A padding value can't be negative

src/css/Properties.js

@@ -50,7 +50,7 @@ var Properties = {
     "-o-animation-name"                : { multi: "none | <ident>", comma: true },
     "-o-animation-play-state"          : { multi: "running | paused", comma: true },
 
-    "appearance"                    : "icon | window | desktop | workspace | document | tooltip | dialog | button | push-button | hyperlink | radio-button | checkbox | menu-item | tab | menu | menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | outline-tree | range | field | combo-box | signature | password | normal | none | inherit",
+    "appearance"                    : "icon | window | desktop | workspace | document | tooltip | dialog | button | push-button | hyperlink | radio | radio-button | checkbox | menu-item | tab | menu | menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | outline-tree | range | field | combo-box | signature | password | normal | none | inherit",
     "azimuth"                       : function (expression) {
         var simple      = "<angle> | leftwards | rightwards | inherit",
             direction   = "left-side | far-left | left | center-left | center | center-right | right | far-right | right-side",

src/css/ValidationTypes.js

@@ -177,7 +177,7 @@ var ValidationTypes = {
         },
 
         "<padding-width>": function(part){
-            return this["<length>"](part) || this["<percentage>"](part);
+            return part.value >= 0 && (this["<length>"](part) || this["<percentage>"](part));
         },
 
         "<shape>": function(part){

tests/css/CSSParserTests.htm

@@ -1797,6 +1797,50 @@ <h1>CSS Parser Tests</h1>
 
         },
 
+        testPaddingLeft1: function(){
+            var parser = new Parser({ strict: true});
+            parser.addListener("property", function(event){
+                assert.isNull(event.invalid);
+            });
+            var result = parser.parse(".foo { padding-left: 6px; }");
+
+        },
+
+        testPaddingLeft2: function(){
+            var parser = new Parser({ strict: true});
+            parser.addListener("property", function(event){
+                assert.isNull(event.invalid);
+            });
+            var result = parser.parse(".foo { padding-left: 3%; }");
+        },
+
+        testPaddingLeft3: function(){
+            var parser = new Parser({ strict: true});
+            parser.addListener("property", function(event){
+                assert.isNull(event.invalid);
+            });
+            var result = parser.parse(".foo { padding-left: inherit; }");
+
+        },
+
+        testInvalidPaddingLeft1: function(){
+            var parser = new Parser({ strict: true});
+            parser.addListener("property", function(event){
+                assert.isNotNull(event.invalid);
+                assert.areEqual("Expected length greater than 0, percentage greater than 0 or inherit but found '-10px'.", event.invalid.message);
+            });
+            var result = parser.parse(".foo { padding-left: -10px; }");
+        },
+
+        testInvalidPaddingLeft2: function(){
+            var parser = new Parser({ strict: true});
+            parser.addListener("property", function(event){
+                assert.isNotNull(event.invalid);
+                assert.areEqual("Expected length, percentage or inherit but found 'auto'.", event.invalid.message);
+            });
+            var result = parser.parse(".foo { padding-left: auto; }");
+        },
+
         testBorderWidth1: function(){
             var parser = new Parser({ strict: true});
             parser.addListener("property", function(event){

tests/css/Validation.js

@@ -1054,6 +1054,21 @@
         }
     }));
 
+    suite.add(new ValidationTestCase({
+        property: "padding-left",
+
+        valid: [
+            "6px",
+            "3%",
+            "inherit"
+        ],
+
+        invalid: {
+            "-10px" : "Expected (<padding-width> | inherit) but found '-10px'.",
+            "auto" : "Expected (<padding-width> | inherit) but found 'auto'."
+        }
+    }));
+
     suite.add(new ValidationTestCase({
         property: "will-change",