diff --git a/clay.cabal b/clay.cabal
--- a/clay.cabal
+++ b/clay.cabal
@@ -1,5 +1,5 @@
 Name:     clay
-Version:  0.7
+Version:  0.8
 Synopsis: CSS preprocessor as embedded Haskell.
 Description:
   Clay is a CSS preprocessor like LESS and Sass, but implemented as an embedded
@@ -11,10 +11,13 @@
   .
   The API documentation can be found in the top level module "Clay".
   .
-  > 0.6 -> 0.7
-  >   - Stop printing banner in compact mode.
-  >   - Generic font family as datatype.
-  >   - Only drop final semicolon if doing compact printing.
+  > 0.7 -> 0.8
+  >   - Print prettier doubles.
+  >   - Loosen type of sym functions.
+  >   - Added some missing multi-side properties.
+  >   - Added content URL support.
+  >   - Added inset box shadows.
+  >   Thanks Deck and James Fisher.
 
 Author:        Sebastiaan Visser
 Maintainer:    Sebastiaan Visser <code@fvisser.nl>
@@ -24,7 +27,7 @@
 License:       BSD3
 License-File:  LICENSE
 Category:      Web, Graphics
-Cabal-Version: >= 1.6
+Cabal-Version: >= 1.8
 Build-Type:    Simple
 
 Source-Repository head
@@ -68,3 +71,15 @@
     base  >= 4    && < 5,
     mtl   >= 1    && < 2.2,
     text  >= 0.11 && < 0.12
+
+Test-Suite Test-Clay
+  Type: exitcode-stdio-1.0
+  HS-Source-Dirs: src
+  Main-Is: Test.hs
+  Build-Depends:
+    base                 >= 4   && < 5,
+    HUnit                >= 1.2 && < 1.3,
+    test-framework       >= 0.8 && < 0.9,
+    test-framework-hunit >= 0.3 && < 0.4
+  Ghc-Options: -Wall
+
diff --git a/src/Clay/Border.hs b/src/Clay/Border.hs
--- a/src/Clay/Border.hs
+++ b/src/Clay/Border.hs
@@ -8,16 +8,16 @@
 -- * Border properties.
 
 , border, borderTop, borderLeft, borderBottom, borderRight
-, borderColor, borderLeftColor, borderRightColor, borderTopColor, borderBottomColor
-, borderStyle, borderLeftStyle, borderRightStyle, borderTopStyle, borderBottomStyle
-, borderWidth, borderLeftWidth, borderRightWidth, borderTopWidth, borderBottomWidth
+, borderColor4, borderColor, borderLeftColor, borderRightColor, borderTopColor, borderBottomColor
+, borderStyle4, borderStyle, borderLeftStyle, borderRightStyle, borderTopStyle, borderBottomStyle
+, borderWidth4, borderWidth, borderLeftWidth, borderRightWidth, borderTopWidth, borderBottomWidth
 
 -- * Outline properties.
 
 , outline, outlineTop, outlineLeft, outlineBottom, outlineRight
-, outlineColor, outlineLeftColor, outlineRightColor, outlineTopColor, outlineBottomColor
-, outlineStyle, outlineLeftStyle, outlineRightStyle, outlineTopStyle, outlineBottomStyle
-, outlineWidth, outlineLeftWidth, outlineRightWidth, outlineTopWidth, outlineBottomWidth
+, outlineColor4, outlineColor, outlineLeftColor, outlineRightColor, outlineTopColor, outlineBottomColor
+, outlineStyle4, outlineStyle, outlineLeftStyle, outlineRightStyle, outlineTopStyle, outlineBottomStyle
+, outlineWidth4, outlineWidth, outlineLeftWidth, outlineRightWidth, outlineTopWidth, outlineBottomWidth
 , outlineOffset
 
 -- * Border radius.
@@ -59,6 +59,9 @@
 borderBottom  a b c = key "border-bottom" (a ! b ! c)
 borderRight   a b c = key "border-right"  (a ! b ! c)
 
+borderColor4 :: Color -> Color -> Color -> Color -> Css
+borderColor4 a b c d = key "border-color" (a ! b ! c ! d)
+
 borderColor, borderLeftColor, borderRightColor, borderTopColor, borderBottomColor :: Color -> Css
 
 borderColor       = key "border-color"
@@ -67,6 +70,9 @@
 borderTopColor    = key "border-top-color"
 borderBottomColor = key "border-bottom-color"
 
