diff --git a/apps/kimi-web/src/components/chat/Composer.vue b/apps/kimi-web/src/components/chat/Composer.vue
index 8c48a01f0..e42a50c72 100644
--- a/apps/kimi-web/src/components/chat/Composer.vue
+++ b/apps/kimi-web/src/components/chat/Composer.vue
@@ -1386,7 +1386,10 @@ function selectModel(modelId: string): void {
   padding: 6px 10px 4px;
   background: color-mix(in srgb, var(--panel2), black 1.5%);
   position: relative;
-  border-radius: 0 0 var(--r-md) var(--r-md);
+  /* Match the .composer-card's inner bottom corners. The card has a 1px
+     border, so the toolbar's radius must be 1px smaller than the card's
+     outer radius to avoid the toolbar's background bulging past the border. */
+  border-radius: 0 0 15px 15px;
 }
 
 .toolbar-left,
diff --git a/apps/kimi-web/src/style.css b/apps/kimi-web/src/style.css
index d958ac07e..6c3125145 100644
--- a/apps/kimi-web/src/style.css
+++ b/apps/kimi-web/src/style.css
@@ -444,6 +444,10 @@ html[data-color-scheme="dark"][data-theme="modern"] {
 }
 :is(html[data-theme="modern"], html[data-theme="kimi"]) .toolbar {
   background: color-mix(in srgb, var(--panel), black 1.5%);
+  /* Match the .composer-card's inner bottom corners. The card has a 1px
+     border, so the toolbar's radius must be 1px smaller than the card's
+     outer radius to avoid the toolbar's background bulging past the border. */
+  border-radius: 0 0 calc(var(--r-md) - 1px) calc(var(--r-md) - 1px);
 }
 :is(html[data-theme="modern"], html[data-theme="kimi"]) .attach-btn {
   width: 26px;