CSS : @media 示例

 .example {
     padding: 20px;
     color: white;
 }
 /* Extra small devices (phones, 600px and down) */
 @media only screen and (max-width: 600px) {
     .example {background: red;}
 }

 /* Small devices (portrait tablets and large phones, 600px and up) */
 @media only screen and (min-width: 600px) {
     .example {background: green;}
 }

 /* Medium devices (landscape tablets, 768px and up) */
 @media only screen and (min-width: 768px) {
     .example {background: blue;}
 } 

 /* Large devices (laptops/desktops, 992px and up) */
 @media only screen and (min-width: 992px) {
     .example {background: orange;}
 } 

 /* Extra large devices (large laptops and desktops, 1200px and up) */
 @media only screen and (min-width: 1200px) {
     .example {background: pink;}
 }