:root {
    --bleeding: 0.5cm;
    --margin: 1cm;
}

@page {
    size: A4;
    margin: 0;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0 auto;
    padding: 0;
    background: rgb(204, 204, 204);
    display: flex;
    flex-direction: column;
}

.page {
    display: inline-block;
    position: relative;
    height: 297mm;
    width: 210mm;
    font-size: 12pt;
    margin: 2em auto;
    padding: calc(var(--bleeding) + var(--margin));
    box-shadow: 0 0 0.5cm rgba(0, 0, 0, 0.5);
    background: white;
}

@media screen {
    .page::after {
        position: absolute;
        content: '';
        top: 0;
        left: 0;
        width: calc(100% - var(--bleeding) * 2);
        height: calc(100% - var(--bleeding) * 2);
        margin: var(--bleeding);
        outline: thin dashed black;
        pointer-events: none;
        z-index: 9999;
    }
}

@media print {
    .page {
        margin: 0;
        overflow: hidden;
    }
}