font-stretch']?.value || ''} ${sizeAndLineHeight.join('/')} ${
-				properties['font-family'].value || ''
-			}`
-				.replace(/  /g, '')
-				.trim()
+			value: values.join(' ')
 		};
 	}
 }
diff --git a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyManager.ts b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyManager.ts
index 36b6d34e0..eca52fddc 100644
--- a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyManager.ts
+++ b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertyManager.ts
@@ -306,6 +306,12 @@ export default class CSSStyleDeclarationPropertyManager {
 			case 'css-float':
 				properties = CSSStyleDeclarationPropertySetParser.getCSSFloat(value, important);
 				break;
+			case 'display':
+				properties = CSSStyleDeclarationPropertySetParser.getDisplay(value, important);
+				break;
+			case 'direction':
+				properties = CSSStyleDeclarationPropertySetParser.getDirection(value, important);
+				break;
 			case 'float':
 				properties = CSSStyleDeclarationPropertySetParser.getFloat(value, important);
 				break;
diff --git a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertySetParser.ts b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertySetParser.ts
index 02ef54cbc..6fbfb1e3f 100644
--- a/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertySetParser.ts
+++ b/packages/happy-dom/src/css/declaration/utilities/CSSStyleDeclarationPropertySetParser.ts
@@ -49,6 +49,37 @@ const FONT_STRETCH = [
 	'ultra-expanded'
 ];
 
+const DISPLAY = [
+	/* Legacy values */
+	'block',
+	'inline',
+	'inline-block',
+	'flex',
+	'inline-flex',
+	'grid',
+	'inline-grid',
+	'flow-root',
+
+	/* Box generation */
+	'none',
+	'contents',
+
+	/* Two-value syntax */
+	'block flow',
+	'inline flow',
+	'inline flow-root',
+	'block flex',
+	'inline flex',
+	'block grid',
+	'inline grid',
+	'block flow-root',
+
+	/* Other values */
+	'table',
+	'table-row',
+	'list-item'
+];
+
 /**
  * Computed style property parser.
  */
@@ -170,6 +201,46 @@ export default class CSSStyleDeclarationPropertySetParser {
 		return null;
 	}
 
+	/**
+	 * Returns display.
+	 *
+	 * @param value Value.
+	 * @param important Important.
+	 * @returns Property values
+	 */
+	public static getDisplay(
+		value: string,
+		important: boolean
+	): {
+		[key: string]: ICSSStyleDeclarationPropertyValue;
+	} {
+		const lowerValue = value.toLowerCase();
+		if (DISPLAY.includes(lowerValue)) {
+			return { display: { value: lowerValue, important } };
+		}
+		return null;
+	}
+
+	/**
+	 * Returns direction.
+	 *
+	 * @param value Value.
+	 * @param important Important.
+	 * @returns Property values
+	 */
+	public static getDirection(
+		value: string,
+		important: boolean
+	): {
+		[key: string]: ICSSStyleDeclarationPropertyValue;
+	} {
+		const lowerValue = value.toLowerCase();
+		if (lowerValue === 'ltr' || lowerValue === 'rtl') {
+			return { direction: { value: lowerValue, important } };
+		}
+		return null;
+	}
+
 	/**
 	 * Returns top.
