diff --git a/assets/css/routes/user-center/credits.css b/assets/css/routes/user-center/credits.css
index 2f2f69af..f6634d36 100644
--- a/assets/css/routes/user-center/credits.css
+++ b/assets/css/routes/user-center/credits.css
@@ -190,6 +190,17 @@
   display: flex;
 }
 
+/* 推广海报弹窗壳与上面两个同构（服务端静态输出 .modal.flex.jc.fade），
+   静止态同样必须显式隐藏，否则 .flex 工具类会使其铺满全屏形成隐形遮罩，
+   拦截整页点击。打开态由 initAffiliatePoster 的内联 display:flex 驱动，
+   关闭撤除内联样式后即回到隐藏规则。 */
+.modal[data-aksrt-affiliate-poster-modal] {
+  display: none;
+}
+.modal[data-aksrt-affiliate-poster-modal].in {
+  display: flex;
+}
+
 .balance-charge-form .zib-widget {
   clear: both;
   background-color: var(--main-bg-color);
diff --git a/inc/helpers/user-center-renderers/affiliate-poster-modal.php b/inc/helpers/user-center-renderers/affiliate-poster-modal.php
index e1fe8933..e0aae2df 100644
--- a/inc/helpers/user-center-renderers/affiliate-poster-modal.php
+++ b/inc/helpers/user-center-renderers/affiliate-poster-modal.php
@@ -19,7 +19,7 @@ if (!empty($GLOBALS['aksrt_affiliate_poster_modal_rendered'])) {
 }
 $GLOBALS['aksrt_affiliate_poster_modal_rendered'] = true;
 ?>
-<div class="modal fade flex jc" id="aksrt-affiliate-poster-modal" tabindex="-1" role="dialog" aria-hidden="true">
+<div class="modal fade flex jc" id="aksrt-affiliate-poster-modal" data-aksrt-affiliate-poster-modal tabindex="-1" role="dialog" aria-hidden="true">
 	<div class="modal-dialog poster-share hover-show" role="document">
 		<div class="modal-content" style="height:220px;overflow:hidden">
 			<div class="poster-imgbox hover-show" data-affiliate-poster-stage></div>
diff --git a/tests/widget-system/referral-qr-contract.test.cjs b/tests/widget-system/referral-qr-contract.test.cjs
index 4a3079f7..ab15eaf8 100644
--- a/tests/widget-system/referral-qr-contract.test.cjs
+++ b/tests/widget-system/referral-qr-contract.test.cjs
@@ -126,6 +126,23 @@ test('poster modal markup is a 1:1 replica of the reference poster-share dialog'
   assert.doesNotMatch(css, /uc-affiliate-poster/)
 })
 
+test('poster modal shell is hidden at rest so it cannot block the whole page', () => {
+  const modal = read('inc', 'helpers', 'user-center-renderers', 'affiliate-poster-modal.php')
+  const script = read('assets', 'js', 'credits.js')
+  const css = read('assets', 'css', 'routes', 'user-center', 'credits.css')
+
+  // 标记、JS 查询与 CSS 钩子必须共用同一个属性，缺一即失效：
+  // 少了标记上的属性，JS 拿不到弹窗、CSS 也隐藏不了它。
+  assert.match(modal, /data-aksrt-affiliate-poster-modal/)
+  assert.match(script, /querySelector\('\[data-aksrt-affiliate-poster-modal\]'\)/)
+
+  // 服务端静态输出的 .modal.flex 必须显式隐藏。main.css 的 .flex{display:flex}
+  // 后加载且与 bootstrap 的 .modal{display:none} 同特异性，不在此回位就会让
+  // 静止态弹窗铺满全屏，叠加 .fade 的 opacity:0 形成隐形遮罩、拦截整页点击。
+  assert.match(css, /\.modal\[data-aksrt-affiliate-poster-modal\]\s*\{\s*display:\s*none;/)
+  assert.match(css, /\.modal\[data-aksrt-affiliate-poster-modal\]\.in\s*\{\s*display:\s*flex;/)
+})
+
 test('invite-code input verifies live against the public REST endpoint', () => {
   const template = read('templates', 'parts', 'auth-content.php')
   assert.match(template, /data-invite-verify/)