/* ITCSS (sort of).
https://www.xfive.co/blog/itcss-scalable-maintainable-css-architecture
--------------------------------------------------------------------------- */

/* -------------------------------------------------------------------------------
@layer settings {}
------------------------------------------------------------------------------- */

    /* Fonts.
    --------------------------------------------------------------------------- */

    /* https://fonts.google.com/specimen/Karla */

    @font-face {
        font-family: 'Karla';
        src: url("../fonts/karla-regular.1e4e4839bb5a.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Karla';
        font-style: italic;
        src: url("../fonts/karla-light-italic.b88dcd3c2183.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Karla';
        font-weight: bold;
        src: url("../fonts/karla-semi-bold.e3cfb3b8dd34.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Karla';
        font-weight: bold;
        font-style: italic;
        src: url("../fonts/karla-bold-italic.bfc4672695dc.woff2") format('woff2');
        font-display: swap;
    }

    /* https://google-webfonts-helper.herokuapp.com/fonts/montserrat */

    @font-face {
        font-family: 'Montserrat';
        src: url("../fonts/montserrat-v23-latin-regular.8c274959f17f.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Montserrat';
        font-style: italic;
        src: url("../fonts/montserrat-v23-latin-italic.497e4dbe1a20.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Montserrat';
        font-weight: bold;
        src: url("../fonts/montserrat-v23-latin-700.ea307b73f237.woff2") format('woff2');
        font-display: swap;
    }

    @font-face {
        font-family: 'Montserrat';
        font-style: italic;
        font-weight: bold;
        src: url("../fonts/montserrat-v23-latin-700italic.d8c504ffdfba.woff2") format('woff2');
        font-display: swap;
    }

    /* https://github.com/kanjialive/kanji-data-media/tree/master/radicals-font */

    @font-face {
        font-family: 'JapaneseRadicals';
        src: url("../fonts/japanese-radicals-regular.8ed9e7648888.woff2") format('woff2');
        font-display: swap;
    }


    /* Variables.
    --------------------------------------------------------------------------- */

    :root {

        /* Font families.
        --------------------------------------------------------------------------- */

        --font-family-main: Karla, JapaneseRadicals, -apple-system, BlinkMacSystemFont, Helvetica, Arial, sans-serif;
        --font-family-secondary: Montserrat, -apple-system, BlinkMacSystemFont, Helvetica, Arial, sans-serif;
        --font-family-mono: Menlo, SFMono-Regular, Consolas, Liberation Mono, Monaco, monospace;

        /* Colors.
        --------------------------------------------------------------------------- */

        --color-black: #000;
        --color-blue-dark: #223843;
        --color-gray-dark: #555;
        --color-gray-light: #f5f5f5;
        --color-gray-medium: #cbcbcb;
        --color-orange: #ff9800;
        --color-red: #fd405c;
        --color-taupe: #dbd3d8;
        --color-white: #eff1f3;

        /* Spacing.
        --------------------------------------------------------------------------- */

        --spacing-normal: 1rem;
        --spacing-narrow: 0.625rem;

        --spacing-normal-small: calc(var(--spacing-normal) / 2);
        --spacing-narrow-small: calc(var(--spacing-narrow) / 2);

        --spacing-normal-large: calc(var(--spacing-normal) * 2);
        --spacing-narrow-large: calc(var(--spacing-narrow) * 2);

        /* Fonts.
        --------------------------------------------------------------------------- */

        /* https://www.fluid-type-scale.com */
        --font-size-default: clamp(1.13rem, 0.86vw + 0.68rem, 1.75rem);

        --font-size-small: 0.8rem;
        --font-size-x-small: 0.5rem;

        /* https://type-scale.com */
        --font-size-h1: 2.488rem;
        --font-size-h2: 2.074rem;
        --font-size-h3: 1.44rem;
        --font-size-h4: 1.2rem;
        --font-size-h5: 1.1rem;

        --line-height-default: 1.70;
        --line-height-heading: 1.15;

        /* Borders.
        --------------------------------------------------------------------------- */

        --border-width-default:  1px;
        --border-radius-default: 2px;

    }

    /* Box-model.
    --------------------------------------------------------------------------- */

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

/* -------------------------------------------------------------------------------
@layer elements {}
------------------------------------------------------------------------------- */

    html {
        color: var(--color-black);
        background: var(--color-white);
        font-family: var(--font-family-main);
        font-size: var(--font-size-default);
        line-height: var(--line-height-default);
        -webkit-font-smoothing: antialiased;
        overflow-y: scroll;
    }

    body {
        margin: 0;
        min-height: 100%;
        word-break: break-word;  /* https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Text/Wrapping_Text */
        overflow-wrap: break-word;
    }

    /* Links.
    --------------------------------------------------------------------------- */

    a,
    a:link,
    a:visited {
        text-decoration: underline;
        color: currentColor;
        background: none;
    }

    a:focus,
    a:hover {
        background: var(--color-white);
        color: var(--color-black);
        text-decoration: none;
    }

    a:active {
        background: var(--color-white);
        color: var(--color-red);
        text-decoration: none;
    }