 	 *
diff --git a/packages/happy-dom/test/css/declaration/CSSStyleDeclaration.test.ts b/packages/happy-dom/test/css/declaration/CSSStyleDeclaration.test.ts
index 5eb70bfdb..d74bc2c92 100644
--- a/packages/happy-dom/test/css/declaration/CSSStyleDeclaration.test.ts
+++ b/packages/happy-dom/test/css/declaration/CSSStyleDeclaration.test.ts
@@ -3,7 +3,7 @@ import Window from '../../../src/window/Window';
 import IWindow from '../../../src/window/IWindow';
 import IDocument from '../../../src/nodes/document/IDocument';
 import IElement from '../../../src/nodes/element/IElement';
-import CSSStyleDeclarationDefaultValues from './data/CSSStyleDeclarationDefaultValues';
+import CSSStyleDeclarationMockedProperties from './data/CSSStyleDeclarationMockedProperties';
 
 function KEBAB_TO_CAMEL_CASE(text: string): string {
 	const parts = text.split('-');
@@ -78,38 +78,38 @@ describe('CSSStyleDeclaration', () => {
 		});
 	});
 
-	for (const property of Object.keys(CSSStyleDeclarationDefaultValues)) {
+	for (const property of Object.keys(CSSStyleDeclarationMockedProperties)) {
 		const camelCaseProperty = KEBAB_TO_CAMEL_CASE(property);
 		describe(`get ${camelCaseProperty}()`, () => {
 			it('Returns style property on element.', () => {
 				const declaration = new CSSStyleDeclaration(element);
 				element.setAttribute(
 					'style',
-					`${property}: ${CSSStyleDeclarationDefaultValues[property]};`
+					`${property}: ${CSSStyleDeclarationMockedProperties[property]};`
 				);
-				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationDefaultValues[property]);
+				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationMockedProperties[property]);
 			});
 
 			it('Returns style property without element.', () => {
 				const declaration = new CSSStyleDeclaration();
-				declaration[camelCaseProperty] = CSSStyleDeclarationDefaultValues[property];
-				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationDefaultValues[property]);
+				declaration[camelCaseProperty] = CSSStyleDeclarationMockedProperties[property];
+				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationMockedProperties[property]);
 			});
 		});
 
 		describe(`set ${camelCaseProperty}()`, () => {
 			it('Sets style property on element.', () => {
 				const declaration = new CSSStyleDeclaration(element);
-				declaration[camelCaseProperty] = CSSStyleDeclarationDefaultValues[property];
+				declaration[camelCaseProperty] = CSSStyleDeclarationMockedProperties[property];
 				expect(element.getAttribute('style')).toBe(
-					`${property}: ${CSSStyleDeclarationDefaultValues[property]};`
+					`${property}: ${CSSStyleDeclarationMockedProperties[property]};`
 				);
 			});
 
 			it('Sets style property without element.', () => {
 				const declaration = new CSSStyleDeclaration();
-				declaration[camelCaseProperty] = CSSStyleDeclarationDefaultValues[property];
-				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationDefaultValues[property]);
+				declaration[camelCaseProperty] = CSSStyleDeclarationMockedProperties[property];
+				expect(declaration[camelCaseProperty]).toBe(CSSStyleDeclarationMockedProperties[property]);
 			});
 		});
 	}
diff --git a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationCamelCaseKeys.ts b/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationCamelCaseKeys.ts
deleted file mode 100644
index 60e73c3ae..000000000
--- a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationCamelCaseKeys.ts
