diff --git a/apps/ai-game-creator-shell/src/styles.css b/apps/ai-game-creator-shell/src/styles.css
index c87664904..af4501670 100644
--- a/apps/ai-game-creator-shell/src/styles.css
+++ b/apps/ai-game-creator-shell/src/styles.css
@@ -7519,3 +7519,16 @@ iframe.preview-frame {
 .game-workbench-chat .planning-lane-runtime-strip{
   max-height: clamp(240px, 52dvh, 640px);
 }
+
+/* 做方案在拿到第一个已登记资源之前，左边的资源画布是空的；工作台此时收成单栏，
+   对话铺满。类名由 view/project-development/index.tsx 的 conversationOnlyWorkbench
+   拼上（planningStartMode && resources.length === 0），画布是 display: none 不是
+   不渲染——页签、缩放、选中状态都保留，第一个资源登记后自动恢复双栏。
+   同批规则曾与上面的策划样式一起被 #193 误删。 */
+.game-workbench-layout.is-conversation-only {
+  grid-template-columns: minmax(0, 1fr);
+}
+
+.game-workbench-layout.is-conversation-only .game-workbench-stage {
+  display: none;
+}
diff --git a/apps/ai-game-creator-shell/tests/appSurface/plan-gdd.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/plan-gdd.suite.ts
index 14f38e183..d6ed7813b 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/plan-gdd.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/plan-gdd.suite.ts
@@ -569,5 +569,14 @@ export function registerPlanGddApprovalTests() {
     expect(styles).toMatch(
       /\.gdd-approval-card__dialog-backdrop\s*\{[^}]*position:\s*fixed/s,
     );
+    // 做方案的单栏工作台不在上面两个组件文件里（类名由
+    // view/project-development/index.tsx 拼出），显式钉住：没有这两条规则时，
+    // 策划项目一打开就是左边一整片空资源画布。它们和策划样式死在 #193 同一刀里。
+    expect(styles).toMatch(
+      /\.game-workbench-layout\.is-conversation-only\s*\{[^}]*grid-template-columns:\s*minmax\(0, 1fr\)/s,
+    );
+    expect(styles).toMatch(
+      /\.game-workbench-layout\.is-conversation-only \.game-workbench-stage\s*\{[^}]*display:\s*none/s,
+    );
   });
 }