    /* Headings.
    --------------------------------------------------------------------------- */

    h1, h2, h3, h4, h5, h6 {
        font-family: var(--font-family-secondary);
        line-height: var(--line-height-heading);
    }

    h1 {
        font-size: var(--font-size-h1);
        /* Don't let headings float. Add more space above, less below. */
        margin: var(--font-size-h1) 0 calc(var(--font-size-h1) / 3);
    }

    h2 {
        font-size: var(--font-size-h2);
        margin: var(--font-size-h2) 0 calc(var(--font-size-h2) / 3);
    }

    h3 {
        font-size: var(--font-size-h3);
        margin: var(--font-size-h3) 0 calc(var(--font-size-h3) / 3);
    }

    h4 {
        font-size: var(--font-size-h4);
        margin: var(--font-size-h4) 0 calc(var(--font-size-h4) / 3);
    }

    h5 {
        font-size: var(--font-size-h5);
        margin: var(--font-size-h5) 0 calc(var(--font-size-h5) / 3);
    }

    /* Divider.
    --------------------------------------------------------------------------- */

    hr {
        width: 100%;
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-width: var(--border-width-default) 0 0 0;

        display: inline-block;
        margin: var(--spacing-normal-large) 0;
    }

    /* Lists.
    --------------------------------------------------------------------------- */

    li {
        margin: var(--spacing-narrow) 0;
    }

    /* iframe.
    --------------------------------------------------------------------------- */

    iframe {
        border: 0;
    }

    /* Definition lists.
    --------------------------------------------------------------------------- */

    dt {
        font-weight: bold;
        padding: var(--spacing-normal) 0 0 0;
    }

    dd {
        margin: 0;
    }

    /* Code.
    --------------------------------------------------------------------------- */

    pre {
        font-size: 90%;
        padding: var(--spacing-narrow-small) var(--spacing-normal-small);
        max-width: 100%;
        overflow: auto;
        background: var(--color-gray-light);
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-radius: var(--border-radius-default);
    }

    code {
        font-size: 80%;
        font-family: var(--font-family-mono);
        padding: 1px 6px;
        background: var(--color-gray-light);
        color: var(--color-black);
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-radius: var(--border-radius-default);
    }

    pre code {
        border: none;
        background: none;
        padding: 0;
        line-height: 25px;
    }

    kbd {
        font-size: 80%;
        display: inline-block;
        vertical-align: middle;
        padding: 0 0.3rem;
        font-family: var(--font-family-mono);
        color: var(--color-black);
        background-color: var(--color-gray-light);
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-bottom: 2px solid var(--color-gray-medium);
        border-radius: 5px;
    }

    /* Blockquotes.
    --------------------------------------------------------------------------- */

    blockquote {
        font-style: italic;
        padding: 0 var(--spacing-normal);
        border-left: .3rem solid var(--color-blue-dark);
        margin-left: 0;
        margin-right: 0;
    }

    /* Tables.
    --------------------------------------------------------------------------- */

    table {
        word-break: normal;  /* https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Text/Wrapping_Text */
        overflow-wrap: normal;
        border-collapse: collapse;
        border-spacing: 0;
        empty-cells: show;
        text-align: left;
        border: var(--border-width-default) solid var(--color-gray-medium);
        margin: var(--spacing-normal-small) 0 var(--spacing-normal) 0;
        font-size: var(--font-size-small);
    }

    table caption {
        padding: var(--spacing-narrow) var(--spacing-normal);
        font-style: italic;
    }

    table thead,
    table tfoot {
        padding: var(--spacing-narrow-small) var(--spacing-normal-small);
        vertical-align: bottom;
    }

    table tfoot {
        vertical-align: top;
    }

    table td,
    table th {
        padding: var(--spacing-narrow-small) var(--spacing-normal-small);
        border: var(--border-width-default) solid var(--color-gray-medium);
        vertical-align: top;
    }

    table > thead > tr {
        background: var(--color-black);
        color: var(--color-white);
    }

    table > tbody > tr {
        background: var(--color-gray-light);
    }

    /* Images.
    --------------------------------------------------------------------------- */

    img {
        max-width: 100%;
        max-height: calc(100vh - 50px);
    }

    figure {
        margin: 0;
    }

    /* Forms.
    --------------------------------------------------------------------------- */

    label {
        display: inline-block;
        cursor: pointer;
    }

    fieldset {
        /*
        Width and min-width are required here to respect 100% textarea max-width within fieldset.
        http://codepen.io/tmsdnl/pen/ByqJgO
        */
        width: 100%;
        min-width: 100%;
        margin: var(--spacing-normal) 0;
        padding: 0;
        border: 0;
        font-size: var(--font-size-small);
    }

    legend {
        width: 100%;
        border-bottom: var(--border-width-default) solid var(--color-gray-medium);
        font-style: italic;
    }

    input:not([type]),
    input[autocomplete],
    input[inputmode],
    input[type="date"],
    input[type="datetime"],
    input[type="datetime-local"],
    input[type="email"],
    input[type="file"],
    input[type="month"],
    input[type="number"],
    input[type="password"],
    input[type="search"],
    input[type="tel"],
    input[type="text"],
    input[type="time"],
    input[type="url"],
    input[type="week"],
    select[multiple],
    textarea {
        display: block;

        appearance: none;
        border-radius: 0;

