style.css

* {
     margin: 0;
     padding: 0;
     box-sizing: content-box;
     font-family: sans-serif;
     border: none;
}

body {
     background-color: #282847;
     color: #282847;
}

main {
     display: flex;
     align-items: center;
     justify-content: center;
     min-height: 100vh;
     padding: 2rem;
}

.generator {
     width: 100%;
     max-width: 640px;
     padding: 2rem 1rem;
     background-color: #fff;
     border-radius: 1rem;
}

/* input:not([type="checbox"]),
button {
     appearance: none;
     outline: none;
     border: none;
     background: none;
} */

input[type="checkbox"] {
     cursor: pointer;
}

.password-wrap {
     position: relative;
     display: flex;
     width: 100%;
     margin-bottom: 1rem;
}

.password-wrap:after {
     content: '';
     display: block;
     position: absolute;
     top: 100%;
     height: 3px;
     left: 0;
     right: 0;
     border-radius: 3px;
     background: linear-gradient(to right, #ad25fc 25%, #518cd4 75%);
}

/* .material-icons {
     font-family: 'Material Icons';
     vertical-align: middle;
} */

.password-wrap input {
     flex: 1 1 0%;
     padding: 0.5rem;
     color: #282847;
     border-radius: 5px;
}

.password-wrap input::placeholder {
     color: #888;
     font-style: italic;
}

.password-wrap button {
     cursor: pointer;
     background: linear-gradient(to bottom, #ad25fc 0%, #518cd4 75%);
     -webkit-background-clip: text;
     -webkit-text-fill-color: transparent;
}

label {
     display: flex;
     user-select: none;
     margin-bottom: 1rem
}

label span {
     display: block;
     flex: 1 1 0%;
     white-space: nowrap;
}

label input[type="number"] {
     text-align: right;
}

button[type="submit"] {
     cursor: pointer;
     padding: 0.5rem 1rem;
     color: #fff;
     font-weight: bold;
     text-transform: uppercase;
     border-radius: 0.25rem;
     background: linear-gradient(to right, #ad25fc 25%, #518cd4 50%);
     background-size: 200%;
     background-position: 25%;
     transition: 0.3s ease-out;
}

button[type="submit"]:hover {
     background-position: 75%;
}