:root {
    --highlight-color: rgb(200,255,200);
    --dark-color: rgb(0,50,20);
}
nav a {
    display: inline-block;
    min-width: 100px;
    text-decoration: none;
}

.btn {
    display: inline-block;
    text-decoration: none;
    padding: 20px 40px;
    border-radius: 5px;
    color: var(--highlight-color);
    background-color: var(--dark-color);
    text-align: center;
    margin: 5px
}