treehouse/static/css/tree.css

/*** Icons ***/

:root {
    --icon-breadcrumb: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTYgMTIgNC00LTQtNCIgZmlsbD0ibm9uZSIgc3Ryb2tlPSIjNTU0MjNlIiBzdHJva2Utd2lkdGg9IjIiLz48L3N2Zz4=');
    --icon-expand: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggY2xpcC1ydWxlPSJldmVub2RkIiBkPSJtNyA1di0zaC0ydjNoLTN2MmgzdjNoMnYtM2gzdi0yeiIgZmlsbD0iIzU1NDIzZSIgZmlsbC1vcGFjaXR5PSIuNSIgZmlsbC1ydWxlPSJldmVub2RkIi8+PC9zdmc+');
    --icon-leaf: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PGNpcmNsZSBjeD0iNiIgY3k9IjYiIGZpbGw9IiM1NTQyM2UiIGZpbGwtb3BhY2l0eT0iLjUiIHI9IjIiLz48L3N2Zz4=');
    --icon-collapse: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTMgNmg2IiBzdHJva2U9IiM1NTQyM2UiIHN0cm9rZS1vcGFjaXR5PSIuNSIgc3Ryb2tlLXdpZHRoPSIyIi8+PC9zdmc+');
    --icon-more: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTQgNiA0IDQgNC00IiBmaWxsPSJub25lIiBzdHJva2U9IiM1NTQyM2UiIHN0cm9rZS1vcGFjaXR5PSIuNSIgc3Ryb2tlLXdpZHRoPSIyIi8+PC9zdmc+');
    --icon-permalink: url("data:image/svg+xml;base64,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");
    --icon-go: url("data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTEwLjU4NTggNy0yLjI5Mjg5LTIuMjkyODkgMS40MTQyMS0xLjQxNDIyIDQuNzA3MDggNC43MDcxMS00LjcwNzA4IDQuNzA3MS0xLjQxNDIxLTEuNDE0MiAyLjI5Mjg5LTIuMjkyOWgtNy41ODU4di0yeiIgZmlsbD0iIzU1NDIzZSIvPjwvc3ZnPg==");
}

@media (prefers-color-scheme: dark) {
    :root {
        --icon-breadcrumb: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTYgMTIgNC00LTQtNCIgZmlsbD0ibm9uZSIgc3Ryb2tlPSIjZDdjZGJmIiBzdHJva2Utd2lkdGg9IjIiLz48L3N2Zz4=');
        --icon-expand: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggY2xpcC1ydWxlPSJldmVub2RkIiBkPSJtNyA1di0zaC0ydjNoLTN2MmgzdjNoMnYtM2gzdi0yeiIgZmlsbD0iI2Q3Y2RiZiIgZmlsbC1vcGFjaXR5PSIuNSIgZmlsbC1ydWxlPSJldmVub2RkIi8+PC9zdmc+');
        --icon-leaf: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PGNpcmNsZSBjeD0iNiIgY3k9IjYiIGZpbGw9IiNkN2NkYmYiIGZpbGwtb3BhY2l0eT0iLjUiIHI9IjIiLz48L3N2Zz4=');
        --icon-collapse: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjEyIiB3aWR0aD0iMTIiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTMgNmg2IiBzdHJva2U9IiNkN2NkYmYiIHN0cm9rZS1vcGFjaXR5PSIuNSIgc3Ryb2tlLXdpZHRoPSIyIi8+PC9zdmc+');
        --icon-permalink: url("data:image/svg+xml;base64,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");
        --icon-go: url("data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTEwLjU4NTggNy0yLjI5Mjg5LTIuMjkyODkgMS40MTQyMS0xLjQxNDIyIDQuNzA3MDggNC43MDcxMS00LjcwNzA4IDQuNzA3MS0xLjQxNDIxLTEuNDE0MiAyLjI5Mjg5LTIuMjkyOWgtNy41ODU4di0yeiIgZmlsbD0iI2Q3Y2RiZiIvPjwvc3ZnPg==");
        --icon-more: url('data:image/svg+xml;base64,PHN2ZyBoZWlnaHQ9IjE2IiB3aWR0aD0iMTYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PHBhdGggZD0ibTQgNiA0IDQgNC00IiBmaWxsPSJub25lIiBzdHJva2U9IiNkN2NkYmYiIHN0cm9rZS1vcGFjaXR5PSIuNSIgc3Ryb2tlLXdpZHRoPSIyIi8+PC9zdmc+');
    }
}