+++ /dev/null
@@ -1,371 +0,0 @@
-export default [
-	'alignContent',
-	'alignItems',
-	'alignSelf',
-	'alignmentBaseline',
-	'all',
-	'animation',
-	'animationDelay',
-	'animationDirection',
-	'animationDuration',
-	'animationFillMode',
-	'animationIterationCount',
-	'animationName',
-	'animationPlayState',
-	'animationTimingFunction',
-	'appearance',
-	'backdropFilter',
-	'backfaceVisibility',
-	'background',
-	'backgroundAttachment',
-	'backgroundBlendMode',
-	'backgroundClip',
-	'backgroundColor',
-	'backgroundImage',
-	'backgroundOrigin',
-	'backgroundPosition',
-	'backgroundPositionX',
-	'backgroundPositionY',
-	'backgroundRepeat',
-	'backgroundRepeatX',
-	'backgroundRepeatY',
-	'backgroundSize',
-	'baselineShift',
-	'blockSize',
-	'border',
-	'borderBlockEnd',
-	'borderBlockEndColor',
-	'borderBlockEndStyle',
-	'borderBlockEndWidth',
-	'borderBlockStart',
-	'borderBlockStartColor',
-	'borderBlockStartStyle',
-	'borderBlockStartWidth',
-	'borderBottom',
-	'borderBottomColor',
-	'borderBottomLeftRadius',
-	'borderBottomRightRadius',
-	'borderBottomStyle',
-	'borderBottomWidth',
-	'borderCollapse',
-	'borderColor',
-	'borderImage',
-	'borderImageOutset',
-	'borderImageRepeat',
-	'borderImageSlice',
-	'borderImageSource',
-	'borderImageWidth',
-	'borderInlineEnd',
-	'borderInlineEndColor',
-	'borderInlineEndStyle',
-	'borderInlineEndWidth',
-	'borderInlineStart',
-	'borderInlineStartColor',
-	'borderInlineStartStyle',
-	'borderInlineStartWidth',
-	'borderLeft',
-	'borderLeftColor',
-	'borderLeftStyle',
-	'borderLeftWidth',
-	'borderRadius',
-	'borderRight',
-	'borderRightColor',
-	'borderRightStyle',
-	'borderRightWidth',
-	'borderSpacing',
-	'borderStyle',
-	'borderTop',
-	'borderTopColor',
-	'borderTopLeftRadius',
-	'borderTopRightRadius',
-	'borderTopStyle',
-	'borderTopWidth',
-	'borderWidth',
-	'bottom',
-	'boxShadow',
-	'boxSizing',
-	'breakAfter',
-	'breakBefore',
-	'breakInside',
-	'bufferedRendering',
-	'captionSide',
-	'caretColor',
-	'clear',
-	'clip',
-	'clipPath',
-	'clipRule',
-	'color',
-	'colorInterpolation',
-	'colorInterpolationFilters',
-	'colorRendering',
-	'colorScheme',
-	'columnCount',
-	'columnFill',
-	'columnGap',
-	'columnRule',
-	'columnRuleColor',
-	'columnRuleStyle',
-	'columnRuleWidth',
-	'columnSpan',
-	'columnWidth',
-	'columns',
-	'contain',
-	'containIntrinsicSize',
-	'content',
-	'contentVisibility',
-	'counterIncrement',
-	'counterReset',
-	'counterSet',
-	'cssFloat',
-	'cursor',
-	'cx',
-	'cy',
-	'd',
-	'direction',
-	'display',
-	'dominantBaseline',
-	'emptyCells',
-	'fill',
-	'fillOpacity',
-	'fillRule',
-	'filter',
-	'flex',
-	'flexBasis',
-	'flexDirection',
-	'flexFlow',
-	'flexGrow',
-	'flexShrink',
-	'flexWrap',
-	'float',
-	'floodColor',
-	'floodOpacity',
-	'font',
-	'fontDisplay',
-	'fontFamily',
-	'fontFeatureSettings',
-	'fontKerning',
-	'fontOpticalSizing',
-	'fontSize',
-	'fontStretch',
-	'fontStyle',
-	'fontVariant',
-	'fontVariantCaps',
-	'fontVariantEastAsian',
-	'fontVariantLigatures',
-	'fontVariantNumeric',
-	'fontVariationSettings',
-	'fontWeight',
-	'gap',
-	'grid',
-	'gridArea',
-	'gridAutoColumns',
-	'gridAutoFlow',
-	'gridAutoRows',
-	'gridColumn',
-	'gridColumnEnd',
-	'gridColumnGap',
-	'gridColumnStart',
-	'gridGap',
-	'gridRow',
-	'gridRowEnd',
-	'gridRowGap',
-	'gridRowStart',
-	'gridTemplate',
-	'gridTemplateAreas',
-	'gridTemplateColumns',
-	'gridTemplateRows',
-	'height',
