diff --git a/packages/parser/css_parser.mly b/packages/parser/css_parser.mly
index d10e882ab..2fd95f3ff 100644
--- a/packages/parser/css_parser.mly
+++ b/packages/parser/css_parser.mly
@@ -226,9 +226,9 @@ style_rule:
   }
 ;
 
-prelude: xs = nonempty_list(loc(component_value_in_prelude)) { xs };
+prelude: xs = loption(nonempty_list(loc(component_value_in_prelude))) { xs };
 
-component_values: xs = nonempty_list(loc(component_value)) { xs };
+component_values: xs = loption(nonempty_list(loc(component_value))) { xs };
 
 declarations:
   | xs = nonempty_list(declaration_or_at_rule); SEMI_COLON?; { xs }
diff --git a/packages/ppx/src/declarations_to_string.re b/packages/ppx/src/declarations_to_string.re
index 77052784c..da44b2377 100644
--- a/packages/ppx/src/declarations_to_string.re
+++ b/packages/ppx/src/declarations_to_string.re
@@ -262,23 +262,29 @@ let max_width =
 let height = apply(Parser.property_height, [%expr "height"], render_size);
 let min_height = apply(Parser.property_height, [%expr "min-height"], render_size);
 let max_height = apply(Parser.property_height, [%expr "max-height"], render_size);
+
+let render_ratio = fun
+  | `Static((a, (), b)) =>
+    [%expr [%e string_of_int(a) |> render_string] ++ "/" ++ [%e string_of_int(b) |> render_string]]
+  | `Integer(i) => [%expr [%e render_integer(i)]];
+
 let aspect_ratio =
   apply(
     Parser.property_media_max_aspect_ratio,
     [%expr "aspect-ratio"],
-    ((a, (), b)) => [%expr [%e string_of_int(a) |> render_string] ++ "/" ++ [%e string_of_int(b) |> render_string]]
+    render_ratio
   );
 let min_aspect_ratio =
   apply(
     Parser.property_media_max_aspect_ratio,
     [%expr "min-aspect-ratio"],
-    ((a, (), b)) => [%expr [%e string_of_int(a) |> render_string] ++ "/" ++ [%e string_of_int(b) |> render_string]]
+    render_ratio
   );
 let max_aspect_ratio =
   apply(
     Parser.property_media_max_aspect_ratio,
     [%expr "max-aspect-ratio"],
-    ((a, (), b)) => [%expr [%e string_of_int(a) |> render_string] ++ "/" ++ [%e string_of_int(b) |> render_string]]
+    render_ratio
   );
 let orientation =
   apply(
diff --git a/packages/ppx/test/css-support/test.expected.re b/packages/ppx/test/css-support/test.expected.re
index 1f47bd7b5..d75e3c550 100644
--- a/packages/ppx/test/css-support/test.expected.re
+++ b/packages/ppx/test/css-support/test.expected.re
@@ -1171,6 +1171,10 @@ CssJs.unsafe({js|background-image|js}, "unset");
 CssJs.unsafe({js|width|js}, "unset");
 CssJs.unsafe({js|clipPath|js}, {js| url('#clip')|js});
 CssJs.unsafe({js|clipPath|js}, {js| inset(50%)|js});
+CssJs.unsafe({js|clipPath|js}, {js| circle()|js});
+CssJs.unsafe({js|clipPath|js}, {js| ellipse()|js});
+CssJs.unsafe({js|clipPath|js}, {js| path('M 20 20 H 80 V 30')|js});
