Introduction to the difference between background and Background-color

How to set Background-color: #aaa; The background of the input box has not changed and set background: #aaa; the background changed, how strange a question, next for everyone to analyze the reasons, encounter similar problems friends can understand

A small problem occurs when you set the style of the input box to become a line.

No matter how to set Background-color: #aaa; The background of the input box has not changed

and set background: #aaa; the background changed.

Later found the reason
Background can set background color, background picture, positioning, etc.

Background-color can only set background color

Set Background-color: #aaa; only change the background color, but at this point there is a default background:repeat;

The setting background: #aaa, which is equivalent to setting the background:no-repeat at the same time;

Both {background-color: #aaa; background:no-repeat;} =={background: #aaa;}