css - What is user agent stylesheet

itemprop="text">

I'm working on a web page
in Google Chrome. It displays correctly with the following
styles.

table {

            display: table;
 border-collapse: separate;
 border-spacing:
            2px;
 border-color:
            gray;
}

It
is important to note that I didn't define these styles. On Chrome dev tools, it says
user agent stylesheet in place of the CSS file
name.

Now if I submit a form and some validation
error occurs, I get the following
stylesheet:

table {

            white-space: normal;
 line-height: normal;
 font-weight:
            normal;
 font-size: medium;

 font-variant:
            normal;
 font-style: normal;
 color: -webkit-text;

            text-align: -webkit-auto;
}
table {
 display:
            table;
 border-collapse: separate;
 border-spacing: 2px;

            border-color:
            gray;

}

The
font-size from these new styles is disturbing my design. Is
there any way to force my stylesheets and if possible, completely overwrite Chrome's
default stylesheet?

itemprop="text">

class="normal">Answer

What are
the target browsers? Different browsers set different default CSS rules. Try including a
CSS reset, such as the rel="noreferrer">meyerweb css reset or href="https://necolas.github.io/normalize.css/"
rel="noreferrer">normalize.css, to remove those defaults. Google "css reset
vs normalize" to see the differences.