update probelm-input-container style

app.css

@@ -151,6 +151,11 @@
 
 .probelm-input-container {
   border: 1px solid rgba(0, 0, 0, 0.15);
+  border-radius: 10px;
+}
+
+.probelm-input-container .probelm-input-container {
+  border: none;
 }
 
 .problem-input-markdown {