<input type="number" class="spin__input" value="50">

body {
    color: rgb(51 65 85);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    margin: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
* {
    box-sizing: border-box;
}

body {
    align-items: center;
    display: flex;
    justify-content: center;
    padding-top: 4rem;
}
.spin__input {
    border: 1px solid rgb(203 213 225);
    border-radius: 0.25rem;
    height: 2rem;
    width: 8rem;
}