/*** Breadcrumbs ***/

.breadcrumbs {
    list-style-type: none;
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;

    height: min-content;

    margin: 0;
    padding: 0;

    align-items: center;

    opacity: 70%;
}

.breadcrumb::before {
    content: '';
    display: inline-block;

    background-image: var(--icon-breadcrumb);
    background-repeat: no-repeat;
    background-position: 50% 50%;
    opacity: 70%;

    width: 32px;
    height: 1.2em;

    vertical-align: text-bottom;
}

.breadcrumb a {
    --recursive-mono: 1.0;
    --recursive-wght: 500;

    color: var(--text-color);
    text-decoration: none;
}

.breadcrumb a:hover {
    text-decoration: underline;
}

/*** Tree ***/

/* Compute an indent level appropriate for the viewport. */
.tree ul {
    padding-left: clamp(12px, 2vw, 24px);
}

/* Top level should not have an indent. */
.tree>ul {
    padding-left: 0;
}

.tree details {

    /* Disable the rightwards chevron in <details> elements */
    &>summary {
        list-style: none;
        cursor: pointer;

        &::-webkit-details-marker {
            display: none;
        }
    }
}

/* Child branches */
.tree li {
    /* <li> elements should not have any bullet points or whatever */
    list-style: none;

    /* Stretch branch content to the full width of the page */
    &>div,
    &>details {
        width: 100%;
    }

    /* Add an underline for leaf branches */
    &>div {
        box-sizing: border-box;

        &:hover {
            border-bottom: 1px solid var(--border-1);
            margin-bottom: -1px;
        }
    }

    &>div,
    &>details>summary {
        /* Child elements are laid out horizontally in a flexbox. */
        display: flex;
        align-items: center;
    }

}

/* <summary> is used for the visual content of branches with children. It's the large horizontal bar
    and notably *excludes* children. */
.tree details>summary {
    /* Slightly round for elegance */
    border-radius: 8px;

    /* Give it a shaded background on hover */
    background-color: transparent;

    &:hover {
        background-color: var(--shaded-background);
    }
}

/* For media without hover functionality, draw a bottom border everywhere as a visual anchor for where to tap */
@media (hover: none) {

    .tree li>div:first-child,
    .tree li>details>summary:first-child {
        border-bottom: 1px solid var(--border-1);
    }

    .tree details>summary {
        /* In that case summaries shall not be rounded. */
        border-radius: 0px;
    }
}

/* The following three elements - bp, bc, and bb - are there in all branches, regardless of their parent. */

/* bp - bullet point */
th-bp {
    display: block;
    width: 28px;
    height: 24px;

    background-image: var(--icon-leaf);
    background-repeat: no-repeat;
    background-position: 50% 50%;

    /* Prevent shrinkage when viewport is too low */
    flex-shrink: 0;
}

/* Change image of th-bp if it has children and/or is collapsible */
.tree details[open]>summary>th-bp {
    background-image: var(--icon-collapse);
}

.tree details:not([open])>summary>th-bp {
    background-image: var(--icon-expand);
}

/* bc - branch content */
th-bc {
    display: block;
    padding-top: 6px;
    padding-bottom: 6px;

    /* Grow to fill the entire available space. This pushes out th-bb to the far right. */
    flex-grow: 1;
}

/* Display a chevron hinting that the collapsed branch has more content in its children. */
.tree details:not([open])>summary>th-bc>:last-child {
    /* Add some padding such that text wraps together with this element. */
    padding-right: 32px;

    &::after {
        content: '\00A0';
        display: inline-block;

        background-image: var(--icon-more);
        background-repeat: no-repeat;
        background-position: 50% 50%;

        width: 16px;
        height: 1.2em;

        vertical-align: text-bottom;
        margin-left: 0.5em;

        margin-right: -32px;
    }
}

/* bb - button bar */
th-bb {
    height: 100%;
    margin: 4px;

    /* Should be displayed on the top of the branch rather than in the middle. */
    align-self: start;

    display: flex;
    flex-direction: row;

    /* Keep the button bar invisible by default. */
    opacity: 0%;
}

/* When the parent is hovered over, display the button bar. */
.tree *:hover>th-bb {
    opacity: 100%;
}

/* For media without hover functionality, th-bb should always be visible */
@media (hover: none) {
    .tree th-bb {
        opacity: 100%;
    }
}

/* Icons (used in the button bar) */
.tree {
    & .icon {
        background-repeat: no-repeat;
        background-position: 50% 50%;
        opacity: 35%;

        width: 24px;
        height: 24px;
    }

    & .icon-permalink {
        background-image: var(--icon-permalink);
    }

    & .icon-go {
        background-image: var(--icon-go);
    }
}

.tree a.navigate {
    background-repeat: no-repeat;
    background-position: 0 50%;
    opacity: 50%;
    color: #000;
    padding-left: 20px;
}

.tree .link-loading {
    padding-left: 24px;
    opacity: 50%;
}

.tree :target,
.tree .target {

    &>details>summary,
    &>div {
        border-bottom: 1px dashed var(--border-2);
        margin-bottom: -1px;
        border-bottom-left-radius: 0;
        border-bottom-right-radius: 0;
    }
}