diff --git a/style.css b/style.css
index a87ac09..a2aaafc 100644
--- a/style.css
+++ b/style.css
@@ -399,3 +399,14 @@
   margin: 0 6px;
   white-space: nowrap;
 }
+
+#chatList {
+  height: 230px;
+  background: linear-gradient(135deg, #fff7fc, #f3faff); /* パステルピンク×薄水色 */
+  border: 1px solid #f0dcec;  /* ほんのりピンクの枠 */
+  border-radius: 20px;
+  padding: 12px;
+  overflow-y: auto;
+  box-shadow: inset 0 0 12px rgba(0, 0, 0, 0.05);
+  font-size: 15px;
+}