-	'hyphens',
-	'imageOrientation',
-	'imageRendering',
-	'inherits',
-	'initialValue',
-	'inlineSize',
-	'isolation',
-	'justifyContent',
-	'justifyItems',
-	'justifySelf',
-	'left',
-	'letterSpacing',
-	'lightingColor',
-	'lineBreak',
-	'lineHeight',
-	'listStyle',
-	'listStyleImage',
-	'listStylePosition',
-	'listStyleType',
-	'margin',
-	'marginBlockEnd',
-	'marginBlockStart',
-	'marginBottom',
-	'marginInlineEnd',
-	'marginInlineStart',
-	'marginLeft',
-	'marginRight',
-	'marginTop',
-	'marker',
-	'markerEnd',
-	'markerMid',
-	'markerStart',
-	'mask',
-	'maskType',
-	'maxBlockSize',
-	'maxHeight',
-	'maxInlineSize',
-	'maxWidth',
-	'maxZoom',
-	'minBlockSize',
-	'minHeight',
-	'minInlineSize',
-	'minWidth',
-	'minZoom',
-	'mixBlendMode',
-	'objectFit',
-	'objectPosition',
-	'offset',
-	'offsetDistance',
-	'offsetPath',
-	'offsetRotate',
-	'opacity',
-	'order',
-	'orientation',
-	'orphans',
-	'outline',
-	'outlineColor',
-	'outlineOffset',
-	'outlineStyle',
-	'outlineWidth',
-	'overflow',
-	'overflowAnchor',
-	'overflowWrap',
-	'overflowX',
-	'overflowY',
-	'overscrollBehavior',
-	'overscrollBehaviorBlock',
-	'overscrollBehaviorInline',
-	'overscrollBehaviorX',
-	'overscrollBehaviorY',
-	'padding',
-	'paddingBlockEnd',
-	'paddingBlockStart',
-	'paddingBottom',
-	'paddingInlineEnd',
-	'paddingInlineStart',
-	'paddingLeft',
-	'paddingRight',
-	'paddingTop',
-	'page',
-	'pageBreakAfter',
-	'pageBreakBefore',
-	'pageBreakInside',
-	'pageOrientation',
-	'paintOrder',
-	'perspective',
-	'perspectiveOrigin',
-	'placeContent',
-	'placeItems',
-	'placeSelf',
-	'pointerEvents',
-	'position',
-	'quotes',
-	'r',
-	'resize',
-	'right',
-	'rowGap',
-	'rubyPosition',
-	'rx',
-	'ry',
-	'scrollBehavior',
-	'scrollMargin',
-	'scrollMarginBlock',
-	'scrollMarginBlockEnd',
-	'scrollMarginBlockStart',
-	'scrollMarginBottom',
-	'scrollMarginInline',
-	'scrollMarginInlineEnd',
-	'scrollMarginInlineStart',
-	'scrollMarginLeft',
-	'scrollMarginRight',
-	'scrollMarginTop',
-	'scrollPadding',
-	'scrollPaddingBlock',
-	'scrollPaddingBlockEnd',
-	'scrollPaddingBlockStart',
-	'scrollPaddingBottom',
-	'scrollPaddingInline',
-	'scrollPaddingInlineEnd',
-	'scrollPaddingInlineStart',
-	'scrollPaddingLeft',
-	'scrollPaddingRight',
-	'scrollPaddingTop',
-	'scrollSnapAlign',
-	'scrollSnapStop',
-	'scrollSnapType',
-	'shapeImageThreshold',
-	'shapeMargin',
-	'shapeOutside',
-	'shapeRendering',
-	'size',
-	'speak',
-	'src',
-	'stopColor',
-	'stopOpacity',
-	'stroke',
-	'strokeDasharray',
-	'strokeDashoffset',
-	'strokeLinecap',
-	'strokeLinejoin',
-	'strokeMiterlimit',
-	'strokeOpacity',
-	'strokeWidth',
-	'syntax',
-	'tabSize',
-	'tableLayout',
-	'textAlign',
-	'textAlignLast',
-	'textAnchor',
-	'textCombineUpright',
-	'textDecoration',
-	'textDecorationColor',
-	'textDecorationLine',
-	'textDecorationSkipInk',
-	'textDecorationStyle',
-	'textIndent',
-	'textOrientation',
-	'textOverflow',
-	'textRendering',
-	'textShadow',
-	'textSizeAdjust',
-	'textTransform',
-	'textUnderlinePosition',
-	'top',
-	'touchAction',
-	'transform',
-	'transformBox',
-	'transformOrigin',
-	'transformStyle',
-	'transition',
-	'transitionDelay',
-	'transitionDuration',
-	'transitionProperty',
-	'transitionTimingFunction',
-	'unicodeBidi',
-	'unicodeRange',
-	'userSelect',
-	'userZoom',
-	'vectorEffect',
-	'verticalAlign',
-	'visibility',
-	'whiteSpace',
-	'widows',
-	'width',
-	'willChange',
-	'wordBreak',
-	'wordSpacing',
