diff --git a/build.gradle.kts b/build.gradle.kts
index 9193f9e..9a23b50 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    kotlin("multiplatform") version "1.5.31"
+    kotlin("multiplatform") version "1.6.10"
     `maven-publish`
     signing
     id("org.jetbrains.dokka") version "1.5.31"
@@ -7,11 +7,10 @@
 }
 
 group = "nl.astraeus"
-version = "1.0.5-SNAPSHOT"
+version = "1.0.6"
 
 repositories {
     mavenCentral()
-    maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
 }
 
 kotlin {

diff --git a/build.gradle.kts b/build.gradle.kts
index 9193f9e..9a23b50 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    kotlin("multiplatform") version "1.5.31"
+    kotlin("multiplatform") version "1.6.10"
     `maven-publish`
     signing
     id("org.jetbrains.dokka") version "1.5.31"
@@ -7,11 +7,10 @@
 }
 
 group = "nl.astraeus"
-version = "1.0.5-SNAPSHOT"
+version = "1.0.6"
 
 repositories {
     mavenCentral()
-    maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
 }
 
 kotlin {
diff --git a/settings.gradle.kts b/settings.gradle.kts
index a22324a..09b3ea5 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,7 +1,5 @@
 pluginManagement {
     repositories {
-        maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
-
         mavenCentral()
 
         maven { setUrl("https://plugins.gradle.org/m2/") }

diff --git a/build.gradle.kts b/build.gradle.kts
index 9193f9e..9a23b50 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    kotlin("multiplatform") version "1.5.31"
+    kotlin("multiplatform") version "1.6.10"
     `maven-publish`
     signing
     id("org.jetbrains.dokka") version "1.5.31"
@@ -7,11 +7,10 @@
 }
 
 group = "nl.astraeus"
-version = "1.0.5-SNAPSHOT"
+version = "1.0.6"
 
 repositories {
     mavenCentral()
-    maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
 }
 
 kotlin {
diff --git a/settings.gradle.kts b/settings.gradle.kts
index a22324a..09b3ea5 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,7 +1,5 @@
 pluginManagement {
     repositories {
-        maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
-
         mavenCentral()
 
         maven { setUrl("https://plugins.gradle.org/m2/") }
diff --git a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt b/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
deleted file mode 100644
index e49c1d4..0000000
--- a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-package nl.astraeus.css.style
-
-import nl.astraeus.css.properties.Color
-
-object CssFunctions {
-
-  fun darken(color: Color, percentage: Int): Color {
-    return color
-  }
-
-}

diff --git a/build.gradle.kts b/build.gradle.kts
index 9193f9e..9a23b50 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    kotlin("multiplatform") version "1.5.31"
+    kotlin("multiplatform") version "1.6.10"
     `maven-publish`
     signing
     id("org.jetbrains.dokka") version "1.5.31"
@@ -7,11 +7,10 @@
 }
 
 group = "nl.astraeus"
-version = "1.0.5-SNAPSHOT"
+version = "1.0.6"
 
 repositories {
     mavenCentral()
-    maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
 }
 
 kotlin {
diff --git a/settings.gradle.kts b/settings.gradle.kts
index a22324a..09b3ea5 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,7 +1,5 @@
 pluginManagement {
     repositories {
-        maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
-
         mavenCentral()
 
         maven { setUrl("https://plugins.gradle.org/m2/") }
diff --git a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt b/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
deleted file mode 100644
index e49c1d4..0000000
--- a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-package nl.astraeus.css.style
-
-import nl.astraeus.css.properties.Color
-
-object CssFunctions {
-
-  fun darken(color: Color, percentage: Int): Color {
-    return color
-  }
-
-}
diff --git a/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt b/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
index 74079ae..28d440c 100644
--- a/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
+++ b/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
@@ -222,7 +222,7 @@
       if (css.isNotBlank()) {
         val builder = StringBuilder()
 
