docs/_static/css/left-sidebar.css

.left-sidebar {
    position: sticky;
    top: var(--topbar-height);
    align-self: start;
    height: calc(100vh - var(--topbar-height));
    overflow-y: auto;
    background: var(--bg-sidebar);
    color: var(--sidebar-fg);
}

/* ---- Captions ("Documentation", "Reference", ...) ------------------- */

.left-sidebar p.caption {
    margin: 16px 0 4px;
    padding: 0 1.618em;
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--sidebar-caption);
}

.left-sidebar p.caption:first-of-type {
    margin-top: 0;
}

/* ---- List structure ------------------------------------------------- */

.left-sidebar ul,
.left-sidebar li {
    list-style: none;
    margin: 0;
    padding: 0;
}

/* ---- Items ---------------------------------------------------------- */

.left-sidebar a,
.left-sidebar a:visited {
    display: block;
    padding: 0.32em 1.2em;
    line-height: 1.4;
    color: var(--sidebar-fg);
    text-decoration: none;
}

.left-sidebar li.toctree-l1 > a {
    text-transform: capitalize;
}

.left-sidebar a:hover {
    background: rgba(255, 255, 255, 0.04);
}

/* ---- Active item ---------------------------------------------------- */

.left-sidebar li.current > a,
.left-sidebar li.current > a:visited {
    background: var(--sidebar-active-bg);
    color: var(--sidebar-active-fg);
    box-shadow:
        inset 3px 0 0 var(--bg-sidebar),
        inset -3px 0 0 var(--bg-sidebar);
}

/* ---- Mobile: off-canvas drawer ------------------------------------- */

@media (max-width: 1024px) {
    .left-sidebar {
        position: fixed;
        top: var(--topbar-height);
        left: 0;
        z-index: 90;
        width: var(--left-sidebar-width);
        max-width: 85vw;
        height: calc(100vh - var(--topbar-height));
        transform: translateX(-100%);
        transition: transform 0.2s ease;
    }

    body.sidebar-open .left-sidebar {
        transform: translateX(0);
        box-shadow: 4px 0 16px rgba(0, 0, 0, 0.35);
    }
}

/* Touch devices: taller nav rows for comfortable tapping. 36px keeps
   them well above the WCAG 2.5.8 (AA) 24px floor without the airy gaps
   the AAA 44px target leaves around single-line items. */
@media (pointer: coarse) {
    .left-sidebar a {
        display: flex;
        align-items: center;
        min-height: 36px;
    }
}

/* ---- Per-item icons (Font Awesome) ---------------------------------- */

.left-sidebar li.toctree-l1 > a::before {
    font-family: var(--doc-icon-font, var(--fa-family-classic));
    font-weight: var(--doc-icon-weight, 900);
    display: inline-block;
    width: 1.3em;
    margin-right: 0.7em;
    font-size: 0.85em;
    text-align: center;
    color: var(--sidebar-caption);
    opacity: 0.85;
    content: var(--doc-icon, "");
}

.left-sidebar li.current > a::before {
    color: var(--sidebar-active-fg);
}