diff --git a/public/css/main.css b/public/css/main.css
index e5e32bb..6dea126 100644
--- a/public/css/main.css
+++ b/public/css/main.css
@@ -4,7 +4,7 @@
 }
 button#push {
   width: 92%;
-  height: 80vh;
+  height: 65vh;
   font-size: 5em;
   font-weight: bold;
   padding: 10px 30px;
@@ -21,6 +21,11 @@
   -webkit-transition: none;
   transition: none;
   text-shadow: 0 1px 1px rgba(0, 0, 0, .3);
+  /* テキストのコピーを禁止する */
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
 }
 button#push:hover {
   border:1px solid #1090c3;