删除没用的 dom

scss/components/_result-box.scss

@@ -75,10 +75,6 @@
     cursor: pointer;
   }
 
-  &-mid {
-    flex-grow: 1;
-  }
-
   &-value {
     background: $ResultBox-value-bg;
     color: $ResultBox-value-color;

src/components/ResultBox.tsx

@@ -169,9 +169,7 @@ export class ResultBox extends React.Component<ResultBoxProps> {
             onFocus={this.handleFocus}
             onBlur={this.handleBlur}
           />
-        ) : (
-          <span className={cx('ResultBox-mid')} />
-        )}
+        ) : null}
 
         {children}