+borderStyle4 :: Stroke -> Stroke -> Stroke -> Stroke -> Css
+borderStyle4 a b c d = key "border-style" (a ! b ! c ! d)
+
 borderStyle, borderLeftStyle, borderRightStyle, borderTopStyle, borderBottomStyle :: Stroke -> Css
 
 borderStyle       = key "border-style"
@@ -75,6 +81,9 @@
 borderTopStyle    = key "border-top-style"
 borderBottomStyle = key "border-bottom-style"
 
+borderWidth4 :: Size Abs -> Size Abs -> Size Abs -> Size Abs -> Css
+borderWidth4 a b c d = key "border-width" (a ! b ! c ! d)
+
 borderWidth, borderLeftWidth, borderRightWidth, borderTopWidth, borderBottomWidth :: Size Abs -> Css
 
 borderWidth       = key "border-width"
@@ -93,6 +102,9 @@
 outlineBottom  a b c = key "outline-bottom" (a ! b ! c)
 outlineRight   a b c = key "outline-right"  (a ! b ! c)
 
+outlineColor4 :: Color -> Color -> Color -> Color -> Css
+outlineColor4 a b c d = key "outline-color" (a ! b ! c ! d)
+
 outlineColor, outlineLeftColor, outlineRightColor, outlineTopColor, outlineBottomColor :: Color -> Css
 
 outlineColor       = key "outline-color"
@@ -101,6 +113,9 @@
 outlineTopColor    = key "outline-top-color"
 outlineBottomColor = key "outline-bottom-color"
 
+outlineStyle4 :: Stroke -> Stroke -> Stroke -> Stroke -> Css
+outlineStyle4 a b c d = key "outline-style" (a ! b ! c ! d)
+
 outlineStyle, outlineLeftStyle, outlineRightStyle, outlineTopStyle, outlineBottomStyle :: Stroke -> Css
 
 outlineStyle       = key "outline-style"
@@ -108,6 +123,9 @@
 outlineRightStyle  = key "outline-right-style"
 outlineTopStyle    = key "outline-top-style"
 outlineBottomStyle = key "outline-bottom-style"
+
+outlineWidth4 :: Size Abs -> Size Abs -> Size Abs -> Size Abs -> Css
+outlineWidth4 a b c d = key "outline-width" (a ! b ! c ! d)
 
 outlineWidth, outlineLeftWidth, outlineRightWidth, outlineTopWidth, outlineBottomWidth :: Size Abs -> Css
 
diff --git a/src/Clay/Box.hs b/src/Clay/Box.hs
--- a/src/Clay/Box.hs
+++ b/src/Clay/Box.hs
@@ -5,6 +5,7 @@
 , boxSizing
 , boxShadow
 , boxShadows
+, insetBoxShadow
 )
 where
 
@@ -15,6 +16,7 @@
 import Clay.Property
 import Clay.Stylesheet
 import Clay.Size
+import Clay.Border
 
 -------------------------------------------------------------------------------
 
@@ -40,3 +42,7 @@
 boxShadows :: [(Size a, Size a, Size a, Color)] -> Css
 boxShadows = prefixed (browsers <> "box-shadow") . map (\(a, b, c, d) -> a ! b ! c ! d)
 
+-------------------------------------------------------------------------------
+
+insetBoxShadow :: Stroke -> Size a -> Size a -> Size a -> Color -> Css
+insetBoxShadow x y w c z = prefixed (browsers <> "box-shadow") (x ! y ! w ! c ! z)
diff --git a/src/Clay/Font.hs b/src/Clay/Font.hs
--- a/src/Clay/Font.hs
+++ b/src/Clay/Font.hs
@@ -99,7 +99,7 @@
   (Size a)
   (Maybe (Size a))
   [Text]
-  [Text]
+  [GenericFontFamily]
 
 instance Val (Required a) where
   value (Required a Nothing  c d) = value (a ! (Literal <$> c) ! d)
diff --git a/src/Clay/Property.hs b/src/Clay/Property.hs
--- a/src/Clay/Property.hs
+++ b/src/Clay/Property.hs
@@ -3,11 +3,11 @@
 
 import Control.Arrow (second)
 import Control.Monad.Writer
+import Data.Fixed (Fixed, HasResolution (resolution), showFixed)
 import Data.List (partition, sort)
 import Data.Maybe
 import Data.String
 import Data.Text (Text, replace)
-import Text.Printf
 
 data Prefixed = Prefixed [(Text, Text)] | Plain Text
   deriving Show
@@ -65,8 +65,14 @@
 instance Val Integer where
   value = fromString . show
 
