Media queries are  simple filters which can be applied to CSS styles. They make it easy to change styles based on the device rendering the content, including the display type, width, height, orientation and even resolution.

use to like below code:

/*For Smartphones (portrait and landscape) ----------- */
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) {
/* Styles */
}
/*for iPads (portrait and landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {
/* Styles */
}
/*For Desktops and laptops ----------- */
@media only screen  and (min-width : 1224px) {
/* Styles */
}

if you want to use media queries in css  go to  https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries for more details.