Please ask: Problem with border attribute in CSS_html/css_WEB-ITnose

I saw a CSS file written like this:
html, body{
background: transparent;
border: 0;
margin: 0;
padding: 0;
vertical-align: baseline;
}
But I read that after the background, you should write the background color | background pattern | background repeat | background attachment | background position
and the values ​​of several attributes should be written after the border. Why do I write one here? If you write one, which one does it represent?

Reply to discussion (solution)

background: transparent; means transparent
background: write only One, the others are the default
. For example, background:#ccc; actually has the same effect as backgroud:#ccc repeat 0 0.
The border is also the same. If you don’t write it, the style and color will be defaulted

background: Write only one, the others are default
==============================
because there is no background attribute , only background-image, background-color,
background-repeat, background-position, etc.
You only write one, so which attribute is this one?
There is also only one font attribute. Which attribute do you use?
Another question: Can I write only one relevant attribute?
So how do you know which attribute this one is?

means the top, right, bottom and left are all 0