diff --git a/packages/web/src/pages/ReportPage.vue b/packages/web/src/pages/ReportPage.vue
index 5739c77..2300a0f 100644
--- a/packages/web/src/pages/ReportPage.vue
+++ b/packages/web/src/pages/ReportPage.vue
@@ -689,19 +689,19 @@
   font-size: 12px;
   opacity: 0.6;
 }
+/* GnTextarea caps its wrapper (.form-group) at 600px — a full prompt
+   deserves the whole modal */
+.ai-prompt-form :deep(.form-group) {
+  max-width: none;
+}
 .ai-prompt-form :deep(textarea.ai-prompt-text) {
   font-family: var(--font-mono, ui-monospace, monospace);
   font-size: 12px;
-  min-width: 480px;
+  width: 100%;
   /* the kit caps textarea height — a full prompt needs room to be reviewed */
   min-height: 420px;
   resize: vertical;
 }
-@media (max-width: 640px) {
-  .ai-prompt-text :deep(textarea) {
-    min-width: 0;
-  }
-}
 .ai-prompt-actions {
   display: flex;
   gap: 8px;