.my-container {
    width: 100%;
    background-color: #fff;
    margin: 1rem auto;
    box-sizing: border-box;
}
button {
    width: 100%;
}
@media screen and (min-width: 600px) {
    body {
        background-color: #fafafa;
        min-height: 100svh;
        min-height: 100vh;
        display: flex;
        align-items: center;
    }
    .my-container {
        width: 600px;
        border-radius: 10px;
        box-shadow: rgba(0, 0, 0, 0.24) 0px 3px 8px;box-shadow: rgba(0, 0, 0, 0.24) 0px 3px 8px;
    }
}