style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html,body{
    height: 100%;
    width: 100%;
    color: #ffff;
    background-color: #111;
}

.main{
    height: 100%;
    width: 100%;
    background-color: #111;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.main h1{
    font-size: 48px;
    display: flex;
    align-items: center;
}

.main h1 span{
    margin: 0 15px;
    display: flex;
    align-items: center;
}

.main h1 span img{
    rotate: 90deg;
    height: 45px;
    transition: 0.3s ease;
}

.main .enc-dec{
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    background: #222;
    border-radius: 8px;
    padding: 8px;
    width: 25%;
    margin: 35px 0;
}

.main .enc-dec h3{
    font-size: 17px;
    display: flex;
    border-radius: 8px;
    align-items: center;
    font-weight: 500;
    cursor: pointer;
    padding: 12px 10px;
    transition: 0.2px ease;
}

.encBtn{
    background-color: #333;
}

.enc-dec h3 span{
    display: flex;
    align-items: center;
    margin-right: 8px;
}

.enc-dec h3 span img{
    height: 22px;
}

.encryption{
    width: 45%;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: space-around;
}

.encryption h5{
    font-size: 18px;
    font-weight: 500;
    color: #a4a2a2;
    margin-bottom: 13px;
}

.encryption textarea{
    outline: none;
    width: 100%;
    height: 70px;
    border: 1px solid #343434;
    padding: 10px;
    border-radius: 8px;
    font-size: 17px;
    background-color: #1c1c1c;
    color: #ffff;
    margin-bottom: 45px;
    resize: vertical;
}

.encryption input{
    outline: none;
    width: 100%;
    border: 1px solid #343434;
    padding: 10px;
    border-radius: 8px;
    font-size: 17px;
    background-color: #1c1c1c;
    color: #ffff;
    margin-bottom: 45px;
}

.encryption button{
    display: flex;
    justify-content: center;
    align-items: center;
    border: none;
    width: 100%;
    background-color: #1c1c1c;
    color: #a4a2a2;
    padding: 10px;
    border-radius: 10px;
    font-size: 18px;
    border: 1px solid #343434;
}

.encryption button span{
    display: flex;
    margin-right: 15px;
}

.encryption button span img{
    height: 22px;
}

.decryption{
    width: 45%;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: space-around;
    /* !! */
    display: none;
}

.decryption h5{
    font-size: 18px;
    font-weight: 500;
    color: #a4a2a2;
    margin-bottom: 13px;
}

.decryption textarea{
    outline: none;
    width: 100%;
    height: 70px;
    border: 1px solid #343434;
    padding: 10px;
    border-radius: 8px;
    font-size: 17px;
    background-color: #1c1c1c;
    color: #ffff;
    margin-bottom: 45px;
}

.decryption input{
    outline: none;
    width: 100%;
    border: 1px solid #343434;
    padding: 10px;
    border-radius: 8px;
    font-size: 17px;
    background-color: #1c1c1c;
    color: #ffff;
    margin-bottom: 45px;
}

.decryption button{
    display: flex;
    justify-content: center;
    align-items: center;
    border: none;
    width: 100%;
    background-color: #1c1c1c;
    color: #a4a2a2;
    padding: 10px;
    border-radius: 10px;
    font-size: 18px;
    border: 1px solid #343434;
}

.decryption button span{
    display: flex;
    margin-right: 15px;
}

.decryption button span img{
    height: 22px;
}

.result{
    padding: 20px;
    border-radius: 10px;
    font-size: 18px ;
    background-color: #1c1c1c;
    border: 1px solid #343434;
    width: 45%;
    margin-top: 40px;
    display: none;    
}

.clickable {
    cursor: pointer;
    border: 1px solid #ccc;
    padding: 10px;
}



/* ? media queries */
@media screen and (max-width:1024px) {
    .main .enc-dec{
        display: flex;
        width: 34%;
    }
}

@media screen and (max-width:768px) {
    .main .enc-dec{
        display: flex;
        flex-direction: column;
        width: 40%;
    }
    .encryption textarea{
        height: 110px;
    }
    .decryption textarea{
        height: 110px;
    }

    .main h1{
        font-size: 40px;
    }
}

@media screen and (max-width:425px) {
    .main .enc-dec{
        display: flex;
        flex-direction: column;
        width: 60%;
    }
    .encryption textarea{
        height: 130px;
    }
    .decryption textarea{
        height: 130px;
    }
    .main h1{
        font-size: 40px;
    }

}