*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html,body{
    height: 100%;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}
.main{
    width: 400px;
    height: 500px;
    background-color: #E8E9EB;
    border: 5px solid black;
    border-radius: 5px;
}
.heading{
    height: 50px;
    font-size: 1.4em;
    font-weight: 600;
    text-align: center;
    padding: 10px;
    border-bottom: 5px solid black;
    background-color:chartreuse;
}
.input-section{
    height: 100px;
    padding: 10px;
    background-color: #E8E9EB;
}
.input-section label{
    font-size: 1.5em;
    font-weight: 500;
}
#numbers{
    width: 100%;
    font-size: 1.5em;
    margin-top: 10px;
    border-radius: 5px;
    padding: 5px;
}
.button-section{
    height: 100px;
    display: flex;
    justify-content: space-evenly;
    align-items: center;
}
button{
    font-size: 2em;
    font-weight: 100;
    padding: 10px;
    border-radius: 20px;
}
button:hover{
    cursor: pointer;
    background-color: green;
    transition: 1s;
    border: none;
}
.result-section{
    height: 240px;
}
.result-section h3{
    font-size: 3em;
    font-weight: 700;
    text-align: center;
    padding: 10px;
}
.result-section p{
    font-size: 2em;
    text-align: center;
    padding: 10px;
}
.error{
    color: red;
    transition: ease-out;
}
@media (max-width: 600px) {
    .main{
        width: 350px;
        height: 500px;
    }
    .heading{
        height: 90px;
        font-size: 1.5em;
    }
    .input-section{
        height: 120px;
    }
    .button-section{
        height: 80px;       
    }
    button{
        font-size: 1.5em;
        font-weight: 500;
        border-radius: 20px;
    }
    .result-section h3{
        font-size: 2em;
        font-weight: 700;
        text-align: center;
    }
    .result-section p{
        font-size: 1.4em;
        text-align: center;
        padding: 10px;
    }
}