docs(Modal): Page jittering (ant-design#56255)

Co-authored-by: liuqiang <qiang.liu@xinjifamily.com>

Author: ug-hero

.dumi/theme/common/styles/Reset.tsx

@@ -58,6 +58,7 @@ export default () => {
 
         body {
           overflow-x: hidden;
+          scrollbar-width: thin;
           color: ${token.colorText};
           font-size: ${token.fontSize}px;
           font-family: ${token.fontFamily};