+CssJs.unsafe({js|clipPath|js}, {js| circle() border-box|js});
 CssJs.unsafe({js|clipPath|js}, {js| border-box|js});
 CssJs.unsafe({js|clipPath|js}, {js| padding-box|js});
 CssJs.unsafe({js|clipPath|js}, {js| content-box|js});
@@ -1211,6 +1215,7 @@ CssJs.unsafe({js|maskRepeat|js}, {js| no-repeat no-repeat|js});
 CssJs.unsafe({js|maskPosition|js}, {js| center|js});
 CssJs.unsafe({js|maskPosition|js}, {js| center center|js});
 CssJs.unsafe({js|maskPosition|js}, {js| left 50%|js});
+CssJs.unsafe({js|maskPosition|js}, {js| bottom 10px right 20px|js});
 CssJs.unsafe({js|maskClip|js}, {js| border-box|js});
 CssJs.unsafe({js|maskClip|js}, {js| padding-box|js});
 CssJs.unsafe({js|maskClip|js}, {js| content-box|js});
@@ -1245,6 +1250,7 @@ CssJs.unsafe({js|mask|js}, {js| url(image.png)|js});
 CssJs.unsafe({js|mask|js}, {js| url(image.png) luminance|js});
 CssJs.unsafe({js|mask|js}, {js| url(image.png) luminance top space|js});
 CssJs.unsafe({js|maskBorderSource|js}, {js| none|js});
+CssJs.unsafe({js|maskBorderSource|js}, {js| url(image.png)|js});
 CssJs.unsafe({js|maskBorderSlice|js}, {js| 0 fill|js});
 CssJs.unsafe({js|maskBorderSlice|js}, {js| 50% fill|js});
 CssJs.unsafe({js|maskBorderSlice|js}, {js| 1.1 fill|js});
@@ -1284,6 +1290,7 @@ CssJs.unsafe({js|maskBorderRepeat|js}, {js| stretch space|js});
 CssJs.unsafe({js|maskBorderRepeat|js}, {js| repeat space|js});
 CssJs.unsafe({js|maskBorderRepeat|js}, {js| round space|js});
 CssJs.unsafe({js|maskBorderRepeat|js}, {js| space space|js});
+CssJs.unsafe({js|maskBorder|js}, {js| url(image.png)|js});
 CssJs.unsafe({js|maskType|js}, {js| luminance|js});
 CssJs.unsafe({js|maskType|js}, {js| alpha|js});
 CssJs.unsafe({js|mixBlendMode|js}, {js| normal|js});
@@ -1326,6 +1333,7 @@ CssJs.unsafe({js|display|js}, {js| flow|js});
 CssJs.unsafe({js|display|js}, {js| flow-root|js});
 CssJs.unsafe({js|filter|js}, {js| none|js});
 CssJs.unsafe({js|filter|js}, {js| url(#id)|js});
+CssJs.unsafe({js|filter|js}, {js| url(image.svg#id)|js});
 CssJs.unsafe({js|filter|js}, {js| blur(5px)|js});
 CssJs.unsafe({js|filter|js}, {js| brightness(0.5)|js});
 CssJs.unsafe({js|filter|js}, {js| contrast(150%)|js});
@@ -1339,6 +1347,7 @@ CssJs.unsafe({js|filter|js}, {js| saturate(150%)|js});
 CssJs.unsafe({js|filter|js}, {js| grayscale(100%) sepia(100%)|js});
 CssJs.unsafe({js|backdropFilter|js}, {js| none|js});
 CssJs.unsafe({js|backdropFilter|js}, {js| url(#id)|js});
+CssJs.unsafe({js|backdropFilter|js}, {js| url(image.svg#id)|js});
 CssJs.unsafe({js|backdropFilter|js}, {js| blur(5px)|js});
 CssJs.unsafe({js|backdropFilter|js}, {js| brightness(0.5)|js});
 CssJs.unsafe({js|backdropFilter|js}, {js| contrast(150%)|js});
@@ -1415,6 +1424,12 @@ CssJs.unsafe({js|scrollMargin|js}, {js| 6px 5px|js});
