body {
    margin: 0;
    padding: 0;
    background-image: url('assets/background.jpeg');
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    text-align: center;
    width: 100%;
    padding: 20px;
    box-sizing: border-box;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.btn {
    border: 1px solid #3498db;
    background: none;
    padding: 10px 20px;
    font-size: 20px;
    font-family: "Montserrat", sans-serif;
    cursor: pointer;
    margin: 10px;
    transition: 0.8s;
    position: relative;
    overflow: hidden;
    display: inline-block;
    min-width: 200px;
}

.btn1,
.btn2 {
    color: #3498db;
}

.btn3,
.btn4 {
    color: #ffffff;
}

.btn1:hover,
.btn2:hover {
    color: #ffffff;
}

.btn3:hover,
.btn4:hover {
    color: #3498db;
}

.btn::before {
    content: "";
    position: absolute;
    left: 0;
    width: 100%;
    height: 0%;
    background: #3498db;
    z-index: -1;
    transition: 0.8s;
}

.btn1::before,
.btn3::before {
    top: 0;
    border-radius: 0 0 50% 50%;
}

.btn2::before,
.btn4::before {
    bottom: 0;
    border-radius: 50% 50% 0 0;
}

.btn3::before,
.btn4::before {
    height: 180%;
}

.btn1:hover::before,
.btn2:hover::before {
    height: 180%;
}

.btn3:hover::before,
.btn4:hover::before {
    height: 0%;
}

@media screen and (max-width: 768px) {
    .container {
        display: flex;
        flex-direction: column !important;
        align-items: center;
        width: 100%;
        max-width: 300px;
        margin: 0 auto;
    }

    .btn {
        width: 100%;
        margin: 10px 0;
    }
}