index.css

html {
    background-color: #f1f1f1;
    color: #333;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    font-size: 20px;
}

html, body {
    align-items: center;
    display: flex;
    height: 100%;
    justify-content: center;
}

ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

li + li {
    margin-top: 10px;
}

form {
    background-color: #fff;
    border-radius: 4px;
    display: flex;
    flex-direction: column;
    padding: 20px;
}

input {
    font-size: .8em;
    margin-top: 5px;
    min-height: 40px;
    padding: 0 10px;
}

button {
    background-color: #03a9f4;
    border: 0;
    font-size: .8em;
    margin-top: 40px;
    padding: 10px;
    text-transform: uppercase;
}

button:hover {
    background-color: #29b6f6;
    cursor: pointer;
}

button:active {
    background-color: #039be5;
}

code {
    background-color: #cdcdcd;
    padding: 0 2px;
}

.field {
    display: flex;
    flex-direction: column;
}

.field-checkbox {
    display: flex;
    align-items: center;
    gap: 7px;
}

.field--hint {
    font-size: .65em;
    margin-top: 10px;
}

.dialog {
    border: 0;
    border-radius: 4px;
    box-shadow: 0 0 20px #757575;
    opacity: 0;
    top: -100vh;
    transform: translateY(-50%);
    transition: top .8s ease-in-out, opacity .4s .6s ease-in-out;
    padding: 40px;
}

.dialog.open {
    opacity: 1;
    top: 50%;
}

.dialog--cross {
    cursor: pointer;
    height: 20px;
    opacity: .3;
    position: absolute;
    right: 10px;
    top: 10px;
    transition: opacity .4s ease-in-out;
    width: 20px;
}

.dialog--cross:hover {
    opacity: 1;
}

.dialog--cross::before, .dialog--cross::after {
    background-color: #333;
    content: ' ';
    height: 18px;
    left: 9px;
    position: absolute;
    width: 2px;
}

.dialog--cross::before {
    transform: rotate(45deg);
}

.dialog--cross::after {
    transform: rotate(-45deg);
}