style.css

@media only screen and (orientation: portrait) {
    .foreImg {
        background-size: 50% !important;
    }
    p {
        font-size: 2vh !important;
    }
    h3, h4 {
        font-size: 4vh !important;
    }
}

.foreImg {
    z-index: 1;
    width: 100%;
    height: 100%;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-repeat: no-repeat;
    background-attachment: scroll;
    background-position: 50% 50%;
    background-size: 25%;
}

.backImg {
    position: fixed;
    width: 100%;
    height: 100%;
    margin: 0;
    background-repeat: repeat;
    background-size: auto;
}

p {
    margin: 0;
    color: yellow;
    font-size: 3vh;
    text-shadow: 0 1px 0 #dede00, 0 2px 0 #ced106,
        0 3px 0 #b8b202, 0 4px 0 #b8c200, 0 5px 0 #a7b000, 0 6px 1px rgba(0, 0, 0, 1), 0 0 5px rgba(0, 0, 0, 1), 0 1px 3px rgba(0, 0, 0, 1), 0 3px 5px rgba(0, 0, 0, 1), 0 5px 10px rgba(0, 0, 0, 1), 0 10px 10px rgba(0, 0, 0, 1), 0 20px 20px rgba(0, 0, 0, 1);
}

h4,
h3 {
    position: fixed;
    z-index: 2;
    width: 100%;
    height: 100%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: yellow;
    cursor: pointer;
    font-size: 6vh;
    text-shadow: 0 1px 0 #dede00, 0 2px 0 #ced106,
        0 3px 0 #b8b202, 0 4px 0 #b8c200, 0 5px 0 #a7b000, 0 6px 1px rgba(0, 0, 0, 1), 0 0 5px rgba(0, 0, 0, 1), 0 1px 3px rgba(0, 0, 0, 1), 0 3px 5px rgba(0, 0, 0, 1), 0 5px 10px rgba(0, 0, 0, 1), 0 10px 10px rgba(0, 0, 0, 1), 0 20px 20px rgba(0, 0, 0, 1);
}

h4,
body {
    margin: 0;
    padding: 0;
    text-align: center;
}

body {
    background-color: white;
}

.box-click {
    position: fixed;
    z-index: 3;

    opacity: 100%;
    
    left: 50%;
    bottom: 10%;
    transform: translate(-50%, -50%);

    padding: 10px;
    cursor: pointer;

    background-color: rgba(255, 255, 255, 0.35);
    -webkit-backdrop-filter: blur(5px);
    backdrop-filter: blur(5px);
    border-radius: 12px;
}

:root {
    --animacao-delay: 0.2s;
}

/* ANIMAÇÃO  */
.box-click, .foreImg, .backImg, p, h4, h3 {
    -moz-transition: var(--animacao-delay);
    -o-transition: var(--animacao-delay);
    -webkit-transition: var(--animacao-delay);
    transition: var(--animacao-delay);
}