自适应的CSS代码片段（常用）

/* Smartphones (portrait and landscape) ----------- */

@media only screen

and (min-device-width : 320px) and (max-device-width : 480px) {

  /* Styles */

}

/* Smartphones (landscape) ----------- */

@media only screen and (min-width : 321px) {

  /* Styles */

}

/* Smartphones (portrait) ----------- */

@media only screen and (max-width : 320px) {

  /* Styles */

}

/* iPads (portrait and landscape) ----------- */

@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {

  /* Styles */

}

/* iPads (landscape) ----------- */

@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) {

  /* Styles */

}

/* iPads (portrait) ----------- */

@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) {

  /* Styles */

}

/* Desktops and laptops ----------- */

@media only screen and (min-width : 1224px) {

  /* Styles */

}

/* Large screens ----------- */

@media only screen and (min-width : 1824px) {

  /* Styles */

}

/* iPhone 4 ----------- */

@media only screen and (-webkit-min-device-pixel-ratio:1.5), only screen and (min-device-pixel-ratio:1.5) {

  /* Styles */

}