My button doesn't go to the right side of my nav

Issue

I tried float and justify content in the header button section but that didn't work too. I think it has to do something with the header. i tried to erase the justify-content element from the header and put it in header ul but that didn't work as well.

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

body {
    background-color: #a99272;
}

button {
cursor: pointer;
border:none;
}
header {
display: flex;
height:80px;
width: 100%;
justify-content: center;
background-color:#0d1010;
align-items: center;
font-size: 1.3em;
border-bottom-left-radius: 10px ;
border-bottom-right-radius: 10px;
}

header img {
position: absolute;
height: 60px;
top:10px;
left: 10px;
}

header nav ul {
list-style: none;
display: flex;
}

header button {
display: flex;
position: absolute;
background-color:#1e3f66;
color: mintcream;
border-radius: 20px;
padding: 10px;
width: 70px;
justify-content: right;
text-align: center;

 }

 nav ul li {
 margin: 10px;
 color: #e8e8e9;
 }

Solution

I had to change the justify-content element from center to space-between.

Answered By - Furkan