*{
    margin: 0px;
    padding: 0px;
}

h1{
    margin-top: 20px;
    font-family: 'Open Sans', sans-serif;
    color:#149B56;
    width: 100%;
    text-align: center;
}

#main{
    margin-top: 30px;
    margin-left: auto;
    margin-right: auto;
    width: 60%;
    border-radius: 5px;
    background-color: #f2f2f2;
    padding: 20px;
    transition: ease-in-out 0.3s;
}

input{
    width: 100%;
    font-size: x-large;
    font-family: Verdana;
    padding:6px;
    border: 1px solid #E0E0E0;
    border-radius:4px;
    transition: 0.3s ease-in;
    outline: none;
}

input:focus{
    border: 1px solid #EF5350;
}

.txt{
    font-family: 'Montserrat', sans-serif;
    color:#149B56;
    font-size: 20px;
    font-weight: 500;
}

.txtResult{
    font-family: 'Montserrat';
    color:#212121;
    font-size: x-large;
    padding-left: -20px;
    width: 100%;
    font-weight: 600;
    word-wrap: break-word;
}

.button{
    padding: 12px 25px;
    font-size: 20px;
    text-align: center;
    cursor: pointer;
    color: #fff;
    background-color: #149B56;
    border: none;
    border-radius: 5px;
    transition: ease-in-out 0.3s;
    margin-top: 10px;
    outline: none;
}

.button:hover{
    background-color: #054B27;
}

.button:active{
  background-color: #054B27;
    box-shadow: 0 4px #666;
    transform: translateY(4px);
}

<!--
label{
    font-size: x-large;
    font-family: 'Montserrat';
}

@media (max-width: 700px){
    .button{
        width: 40%;
        font-size: 20px;
    }
}

@media (max-width: 500px){
    div{
        width: 90%;
    }

    .button{
        width: 40%;
        font-size: 15px;
    }
}

@media (max-width: 300px){
    div{
        width: 90%;
    }

    .button{
        font-size: 15px;
    }
}
-->