+data E5 = E5
+instance HasResolution E5 where resolution _ = 100000
+
 instance Val Double where
-  value = fromString . printf "%.5f"
+  value = fromString . showFixed' . realToFrac
+    where
+      showFixed' :: Fixed E5 -> String
+      showFixed' = showFixed True
 
 instance Val Value where
   value = id
diff --git a/src/Clay/Render.hs b/src/Clay/Render.hs
--- a/src/Clay/Render.hs
+++ b/src/Clay/Render.hs
@@ -75,36 +75,64 @@
 -- used by default.
 
 render :: Css -> Lazy.Text
-render = renderWith pretty []
+render = renderWith pretty
 
 -- | Render a stylesheet with a custom configuration and an optional outer
 -- scope.
 
-renderWith :: Config -> [App] -> Css -> Lazy.Text
-renderWith cfg top (S c)
+renderWith :: Config -> Css -> Lazy.Text
+renderWith cfg (S c)
   = renderBanner cfg
   . toLazyText
-  . rules cfg top
+  . cssRules cfg
+  . flattenRules
   . execWriter
   $ c
 
+-------------------------------------------------------------------------------
+
+-- | The AST of a CSS3 file.
+
+data Css3
+  = Css3Query MediaQuery [Css3]
+  | Css3Rule [App] [(Key (), Value)]
+  | Css3Font       [(Key (), Value)]
+
+flattenRules :: [Rule] -> [Css3]
+flattenRules rules =
+  let
+    property p = case p of
+      Property k v -> (k, v)
+      _            -> error "only properties are allowed in @font-face"
+
+    nestApp app css = case css of
+      Css3Query q cs -> Css3Query q $ map (nestApp app) cs
+      Css3Rule as ps -> Css3Rule (app:as) ps
+      Css3Font ps    -> Css3Font ps
+
+    (props, nests, qrys, faces) = foldr
+      (\r (ps,ns,qs,fs) -> case r of
+        Property k v -> ((k, v):ps,          ns,          qs,     fs)
+        Nested a rs' -> (       ps, (a, rs'):ns,          qs,     fs)
+        Query q  rs' -> (       ps,          ns, (q, rs'):qs,     fs)
+        Face     rs' -> (       ps,          ns,          qs, rs':fs))
+      ([],[],[],[])
+      rules
+  in
+    (if null props then [] else [Css3Rule [] props])                      ++
+    concatMap (\(app, rs') -> map (nestApp app) (flattenRules rs')) nests ++
+    map       (\(q,   rs') -> Css3Query q (flattenRules rs'))       qrys  ++
+    map       (\      rs'  -> Css3Font $ map property rs')          faces
+
+-------------------------------------------------------------------------------
+
 renderBanner :: Config -> Lazy.Text -> Lazy.Text
 renderBanner cfg =
   if banner cfg
   then (<> "\n/* Generated with Clay, http://fvisser.nl/clay */")
   else id
 
-query :: Config -> MediaQuery -> [App] -> [Rule] -> Builder
-query cfg q sel rs =
-  mconcat
-    [ mediaQuery q
-    , newline cfg
-    , "{"
-    , newline cfg
-    , rules cfg sel rs
-    , "}"
-    , newline cfg
-    ]
+-------------------------------------------------------------------------------
 
 mediaQuery :: MediaQuery -> Builder
 mediaQuery (MediaQuery no ty fs) = mconcat
@@ -127,42 +155,15 @@
     Just (Value v) -> mconcat
       [ "(" , fromText k , ": " , fromText (plain v) , ")" ]
 
