This is my code.
I'm still a beginner in CSS
that's why I'm asking this question please help me i've tried everything.
the problem is when ever i add padding to the header it seem like its pushing all the elements in the header to the right
am I missing something here?

```
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>To do list app</title>

    <style type="text/css">
        header {
    width: 100%;
    height: 80px;
    position: fixed;
    padding: 15px;
    top: 0;
    left: 0;
    z-index: 5;
    background: #25b99a;
    box-shadow: 0px 2px 4px rgba(44,62,80,0.15);
    border-bottom-right-radius: 10px;
    border-bottom-left-radius: 10px;

}

header input {
    width: 100%;
    height: 50px;
    float: left;
    background: rgba(255,255,255, 0.2);
    border-radius: 5px;
    border-bottom-right-radius: 25px;
    border-top-right-radius: 25px;
    border: 0px;
    box-shadow: none;
    outline: none;

    -webkit-appearance: none;
    -moz-appearance: none;
    -ms-appearance: none;
    -o-appearance: none;
    appearance: none;
}

    </style>
</head>
<body>

    <header>
    <input type="text" placeholder="Enter an activity..">
    </header>

</body>
</html>

```