CSS implementation boundary concave state

The method for implementing the boundary concave state in CSS is: Set the Left and Right Border of the control (basically black and white)

For example (adjust the color ):

Border-left: 1px solid # e4e4e4;

Border-Right: 1px solid red;

 

Under normal circumstances, the border length is appended to the corresponding control. If you want to include the Border width in the control, that is, to display the border effect within the control border, you can use the following methods:

That is, add the following statement to CSS:

Box-sizing: border-box; this is for IE browser

-Moz-box-sizing: border-box; this is for the Firefox browser.

-Webit-box-sizing: border-box; this is for chrome