body {
    text-align: center;
}

img {
    z-index: 99;
}

h1,
h2 {
    font-family: Helvetica, sans-serif;
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 1.5rem;
}

/* -- Styles for the pop-up -- */

/* -- Adapted from https://sabe.io/tutorials/how-to-create-modal-popup-box -- */

.popup {
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    visibility: hidden;
    z-index: 99;
}

.popup-content {
    position: absolute;
    top: 40%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    background: white;
    padding: 1rem 2.5rem 2rem 2.5rem;
    width: 15rem;
    border-radius: 0.5rem;
}

.close-button {
    margin: 0 auto;
    width: 11rem;
    line-height: 2rem;
    text-align: center;
    cursor: pointer;
    border-radius: 0.25rem;
    background-color: rgb(231, 231, 231);
    border: 1px solid rgb(170, 170, 170);
}

.close-button:hover {
    background-color: darkgray;
}

.show-popup {
    opacity: 1;
    visibility: visible;
    -webkit-transform: scale(1.0);
    -ms-transform: scale(1.0);
    transform: scale(1.0);
    -webkit-transition: visibility 0s linear 0s, opacity 0.25s 0s, -webkit-transform 0.25s;
    transition: visibility 0s linear 0s, opacity 0.25s 0s, -webkit-transform 0.25s;
    -o-transition: visibility 0s linear 0s, opacity 0.25s 0s, transform 0.25s;
    transition: visibility 0s linear 0s, opacity 0.25s 0s, transform 0.25s;
    transition: visibility 0s linear 0s, opacity 0.25s 0s, transform 0.25s, -webkit-transform 0.25s;
}