html {
    width: 1280px;
    margin-left: auto;
    margin-right: auto;
}

header {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

ul {
    display: flex;
}

li{
    padding: 10px 20px;
    list-style-type: none;
}
a {
    text-decoration: none;
    color: black;
}

#logo {
    padding: 5px;
    background: transparent url("../img/logo.png") no-repeat center;
    background-size: contain;
    width:250px;
    height:100px;
    z-index: 1;
}

.instruction {
    display: flex;
    justify-content: center;
    align-items: center;
}