 CssJs.unsafe({js|scrollMargin|js}, {js| 10px 20px 30px|js});
 CssJs.unsafe({js|scrollMargin|js}, {js| 10px 20px 30px 40px|js});
 CssJs.unsafe({js|scrollMargin|js}, {js| 20px 3em 1in 5rem|js});
+CssJs.unsafe({js|scrollMargin|js}, {js| calc(2px)|js});
+CssJs.unsafe({js|scrollMargin|js}, {js| calc(3 * 25px)|js});
+CssJs.unsafe(
+  {js|scrollMargin|js},
+  {js| calc(3 * 25px) 5px 10em calc(1vw - 5px)|js},
+);
 CssJs.unsafe({js|scrollMarginBlock|js}, {js| 10px|js});
 CssJs.unsafe({js|scrollMarginBlock|js}, {js| 10px 10px|js});
 CssJs.unsafe({js|scrollMarginBlockEnd|js}, {js| 10px|js});
@@ -1435,6 +1450,13 @@ CssJs.unsafe({js|scrollPadding|js}, {js| 10px 20px 30px 40px|js});
 CssJs.unsafe({js|scrollPadding|js}, {js| 10px auto 30px auto|js});
 CssJs.unsafe({js|scrollPadding|js}, {js| 10%|js});
 CssJs.unsafe({js|scrollPadding|js}, {js| 20% 3em 1in 5rem|js});
+CssJs.unsafe({js|scrollPadding|js}, {js| calc(2px)|js});
+CssJs.unsafe({js|scrollPadding|js}, {js| calc(50%)|js});
+CssJs.unsafe({js|scrollPadding|js}, {js| calc(3 * 25px)|js});
+CssJs.unsafe(
+  {js|scrollPadding|js},
+  {js| calc(3 * 25px) 5px 10% calc(10% - 5px)|js},
+);
 CssJs.unsafe({js|scrollPaddingBlock|js}, {js| 10px|js});
 CssJs.unsafe({js|scrollPaddingBlock|js}, {js| 50%|js});
 CssJs.unsafe({js|scrollPaddingBlock|js}, {js| 10px 50%|js});
@@ -1692,6 +1714,8 @@ CssJs.maxHeight(`maxContent);
 CssJs.maxHeight(`minContent);
 CssJs.unsafe({js|maxHeight|js}, {js| fit-content(10%)|js});
 CssJs.unsafe({js|aspectRatio|js}, {js| auto|js});
+CssJs.unsafe({js|aspectRatio|js}, {js| 2|js});
+CssJs.unsafe({js|aspectRatio|js}, {js| 16 / 9|js});
 CssJs.width(`fitContent);
 CssJs.minWidth(`fitContent);
 CssJs.maxWidth(`fitContent);
diff --git a/packages/ppx/test/css-support/test.re b/packages/ppx/test/css-support/test.re
index 248497c72..97ff1be89 100644
--- a/packages/ppx/test/css-support/test.re
+++ b/packages/ppx/test/css-support/test.re
@@ -1892,11 +1892,11 @@
 /* CSS Masking Module Level 1 */
 [%css {|clip-path: url('#clip')|}];
 [%css {|clip-path: inset(50%)|}];
-/* [%css {|clip-path: circle()|}]; */
-/* [%css {|clip-path: ellipse()|}]; */
+[%css {|clip-path: circle()|}];
+[%css {|clip-path: ellipse()|}];
 /* [%css {|clip-path: polygon(0 10px, 30px 0)|}]; */
-/* [%css {|clip-path: path('M 20 20 H 80 V 30')|}]; */
-/* [%css {|clip-path: circle() border-box|}]; */
+[%css {|clip-path: path('M 20 20 H 80 V 30')|}];
+[%css {|clip-path: circle() border-box|}];
 [%css {|clip-path: border-box|}];
 [%css {|clip-path: padding-box|}];
 [%css {|clip-path: content-box|}];
@@ -1908,6 +1908,7 @@
 [%css {|clip-rule: nonzero|}];
 [%css {|clip-rule: evenodd|}];
 [%css {|mask-image: none|}];
+/* TODO: Parser.re don't contain linear-gradient as valid mask-image */
 /* [%css {|mask-image: linear-gradient(black 0%, transparent 100%)|}]; */
