CSS Specification < one >

See

1. Add ";" after each style attribute ------------Convenient compression Tool "segmentation".

2. Use of spaces

1{2     display: none;
}

. Selector and { preceded by a space

. Property name : after a space

. Property name : no spaces before

3. There must be a newline between multiple selectors, so it is clearer

A.BTN, input.btn, input{      display:none;              }    

4.Class, as far as possible not to appear in capital letters, the use of "-" segmentation, so clear,

1 /*  */2{3     font-weight: bold;}
/**/4{5     font-weight: Bold ; }

5. Do not write the style as a single line, so it is inconvenient to annotate

1{margin: 10px; background-color: #efefef;}

6. Try not to use "*" to select elements

1 /* don't write like that . */ 2  {3    margin: 0;  4    padding: 05 }

Because: only a subset of the elements in the browser have the default margin padding feature.
7.

CSS specification < A;