refactor: remove unused overflow SCSS file and import

src/static/scss/index.scss

@@ -1,4 +1,3 @@
 @import "./background.scss";
 @import "./border.scss";
 @import "./font-family.scss";
-@import "./overflow.scss";

src/static/scss/overflow.scss

@@ -1,8 +0,0 @@
-// 溢出
-.overflow-hidden {
-  overflow: hidden;
-}
-
-.overflow-auto {
-  overflow: auto;
-}