HTML and CSS navigation bar not fitting to the top and left/right of screen-CodePudding

I have been having trouble fitting the navigation bar to the left, right and top of the screen. I haven't thought to much of it until now. I have simplified my code so none of the extra stuff is there.

HTML:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>FallsTracker</title>
    <link rel="stylesheet" href="save3.css">
</head>
<body>
    <header >
        <a >FallsTracker</a>
    </header>
</body>
</html>

CSS:

    padding: 0;
}



.navbar {
    width: 100%;
    background-color: grey;
    color: white;
}

Again, I want the navbar to fit to the left, right and top of the screen. I assumed this would work because I have padding at 0 for the body. I've tried having the padding at "none" as well but that didn't work either. I have followed tutorials for navigation bars and run into the same problem.

Here is a screenshot of what I see:

CodePudding user response：

please add this to your style.css file

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}