* {
    margin: 0;
    padding: 0;
}
html, body {
    width: 100%;
    height: 100%;
    font-family: 'Meiryo';
    font-size: 62.5%;
}
.wrapper {
    display: flex;
    align-items: center;
    height: 100%;
    background: url('../../images/warning-bg.jpg') center;
    background-size: cover;
}
.content {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    padding: 0 20px;
}
.content-inner {
    text-align: center;
}
.caution {
    max-height: 400px;
    height: 100%;
}
.message {
    color: white;
    font-size: 3.5rem;
    text-shadow: 3px 3px 2px red, -3px 3px 2px red, 3px -3px 2px red, -3px -3px 2px red;
    margin-top: 20px;
}

/* for tablet */
@media screen and (max-width: 1023px) and (min-width: 768px) {
    .caution {
        max-height: 300px;
    }
    .message {
        font-size: 3.0rem;
    }
}
/* for smartphone */
@media screen and (max-width: 767px) {
    .caution {
        max-height: 250px;
    }
    .message {
        font-size: 2.5rem;
    }
}