body {
}

hr.a {
    height: 150vw;
}

hr.b {
    height: 42vw;
}

hr.c {
    height: 10vw;
}

.alert {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    color: #fff;
    z-index: 2;
    white-space: nowrap;
    text-align: center;
}

    .alert > hr {
        border:0;
        display: inline-block;
        height: 100%;
        width: 0;
        vertical-align: middle;
    }

    .alert > div {
        display: inline-block;
        width: 75%;
        padding: 2rem 0;
        vertical-align: middle;
        background-color: rgba(0, 0, 0, 0.65);
        border-radius: 0.5rem;
        white-space: normal;
        text-align: center;
    }

        .alert > div > em {
            display: block;
            padding: 0.5rem 0;
            font-size: 0.9375rem;
            line-height: 1.375rem;
            font-style: normal;
            font-weight: bold;
        }

            .alert > div > em:empty {
                display: none;
            }

        .alert > div > i {
            display: block;
            padding: 0.5rem 0;
            font-size: 0.9375rem;
            line-height: 1.375rem;
            font-style: normal;
        }

            .alert > div > i:empty {
                display: none;
            }