blog/src/lib/Sidenote.svelte

<style>
    /* always applicable */
    :global(body) {
        counter-reset: sidenote;
    }

    .counter {
        counter-increment: sidenote;
        color: #444;
        margin-left: 0.05rem;
    }

    .counter:after {
        font-size: 0.75em;
        position: relative;
        bottom: 0.3rem;
        color: #8c0606;
    }

    .sidenote {
        color: #555;
        font-size: 0.8rem;
    }

    .sidenote:before {
        content: counter(sidenote) " ";
        /* absolute positioning puts it at the top-left corner of the sidenote, overlapping with the content
        (because the sidenote is floated it counts as a positioned parent, I think) */
        position: absolute;
        /* translate moves it out to the left (and just a touch up to mimic the superscript efect)
        -100% refers to the width of the element, so it pushes it out further if necessary (i.e. two digits instead of one) */
        transform: translate(calc(-100% - 0.2rem), -0.15rem);
        font-size: 0.75rem;
        color: #8c0606;
    }

    .sidenote-toggle {
        display: none;
    }

    /* desktop display */
    @media(min-width: 70em) {
        .counter:after {
            content: counter(sidenote);
        }

        .sidenote {
            --gap: 2rem;
            --sidenote-width: min(14rem, calc(50vw - var(--gap) - var(--content-width) / 2));
            width: var(--sidenote-width);
            hyphens: auto;
            position: relative;
            float: right;
            clear: right;
            margin-right: calc(0rem - var(--sidenote-width) - var(--gap)); /* gives us 2rem of space between content and sidenote */
            margin-bottom: 0.7rem;
        }

        /* fade-in animation */
        .sidenote {
            opacity: 0;
            animation: fade-in 600ms ease-out;
            animation-delay: 500ms;
             animation-fill-mode: forwards; 
        }
        @keyframes fade-in {
            from {opacity: 0;}
            to {opacity: 1;}
        }

        .nested.sidenote {
            margin-right: 0;
            margin-top: 0.7rem;
            margin-bottom: 0;
        }

        .dismiss {
            display: none;
        }
    }

    /* mobile display */
    @media (max-width: 70em) {
        .counter:after {
            content: "[" counter(sidenote) "]";
        }

        .counter:hover:after {
            color: #000;
            cursor: pointer;
        }

        .sidenote {
            box-sizing: border-box;
            position: fixed;
            z-index: 1;
            left: 0;
            bottom: 0;
            width: 100vw;
            padding-top: 1rem;
            padding-bottom: 1rem;
            --pad: max(1rem, calc(50vw - var(--content-width) / 2));
            padding-left: var(--pad);
            padding-right: var(--pad);
            background-color: #fff;
            box-shadow: 0 -2px 4px -1px rgba(0, 0, 0, 0.06), 0 -2px 12px -2px rgba(0, 0, 0, 0.1);
            display: none;
        }

        .sidenote-toggle:checked + .sidenote {
            display: block;
        }

        .dismiss {
            position: absolute;
            right: 1.5rem;
            top: -0.2rem;

            font-size: 1.25rem;
            color: #8c0606;
            cursor: pointer;
        }
        .dismiss:hover {
            transform: scale(1.1);
            font-weight: 800;
        }

    }
</style>

<script context="module">
    var activeToggle = null;
</script>

<script>
    import { onMount } from 'svelte';

    let noteBody;
    let nested = false;
    onMount(() => {
        // check to see if the parent node is also a sidenote, if so move this one to the end
        let parentNote = noteBody.parentElement.closest('span.sidenote');
        if (parentNote) {
            noteBody.remove();
            parentNote.appendChild(noteBody);
            nested = true;
        }
    });


    const id = Math.random().toString().slice(2);
    let toggle;

    function toggleState() {
        if (activeToggle === toggle) {
            activeToggle = null;
        }
        else if (activeToggle !== null) {
            activeToggle.checked = false;
            activeToggle = toggle;
        }
        else {
            activeToggle = toggle;
        }
    }
</script>

<label for={id} on:click={toggleState} class="counter"></label>
<input {id} bind:this={toggle} type="checkbox" class="sidenote-toggle" />
<span class="sidenote" class:nested bind:this={noteBody}>
    <label class="dismiss" for={id} on:click={toggleState}>&times;</label>
    <slot></slot>
</span>