diff --git a/components/style/properties/shorthand/padding.mako.rs b/components/style/properties/shorthand/padding.mako.rs
index c07a80b1e04..2972fb45259 100644
--- a/components/style/properties/shorthand/padding.mako.rs
+++ b/components/style/properties/shorthand/padding.mako.rs
@@ -4,6 +4,6 @@
 
 <%namespace name="helpers" file="/helpers.mako.rs" />
 
-${helpers.four_sides_shorthand("padding", "padding-%s", "specified::LengthOrPercentage::parse",
+${helpers.four_sides_shorthand("padding", "padding-%s", "specified::LengthOrPercentage::parse_non_negative",
                                spec="https://drafts.csswg.org/css-box-3/#propdef-padding",
                                allow_quirks=True)}
diff --git a/tests/wpt/metadata-css/css21_dev/html4/c5510-padn-002.htm.ini b/tests/wpt/metadata-css/css21_dev/html4/c5510-padn-002.htm.ini
deleted file mode 100644
index 2688c52e5da..00000000000
--- a/tests/wpt/metadata-css/css21_dev/html4/c5510-padn-002.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[c5510-padn-002.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/css21_dev/html4/padding-009.htm.ini b/tests/wpt/metadata-css/css21_dev/html4/padding-009.htm.ini
deleted file mode 100644
index 14a459b2d0e..00000000000
--- a/tests/wpt/metadata-css/css21_dev/html4/padding-009.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[padding-009.htm]
-  type: reftest
-  expected: FAIL