        background-clip: padding-box;
        font-size: inherit;
        font-family: inherit;
        color: var(--color-black);
        max-width: 100%;
        margin: 0;
        padding: var(--spacing-narrow) var(--spacing-normal);
        background: var(--color-gray-light);
        border: var(--border-width-default) solid var(--color-gray-medium);
    }

    select {
        font-size: inherit;
        font-family: inherit;
    }

    input[type="file"] {
        cursor: pointer;
    }

    input[type=file]::-webkit-file-upload-button {
        vertical-align: top;
    }

    input[type="checkbox"],
    input[type="radio"] {
        margin-top: 0;
        margin-bottom: 0;
        vertical-align: middle;
        position: relative;
        top: -1px;
    }

    textarea {
        min-height: 150px;
    }

    /* Buttons.
    --------------------------------------------------------------------------- */

    button,
    input[type="submit"],
    input[type="reset"],
    input[type="button"] {

        appearance: none;
        border-radius: 0;

        font-size: inherit;
        font-weight: bold;

        text-align: center;
        cursor: pointer;

        padding: var(--spacing-narrow) var(--spacing-normal);
        margin: 0;
        white-space: nowrap;

        color: var(--color-black);
        background: var(--color-gray-light);
        border: var(--border-width-default) solid var(--color-gray-medium);

    }

    button[disabled],
    input[type="submit"][disabled],
    input[type="reset"][disabled],
    input[type="button"][disabled] {
        opacity: .5;
        cursor: not-allowed;
    }

    button:focus,
    button:enabled:hover,
    input[type="submit"]:focus,
    input[type="submit"]:enabled:hover,
    input[type="reset"]:focus,
    input[type="reset"]:enabled:hover,
    input[type="button"]:focus,
    input[type="button"]:enabled:hover {
        color: var(--color-white);
        background: var(--color-black);
        border-color: var(--color-black);
    }

    button:active,
    button:enabled:active,
    input[type="submit"]:active,
    input[type="submit"]:enabled:active,
    input[type="reset"]:active,
    input[type="reset"]:enabled:active,
    input[type="button"]:active,
    input[type="button"]:enabled:active {
        color: var(--color-white);
        background: var(--color-red);
        border-color: var(--color-white);
    }

    /* Details/Summary.
    --------------------------------------------------------------------------- */

    details {
        font-size: var(--font-size-small);
        margin: var(--spacing-normal-large) 0;
        padding: var(--spacing-narrow) var(--spacing-normal);
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-radius: var(--border-radius-default);
    }

    summary {
        cursor: pointer;
        font-weight: bold;
    }

        summary:focus,
        summary:hover {
            color: var(--color-red);
        }

    details[open] > *:last-child {
        margin-bottom: 0;
        padding-bottom: 0;
    }

/* -------------------------------------------------------------------------------
@layer layout {}
------------------------------------------------------------------------------- */

    /* Skip-links.
    --------------------------------------------------------------------------- */

    .skip-links {
        position: absolute;
        width: 100%;
        text-align: center;
        z-index: 1;
    }

    .skip-links ul,
    .skip-links li {
        margin: 0;
        padding: 0;
        list-style: none;
    }

    .skip-links a {
        display: inline-block;
        position: absolute;
        left: -100%;
        top: 20px;
        width: 90%;
        padding: var(--spacing-normal);
        background: var(--color-black);
        color: var(--color-white);
        border: 5px solid var(--color-red);
        outline: 5px solid var(--color-orange);
        outline-offset: 0;
        font-size: var(--font-size-h4);
    }

    .skip-links a:focus,
    .skip-links a:active {
        position: relative;
        left: 0;
        text-decoration: underline;
    }

    /* Main grid.

    https://medium.com/@igloude/how-css-grid-makes-single-columns-better-def5a7dd5045

    Usage:

        <div class="grid">
            <div class="grid-item"></div>
            <div class="grid-item grid-item-full-width"></div>
            <div class="grid-item"></div>
            …
        </div>

    --------------------------------------------------------------------------- */

    .grid {
        /* Main grid container */
        display: grid;
        grid-template-columns:
            [left] minmax(1em, auto)
            [content-start] minmax(0, 960px) [content-end]
            minmax(1em, auto) [right];
    }

        .grid .grid-item {
            grid-column: content;
        }

        :not(header).grid .grid-item {
            padding-bottom: var(--spacing-normal);
        }

        .grid .grid-item-full-width {
            /* As grid item */
            grid-column: left / right;
            /* As sub-grid container */
            display: inherit;
            grid-template-columns: inherit;
        }

        .grid .grid-item-full-width > * {
            /* Every direct child of `grid-item-full-width` is a grid item. */
            grid-column: content;
        }

    /* Full width container in limited width parent.