-	'wordWrap',
-	'writingMode',
-	'x',
-	'y',
-	'zIndex',
-	'zoom'
-];
diff --git a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationKebabCaseKeys.ts b/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationKebabCaseKeys.ts
deleted file mode 100644
index c6fa9f9c0..000000000
--- a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationKebabCaseKeys.ts
+++ /dev/null
@@ -1,371 +0,0 @@
-export default [
-	'align-content',
-	'align-items',
-	'align-self',
-	'alignment-baseline',
-	'all',
-	'animation',
-	'animation-delay',
-	'animation-direction',
-	'animation-duration',
-	'animation-fill-mode',
-	'animation-iteration-count',
-	'animation-name',
-	'animation-play-state',
-	'animation-timing-function',
-	'appearance',
-	'backdrop-filter',
-	'backface-visibility',
-	'background',
-	'background-attachment',
-	'background-blend-mode',
-	'background-clip',
-	'background-color',
-	'background-image',
-	'background-origin',
-	'background-position',
-	'background-position-x',
-	'background-position-y',
-	'background-repeat',
-	'background-repeat-x',
-	'background-repeat-y',
-	'background-size',
-	'baseline-shift',
-	'block-size',
-	'border',
-	'border-block-end',
-	'border-block-end-color',
-	'border-block-end-style',
-	'border-block-end-width',
-	'border-block-start',
-	'border-block-start-color',
-	'border-block-start-style',
-	'border-block-start-width',
-	'border-bottom',
-	'border-bottom-color',
-	'border-bottom-left-radius',
-	'border-bottom-right-radius',
-	'border-bottom-style',
-	'border-bottom-width',
-	'border-collapse',
-	'border-color',
-	'border-image',
-	'border-image-outset',
-	'border-image-repeat',
-	'border-image-slice',
-	'border-image-source',
-	'border-image-width',
-	'border-inline-end',
-	'border-inline-end-color',
-	'border-inline-end-style',
-	'border-inline-end-width',
-	'border-inline-start',
-	'border-inline-start-color',
-	'border-inline-start-style',
-	'border-inline-start-width',
-	'border-left',
-	'border-left-color',
-	'border-left-style',
-	'border-left-width',
-	'border-radius',
-	'border-right',
-	'border-right-color',
-	'border-right-style',
-	'border-right-width',
-	'border-spacing',
-	'border-style',
-	'border-top',
-	'border-top-color',
-	'border-top-left-radius',
-	'border-top-right-radius',
-	'border-top-style',
-	'border-top-width',
-	'border-width',
-	'bottom',
-	'box-shadow',
-	'box-sizing',
-	'break-after',
-	'break-before',
-	'break-inside',
-	'buffered-rendering',
-	'caption-side',
-	'caret-color',
-	'clear',
-	'clip',
-	'clip-path',
-	'clip-rule',
-	'color',
-	'color-interpolation',
-	'color-interpolation-filters',
-	'color-rendering',
-	'color-scheme',
-	'column-count',
-	'column-fill',
-	'column-gap',
-	'column-rule',
-	'column-rule-color',
-	'column-rule-style',
-	'column-rule-width',
-	'column-span',
-	'column-width',
-	'columns',
-	'contain',
-	'contain-intrinsic-size',
-	'content',
-	'content-visibility',
-	'counter-increment',
-	'counter-reset',
-	'counter-set',
-	'css-float',
-	'cursor',
-	'cx',
-	'cy',
-	'd',
-	'direction',
-	'display',
-	'dominant-baseline',
-	'empty-cells',
-	'fill',
-	'fill-opacity',
-	'fill-rule',
-	'filter',
-	'flex',
-	'flex-basis',
-	'flex-direction',
-	'flex-flow',
-	'flex-grow',
-	'flex-shrink',
-	'flex-wrap',
-	'float',
-	'flood-color',
-	'flood-opacity',
-	'font',
-	'font-display',
-	'font-family',
-	'font-feature-settings',
-	'font-kerning',
-	'font-optical-sizing',
-	'font-size',
