popup.css

body {
    min-width: 8em;
    background: #fdfdfd;
}

hr {
    width: 100%;
    border: 0;
    height: 0;
    margin: 0.6em 0;
}

h1 {
    text-align: center;
    font-size: 18px;
    padding: 5px 15px;
    color: #777777;
    font-weight: 600;
}

h2 {
    text-align: left;
    font-size: 15px;
    color: #777777;
    font-weight: 200;
    padding: 0 10px;
}

button {
    background: #fff;
    cursor: pointer;
    border: 0;
    color: #4a4a4a;
    text-shadow: none;
    border-radius: 4px;
    padding: 5px 10px;
    width: 260px;
    box-shadow: 0 1px 4px 0 rgba(0, 0, 0, 0.2);
    margin: 5px;
    transition: all 0.15s ease;
}

button:hover {
    filter: brightness(1.05);
    transform: translateY(-1px);
    box-shadow: 0px 3px 6px rgba(0, 0, 0, 0.15);
}

.primary {
    background: #1385ff;
    color: #fff;
    font-size: 16px;
}