set width and height for mobiel deviceby using @media code example

Example 1: media query for mobile view css

@media only screen and (max-width: 600px) {
  body {
    background-color: lightblue;
  }
}

Example 2: css media query

/* BOOSTRAP MEDIA BREAKPOINTS */
/* Small devices (landscape phones, 576px and up) */
@media (min-width: 576px) {  
  .selector {
  	background-color:#f00;
  }
}
/* Medium devices (tablets, 768px and up) The navbar toggle appears at this breakpoint */
@media (min-width: 768px) {}
/* Large devices (desktops, 992px and up) */
@media (min-width: 992px) {}
/* Extra large devices (large desktops, 1200px and up) */
@media (min-width: 1200px) {}