*,
*::after,
*::before {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
    width: 100%;
}

/* This code effectively outlines the ICB */
html {
    outline: 10px dashed red;
    outline-offset: -10px;
}

#debug,
#visualviewport,
#layoutviewport {
    padding: 1em;
    overflow-y: hidden;
    pointer-events: none;
}

#layoutviewport {
    position: fixed;
    inset: 0;
    border: 5px dotted blue;
    z-index: 999;
}

.someClass {
    width: 100%;
    height: 20px;
}