The width CSS media feature can be used to test the width of the viewport (or the page box, for paged media).
Syntax
The width feature is specified as a <length> value representing the viewport width. It is a range feature, meaning that you can also use the prefixed min-width and max-width variants to query minimum and maximum values, respectively.
Examples
HTML
<div>Watch this element as you resize your viewport's width.</div>
CSS
/* Exact width */
@media (width: 360px) {
div {
color: red;
}
}
/* Minimum width */
@media (min-width: 35rem) {
div {
background: yellow;
}
}
/* Maximum width */
@media (max-width: 50rem) {
div {
border: 2px solid blue;
}
}