    Breaking out with viewport units and calc.
    https://cloudfour.com/thinks/breaking-out-with-viewport-units-and-calc/#flipping-the-script

    Usage:

        <figure class="full-width-break-out-of-container">
            <img src="img/puissances_negatives.svg" alt="">
        </figure>

        <div class="full-width-break-out-of-container">
            <table>
                …
            </table>
        </div>

    --------------------------------------------------------------------------- */

    .full-width-break-out-of-container {
        margin-left: calc(-50vw + 55%);
        margin-right: calc(-50vw + 55%);
        /* Use overflow to display an horizontal scrollbar on small size screen for large tables. */
        overflow: auto;
    }

        /* For any viewport > min-width. */
        @media (min-width: 2000px) {
            .full-width-break-out-of-container {
                /*
                Creating a sticky table header with #CSS should be as simple as:

                    thead {
                        position: sticky;
                        top: 0;
                    }

                But things go wrong as soon as any ancestor has a non-default value for overflow.
                https://stackoverflow.com/a/44929597

                So this is a compromise to make "sticky table headers" work with big screens

                See `table.sticky thead`.
                */
                overflow: visible;
            }
        }

        .full-width-break-out-of-container > * {
            max-width: calc(960px * 2);
            margin-left: auto;
            margin-right: auto;
        }

        .full-width-break-out-of-container > img {
            display: block;
            max-height: 90vh;
            max-width: 90vw;
        }

    /* KaTeX.
    --------------------------------------------------------------------------- */

    /*
        Wide formulas overflow on narrow screens — KaTeX doesn't solve this
        itself, so we add a horizontal scrollbar.
    */
    :not(td):has(> .katex-display),
    :is(ol, ul):has(.katex) {
        display: block;
        overflow-y: hidden;
        overflow-x: auto;
    }


/* -------------------------------------------------------------------------------
@layer components {}
------------------------------------------------------------------------------- */

    /* Header.
    --------------------------------------------------------------------------- */

    .main-header {
        background: #000;
        color: #fff;
        padding-top: var(--spacing-normal);
        padding-bottom: 0;
        border-bottom: 5px solid #fd405c;
        outline: 5px solid #ff9800;
        outline-offset: 0;
        margin-bottom: 5px;  /* Don't hide the bottom outline. */
    }

        .main-header nav ul {
            list-style: none;
            margin: 0;
            padding: 0;

            /* Move the image in the logo to the left. */
            position: relative;
            left: -40px;

            display: flex;
            flex-flow: row wrap;
            justify-content: flex-start;
            align-items: flex-end;
            gap: .9rem;
        }

        /* For any viewport < max-width. */
        @media (max-width: 1060px) {
            .main-header nav ul {
                left: 0;
            }
        }

        .main-header nav li {
            margin: 0;
            padding: 0;
        }

        .main-header nav a.main-header__logo,
        .main-header nav a.main-header__logo:link,
        .main-header nav a.main-header__logo:visited {
            display: block;
            width: 200px;
            position: relative;
            top: -3px;
            /* https://codepen.io/sosuke/pen/Pjoqqp */
            /* --color-white */
            filter: invert(97%) sepia(7%) saturate(62%) hue-rotate(166deg) brightness(99%) contrast(94%);
        }

            .main-header nav a.main-header__logo:focus,
            .main-header nav a.main-header__logo:hover,
            .main-header nav a.main-header__logo:active {
                /* https://codepen.io/sosuke/pen/Pjoqqp */
                /* --color-red */
                filter: invert(47%) sepia(53%) saturate(6464%) hue-rotate(329deg) brightness(101%) contrast(98%);
            }

        .main-header a,
        .main-header a:link,
        .main-header a:visited {
            font-size: var(--font-size-small);
            font-weight: bold;
            text-decoration: none;
            color: var(--color-white);
        }

        .main-header a:focus,
        .main-header a:hover {
            text-decoration: underline;
            background: none;
        }

        .main-header a:active,
        .main-header a.active {
            text-decoration: underline;
            color: var(--color-red);
            background: none;
        }

        /* For any viewport < max-width. */
        @media (max-width: 400px) {
            .main-header nav li:first-child,
            .main-header nav a.main-header__logo,
            .main-header nav a.main-header__logo:link,
            .main-header nav a.main-header__logo:visited,
            .main-header nav a.main-header__logo img {
                width: 150px;
            }
            .main-header nav ul {
                row-gap: 0;
            }
        }

    /* Footer.
    --------------------------------------------------------------------------- */

   .main-footer {
        margin: 0;
        padding: 0;
        border-top: 3px solid var(--color-blue-dark);
        font-family: var(--font-family-secondary);
        font-size: var(--font-size-small);
    }

        .main-footer__blockquote {
            margin: var(--spacing-normal-large) 0 var(--spacing-normal) 0;
            padding: 0;
            border: 0;
            background: none;
            font-size: 0;
        }

            .main-footer__blockquote__cite {
                display: block;
                font-style: normal;
            }

            .main-footer__blockquote__quote,
            .main-footer__blockquote__cite-reload,
            .main-footer__blockquote__cite-source {
                display: inline-block;
                margin: 0;
                font-size: var(--font-size-small);
                padding: var(--spacing-narrow) var(--spacing-normal);
                border: var(--border-width-default) solid var(--color-gray-medium);
            }

            .main-footer__blockquote__cite-reload,
            .main-footer__blockquote__cite-source {
                font-size: var(--font-size-x-small);
                border-top: 0;
                position: relative;
                top: -1px;
            }

            .main-footer__blockquote__cite-source {
                position: relative;
                left: -1px;
            }

