diff --git a/src/builtin/functions/color/hsl.rs b/src/builtin/functions/color/hsl.rs
index fb742eb..359afd5 100644
--- a/src/builtin/functions/color/hsl.rs
+++ b/src/builtin/functions/color/hsl.rs
@@ -18,7 +18,9 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
         return Err(("Missing argument $channels.", args.span()).into());
     }
 
-    if args.len() == 1 {
+    let len = args.len();
+
+    if len == 1 {
         let mut channels = match args.get_err(0, "channels")? {
             Value::List(v, ..) => v,
             _ => return Err(("Missing argument $channels.", args.span()).into()),
@@ -99,30 +101,42 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
             Number::one(),
         ))))
     } else {
-        let hue = match args.get_err(0, "hue")? {
+        let hue = args.get_err(0, "hue")?;
+        let saturation = args.get_err(1, "saturation")?;
+        let lightness = args.get_err(2, "lightness")?;
+        let alpha = args.default_arg(
+            3,
+            "alpha",
+            Value::Dimension(Some(Number::one()), Unit::None, true),
+        )?;
+
+        if [&hue, &saturation, &lightness, &alpha]
+            .iter()
+            .copied()
+            .any(Value::is_special_function)
+        {
+            return Ok(Value::String(
+                format!(
+                    "{}({})",
+                    name,
+                    Value::List(
+                        if len == 4 {
+                            vec![hue, saturation, lightness, alpha]
+                        } else {
+                            vec![hue, saturation, lightness]
+                        },
+                        ListSeparator::Comma,
+                        Brackets::None
+                    )
+                    .to_css_string(args.span(), false)?
+                ),
+                QuoteKind::None,
+            ));
+        }
+
+        let hue = match hue {
             Value::Dimension(Some(n), ..) => n,
             Value::Dimension(None, ..) => todo!(),
-            v if v.is_special_function() => {
-                let saturation = args.get_err(1, "saturation")?;
-                let lightness = args.get_err(2, "lightness")?;
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    v.to_css_string(args.span(), parser.options.is_compressed())?,
-                    saturation.to_css_string(args.span(), parser.options.is_compressed())?,
-                    lightness.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!("$hue: {} is not a number.", v.inspect(args.span())?),
@@ -131,29 +145,9 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let saturation = match args.get_err(1, "saturation")? {
+        let saturation = match saturation {
             Value::Dimension(Some(n), ..) => n / Number::from(100),
             Value::Dimension(None, ..) => todo!(),
-            v if v.is_special_function() => {
-                let lightness = args.get_err(2, "lightness")?;
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    hue.to_string(parser.options.is_compressed()),
-                    v.to_css_string(args.span(), parser.options.is_compressed())?,
-                    lightness.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!(
@@ -165,28 +159,9 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let lightness = match args.get_err(2, "lightness")? {
+        let lightness = match lightness {
             Value::Dimension(Some(n), ..) => n / Number::from(100),
             Value::Dimension(None, ..) => todo!(),
-            v if v.is_special_function() => {
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    hue.to_string(parser.options.is_compressed()),
-                    saturation.to_string(parser.options.is_compressed()),
-                    v.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!(
@@ -198,11 +173,7 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let alpha = match args.default_arg(
-            3,
-            "alpha",
-            Value::Dimension(Some(Number::one()), Unit::None, true),
-        )? {
+        let alpha = match alpha {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => n / Number::from(100),
             Value::Dimension(None, ..) => todo!(),
@@ -216,19 +187,6 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                return Ok(Value::String(
-                    format!(
-                        "{}({}, {}, {}, {})",
-                        name,
-                        hue.to_string(parser.options.is_compressed()),
-                        saturation.to_string(parser.options.is_compressed()),
-                        lightness.to_string(parser.options.is_compressed()),
-                        v.to_css_string(args.span(), parser.options.is_compressed())?
-                    ),
-                    QuoteKind::None,
-                ));
-            }
             v => {
                 return Err((
                     format!("$alpha: {} is not a number.", v.inspect(args.span())?),
diff --git a/src/builtin/functions/color/rgb.rs b/src/builtin/functions/color/rgb.rs
index 9917d8a..ac85b20 100644
--- a/src/builtin/functions/color/rgb.rs
+++ b/src/builtin/functions/color/rgb.rs
@@ -20,7 +20,9 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
         return Err(("Missing argument $channels.", args.span()).into());
     }
 
-    if args.len() == 1 {
+    let len = args.len();
+
+    if len == 1 {
         let mut channels = match args.get_err(0, "channels")? {
             Value::List(v, ..) => v,
             _ => return Err(("Missing argument $channels.", args.span()).into()),
@@ -150,7 +152,7 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
         let color = Color::from_rgba(red, green, blue, Number::one());
 
