diff --git a/src/parse/properties/utils.c b/src/parse/properties/utils.c
index 687e8d9..01e1219 100644
--- a/src/parse/properties/utils.c
+++ b/src/parse/properties/utils.c
@@ -487,34 +487,75 @@ static bool parse_rgb(
  *
  * \param vector  Vector of tokens to process
  * \param ctx     Pointer to vector iteration context
- * \param colour_channels Number of colour channels to expect
  * \param result  Pointer to location to receive result (AARRGGBB)
  * \return true on success, false on error.
  */
 static bool parse_hsl(
 		const parserutils_vector *vector,
 		int32_t *ctx,
-		int colour_channels,
 		uint32_t *result)
 {
 	const css_token *token;
 	size_t consumed = 0;
 	css_fixed hue, sat, lit;
 	int32_t alpha = 255;
+	bool legacy = false;
+	css_error error;
 	uint8_t r = 0, g = 0, b = 0, a = 0xff;
 
 	/* hue is a number without a unit representing an
-	 * angle (0-360) degrees
+	 * angle (0-360) degrees, or it can be an angle dimension.
 	 */
 	consumeWhitespace(vector, ctx);
 
 	token = parserutils_vector_iterate(vector, ctx);
-	if ((token == NULL) || (token->type != CSS_TOKEN_NUMBER))
+	if ((token == NULL) ||
+			(token->type != CSS_TOKEN_NUMBER &&
+			 token->type != CSS_TOKEN_DIMENSION)) {
 		return false;
+	}
 
 	hue = css__number_from_lwc_string(token->idata, false, &consumed);
-	if (consumed != lwc_string_length(token->idata))
-		return false; /* failed to consume the whole string as a number */
+
+	switch (token->type) {
+	case CSS_TOKEN_NUMBER:
+		if (consumed != lwc_string_length(token->idata)) {
+			return false; /* failed to consume the whole string as a number */
+		}
+		break;
+	case CSS_TOKEN_DIMENSION: {
+		size_t len = lwc_string_length(token->idata);
+		const char *data = lwc_string_data(token->idata);
+		uint32_t unit = UNIT_DEG;
+
+		error = css__parse_unit_keyword(
+				data + consumed,
+				len - consumed,
+				&unit);
+		if (error != CSS_OK) {
+			return false;
+		}
+
+		switch (unit) {
+		case UNIT_DEG:
+			break;
+		case UNIT_RAD:
+			hue = FDIV(FMUL(hue, F_180), F_PI);
+			break;
+		case UNIT_GRAD:
+			hue = FMUL(hue, FLTTOFIX(0.9));
+			break;
+		case UNIT_TURN:
+			hue = FMUL(hue, F_360);
+			break;
+		default:
+			return false;
+		}
+	}
+		break;
+	default:
+		return false; /* unexpected token type */
+	}
 
 	/* Normalise hue to the range [0, 360) */
 	while (hue < 0)
@@ -524,21 +565,32 @@ static bool parse_hsl(
 
 	consumeWhitespace(vector, ctx);
 
-	token = parserutils_vector_iterate(vector, ctx);
-	if (!tokenIsChar(token, ','))
+	token = parserutils_vector_peek(vector, *ctx);
+	if (token == NULL) {
 		return false;
+	}
 
+	if (tokenIsChar(token, ',')) {
+		parserutils_vector_iterate(vector, ctx);
+		consumeWhitespace(vector, ctx);
+		legacy = true;
+	}
 
 	/* saturation */
-	consumeWhitespace(vector, ctx);
-
 	token = parserutils_vector_iterate(vector, ctx);
-	if ((token == NULL) || (token->type != CSS_TOKEN_PERCENTAGE))
+	if (token == NULL)
 		return false;
 