        .main-footer nav {
            margin: var(--spacing-normal-small) 0;
            padding: 0;
        }

            .main-footer nav ul {
                list-style: none;
                margin: 0;
                padding: 0;

                display: flex;
                flex-flow: row wrap;
                justify-content: flex-start;
                align-items: flex-end;
                gap: var(--spacing-normal-small);
            }

            .main-footer nav ul li {
                margin: 0;
                padding: 0;
            }

        .main-footer__legal {
            border-top: var(--border-width-default) solid var(--color-gray-medium);
            font-size: var(--font-size-x-small);
            margin: var(--spacing-normal) 0 0 0;
            padding: var(--spacing-narrow-small) 0 0 0;
        }

        .main-footer a,
        .main-footer a:link,
        .main-footer a:visited {
            text-decoration: underline;
            color: var(--color-blue-dark);
        }

        .main-footer a:focus,
        .main-footer a:hover {
            text-decoration: none;
        }

        .main-footer a:active,
        .main-footer a.active {
            text-decoration: none;
            color: var(--color-red);
        }

        .main-footer a[lang]::after {
            content: " ( " attr(lang) " ) ";
            font-size: var(--font-size-x-small);
            text-transform: uppercase;
        }

    /* Kemar.
    --------------------------------------------------------------------------- */

    .kemar {
        text-align: right;
        padding: var(--spacing-normal);
        font-size: var(--font-size-x-small);
    }

        .kemar img {
            width: 100px;
            vertical-align: middle;
            /* https://codepen.io/sosuke/pen/Pjoqqp */
            /* --color-blue-dark */
            filter: invert(18%) sepia(19%) saturate(1031%) hue-rotate(155deg) brightness(93%) contrast(91%);
        }

    /* Button links.
    --------------------------------------------------------------------------- */

    a.btn,
    a.btn:link,
    a.btn:visited {
        display: inline-block;
        text-decoration: none;
        text-align: center;
        padding: var(--spacing-narrow) var(--spacing-normal);
        font-size: var(--font-size-small);
        font-weight: bold;
        background: var(--color-white);
        border: var(--border-width-default) solid var(--color-gray-medium);
        color: var(--color-black);
    }

    a.btn:focus,
    a.btn:hover {
        text-decoration: none;
        background: var(--color-black);
        border-color: var(--color-black);
        color: var(--color-white);
    }

    a.btn:active {
        text-decoration: none;
        background: var(--color-red);
        border-color: var(--color-white);
        color: var(--color-white);
    }

    /* Chevrons.
    --------------------------------------------------------------------------- */

    .chevron-left::before {
        content: "‹";
        line-height: 0;
        font-size: var(--font-size-h4);
        padding: 0 var(--spacing-narrow) 0 0;
        vertical-align: sub;
    }

    .chevron-right::after {
        content: "›";
        line-height: 0;
        font-size: var(--font-size-h4);
        padding: 0 0 0 var(--spacing-narrow);
        vertical-align: sub;
    }

    /* Zebra tables.
    See also https://tau.gr/posts/2018-03-23-html-table-merged-cells-stripe/
    with multiple `tbody`.
    --------------------------------------------------------------------------- */

    table.zebra > tbody > tr:nth-child(even) {
        background: none;
    }

    table.zebra > tbody > tr:nth-child(odd) {
        background: var(--color-gray-light);
    }

    /* Sticky table header.
     See `.full-width-break-out-of-container`
    --------------------------------------------------------------------------- */

    table.sticky thead {
        position: sticky;
        top: 0;
    }

        table.sticky thead th {
            /* Use `outline` as a hack to display borders on sticky headers. */
            outline: 1px solid var(--color-gray-medium);
        }

    /* Sub heading.
    --------------------------------------------------------------------------- */

    .main-title__before,
    .main-title__after {
        display: block;
    }

    .main-title__before {
        font-size: var(--font-size-h4);
    }

    .main-title__after {
        margin-top: var(--spacing-narrow-small);
        font-size: var(--font-size-h5);
    }

    /* Parental Advisory Label.
    --------------------------------------------------------------------------- */
    .parental-advisory-label {
        max-width: 6rem;
    }

    /* Social icons.
    --------------------------------------------------------------------------- */

    a.social-icon,
    a.social-icon:link,
    a.social-icon:visited {

        display: inline-block;
        vertical-align: middle;
        margin: 0;
        padding: 4px 5px;
        width: 40px;
        height: 40px;

        /* 3 rules for image-replacement */
        text-indent: 200%;
        white-space: nowrap;
        overflow: hidden;

        color: var(--color-white);
        background-color: var(--color-red);
        background-repeat: no-repeat;
        background-position: 50% 50%;
        background-size: contain;
        background-origin: content-box;

        border-radius: 10%;

