style.css

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

body {
    background-color: whitesmoke;
    opacity: 0.9;

}

.main_div {
    align-items: center;
    align-content: center;
    display: flex;
    justify-content: center;
    margin-top: 220px;
}

.password_div>h1 {
    text-align: center;
}

.pass {
    height: 200px;
    width: 400px;
    background-color: white;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    padding-bottom: 80px;
    font-size: 40px;
    border-radius: 10px;
    border: 2px solid black;

}

.myBtn {
    padding: 15px 25px;
    font-size: 24px;
    margin-left: 100px;
    margin-top: 20px;
    text-align: center;
    cursor: pointer;
    outline: none;
    color: #fff;
    background-color: #008DDA;
    border: none;
    border-radius: 15px;
    box-shadow: 0 9px #999;
}

.myBtn:hover {
    background-color: #378CE7
}

.myBtn:active {
    background-color: #387ADF;
    box-shadow: 0 5px #666;
    transform: translateY(4px);
}