/*
 * Silver Glass — layer 2: page chrome.
 *
 * Sticky glass header, navigation, footer, breadcrumbs. Everything here resolves
 * to a token from main.css.
 */

/* --- Sticky glass header --- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--glass-strong);
    -webkit-backdrop-filter: var(--blur);
    backdrop-filter: var(--blur);
    border-bottom: 1px solid var(--hairline);
    box-shadow: var(--shadow-sm);
}

.nav {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 1.25rem;
    min-height: var(--header-h);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav__brand {
    display: inline-flex;
    align-items: center;
    gap: .55rem;
    font-weight: 700;
    color: var(--ink-900);
    text-decoration: none;
    letter-spacing: -.01em;
    white-space: nowrap;
}

.nav__brand:hover {
    color: var(--accent-strong);
}

.nav__mark {
    display: inline-grid;
    place-items: center;
    width: 28px;
    height: 28px;
    border-radius: 9px;
    background: linear-gradient(150deg, var(--silver-400), var(--silver-600));
    color: var(--white);
    font-size: .78rem;
    font-weight: 700;
}

.nav__links {
    display: flex;
    align-items: center;
    gap: .25rem;
    list-style: none;
    margin: 0;
    padding: 0;
    flex: 1;
}

/* Pushes whatever follows it to the far right. */
.nav__spacer {
    flex: 1;
}

.nav__link {
    display: inline-block;
    padding: .45rem .7rem;
    border-radius: var(--radius-sm);
    color: var(--ink-700);
    text-decoration: none;
    font-size: .94rem;
    font-weight: 550;
    white-space: nowrap;
}

.nav__link:hover {
    background: var(--accent-soft);
    color: var(--accent-strong);
}

.nav__link.is-active {
    background: var(--accent-soft);
    color: var(--accent-strong);
}

/* --- Dropdown --- */
.nav__dd {
    position: relative;
}

.nav__dd-panel {
    position: absolute;
    top: calc(100% + .4rem);
    left: 0;
    min-width: 210px;
    padding: .35rem;
    list-style: none;
    margin: 0;
    border-radius: var(--radius);
    border: 1px solid var(--hairline);

    /*
     * Opaque, and blur explicitly off. This panel covers page content and sits
     * inside the blurred header; a translucent fill can be dropped where
     * backdrop-filter is unsupported, letting content bleed through.
     */
    background: var(--surface-solid);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    box-shadow: var(--shadow-md);

    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity .15s ease, transform .15s ease, visibility .15s;
}

.nav__dd:hover .nav__dd-panel,
.nav__dd:focus-within .nav__dd-panel {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav__dd-panel .nav__link {
    display: block;
}

/* --- Mobile toggle --- */
.nav__toggle {
    display: none;
    margin-left: auto;
    padding: .45rem .7rem;
    font: inherit;
    font-size: .9rem;
    color: var(--ink-700);
    background: var(--glass-faint);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-sm);
    cursor: pointer;
}

.nav__toggle:hover {
    background: var(--accent-soft);
    color: var(--accent-strong);
}

@media (max-width: 900px) {
    .nav {
        flex-wrap: wrap;
        padding-top: .6rem;
        padding-bottom: .6rem;
    }

    .nav__toggle {
        display: inline-block;
    }

    .nav__links {
        display: none;
        flex-basis: 100%;
        flex-direction: column;
        align-items: stretch;
        gap: .15rem;
        margin-top: .6rem;
        padding: .5rem;
        border-radius: var(--radius);
        border: 1px solid var(--hairline);

        /* Same rule as the dropdown: this panel covers content, so it is opaque. */
        background: var(--surface-solid);
        -webkit-backdrop-filter: none;
        backdrop-filter: none;
        box-shadow: var(--shadow-md);
    }

    .nav__links.is-open {
        display: flex;
    }

    .nav__spacer {
        display: none;
    }

    .nav__dd-panel {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: 0;
        padding: 0 0 0 .6rem;
        background: transparent;
    }
}

/* --- Breadcrumbs --- */
.breadcrumbs {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: .4rem;
    font-size: .88rem;
    color: var(--ink-400);
    margin: 0 0 1.25rem;
}

.breadcrumbs a {
    color: var(--ink-500);
    text-decoration: none;
}

.breadcrumbs a:hover {
    color: var(--accent-strong);
    text-decoration: underline;
}

.breadcrumbs .sep {
    color: var(--silver-400);
}

/* --- Footer --- */
.site-footer {
    margin-top: 3rem;
    border-top: 1px solid var(--hairline);
    background: var(--glass);
    -webkit-backdrop-filter: var(--blur);
    backdrop-filter: var(--blur);
}

.site-footer__inner {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 2rem 1.25rem 1.5rem;
    /*
     * Flex rather than grid, deliberately. The footer partial is shared, so the
     * number of link columns is not fixed; a grid track list would have to name
     * a count and would break silently when a column is added.
     *
     * This replaced `1.4fr repeat(auto-fit, minmax(150px, 1fr))`, which is an
     * invalid track list — an auto-repeat cannot be combined with `fr` sizing —
     * so the whole declaration was dropped and every child stacked.
     */
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
    gap: 1.5rem 3rem;
}

/* The brand block takes the slack so the link columns sit to the right. */
.site-footer__intro {
    flex: 1 1 280px;
    min-width: 0;
}

.site-footer__brand {
    font-weight: 700;
    color: var(--ink-900);
    margin-bottom: .35rem;
}

.site-footer__tag {
    color: var(--ink-500);
    font-size: .92rem;
    margin: 0;
}

.site-footer__col {
    flex: 0 1 auto;
    min-width: 140px;
}

.site-footer__col h3 {
    font-size: .82rem;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--ink-400);
    margin: 0 0 .5rem;
}

.site-footer__col ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.site-footer__col li {
    margin: .25rem 0;
}

.site-footer__col a {
    color: var(--ink-700);
    text-decoration: none;
    font-size: .93rem;
}

.site-footer__col a:hover {
    color: var(--accent-strong);
    text-decoration: underline;
}

.site-footer__base {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 1.25rem 1.75rem;
    color: var(--ink-400);
    font-size: .86rem;
}

@media (max-width: 700px) {
    .site-footer__inner {
        flex-direction: column;
        gap: 1.5rem;
    }

    /*
     * Load-bearing, not tidy-up. flex-basis sizes the main axis, which is
     * vertical once the direction is column, so the 280px basis above becomes a
     * 280px tall box and opens a large dead gap under the tagline.
     */
    .site-footer__intro {
        flex: 0 0 auto;
    }
}