*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body{
    text-align: center;
    width: 100%;
    height: 100vh;
    background-color: #212121;
    color: #ffff;
}
.center{
    /* border: 2px solid red; */
    /* margin: 10px 30px; */
    padding: 14px 10px;
    border-radius: 10px;
    background-color: #524f4f;
    text-align: center;
    max-width: 500px;
    margin: 50px auto;
}
h1{
    font-size: 3rem;
    margin: 10px 0;
}
p{
    margin: 10px 0;
}
h2{
    font-size: 2rem;
    margin: 20px 0;
}
form input{
    margin: 10px auto;
    display: block;
}
#num{
    font-size: 1.3rem;
    text-align: center;
    width: 200px;
    padding: 10px 5px;
}
#submt, #submtt{
    padding: 10px 10px;
    border-radius: 5px;
    font-weight: 600;
    margin: 20px auto;
}
#submt:hover{
    cursor: pointer;
    background-color: #212121;
    color: #ffff;
    transition: all 0.4s ease-in-out;
}
@media (max-width:767px) {
    .center{
        padding: 7px 7px;
        max-width: 400px;
        margin: 10px auto;
    }
    h1{
        font-size: 2rem;
    }
    p{
        margin: 7px 2px;
    }
    h2{
        font-size: 1.4rem;
        margin: 10px 0;
    }
    form input{
        margin: 10px auto;
        border-radius: 10px;
    }
    #num{
        font-size: 1rem;
        text-align: center;
        width: 150px;
        padding: 10px 5px;
    }
    #submt, #submtt{
        padding: 10px 6px;
        border-radius: 5px;
        font-weight: 500;
        margin: 10px auto;
    }
}

@media (max-width:426px) {
    .center{
        padding: 7px 7px;
        max-width: 300px;
        margin: 10px auto;
    }
}
@media (max-width:376px) {
    .center{
        max-width: 250px;
    }
    p{
        margin: 7px 2px;
    }
    h2{
        font-size: 1rem;
        font-weight: 600;
    }
    #num{
        font-size: 1rem;
        width: 130px;
        padding: 6px 5px;
    }
    #submt, #submtt{
        padding: 7px 6px;
        font-weight: 400;
    }
}
@media (max-width:321px) {
    .center{
        max-width: 230px;
    }
    h1{
        font-size: 1.7rem;
        padding:  10px;
        margin: 10px auto;
    }
}