         Ok(Value::Color(Box::new(color)))
-    } else if args.len() == 2 {
+    } else if len == 2 {
         let color = match args.get_err(0, "color")? {
             Value::Color(c) => c,
             v if v.is_special_function() => {
@@ -210,7 +212,40 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
         };
         Ok(Value::Color(Box::new(color.with_alpha(alpha))))
     } else {
-        let red = match args.get_err(0, "red")? {
+        let red = args.get_err(0, "red")?;
+        let green = args.get_err(1, "green")?;
+        let blue = args.get_err(2, "blue")?;
+        let alpha = args.default_arg(
+            3,
+            "alpha",
+            Value::Dimension(Some(Number::one()), Unit::None, true),
+        )?;
+
+        if [&red, &green, &blue, &alpha]
+            .iter()
+            .copied()
+            .any(Value::is_special_function)
+        {
+            return Ok(Value::String(
+                format!(
+                    "{}({})",
+                    name,
+                    Value::List(
+                        if len == 4 {
+                            vec![red, green, blue, alpha]
+                        } else {
+                            vec![red, green, blue]
+                        },
+                        ListSeparator::Comma,
+                        Brackets::None
+                    )
+                    .to_css_string(args.span(), false)?
+                ),
+                QuoteKind::None,
+            ));
+        }
+
+        let red = match red {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => {
                 (n / Number::from(100)) * Number::from(255)
@@ -226,27 +261,6 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                let green = args.get_err(1, "green")?;
-                let blue = args.get_err(2, "blue")?;
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    v.to_css_string(args.span(), parser.options.is_compressed())?,
-                    green.to_css_string(args.span(), parser.options.is_compressed())?,
-                    blue.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!("$red: {} is not a number.", v.inspect(args.span())?),
@@ -255,7 +269,7 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let green = match args.get_err(1, "green")? {
+        let green = match green {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => {
                 (n / Number::from(100)) * Number::from(255)
@@ -271,26 +285,6 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                let blue = args.get_err(2, "blue")?;
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    red.to_string(parser.options.is_compressed()),
-                    v.to_css_string(args.span(), parser.options.is_compressed())?,
-                    blue.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!("$green: {} is not a number.", v.inspect(args.span())?),
@@ -299,7 +293,7 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let blue = match args.get_err(2, "blue")? {
+        let blue = match blue {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => {
                 (n / Number::from(100)) * Number::from(255)
@@ -315,25 +309,6 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                let mut string = format!(
-                    "{}({}, {}, {}",
-                    name,
-                    red.to_string(parser.options.is_compressed()),
-                    green.to_string(parser.options.is_compressed()),
-                    v.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                if !args.is_empty() {
-                    string.push_str(", ");
-                    string.push_str(
-                        &args
-                            .get_err(3, "alpha")?
-                            .to_css_string(args.span(), parser.options.is_compressed())?,
-                    );
-                }
-                string.push(')');
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!("$blue: {} is not a number.", v.inspect(args.span())?),
@@ -342,11 +317,7 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let alpha = match args.default_arg(
-            3,
-            "alpha",
-            Value::Dimension(Some(Number::one()), Unit::None, true),
-        )? {
+        let alpha = match alpha {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => n / Number::from(100),
             Value::Dimension(None, ..) => todo!(),
@@ -360,17 +331,6 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                let string = format!(
-                    "{}({}, {}, {}, {})",
-                    name,
-                    red.to_string(parser.options.is_compressed()),
-                    green.to_string(parser.options.is_compressed()),
-                    blue.to_string(parser.options.is_compressed()),
-                    v.to_css_string(args.span(), parser.options.is_compressed())?
-                );
-                return Ok(Value::String(string, QuoteKind::None));
-            }
             v => {
                 return Err((
                     format!("$alpha: {} is not a number.", v.inspect(args.span())?),
diff --git a/tests/color.rs b/tests/color.rs
index 57c9654..0742280 100644
--- a/tests/color.rs
+++ b/tests/color.rs
@@ -737,6 +737,26 @@ test!(
     "a {\n  color: rgba(1 2 max(3, 3));\n}\n",
     "a {\n  color: rgba(1, 2, max(3, 3));\n}\n"
 );
+test!(
+    rgb_special_fn_4_arg_maintains_units,
+    "a {\n  color: rgb(1, 0.02, 3%, max(0.4));\n}\n",
+    "a {\n  color: rgb(1, 0.02, 3%, max(0.4));\n}\n"
+);
+test!(
+    rgb_special_fn_3_arg_maintains_units,
+    "a {\n  color: rgb(1, 0.02, max(0.4));\n}\n",
+    "a {\n  color: rgb(1, 0.02, max(0.4));\n}\n"
+);
+test!(
+    hsl_special_fn_4_arg_maintains_units,
+    "a {\n  color: hsl(1, 0.02, 3%, max(0.4));\n}\n",
+    "a {\n  color: hsl(1, 0.02, 3%, max(0.4));\n}\n"
+);
+test!(
+    hsl_special_fn_3_arg_maintains_units,
+    "a {\n  color: hsl(1, 0.02, max(0.4));\n}\n",
+    "a {\n  color: hsl(1, 0.02, max(0.4));\n}\n"
+);
 test!(
     #[ignore = "we do not check if interpolation occurred"]
     interpolated_named_color_is_not_color,