body {

    text-align: center;
}

button {
    background-color: rgba(0,0,0,0);
    outline: none;
}

h2 {
    margin-bottom: 10px;
}

.btn {
    margin-bottom: 10px;
    margin-left: auto;
    margin-right: auto;
    display: block;
}




.panel {
    margin-top: 20px;
    float: none;
}

@media (min-width: 768px) {
    .panel {
        width: 50%;
        margin-left: auto;
        margin-right: auto;
    }
}

@media (min-width: 1024px) {
    .panel {
        width: 30%;
        margin-left: auto;
        margin-right: auto;
    }
}