style.css

@import url('https://fonts.googleapis.com/css2?family=Roboto&display=swap');

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

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #4E5BB1;
    font-family: 'Roboto', sans-serif;
}

.container {
    width: 480px;
    height: 320px;
    background-color: rgba(201, 201, 201, 0.377);
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    font-size: 20px;
}

ul {
    list-style: none;
}

#pass_start {
    margin-top: 10px;
    border: none;
    padding: 14px 0;
    border-radius: 4px;
    color: #fff;
    background-color: #5d71dd;
    cursor: pointer;
    transition: background-color 0.1s ease-in-out;
    width: 120px;
    text-align: center;
    box-shadow: 4px 4px 4px rgb(135 135 135 / 50%);
    font-size: 16px;
}

#pass_start:hover {
    background-color: #5d70dda8;
}

#passLenght {
    padding: 0 6px;
    width: 60px;
    height: 26px;
    background-color: #efefef;
    border-radius: 4px;
    border: none;
    margin: 8px;
    font-size: 14px;
}

#result {
    margin-top: 4px;
    text-align: center;
    width: 100%;
    background-color: rgba(228, 228, 228, 0.377);
    font-size: 24px;
}