How can i make box with no white space in webpage with css?

Question

The margins from left and right in web page shows white space which is the color of the background , i want to remove it ,how?

this is my css:

.box-one {
    background-color: #c8d6e5;
    height: 300px;
    width:200;
    margin-top: 1200px;
    margin-left: 40px;
    margin-right: 40px;
    margin-bottom: 29px;
}

Answer 1

Just add font-size: 0 to remove all white spaces, including text.

But if you're looking to maintain text, try padding: 0.

Answer 2

width:auto;

And remove the margin left and right and add padding instead!