    }

    a.social-icon.github { background-image: url("../img/social/social-github-white.5550d531fe9d.svg"); }
    a.social-icon.linkedin { background-image: url("../img/social/social-linkedin-white.e8bf6be8c270.svg"); }
    a.social-icon.twitter { background-image: url("../img/social/social-twitter-white.bfad0f130741.svg"); }
    a.social-icon.pinterest { background-image: url("../img/social/social-pinterest-white.6d81b275ea5a.svg"); }
    a.social-icon.mastodon { background-image: url("../img/social/social-mastodon-white.dd4f91cc7486.svg"); }

    a.social-icon:focus,
    a.social-icon:hover {
        background-color: var(--color-blue-dark);
    }

    a.social-icon:active {
        background-color: var(--color-orange);
    }

    /* Timeline.
    --------------------------------------------------------------------------- */

    dl.timeline {
        border-left: var(--border-width-default) solid var(--color-gray-medium);
        margin: 0 0 0 1em;
        padding-top: var(--spacing-normal-large);
    }

    dl.timeline dt {
        position: relative;
        padding: 0 0 0 3.2rem;
    }

        dl.timeline dt::before {
            content: "";
            position: absolute;
            left: 0;
            top: 50%;
            height: 1px;
            background-color: var(--color-gray-medium);
            width: 1.8rem;
        }

        dl.timeline dt::after {
            content: "";
            position: absolute;
            left: 1.8rem;
            top: calc(50% - 7px);
            width: 15px;
            height: 15px;
            border-radius: 10px;
            background: var(--color-red);
        }

        dl.timeline dt ul {
            list-style: none;
            margin: 0;
            padding: 0;
            font-weight: bold;
            line-height: var(--line-height-heading);
            font-family: var(--font-family-secondary);
        }

            dl.timeline dt li {
                margin: 0;
                padding: 0;
            }

            dl.timeline dt .timeline__dt-line-1 {
                color: var(--color-gray-dark);
                font-size: var(--font-size-small);
            }

            dl.timeline dt .timeline__dt-line-2 {
                font-size: var(--font-size-h4);
            }

            dl.timeline dt .timeline__dt-line-3 {
                color: var(--color-orange);
                font-size: var(--font-size-h6);
            }

        dl.timeline dd {
            margin: 0;
            padding: 0 0 0 3.2rem;
            padding-bottom: var(--spacing-normal-large);
        }

            dl.timeline .timeline__dd-intro {
                color: var(--color-gray-dark);
            }

    /* Titles list.
    --------------------------------------------------------------------------- */

    .titles-list {
        font-family: var(--font-family-secondary);
        font-weight: bold;
    }

        .titles-list li {
            margin: var(--spacing-normal) 0;
        }

        .titles-list li::marker {
            color: var(--color-orange);
        }

        ul.titles-list li::marker {
            font-size: var(--font-size-h5);
        }

        .titles-list li a {
            text-decoration: none;
        }

            .titles-list li a .titles-list__title,
            .titles-list li a:link .titles-list__title,
            .titles-list li a:visited .titles-list__title {
                text-decoration: underline;
            }

            .titles-list li a:focus .titles-list__title,
            .titles-list li a:hover .titles-list__title {
                text-decoration: none;
            }

            .titles-list li a:active .titles-list__title {
                text-decoration: none;
            }

            .titles-list li a .metadata,
            .titles-list li a:link .metadata,
            .titles-list li a:visited .metadata {
                border-color: var(--color-gray-medium);
                color: var(--color-gray-dark);
            }

            .titles-list li a:focus .metadata,
            .titles-list li a:hover .metadata {
                border-color: var(--color-black);
                color: var(--color-black);
            }

            .titles-list li a:active .metadata {
                border-color: var(--color-red);
                color: var(--color-red);
            }

        .titles-list .titles-list__search_result {
            font-family: var(--font-family-main);
            font-style: italic;
            font-weight: normal;
            color: var(--color-gray-dark);
            display: block;
            margin: var(--spacing-narrow-small) 0;
        }

    /* Article header.
    --------------------------------------------------------------------------- */

    .article-header {
        padding-bottom: var(--spacing-normal-large);
    }

    /* Metadata.
    --------------------------------------------------------------------------- */

    .metadata {
        display: inline-block;
        border: var(--border-width-default) solid var(--color-gray-medium);
        color: var(--color-gray-dark);
        font-family: var(--font-family-main);
        font-size: var(--font-size-small);
        font-weight: normal;
        padding: var(--spacing-narrow-small) var(--spacing-normal-small);
        vertical-align: middle;
        text-decoration: none;
    }

    .metadata-notes {
        margin-bottom: calc(var(--spacing-narrow-small) * -1);
    }

        .metadata-notes .metadata {
            margin: 0 0 var(--spacing-narrow-small) 0;
        }

    /* Prev-Next nav.
    --------------------------------------------------------------------------- */

    .prev-next-nav {
        display: flex;
        gap: var(--spacing-normal);
    }

        .prev-next-nav a.btn {
            flex: 1 1 50%;
            display: flex ;
            flex-direction: column;
            justify-content: flex-start;
        }

        .prev-next-nav__title {
            padding-top: var(--spacing-normal-small);
            margin-top: var(--spacing-normal-small);
            border-top: 1px solid var(--color-gray-medium);
        }

    /* Search.
    --------------------------------------------------------------------------- */

    .search-form {
        padding: 0;
        margin: var(--spacing-normal) 0 0 0;
        display: flex;
        position: relative;
    }

        .search-form__q {
            flex: 2 1 calc(80% + 1px);
            max-width: 80%;
        }

        .search-form__submit {
            position: relative;
            left: -1px;
        }

