i want to give css for mobile view and tablet view. i have created media tag and wrote the code but its not working i have wrote 

at top of the phtml file and wrote class name for which i have give css like below

```
<code>
<meta name="viewport" content="width=device-width,initial-scale=1.0"> //at top
@media only screen and (max-device-width: 1000px)
{.numbertext
 {
   font-size: 50px;
   color: red;
 }
}
</code>

```

please help me how should i write to get correct output