public/styles/components/_overlay.scss

$offset-for-header: 51px;

.overlay--hidden {
    display: none;
}

.overlay--visible {
    @extend %overlay;
    // display: inherit;
}

%overlay {
    position: fixed;
    width: 100%;
    height: 100%;
    top: $offset-for-header;
    background-color: hsla(0, 0%, 93%, 0.9);

    display: flex;
    justify-content: center;
    align-items: center;
}

.overlay__messageBox {
    box-sizing: border-box;
    margin-top: -1 * $offset-for-header;
    background-color: white;
    border: 3px solid $c-highlight-blue;
    padding: 110px 60px 0 60px;
    height: 385px;
    width: 765px;

    display: flex;
    justify-content: center;
    align-items: flex-start;

    position: relative;
}

.overlay__close {
    @extend %icon__cross;
    position: absolute;
    top: 20px;
    right: 20px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.overlay__image {
    margin-right: 30px;
    background-image: url('../images/hands-phone-200.png');
    height: 166px;
    flex: 0 0 200px;
}

.overlay__text {
    @extend %fs-data-6;
    display: block;
    padding: 0px;
}

.overlay__ok {
    @extend %button-cta--confirm;
    display: inline-block;
    margin-top: 10px;
    cursor: pointer;
}