fix: button spacing in mask layer

Add gap to message-box buttons in dark theme.

Author: sheepzh

src/content-script/limit/modal/style/modal.css

@@ -23,4 +23,9 @@ body {
 
 html[data-theme=dark] body {
     background-color: var(--el-fill-color-dark);
-}
+}
+
+/* Fix message-box buttons */
+.el-message-box__btns {
+    gap: 12px;
+}