fix: popover background color in dark mode (#5783)

* 修复dark主题下的弹出层背景色在某些浏览器上表现为完全透明的问题

Author: mynetfan

packages/@core/base/design/src/design-tokens/dark.css

@@ -19,7 +19,7 @@
   /* --popover: 222.82deg 8.43% 12.27%; */
 
   /* 弹出层的背景色与主题区域背景色太过接近  */
-  --popover: 0 0 14.2%;
+  --popover: 0 0% 14.2%;
   --popover-foreground: 210 40% 98%;
 
   /* Muted backgrounds such as <TabsList />, <Skeleton /> and <Switch /> */