:root
{
    --color_text_pri: black;
    --color_text_hover: #95d04a;
    --color_pri: white;
    --margin: 100px;
    --padding: 3px;
}
html, body
{
    height: 100%;
    margin: 0;
    padding: 0;
    font-family: nunitoextralight, sans-serif;
}
a.btn
{
    font-size: 1.5em;
    padding: 10px 20px 10px 20px;
    text-decoration: none;
    color: white;
    background-color: var(--color_text_hover);
    border-radius: calc(2 * var(--padding) );
}