    /* Tweets.
    --------------------------------------------------------------------------- */

    .tweets {
        padding: 0;
        margin: 0;
        list-style: none;
        display: flex;
        flex-flow: row wrap;
        gap: var(--spacing-normal-small);
    }

        .tweets__item {
            padding: var(--spacing-normal) 0;
            margin: 0;
            width: 100%;
            display: flex;
            flex-flow: column nowrap;
        }

        .tweets__item__media {
            margin: 0;
            width: max-content;
            max-width: 100%;
        }

            .tweets__item__media:has(> img) {
                border: var(--border-width-default) solid var(--color-gray-medium);
                border-bottom: 0;
            }

            .tweets__item__media img {
                display: block;
            }

        .tweets__item__text {
            border: var(--border-width-default) solid var(--color-gray-medium);
            padding: var(--spacing-normal);
            width: 100%;
        }

            .tweets__item__text a {
                font-size: var(--font-size-small);
                color: var(--color-gray-dark);
            }

            .tweets__item__text a:not(.hashtag) {
                display: inline-block;
                width: 100%;
            }

        .tweets__item__footer {
            border: var(--border-width-default) solid var(--color-gray-medium);
            font-family: var(--font-family-secondary);
            font-size: var(--font-size-x-small);
            font-style: normal;
            font-weight: bold;
            padding: var(--spacing-normal);
            width: max-content;
            position: relative;
            top: -1px;
        }

            .tweets__item__footer a.tweets__item__footer__twitter-link {
                background: transparent url("../img/social/social-twitter-black.56b9a21b69e2.svg") no-repeat 0 50%;
                background-size: var(--font-size-small);
                padding-left: var(--spacing-normal);
            }

            .tweets__item__footer a.tweets__item__footer__mastodon-link {
                background: transparent url("../img/social/social-mastodon-black.f241581c921c.svg") no-repeat 0 50%;
                background-size: var(--font-size-small);
                padding-left: var(--spacing-normal);
            }

            .tweets__item__footer a.tweets__item__footer__internal-link {
                margin-left: var(--spacing-narrow);
            }

        .simple-list {
            padding: 0;
            margin: var(--spacing-normal-small) 0 0 0;
            list-style: none;
            display: flex;
            flex-flow: row wrap;
            gap: 0 var(--spacing-normal-small);
        }

            .simple-list li {
                padding: 0;
                margin: 0;
                font-size: var(--font-size-small);
            }

            .simple-list a:focus,
            .simple-list a:hover {
                text-decoration: none;
                background: none;
            }

            .simple-list a:active,
            .simple-list a.active {
                text-decoration: underline;
                color: var(--color-red);
                background: none;
            }

    /* Alert messages.
    --------------------------------------------------------------------------- */

    .alert {
        margin: var(--spacing-normal-large) 0;
        padding: var(--spacing-narrow) var(--spacing-normal);
        background: var(--color-white);
        border-radius: var(--border-radius-default);
        border: 5px solid var(--color-orange);
        color: var(--color-black);
        font-size: var(--font-size-small);
        font-weight: bold;
    }

    /* Highlight.
    --------------------------------------------------------------------------- */

    .highlight {
        background: #fdcd20;
    }

    /* Breadcrumbs.
    --------------------------------------------------------------------------- */

    .breadcrumb {
        font-size: var(--font-size-small);
    }

        .breadcrumb__list {
            list-style: none;
            padding: 0;
        }

            .breadcrumb__list li {
                display: inline;
            }

            .breadcrumb__list li:not(:last-child)::after {
                content: "  ›  ";
            }

    /* Auto-suggest.
    --------------------------------------------------------------------------- */

    .suggest-list {
        position: absolute;
        /*
        Next 3 lines are set via JS:
        - top: <val>;
        - left: <val>;
        - width: <val>;
        */
        z-index: 1000;
        margin: 0;
        padding: 0;
        list-style: none;
        font-family: var(--font-family-secondary);
        font-size: var(--font-size-small);
        font-weight: bold;
    }

        .suggest-list li {
            margin: 0;
            padding: 0;
        }

            .suggest-list a,
            .suggest-list a:link,
            .suggest-list a:visited {
                text-decoration: none;
                display: block;
                color: var(--color-black);
                background: var(--color-taupe);
                padding: var(--spacing-narrow-small) var(--spacing-normal-small);
                border: var(--border-width-default) solid var(--color-gray-medium);
            }

            .suggest-list a:focus,
            .suggest-list a:hover,
            .suggest-list a:active,
            .suggest-list li.selected a {
                color: var(--color-white);
                background: var(--color-black);
            }

    /* E-mail obfuscation.
    --------------------------------------------------------------------------- */

    .js-ertl {
        unicode-bidi: bidi-override;
        direction: rtl;
        text-align: left;
    }

    /* Heading links.
    --------------------------------------------------------------------------- */

    a.js-heading-links {
        color: var(--color-gray-medium);
    }

    /* Spinner.
    https://github.com/tobiasahlin/SpinKit
    --------------------------------------------------------------------------- */

    @keyframes bouncedelay {
        0%, 80%, 100% {
            transform: scale(0.0);
        } 40% {
            transform: scale(1.0);
        }
    }

