horizontal line and right way to code it in html, css

hr {

display: block;

height: 1px;

border: 0;

border-top: 1px solid #ccc;

margin: 1em 0;

padding: 0;

}

Here is how html5boilerplate does it:
hr {
display: block;
height: 1px;
border: 0;
border-top: 1px solid #ccc;
margin: 1em 0;
padding: 0;
}

I’d go for semantic markup, use an

.
Unless it’s just a border what you want, then you can use a combination of padding, border and margin, to get the desired bound.