-	'font-stretch',
-	'font-style',
-	'font-variant',
-	'font-variant-caps',
-	'font-variant-east-asian',
-	'font-variant-ligatures',
-	'font-variant-numeric',
-	'font-variation-settings',
-	'font-weight',
-	'gap',
-	'grid',
-	'grid-area',
-	'grid-auto-columns',
-	'grid-auto-flow',
-	'grid-auto-rows',
-	'grid-column',
-	'grid-column-end',
-	'grid-column-gap',
-	'grid-column-start',
-	'grid-gap',
-	'grid-row',
-	'grid-row-end',
-	'grid-row-gap',
-	'grid-row-start',
-	'grid-template',
-	'grid-template-areas',
-	'grid-template-columns',
-	'grid-template-rows',
-	'height',
-	'hyphens',
-	'image-orientation',
-	'image-rendering',
-	'inherits',
-	'initial-value',
-	'inline-size',
-	'isolation',
-	'justify-content',
-	'justify-items',
-	'justify-self',
-	'left',
-	'letter-spacing',
-	'lighting-color',
-	'line-break',
-	'line-height',
-	'list-style',
-	'list-style-image',
-	'list-style-position',
-	'list-style-type',
-	'margin',
-	'margin-block-end',
-	'margin-block-start',
-	'margin-bottom',
-	'margin-inline-end',
-	'margin-inline-start',
-	'margin-left',
-	'margin-right',
-	'margin-top',
-	'marker',
-	'marker-end',
-	'marker-mid',
-	'marker-start',
-	'mask',
-	'mask-type',
-	'max-block-size',
-	'max-height',
-	'max-inline-size',
-	'max-width',
-	'max-zoom',
-	'min-block-size',
-	'min-height',
-	'min-inline-size',
-	'min-width',
-	'min-zoom',
-	'mix-blend-mode',
-	'object-fit',
-	'object-position',
-	'offset',
-	'offset-distance',
-	'offset-path',
-	'offset-rotate',
-	'opacity',
-	'order',
-	'orientation',
-	'orphans',
-	'outline',
-	'outline-color',
-	'outline-offset',
-	'outline-style',
-	'outline-width',
-	'overflow',
-	'overflow-anchor',
-	'overflow-wrap',
-	'overflow-x',
-	'overflow-y',
-	'overscroll-behavior',
-	'overscroll-behavior-block',
-	'overscroll-behavior-inline',
-	'overscroll-behavior-x',
-	'overscroll-behavior-y',
-	'padding',
-	'padding-block-end',
-	'padding-block-start',
-	'padding-bottom',
-	'padding-inline-end',
-	'padding-inline-start',
-	'padding-left',
-	'padding-right',
-	'padding-top',
-	'page',
-	'page-break-after',
-	'page-break-before',
-	'page-break-inside',
-	'page-orientation',
-	'paint-order',
-	'perspective',
-	'perspective-origin',
-	'place-content',
-	'place-items',
-	'place-self',
-	'pointer-events',
-	'position',
-	'quotes',
-	'r',
-	'resize',
-	'right',
-	'row-gap',
-	'ruby-position',
-	'rx',
-	'ry',
-	'scroll-behavior',
-	'scroll-margin',
-	'scroll-margin-block',
-	'scroll-margin-block-end',
-	'scroll-margin-block-start',
-	'scroll-margin-bottom',
-	'scroll-margin-inline',
-	'scroll-margin-inline-end',
-	'scroll-margin-inline-start',
-	'scroll-margin-left',
-	'scroll-margin-right',
-	'scroll-margin-top',
-	'scroll-padding',
-	'scroll-padding-block',
-	'scroll-padding-block-end',
-	'scroll-padding-block-start',
-	'scroll-padding-bottom',
-	'scroll-padding-inline',
-	'scroll-padding-inline-end',
-	'scroll-padding-inline-start',
-	'scroll-padding-left',
-	'scroll-padding-right',
-	'scroll-padding-top',
-	'scroll-snap-align',
-	'scroll-snap-stop',
-	'scroll-snap-type',
-	'shape-image-threshold',
-	'shape-margin',
-	'shape-outside',
-	'shape-rendering',
-	'size',
-	'speak',
-	'src',
-	'stop-color',
-	'stop-opacity',
-	'stroke',
-	'stroke-dasharray',
-	'stroke-dashoffset',
-	'stroke-linecap',
-	'stroke-linejoin',
-	'stroke-miterlimit',
-	'stroke-opacity',
-	'stroke-width',
-	'syntax',
-	'tab-size',
-	'table-layout',
-	'text-align',
