pages/src/lib/content.svelte

<div class="content">
    <slot />
</div>

<style>
    .content {
        width: 100%;
        max-width: var(--page-width);
        margin: 0 auto;
        padding: 0 24px;
    }

    @media screen and (max-width: 800px) {
        .content {
            padding: 0 8px;
        }
    }
</style>