-face :: Config -> [Rule] -> Builder
-face cfg rs = mconcat
-  [ "@font-face"
-  , rules cfg [] rs
-  ]
-
-rules :: Config -> [App] -> [Rule] -> Builder
-rules cfg sel rs = mconcat
-  [ rule cfg sel (mapMaybe property rs)
-  , newline cfg
-  , (\(a, b) -> rules cfg (a : sel) b) `foldMap` mapMaybe nested  rs
-  , (\(a, b) -> query cfg  a   sel  b) `foldMap` mapMaybe queries rs
-  , (\ns     -> face  cfg          ns) `foldMap` mapMaybe faces   rs
-  ]
-  where property (Property k v) = Just (k, v)
-        property _              = Nothing
-        nested   (Nested a ns ) = Just (a, ns)
-        nested   _              = Nothing
-        queries  (Query q ns  ) = Just (q, ns)
-        queries  _              = Nothing
-        faces    (Face ns     ) = Just ns
-        faces    _              = Nothing
-
-rule :: Config -> [App] -> [(Key (), Value)] -> Builder
-rule _   _   []    = mempty
-rule cfg sel props =
-  let xs = collect =<< props
-   in mconcat
-      [ selector cfg (merger sel)
-      , newline cfg
-      , "{"
-      , newline cfg
-      , properties cfg xs
-      , "}"
-      , newline cfg
-      ]
+cssRules :: Config -> [Css3] -> Builder
+cssRules cfg = (mconcat .) $ map $ \c -> mconcat $ case c of
+  Css3Query  q cs -> [ mediaQuery q,                        block $ cssRules cfg cs ]
+  Css3Rule sel ps -> [ selector cfg (merger $ reverse sel), propertyBlock ps        ]
+  Css3Font     ps -> [ "@font-face",                        propertyBlock ps        ]
+  where
+    propertyBlock = block . properties cfg . concatMap collect
+    block inner = mconcat [ nl, "{", nl, inner, "}", nl, nl ]
+    nl = newline cfg
 
 merger :: [App] -> Selector
 merger []     = "" -- error "this should be fixed!"
diff --git a/src/Clay/Size.hs b/src/Clay/Size.hs
--- a/src/Clay/Size.hs
+++ b/src/Clay/Size.hs
@@ -21,7 +21,7 @@
 , ex
 , pct
 
--- * Shorthands for mutli size-valued properties.
+-- * Shorthands for properties that can be applied separately to each box side.
 
 , sym
 , sym2
@@ -108,13 +108,13 @@
 
 -------------------------------------------------------------------------------
 
-sym :: (Size a -> Size a -> Size a -> Size a -> Css) -> Size a -> Css
+sym :: (a -> a -> a -> a -> Css) -> a -> Css
 sym k a = k a a a a
 
-sym3 :: (Size a -> Size a -> Size a -> Size a -> Css) -> Size a -> Size a -> Size a -> Css
+sym3 :: (a -> a -> a -> a -> Css) -> a -> a -> a -> Css
 sym3 k tb l r = k tb l tb r
 
-sym2 :: (Size a -> Size a -> Size a -> Size a -> Css) -> Size a -> Size a -> Css
+sym2 :: (a -> a -> a -> a -> Css) -> a -> a -> Css
 sym2 k tb lr = k tb lr tb lr
 
 -------------------------------------------------------------------------------
diff --git a/src/Clay/Text.hs b/src/Clay/Text.hs
--- a/src/Clay/Text.hs
+++ b/src/Clay/Text.hs
@@ -67,6 +67,7 @@
 , attrContent
 , stringContent
 , uriContent
+, urlContent
 , openQuote, closeQuote, noOpenQuote, noCloseQuote
 
 )
@@ -229,6 +230,9 @@
 
 uriContent :: Text -> Content
 uriContent u = Content ("uri(" <> value (Literal u) <> ")")
+
+urlContent :: Text -> Content
+urlContent u = Content ("url(" <> value (Literal u) <> ")")
 
 openQuote, closeQuote, noOpenQuote, noCloseQuote :: Content
 
diff --git a/src/Test.hs b/src/Test.hs
new file mode 100644
--- /dev/null
+++ b/src/Test.hs
@@ -0,0 +1,13 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Main where
+
+import Test.Framework (defaultMain)
+import Test.Framework.Providers.HUnit (testCase)
+import Test.HUnit.Base ((@?=))
+
+import Clay.Render (renderWith, compact)
+
+main :: IO ()
+main = defaultMain
+  [ testCase "empty Clay produces empty compact CSS" $ renderWith compact (return ()) @?= ""
+  ]