style.css

body {
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #262a2f;
    font-family: sans-serif;
}

.generatorcard {
    width: 400px;
    padding: 20px 30px;
    border-radius: 10px;
    box-shadow: 1px 1px 10px rgba(255, 255, 255, 70%);
    background-color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.inputOfGenerator {
    width: 100%;
    padding: 10px 8px;
    border-radius: 10px;
    margin: 10px;
    float: left;
    border: 1px solid #262a2f;
}

.enter-your-txt {
    width: 100%;
}

.btn-of-generator {
    width: 100%;
    height: 40px;
    background-color: #494eea;
    color: white;
    border: 0;
    outline: 0;
    border-radius: 5px;
    box-shadow: 0 10px 10px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    margin: 20px 0;
    font-weight: bold;
    transition: all .5s;
}

.btn-of-generator:hover {
    background-color: rgb(60, 65, 202);
}

.imgdiv {
    width: 200px;
    border-radius: 5px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 1s;
}

.imgQr {
    width: 100%;
    height: 100%;
}

.imgdiv.show-img {
    max-height: 300px;
    margin: 10px auto;
    border: 1px solid #d1d1d1;
}

.error {
    animation: shake 0.1s linear 10;
}

@keyframes shake {
    0%{
        transform: translateX(0);
    }
    25%{
        transform: translateX(-2px);
    }
    50%{
        transform: translateX(0);
    }
    75%{
        transform: translateX(2px);
    }
    100%{
        transform: translateX(0);
    }
}