diff --git a/build.sbt b/build.sbt
index 2ace2112..b09747ed 100644
--- a/build.sbt
+++ b/build.sbt
@@ -24,7 +24,7 @@ lazy val root = project
 "org.scala-lang" %% "scala3-staging" % scalaVersion.value,
 "org.scala-lang.modules" %% "scala-parser-combinators" % "2.4.0",
 "ch.qos.logback" % "logback-classic" % "1.5.18",
- "org.scalacheck" %% "scalacheck" % "1.18.1" % Test,
+ "org.scalacheck" %% "scalacheck" % "1.19.0" % Test,
 "org.scalameta" %% "munit" % "1.1.1" % Test,
 "org.scalameta" %% "munit-scalacheck" % "1.1.0" % Test,
 "com.eed3si9n.expecty" %% "expecty" % "0.17.0" % Test,
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://patch-diff.githubusercontent.com/raw/deanwampler/programming-scala-book-code-examples/pull/184.diff">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://patch-diff.githubusercontent.com/raw/deanwampler/programming-scala-book-code-examples/pull/184.diff" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>