 [%css {|mask-image: url(image.png)|}];
 [%css {|mask-mode: alpha|}];
@@ -1938,7 +1939,8 @@
 [%css {|mask-position: center|}];
 [%css {|mask-position: center center|}];
 [%css {|mask-position: left 50%|}];
-/* [%css {|mask-position: bottom 10px right 20px|}]; */
+[%css {|mask-position: bottom 10px right 20px|}];
+/* TODO: mask-position is incomplete in Parser.re */
 /* [%css {|mask-position: bottom 10px right|}]; */
 /* [%css {|mask-position: top right 10px|}]; */
 [%css {|mask-clip: border-box|}];
@@ -1975,7 +1977,7 @@
 [%css {|mask: url(image.png) luminance|}];
 [%css {|mask: url(image.png) luminance top space|}];
 [%css {|mask-border-source: none|}];
-/* [%css {|mask-border-source: url(image.png)|}]; */
+[%css {|mask-border-source: url(image.png)|}];
 [%css {|mask-border-slice: 0 fill|}];
 [%css {|mask-border-slice: 50% fill|}];
 [%css {|mask-border-slice: 1.1 fill|}];
@@ -2015,7 +2017,8 @@
 [%css {|mask-border-repeat: repeat space|}];
 [%css {|mask-border-repeat: round space|}];
 [%css {|mask-border-repeat: space space|}];
-/* [%css {|mask-border: url(image.png)|}]; */
+[%css {|mask-border: url(image.png)|}];
+/* TODO: Parser.re is incomplete */
 /* [%css {|mask-border: url(image.png) 10px|}]; */
 /* [%css {|mask-border: url(image.png) space|}]; */
 /* [%css {|mask-border: url(image.png) 1 fill|}]; */
@@ -2143,7 +2146,7 @@
 /* Filter Effects Module Level 1 */
 [%css {|filter: none|}];
 [%css {|filter: url(#id)|}];
-/* [%css {|filter: url(image.svg#id)|}]; */
+[%css {|filter: url(image.svg#id)|}];
 [%css {|filter: blur(5px)|}];
 [%css {|filter: brightness(0.5)|}];
 [%css {|filter: contrast(150%)|}];
@@ -2170,7 +2173,7 @@
 /* Filter Effects Module Level 2 */
 [%css {|backdrop-filter: none|}];
 [%css {|backdrop-filter: url(#id)|}];
-/* [%css {|backdrop-filter: url(image.svg#id)|}]; */
+[%css {|backdrop-filter: url(image.svg#id)|}];
 [%css {|backdrop-filter: blur(5px)|}];
 [%css {|backdrop-filter: brightness(0.5)|}];
 [%css {|backdrop-filter: contrast(150%)|}];
@@ -2292,9 +2295,9 @@
 [%css {|scroll-margin: 10px 20px 30px|}];
 [%css {|scroll-margin: 10px 20px 30px 40px|}];
 [%css {|scroll-margin: 20px 3em 1in 5rem|}];
-/* [%css {|scroll-margin: calc(2px)|}]; */
-/* [%css {|scroll-margin: calc(3 * 25px)|}]; */
-/* [%css {|scroll-margin: calc(3 * 25px) 5px 10em calc(1vw - 5px)|}]; */
+[%css {|scroll-margin: calc(2px)|}];
+[%css {|scroll-margin: calc(3 * 25px)|}];
+[%css {|scroll-margin: calc(3 * 25px) 5px 10em calc(1vw - 5px)|}];
 [%css {|scroll-margin-block: 10px|}];
 [%css {|scroll-margin-block: 10px 10px|}];
 [%css {|scroll-margin-block-end: 10px|}];
@@ -2315,10 +2318,10 @@
 [%css {|scroll-padding: 10px auto 30px auto|}];
 [%css {|scroll-padding: 10%|}];
 [%css {|scroll-padding: 20% 3em 1in 5rem|}];
