diff --git a/core/shared/src/main/scala/scalacss/internal/Css.scala b/core/shared/src/main/scala/scalacss/internal/Css.scala
index 27f7536a..2061451d 100644
--- a/core/shared/src/main/scala/scalacss/internal/Css.scala
+++ b/core/shared/src/main/scala/scalacss/internal/Css.scala
@@ -2,17 +2,25 @@ package scalacss.internal
 
 object Css {
 
-  def apply(ss: TraversableOnce[StyleA], kfs: TraversableOnce[Keyframes], ff: TraversableOnce[FontFace[String]])(implicit env: Env): Css =
-    styles(ss) append keyframes(kfs) append fontFaces(ff)
+  def apply(ss: TraversableOnce[StyleA],
+            kfs: TraversableOnce[Keyframes],
+            ff: TraversableOnce[FontFace[String]])
+           (implicit env: Env): Css = {
+    val b = Vector.newBuilder[CssEntry]
+    b ++= styles(ss)
+    b ++= keyframes(kfs)
+    b ++= fontFaces(ff)
+    b.result()
+  }
 
   def styles(ss: TraversableOnce[StyleA])(implicit env: Env): StyleStream =
-    ss.toStream flatMap styleA
+    ss.toIterator.flatMap(styleA).toVector
 
   def keyframes(kfs: TraversableOnce[Keyframes])(implicit env: Env): KeyframeStream =
-    kfs.toStream map keyframes
+    kfs.toIterator.map(keyframes).toList
 
   def fontFaces(ff: TraversableOnce[FontFace[String]]): FontFaceStream =
-    ff.toStream map fontFaces
+    ff.toIterator.map(fontFaces).toList
 
   def className(cn: ClassName): CssSelector =
     "." + cn.value
@@ -36,21 +44,21 @@ object Css {
     style(className(s.className), s.style)
 
   def style(sel: CssSelector, s: StyleS)(implicit env: Env): StyleStream = {
-    def main: StyleStream =
-      s.data.toStream.flatMap {
+    def main: Iterator[CssEntry.Style] =
+      s.data.iterator.flatMap {
         case (cond, avs) =>
           val kvs = avs.avIterator.map(_(env)).foldLeft(Vector.empty[CssKV])(_ ++ _)
-          NonEmptyVector.maybe(kvs, Stream.empty[CssEntry.Style]) {c =>
+          NonEmptyVector.maybe(kvs, List.empty[CssEntry.Style]) { c =>
             val mq = mediaQuery(cond)
-            val s  = selector(sel, cond)
-            Stream(CssEntry.Style(mq, s, c))
+            val s = selector(sel, cond)
+            CssEntry.Style(mq, s, c) :: Nil
           }
         }
 
-    def exts: StyleStream =
-      s.unsafeExts.toStream.flatMap(unsafeExt(sel, _))
+    def exts: Iterator[CssEntry.Style] =
+      s.unsafeExts.toIterator.flatMap(unsafeExt(sel, _))
 
-    main append exts
+    (main ++ exts).toVector
   }
 
   def unsafeExt(root: CssSelector, u: Style.UnsafeExt)(implicit env: Env): StyleStream = {
@@ -62,9 +70,9 @@ object Css {
   type ByMediaQuery       = Map[CssMediaQueryO, ValuesByMediaQuery]
 
   def separateStylesAndKeyframes(c: Css): (StyleStream, KeyframeStream, FontFaceStream) = {
-    val styles = Stream.newBuilder[CssEntry.Style]
-    val animations = Stream.newBuilder[CssEntry.Keyframes]
-    val fontFaces = Stream.newBuilder[CssEntry.FontFace]
+    val styles = Vector.newBuilder[CssEntry.Style]
+    val animations = List.newBuilder[CssEntry.Keyframes]
+    val fontFaces = List.newBuilder[CssEntry.FontFace]
     c.foreach {
       case e: CssEntry.Style => styles += e
       case e: CssEntry.Keyframes => animations += e
@@ -82,14 +90,14 @@ object Css {
     }
   }
 
-  def flatten(css: StyleStream): Stream[(CssMediaQueryO, CssSelector, CssKV)] =
+  def flatten(css: StyleStream): Vector[(CssMediaQueryO, CssSelector, CssKV)] =
     css.flatMap { case CssEntry.Style(mq, sel, kvs) =>
-      kvs.toStream.map(kv => (mq, sel, kv))
+      kvs.iterator.map(kv => (mq, sel, kv))
     }
 
   type Flat4 = (CssMediaQueryO, CssSelector, String, String)
-  def flatten4(css: StyleStream): Stream[Flat4] =
+  def flatten4(css: StyleStream): Vector[Flat4] =
     css.flatMap { case CssEntry.Style(mq, sel, kvs) =>
-      kvs.toStream.map(kv => (mq, sel, kv.key, kv.value))
+      kvs.iterator.map(kv => (mq, sel, kv.key, kv.value))
     }
 }
\ No newline at end of file
diff --git a/core/shared/src/main/scala/scalacss/internal/NonEmptyVector.scala b/core/shared/src/main/scala/scalacss/internal/NonEmptyVector.scala
index 8f453326..e305d2bd 100644
--- a/core/shared/src/main/scala/scalacss/internal/NonEmptyVector.scala
+++ b/core/shared/src/main/scala/scalacss/internal/NonEmptyVector.scala
@@ -61,7 +61,6 @@ final class NonEmptyVector[+A](val head: A, val tail: Vector[A]) {
     foldMapLeft1(f)((b, a) => g(b, f(a)))
 
   def toSet[B >: A] = whole.toSet[B]
-  def toStream      = whole.toStream
 }
 
 // =====================================================================================================================
diff --git a/core/shared/src/main/scala/scalacss/internal/package.scala b/core/shared/src/main/scala/scalacss/internal/package.scala
index ef20373d..25cbf242 100644
--- a/core/shared/src/main/scala/scalacss/internal/package.scala
+++ b/core/shared/src/main/scala/scalacss/internal/package.scala
@@ -34,15 +34,15 @@ package object internal {
   type KeyframeAnimationName = ClassName
   type KeyframeSelector      = Percentage[_]
 
-  type StyleStream    = Stream[CssEntry.Style]
-  type KeyframeStream = Stream[CssEntry.Keyframes]
-  type FontFaceStream = Stream[CssEntry.FontFace]
+  type StyleStream    = Vector[CssEntry.Style]
+  type KeyframeStream = List[CssEntry.Keyframes]
+  type FontFaceStream = List[CssEntry.FontFace]
 
   /**
    * A stylesheet in its entirety. Normally turned into a `.css` file or a `<style>` tag.
    */
-  type Css = Stream[CssEntry]
-  implicit def univEqCss: UnivEq[Css] = UnivEq.univEqStream
+  type Css = Vector[CssEntry]
+  implicit def univEqCss: UnivEq[Css] = UnivEq.univEqVector
 
   type WarningMsg = String
   final case class Warning(cond: Cond, msg: WarningMsg)
diff --git a/doc/history/0.5.md b/doc/history/0.5.md
index 23276069..1e9b844a 100644
--- a/doc/history/0.5.md
+++ b/doc/history/0.5.md
@@ -69,3 +69,5 @@
   * scalajs-react 1.0.0.
 
 * Compile for Scala 2.12 with `-opt:l:method`
+
+* Replace all instance of `Stream` with `List`, `Vector` or `Iterator`