body {
    margin: 0;
    padding: 0;
    background: #2d3436;
}

.button-container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.btn {
    position: relative;
    display: block;
    color: white;
    font-size: 14px;
    font-family: 'Audiowide', cursive;
    text-decoration: none;
    margin: 30px 0;
    border: 2px solid #22a6b3;
    padding: 14px 70px;
    text-transform: uppercase;
    overflow: hidden;
    transition: 1s all ease;
}

.btn::before {
    background: #22a6b3;
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: -1;
    transition: 0.6s all ease;
}

.btn1::before {
    width: 0;
    height: 100%;
}

.btn1:hover::before {
    width: 100%;
}

.btn2::before {
    width: 100%;
    height: 0;
}

.btn2:hover::before {
    height: 100%;
}

.btn3::before {
    width: 100%;
    height: 0%;
    transform: translate(-50%, -50%) rotate(45deg);
}

.btn3:hover::before {
    height: 420%;
}

.btn4::before {
    width: 100%;
    height: 0%;
    transform: translate(-50%, -50%) rotate(-45deg);
}

.btn4:hover::before {
    height: 420%;
}