-        check (allowCommaInSelector || !name.contains(',')) {
+        check (allowCommaInSelector || (name.indexOf(',') == -1)) {
           "Comma is not allowed in selector (option is set in generateCss call)"
         }
 
@@ -862,6 +862,10 @@
     props["content"] = prp(content)
   }
 
+  fun content(content: String) {
+    props["content"] = prp(content)
+  }
+
   fun counterIncrement(increment: String) {
     props["counter-increment"] = prp(increment)
   }
@@ -1610,6 +1614,8 @@
     addStyle("::${selector.description()}", style)
   }
 
+  fun not(name: DescriptionProvider): DescriptionProvider = ValueDescriptionProvider(":not(${name.description()})")
+  @Deprecated("Use select(not(...)) instead.")
   fun not(selector: DescriptionProvider, style: Css) {
     addStyle(":not(${selector.description()})", style)
   }

diff --git a/build.gradle.kts b/build.gradle.kts
index 9193f9e..9a23b50 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    kotlin("multiplatform") version "1.5.31"
+    kotlin("multiplatform") version "1.6.10"
     `maven-publish`
     signing
     id("org.jetbrains.dokka") version "1.5.31"
@@ -7,11 +7,10 @@
 }
 
 group = "nl.astraeus"
-version = "1.0.5-SNAPSHOT"
+version = "1.0.6"
 
 repositories {
     mavenCentral()
-    maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
 }
 
 kotlin {
diff --git a/settings.gradle.kts b/settings.gradle.kts
index a22324a..09b3ea5 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,7 +1,5 @@
 pluginManagement {
     repositories {
-        maven { setUrl("https://dl.bintray.com/kotlin/kotlin-eap") }
-
         mavenCentral()
 
         maven { setUrl("https://plugins.gradle.org/m2/") }
diff --git a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt b/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
deleted file mode 100644
index e49c1d4..0000000
--- a/src/commonMain/kotlin/nl/astraeus/css/style/CssFunctions.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-package nl.astraeus.css.style
-
-import nl.astraeus.css.properties.Color
-
-object CssFunctions {
-
-  fun darken(color: Color, percentage: Int): Color {
-    return color
-  }
-
-}
diff --git a/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt b/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
index 74079ae..28d440c 100644
--- a/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
+++ b/src/commonMain/kotlin/nl/astraeus/css/style/Style.kt
@@ -222,7 +222,7 @@
       if (css.isNotBlank()) {
         val builder = StringBuilder()
 
-        check (allowCommaInSelector || !name.contains(',')) {
+        check (allowCommaInSelector || (name.indexOf(',') == -1)) {
           "Comma is not allowed in selector (option is set in generateCss call)"
         }
 
@@ -862,6 +862,10 @@
     props["content"] = prp(content)
   }
 
+  fun content(content: String) {
+    props["content"] = prp(content)
+  }
+
   fun counterIncrement(increment: String) {
     props["counter-increment"] = prp(increment)
   }
@@ -1610,6 +1614,8 @@
     addStyle("::${selector.description()}", style)
   }
 
+  fun not(name: DescriptionProvider): DescriptionProvider = ValueDescriptionProvider(":not(${name.description()})")
+  @Deprecated("Use select(not(...)) instead.")
   fun not(selector: DescriptionProvider, style: Css) {
     addStyle(":not(${selector.description()})", style)
   }
diff --git a/src/commonTest/kotlin/nl/astraeus/css/TestCalcExpression.kt b/src/commonTest/kotlin/nl/astraeus/css/TestCalcExpression.kt
index 65739cf..a01ef72 100644
--- a/src/commonTest/kotlin/nl/astraeus/css/TestCalcExpression.kt
+++ b/src/commonTest/kotlin/nl/astraeus/css/TestCalcExpression.kt
@@ -9,7 +9,6 @@
 
 class TestCalcExpression {
 
-
   @Test
   fun testCalcExpression() {
     val a = calc(10.px + 20.px - 5.em)