diff --git a/src/AngleSharp.Css.Tests/Declarations/CssGridProperty.cs b/src/AngleSharp.Css.Tests/Declarations/CssGridProperty.cs
index 87b5e323..7d366d01 100644
--- a/src/AngleSharp.Css.Tests/Declarations/CssGridProperty.cs
+++ b/src/AngleSharp.Css.Tests/Declarations/CssGridProperty.cs
@@ -527,6 +527,139 @@ public void CssGridAreaSingleValueLegal()
             Assert.AreEqual("2 / auto / auto / auto", property.Value);
         }
 
+        [Test]
+        public void CssGridAreaTextValueLegal1()
+        {
+            var source = "#nav-header {grid-area: aaa; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: aaa / aaa / aaa / aaa }";
+            Assert.AreEqual(expected, text);
+        }
+
+
+        [Test]
+        public void CssGridAreaTextValueLegal2()
+        {
+            var source = "#nav-header {grid-area: aaa / bbb; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: aaa / bbb / aaa / bbb }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal3()
+        {
+            var source = "#nav-header {grid-area: 1 / 2; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: 1 / 2 / auto / auto }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal4()
+        {
+            var source = "#nav-header {grid-area: aaa / 2; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: aaa / 2 / aaa / auto }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal5()
+        {
+            var source = "#nav-header {grid-area: aaa / bbb / ccc; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: aaa / bbb / ccc / bbb }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal6()
+        {
+            var source = "#nav-header {grid-area: aaa / bbb / ccc; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: aaa / bbb / ccc / bbb }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal7()
+        {
+            var source = "#nav-header {grid-area: 1; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: 1 / auto / auto / auto }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueLegal8()
+        {
+            var source = "#nav-header {grid-area: 2 / aaa; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: 2 / aaa / auto / aaa }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueIllegal1()
+        {
+            var source = "#nav-header {grid-area: 2a / 3%; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueIllegal2()
+        {
+            var source = "#nav-header {grid-area: 2a; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueTrim1()
+        {
+            var source = "#nav-header {grid-area: 9999999; }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: 10000 / auto / auto / auto }";
+            Assert.AreEqual(expected, text);
+        }
+
+        [Test]
+        public void CssGridAreaTextValueTrim2()
+        {
+            var source = "#nav-header {grid-area: 9999999 / 8888888 }";
+            var css = ParseStyleSheet(source);
+            var text = css.Rules[0].CssText;
+
+            var expected = "#nav-header { grid-area: 10000 / 10000 / auto / auto }";
+            Assert.AreEqual(expected, text);
+        }
+
         [Test]
         public void CssGridAutoFlowAndRepeatLegal()
         {
diff --git a/src/AngleSharp.Css/Declarations/GridAreaDeclaration.cs b/src/AngleSharp.Css/Declarations/GridAreaDeclaration.cs
index eca5c752..59b875b7 100644
--- a/src/AngleSharp.Css/Declarations/GridAreaDeclaration.cs
+++ b/src/AngleSharp.Css/Declarations/GridAreaDeclaration.cs
@@ -2,6 +2,7 @@ namespace AngleSharp.Css.Declarations
 {
     using AngleSharp.Css.Converters;
     using AngleSharp.Css.Dom;
+    using AngleSharp.Css.Parser;
     using AngleSharp.Css.Values;
     using AngleSharp.Text;
     using System;
@@ -9,6 +10,8 @@ namespace AngleSharp.Css.Declarations
 
     static class GridAreaDeclaration
     {
+        private const int MaximumGridSize = 10000;
+        
         public static readonly String Name = PropertyNames.GridArea;
 
         public static readonly String[] Longhands = new[]
@@ -42,7 +45,7 @@ public ICssValue[] Split(ICssValue value)
                 {
                     return new[]
                     {
-                        tuple.Items[0],
+                        GetItem(tuple, 0),
                         GetItem(tuple, 1),
                         GetItem(tuple, 2),
                         GetItem(tuple, 3),
@@ -56,21 +59,45 @@ private static ICssValue GetItem(CssTupleValue tuple, Int32 index)
             {
                 if (tuple.Items.Length > index)
                 {
+                    if (int.TryParse(tuple.Items[index].CssText, out int value))
+                    {
+                        if (value > MaximumGridSize)
+                        {
+                            return new Constant<Object>(MaximumGridSize.ToString(), null);
+                        }
+                    }
                     return tuple.Items[index];
                 }
 
-                return GetItemSimple(tuple, index / 2);
+                return GetItemSimple(tuple, index);
             }
 
             private static ICssValue GetItemSimple(CssTupleValue tuple, Int32 index)
             {
-                if (tuple.Items.Length > index)
+                var val = UnitParser.ParseUnit(new StringSource(tuple.Items[0].CssText));
+                if (index <= 2)
                 {
-                    var nested = tuple.Items[index] as CssTupleValue;
-
-                    if (nested != null && nested.Items.Length == 3 && nested.Items[0] == null && nested.Items[1] == null)
+                    if (tuple.Items.Length <= index)
+                    {
+                       
+                        if (!int.TryParse(tuple.Items[0].CssText, out int _))
+                        {
+                            return tuple.Items[0];
+                        }
+                    }
+                }
+                else if (index == 3)
+                {
+                    if (tuple.Items.Length > 1)
+                    {
+                        if (!int.TryParse(tuple.Items[1].CssText, out int _))
+                        {
+                            return tuple.Items[1];
+                        }
+                    }
+                    else if (!int.TryParse(tuple.Items[0].CssText, out int _))
                     {
-                        return nested.Items[2];
+                        return tuple.Items[0];
                     }
                 }