-/* [%css {|scroll-padding: calc(2px)|}]; */
-/* [%css {|scroll-padding: calc(50%)|}]; */
-/* [%css {|scroll-padding: calc(3 * 25px)|}]; */
-/* [%css {|scroll-padding: calc(3 * 25px) 5px 10% calc(10% - 5px)|}]; */
+[%css {|scroll-padding: calc(2px)|}];
+[%css {|scroll-padding: calc(50%)|}];
+[%css {|scroll-padding: calc(3 * 25px)|}];
+[%css {|scroll-padding: calc(3 * 25px) 5px 10% calc(10% - 5px)|}];
 [%css {|scroll-padding-block: 10px|}];
 [%css {|scroll-padding-block: 50%|}];
 [%css {|scroll-padding-block: 10px 50%|}];
@@ -2522,6 +2525,7 @@
 [%css {|list-style-type: other-style|}];
 [%css {|list-style-type: inside|}];
 [%css {|list-style-type: outside|}];
+/* TODO: escape chars lexing is half broken */
 /* [%css {|list-style-type: \32 style|}]; */
 [%css {|list-style-type: "-"|}];
 [%css {|list-style-type: '-'|}];
@@ -2631,8 +2635,8 @@
 
 /* CSS Box Sizing Module Level 4 */
 [%css {|aspect-ratio: auto|}];
-/* [%css {|aspect-ratio: 2|}]; */
-/* [%css {|aspect-ratio: 16 / 9|}]; */
+[%css {|aspect-ratio: 2|}];
+[%css {|aspect-ratio: 16 / 9|}];
 /* [%css {|aspect-ratio: auto 16 / 9|}]; */
 /* [%css {|contain-intrinsic-size: none|}]; */
 /* [%css {|contain-intrinsic-size: 10px|}]; */
diff --git a/packages/reason-css-parser/lib/Parser.re b/packages/reason-css-parser/lib/Parser.re
index eaac04e91..546542d8e 100644
--- a/packages/reason-css-parser/lib/Parser.re
+++ b/packages/reason-css-parser/lib/Parser.re
@@ -877,7 +877,7 @@ and pseudo_class_selector = [%value.rec "':' <ident-token> | ':' <function-token
 and pseudo_element_selector = [%value.rec "':' <pseudo-class-selector>"]
 and pseudo_page = [%value.rec "':' [ 'left' | 'right' | 'first' | 'blank' ]"]
 and quote = [%value.rec "'open-quote' | 'close-quote' | 'no-open-quote' | 'no-close-quote'"]
-and ratio = [%value.rec "<integer> '/' <integer>"]
+and ratio = [%value.rec "<integer> '/' <integer> | <integer>"]
 and relative_selector = [%value.rec "[ <combinator> ]? <complex-selector>"]
 and relative_selector_list = [%value.rec "[ <relative-selector> ]#"]
 and relative_size = [%value.rec "'larger' | 'smaller'"]
diff --git a/packages/renderer/ast_renderer.re b/packages/renderer/ast_renderer.re
index d97ea649f..da5cd6cfd 100644
--- a/packages/renderer/ast_renderer.re
+++ b/packages/renderer/ast_renderer.re
@@ -186,7 +186,7 @@ and render_component_value = (ast: with_loc(Component_value.t)) => {
   | Function(name, body) =>
     let body =
       body |> fst |> List.map(render_component_value) |> String.concat(", ");
-    "Function(" ++ fst(name) ++ ", " ++ body ++ ")";
+    "Function(" ++ fst(name) ++ ", [" ++ body ++ "])";
   | Hash(string) => "Hash(" ++ string ++ ")"
   | Number(string) => "Number(" ++ string ++ ")"
   | Unicode_range(string) => "Unicode_range(" ++ string ++ ")"