diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Revision history for reflex-vty
 
+## 0.3.1.0
+
+* Replace `mempty` with `defAttr` for Attr from Graphics.Vty to make it compatible with vty-5.34
+
 ## 0.3.0.0
 
 * Re-design `textInput`, `TextInput` and `TextInputConfig`.
diff --git a/reflex-vty.cabal b/reflex-vty.cabal
--- a/reflex-vty.cabal
+++ b/reflex-vty.cabal
@@ -1,5 +1,5 @@
 name: reflex-vty
-version: 0.3.0.0
+version: 0.3.1.0
 synopsis: Reflex FRP host and widgets for VTY applications
 description:
   Build terminal applications using functional reactive programming (FRP) with Reflex FRP (<https://reflex-frp.org>).
@@ -18,7 +18,7 @@
   ChangeLog.md
 extra-doc-files: doc/tasks.png
 tested-with:
-  GHC ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.2
+  GHC ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.7
 
 source-repository head
   type: git
@@ -39,7 +39,7 @@
                  , Reflex.Spider.Orphans
                  , Control.Monad.NodeId
   build-depends:
-    base >= 4.10.0 && < 4.15,
+    base >= 4.10.0 && < 4.16,
     bimap >= 0.3.3 && < 0.5,
     containers >= 0.5.0 && < 0.7,
     mtl >= 2.2.2 && < 2.3,
@@ -56,7 +56,7 @@
     ref-tf >= 0.4.0 && < 0.6,
     reflex >= 0.8 && < 0.9,
     time >= 1.8.0 && < 1.10,
-    vty >= 5.28 && < 5.34
+    vty >= 5.28 && < 5.38
   hs-source-dirs: src
   default-language: Haskell2010
   ghc-options: -Wall
@@ -150,5 +150,5 @@
     reflex-vty,
     text,
     extra,
-    hspec >= 2.7 && < 2.8
+    hspec >= 2.7 && < 2.9
   default-language: Haskell2010
diff --git a/src/Reflex/Vty/Widget/Input.hs b/src/Reflex/Vty/Widget/Input.hs
--- a/src/Reflex/Vty/Widget/Input.hs
+++ b/src/Reflex/Vty/Widget/Input.hs
@@ -14,6 +14,7 @@
 import Control.Monad (join)
 import Control.Monad.Fix (MonadFix)
 import Data.Default (Default(..))
+import Data.List (foldl')
 import Data.Text (Text)
 import qualified Graphics.Vty as V
 import Reflex
@@ -144,15 +145,19 @@
     , not <$ space
     , const <$> _checkboxConfig_setValue cfg
     ]
-  let bold = V.withStyle mempty V.bold
-  depressed <- hold mempty $ leftmost
-    [ bold <$ md
-    , mempty <$ mu
+  depressed <- hold V.defaultStyleMask $ leftmost
+    [ V.bold <$ md
+    , V.defaultStyleMask <$ mu
     ]
-  let focused = ffor (current f) $ \x -> if x then bold else mempty
-  let attrs = mconcat <$> sequence [_checkboxConfig_attributes cfg, depressed, focused]
+  let focused = ffor (current f) $ \x -> if x then V.bold else V.defaultStyleMask
+  let attrs = combineStyles
+        <$> _checkboxConfig_attributes cfg
+        <*> sequence [depressed, focused]
   richText (RichTextConfig attrs) $ join . current $ ffor v $ \checked ->
     if checked
       then _checkboxStyle_checked <$> _checkboxConfig_checkboxStyle cfg
       else _checkboxStyle_unchecked <$> _checkboxConfig_checkboxStyle cfg
   return v
+  where
+    combineStyles :: V.Attr -> [V.Style] -> V.Attr
+    combineStyles x xs = foldl' V.withStyle x xs