+	if ((token->type != CSS_TOKEN_PERCENTAGE) &&
+	    (token->type != CSS_TOKEN_NUMBER || legacy)) {
+		return false;
+	}
+
 	sat = css__number_from_lwc_string(token->idata, false, &consumed);
-	if (consumed != lwc_string_length(token->idata))
-		return false; /* failed to consume the whole string as a number */
+	if (consumed != lwc_string_length(token->idata)) {
+		/* failed to consume the whole string as a number */
+		return false;
+	}
 
 	/* Normalise saturation to the range [0, 100] */
 	if (sat < INTTOFIX(0))
@@ -548,21 +600,30 @@ static bool parse_hsl(
 
 	consumeWhitespace(vector, ctx);
 
-	token = parserutils_vector_iterate(vector, ctx);
-	if (!tokenIsChar(token, ','))
-		return false;
+	if (legacy) {
+		token = parserutils_vector_iterate(vector, ctx);
+		if (token == NULL || !tokenIsChar(token, ',')) {
+			return false;
+		}
 
+		consumeWhitespace(vector, ctx);
+	}
 
 	/* lightness */
-	consumeWhitespace(vector, ctx);
-
 	token = parserutils_vector_iterate(vector, ctx);
-	if ((token == NULL) || (token->type != CSS_TOKEN_PERCENTAGE))
+	if (token == NULL)
 		return false;
 
+	if ((token->type != CSS_TOKEN_PERCENTAGE) &&
+	    (token->type != CSS_TOKEN_NUMBER || legacy)) {
+		return false;
+	}
+
 	lit = css__number_from_lwc_string(token->idata, false, &consumed);
-	if (consumed != lwc_string_length(token->idata))
-		return false; /* failed to consume the whole string as a number */
+	if (consumed != lwc_string_length(token->idata)) {
+		/* failed to consume the whole string as a number */
+		return false;
+	}
 
 	/* Normalise lightness to the range [0, 100] */
 	if (lit < INTTOFIX(0))
@@ -574,28 +635,32 @@ static bool parse_hsl(
 
 	token = parserutils_vector_iterate(vector, ctx);
 
-	if (colour_channels == 6) {
-		/* alpha */
-
-		if (!tokenIsChar(token, ','))
-			return false;
-
+	if (( legacy && tokenIsChar(token, ',')) ||
+	    (!legacy && tokenIsChar(token, '/'))) {
 		consumeWhitespace(vector, ctx);
 
 		token = parserutils_vector_iterate(vector, ctx);
-		if ((token == NULL) || (token->type != CSS_TOKEN_NUMBER))
+		if ((token == NULL) ||
+				(token->type != CSS_TOKEN_NUMBER &&
+				 token->type != CSS_TOKEN_PERCENTAGE)) {
 			return false;
+		}
 
 		alpha = css__number_from_lwc_string(token->idata, false, &consumed);
-		if (consumed != lwc_string_length(token->idata))
-			return false; /* failed to consume the whole string as a number */
+		if (consumed != lwc_string_length(token->idata)) {
+			/* failed to consume the whole string as a number */
+			return false;
+		}
 
-		alpha = FIXTOINT(FMUL(alpha, F_255));
+		if (token->type != CSS_TOKEN_NUMBER) {
+			alpha = FIXTOINT(FMUL(alpha, F_255));
+		} else {
+			alpha = FIXTOINT(FDIV(FMUL(alpha, F_255), F_100));
+		}
 
 		consumeWhitespace(vector, ctx);
 
 		token = parserutils_vector_iterate(vector, ctx);
-
 	}
 
 	if (!tokenIsChar(token, ')'))
@@ -731,7 +796,7 @@ css_error css__parse_colour_specifier(css_language *c,
 				goto invalid;
 			}
 		} else if (colour_channels == 5 || colour_channels == 6) {
-			if (!parse_hsl(vector, ctx, colour_channels, result)) {
+			if (!parse_hsl(vector, ctx, result)) {
 				goto invalid;
 			}
 		} else {