-	'text-align-last',
-	'text-anchor',
-	'text-combine-upright',
-	'text-decoration',
-	'text-decoration-color',
-	'text-decoration-line',
-	'text-decoration-skip-ink',
-	'text-decoration-style',
-	'text-indent',
-	'text-orientation',
-	'text-overflow',
-	'text-rendering',
-	'text-shadow',
-	'text-size-adjust',
-	'text-transform',
-	'text-underline-position',
-	'top',
-	'touch-action',
-	'transform',
-	'transform-box',
-	'transform-origin',
-	'transform-style',
-	'transition',
-	'transition-delay',
-	'transition-duration',
-	'transition-property',
-	'transition-timing-function',
-	'unicode-bidi',
-	'unicode-range',
-	'user-select',
-	'user-zoom',
-	'vector-effect',
-	'vertical-align',
-	'visibility',
-	'white-space',
-	'widows',
-	'width',
-	'will-change',
-	'word-break',
-	'word-spacing',
-	'word-wrap',
-	'writing-mode',
-	'x',
-	'y',
-	'z-index',
-	'zoom'
-];
diff --git a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationDefaultValues.ts b/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationMockedProperties.ts
similarity index 94%
rename from packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationDefaultValues.ts
rename to packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationMockedProperties.ts
index 335e05b30..f3651cd11 100644
--- a/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationDefaultValues.ts
+++ b/packages/happy-dom/test/css/declaration/data/CSSStyleDeclarationMockedProperties.ts
@@ -16,6 +16,8 @@ export default {
 	appearance: 'none',
 	'backdrop-filter': 'none',
 	'backface-visibility': 'visible',
+	background:
+		'center / contain no-repeat url("../../media/examples/firefox-logo.svg"), #eee 35% url("../../media/examples/lizard.png")',
 	'background-attachment': 'scroll',
 	'background-blend-mode': 'normal',
 	'background-clip': 'border-box',
@@ -27,6 +29,11 @@ export default {
 	'background-size': 'auto',
 	'baseline-shift': '0px',
 	'block-size': 'auto',
+	border: '1rem solid red',
+	'border-top': '1rem solid red',
+	'border-right': '1rem solid red',
+	'border-bottom': '1rem solid red',
+	'border-left': '1rem solid red',
 	'border-block-end-color': 'rgb(0, 0, 0)',
 	'border-block-end-style': 'none',
 	'border-block-end-width': '0px',
@@ -65,6 +72,7 @@ export default {
 	'border-top-right-radius': '0px',
 	'border-top-style': 'none',
 	'border-top-width': '0px',
+	'border-radius': '1px 2px 3px 4px',
 	bottom: 'auto',
 	'box-shadow': 'none',
 	'box-sizing': 'content-box',
@@ -107,6 +115,7 @@ export default {
 	'fill-opacity': '1',
 	'fill-rule': 'nonzero',
 	filter: 'none',
+	flex: '1 2 fill',
 	'flex-basis': 'auto',
 	'flex-direction': 'row',
 	'flex-grow': '0',
@@ -115,6 +124,7 @@ export default {
 	float: 'none',
 	'flood-color': 'rgb(0, 0, 0)',
 	'flood-opacity': '1',
+	font: 'italic small-caps bold 2rem/2.2 cursive',
 	'font-family': 'Roboto, system-ui, sans-serif',
 	'font-kerning': 'auto',
 	'font-optical-sizing': 'auto',
@@ -162,6 +172,7 @@ export default {
 	'list-style-image': 'none',
 	'list-style-position': 'outside',
 	'list-style-type': 'disc',
+	margin: '1px 2px 3px 4px',
 	'margin-block-end': '0px',
 	'margin-block-start': '0px',
 	'margin-bottom': '0px',
@@ -202,6 +213,7 @@ export default {
 	'overflow-y': 'visible',
 	'overscroll-behavior-block': 'auto',
 	'overscroll-behavior-inline': 'auto',
+	padding: '1px 2px 3px 4px',
 	'padding-block-end': '0px',
 	'padding-block-start': '0px',
 	'padding-bottom': '0px',