html - What should be the minimum width to make footer responsive? -

I am trying to make the footer of my site responsive. I'm using 400 pixels minimum width for the website to increase the height of the footer but it does not work. Please tell me how I can increase the footer height for smaller screens.

Here is the code,

  @ media screen and (minimum-width: 400px;) {# copyright (height: 50px;}}  

Edit: Here is my code,

  @ media screen and (max-width: 400px) {# copyright (height: 50px;}}  

This should be maximum-width so that you can target the screen to 400px width. If you are asking to apply the minimum width is 400px :)

  #copyright {height: 20px; background: # 000; color: #fff;} @media in hand, only screen and (max-width: 400px) Only screen and (max-device-width: 400px) {# copyright [height: 50px; background: # f00;}}  

  & lt; Div id = "copyright" & gt; Copyright & lt; Div & gt;