body {
    height: 100vh;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
} 

.useLandscape {
    display: none;
}

canvas {
    vertical-align: top;
}

.my-element {
    height: 100vh; /* Fallback for browsers that do not support Custom Properties */
    height: calc(var(--vh, 1vh) * 100);
  }

@media screen and (orientation:portrait) {
    canvas {
        display: none;
    }
    .useLandscape {
        display: block;
    }
}