    .spinner {
        width: 70px;
        text-align: center;
        display: inline-block;
        background: var(--color-white);
    }

    .spinner > span {
        vertical-align: middle;
        width: 18px;
        height: 18px;
        background: var(--color-blue-dark);
        display: inline-block;
        animation: bouncedelay 1.4s infinite ease-in-out;
        /* Prevent first frame from flickering when animation starts. */
        animation-fill-mode: both;
    }

    .spinner .bounce1 {
        animation-delay: -0.32s;
    }

    .spinner .bounce2 {
        animation-delay: -0.16s;
    }

    /* CV Portrait.
    --------------------------------------------------------------------------- */

    img.cv-portrait {
        border: 5px solid var(--color-gray-light);
    }

/* -------------------------------------------------------------------------------
@layer utilities {}
------------------------------------------------------------------------------- */

    /* Popover.
    --------------------------------------------------------------------------- */

    button[popovertarget] {
        appearance: none;
        margin: 0;
        padding: 0;
        border: none;
        border-radius: 0;
        font: inherit;
        font-weight: normal;
        white-space: normal;
        background: none;
        color: currentColor;
        text-decoration: underline;
        cursor: pointer;
    }

    button[popovertarget]:focus,
    button[popovertarget]:enabled:hover,
    button[popovertarget]:active,
    button[popovertarget]:enabled:active {
        color: currentColor;
        background: none;
        text-decoration: none;
    }

    :popover-open {
        width: 40vw;
        margin: auto;
        padding: var(--spacing-normal);
        color: var(--color-black);
        background: var(--color-white);
        border: var(--border-width-default) solid var(--color-gray-medium);
        border-radius: var(--border-radius-default);
        box-shadow: 0px 5px 5px -3px rgba(0, 0, 0, 0.2), 0px 8px 10px 1px rgba(0, 0, 0, 0.14), 0px 3px 14px 2px rgba(0, 0, 0, 0.12);
    }

    /* Color.
    --------------------------------------------------------------------------- */

    .color-black { color: var(--color-dark); }
    .color-blue-dark { color: var(--color-blue-dark); }
    .color-orange { color: var(--color-orange); }
    .color-red { color: var(--color-red); }
    .color-taupe { color: var(--color-taupe); }
    .color-white { color: var(--color-white); }

    /* Backgrounds.
    --------------------------------------------------------------------------- */

    .bkg-blue-dark {
        background: var(--color-blue-dark);
        color: var(--color-white);
    }

    .bkg-red {
        background: var(--color-red);
        color: var(--color-white);
    }

    .bkg-orange {
        background: var(--color-orange);
        color: var(--color-black);
    }

    .bkg-taupe {
        background: var(--color-taupe);
    }

    /* Width.
    --------------------------------------------------------------------------- */

    .width-100 {
        width: 100%;
    }

    /* TH width.
    --------------------------------------------------------------------------- */

    .col-15vw {
        width: 15vw;
        min-width: 400px;
    }

    .col-25vw {
        width: 25vw;
        min-width: 400px;
    }

    .col-30vw {
        width: 30vw;
        min-width: 400px;
    }

    .col-35vw {
        width: 35vw;
        min-width: 400px;
    }

    .col-45vw {
        width: 45vw;
        min-width: 400px;
    }

    .col-50vw {
        width: 50vw;
        min-width: 400px;
    }

    .col-100vw {
        width: 100vw;
    }

    /* Text.
    --------------------------------------------------------------------------- */

    .text-center {
        text-align: center;
    }

    .font-size-small {
        font-size: var(--font-size-small);
    }

    .font-size-big {
        font-size: var(--font-size-h3);
    }

    .vertical-align-middle {
        vertical-align: middle;
    }

     /* Hide keyboard shortcuts hints on mobile.
    --------------------------------------------------------------------------- */

    @media (hover: none) and (pointer: coarse) {
        .keyboard-hint {
            display: none;
        }
    }

    /* Furigana.
    --------------------------------------------------------------------------- */

    .js-no-furigana rt {
        visibility: hidden;
    }

    .js-furigana-indicator,
    .js-furigana-indicator:link,
    .js-furigana-indicator:visited {
        position: fixed;
        bottom: 1rem;
        right: 1rem;
        padding: var(--spacing-narrow-small) var(--spacing-narrow);
        font-size: var(--font-size-small);
        background: var(--color-blue-dark);
        color: var(--color-white);
        text-decoration: none;
        border-radius: .25rem;
        cursor: pointer;
        z-index: 9999;
        opacity: .5;
    }

    .js-furigana-indicator:hover,
    .js-furigana-indicator:focus,
    .js-furigana-indicator:active {
        text-decoration: underline;
    }

    .js-furigana-indicator--off {
        opacity: .25;
    }

    /* Utils.
    --------------------------------------------------------------------------- */

    .js-display-none {
        display: none;
    }

    .js-article h1 {
        color: var(--color-red);
    }

    .js-filter-list {
        padding: 0;
        margin: 0;
        display: flex;
        flex-wrap: wrap;
        list-style: none;
    }

        .js-filter-list li {
            padding: 0 var(--spacing-normal) 0 0;
            margin: 0;
        }