/* ==========================================================================
   Silver Glass — shared/layout.css
   Container, sticky glass header and nav, footer, breadcrumbs.
   Authority: .agents/design/design-system.md (section 5).
   ========================================================================== */

/* --- Container ------------------------------------------------------------ */

.container {
    width: 100%;
    max-width: var(--maxw);
    margin-inline: auto;
    padding-inline: clamp(1rem, .55rem + 1.9vw, 1.75rem);
}

.container.narrow {
    max-width: 880px;
}

/* --- Page shell ----------------------------------------------------------- */

.site-main {
    display: block;
    padding-block: clamp(1.75rem, 1.2rem + 2.2vw, 3rem) clamp(2.5rem, 2rem + 2.5vw, 4rem);
}

/* Vertical rhythm between the blocks of a page, at either nesting level. */
.site-main > * + *,
.site-main .container > * + * {
    margin-top: clamp(1.25rem, 1rem + 1vw, 2rem);
}

/* --- 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 {
    display: flex;
    align-items: center;
    gap: 1rem;
    min-height: var(--header-h);
}

/* --- Brand ---------------------------------------------------------------- */

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

.nav__brand:hover {
    color: var(--ink-900);
}

.nav__brand-mark {
    display: inline-grid;
    place-items: center;
    width: 34px;
    height: 34px;
    border-radius: var(--radius-sm);
    background: linear-gradient(150deg, var(--accent), var(--accent-strong));
    color: var(--white);
    font-size: .8rem;
    font-weight: 700;
    letter-spacing: .01em;
    box-shadow: var(--shadow-sm);
}

.nav__brand-text {
    font-size: .98rem;
    letter-spacing: -.01em;
}

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

.nav__links {
    display: flex;
    flex: 1;
    align-items: center;
    gap: .2rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.nav__spacer {
    flex: 1;
}

.nav__link {
    display: inline-flex;
    align-items: center;
    gap: .3rem;
    padding: .45rem .7rem;
    border: 0;
    border-radius: 999px;
    background: none;
    color: var(--ink-700);
    font-family: inherit;
    font-size: .92rem;
    font-weight: 550;
    text-decoration: none;
    white-space: nowrap;
    cursor: pointer;
    transition: background-color .15s ease, color .15s ease;
}

.nav__link:hover {
    background: var(--accent-soft);
    color: var(--ink-900);
}

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

.nav__link--cta {
    background: var(--glass);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-sm);
    color: var(--accent-strong);
}

.nav__link--cta:hover {
    background: var(--white);
    color: var(--ink-900);
}

.nav__caret {
    width: 10px;
    height: 10px;
    flex: none;
    transition: transform .15s ease;
}

/* --- Dropdown ------------------------------------------------------------- */

.nav__dd {
    position: relative;
}

.nav__dd-menu {
    position: absolute;
    top: calc(100% + .35rem);
    left: 0;
    z-index: 60;
    min-width: 200px;
    margin: 0;
    padding: .35rem;
    list-style: none;
    border: 1px solid var(--hairline);
    border-radius: var(--radius-sm);
    /* Content-covering overlay: opaque, never blurred. Design system section 3. */
    background: var(--white);
    -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-menu,
.nav__dd:focus-within .nav__dd-menu,
.nav__dd.is-open .nav__dd-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav__dd:hover .nav__caret,
.nav__dd:focus-within .nav__caret,
.nav__dd.is-open .nav__caret {
    transform: rotate(180deg);
}

.nav__dd-menu a {
    display: block;
    padding: .45rem .6rem;
    border-radius: 8px;
    color: var(--ink-700);
    font-size: .9rem;
    text-decoration: none;
}

.nav__dd-menu a:hover,
.nav__dd-menu a.is-active {
    background: var(--accent-soft);
    color: var(--accent-strong);
}

/* --- Mobile toggle -------------------------------------------------------- */

.nav__toggle {
    display: none;
    flex: none;
    width: 40px;
    height: 40px;
    margin-left: auto;
    padding: 0;
    border: 1px solid var(--hairline);
    border-radius: var(--radius-sm);
    background: var(--glass);
    cursor: pointer;
}

.nav__toggle-bar,
.nav__toggle-bar::before,
.nav__toggle-bar::after {
    display: block;
    width: 17px;
    height: 2px;
    margin-inline: auto;
    border-radius: 2px;
    background: var(--ink-700);
    transition: transform .15s ease, opacity .15s ease;
}

.nav__toggle-bar::before,
.nav__toggle-bar::after {
    content: "";
    position: relative;
}

.nav__toggle-bar::before {
    top: -5px;
}

.nav__toggle-bar::after {
    top: 3px;
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar {
    background: transparent;
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar::before {
    top: -1px;
    transform: rotate(45deg);
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar::after {
    top: -3px;
    transform: rotate(-45deg);
}

/* --- Responsive nav ------------------------------------------------------- */

@media (max-width: 900px) {

    .nav {
        flex-wrap: wrap;
    }

    .nav__toggle {
        display: block;
    }

    .nav__links {
        display: none;
        flex: 1 0 100%;
        flex-direction: column;
        align-items: stretch;
        gap: .1rem;
        margin: 0 calc(-1 * clamp(1rem, .55rem + 1.9vw, 1.75rem));
        padding: .5rem clamp(1rem, .55rem + 1.9vw, 1.75rem) 1rem;
        /* Content-covering overlay: opaque, never blurred. Design system section 3. */
        background: var(--white);
        -webkit-backdrop-filter: none;
        backdrop-filter: none;
        border-top: 1px solid var(--hairline);
        box-shadow: var(--shadow-md);
    }

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

    .nav__spacer {
        display: none;
    }

    .nav__link {
        justify-content: space-between;
        border-radius: var(--radius-sm);
        padding: .6rem .75rem;
    }

    .nav__link--cta {
        margin-top: .4rem;
        justify-content: center;
    }

    /* The dropdown flattens into an indented sublist — no overlay on mobile. */
    .nav__dd-menu {
        position: static;
        min-width: 0;
        margin: .1rem 0 .3rem .75rem;
        padding: 0 0 0 .5rem;
        border: 0;
        border-left: 2px solid var(--hairline);
        border-radius: 0;
        background: none;
        box-shadow: none;
        opacity: 1;
        visibility: visible;
        transform: none;
    }

    .nav__caret {
        display: none;
    }
}

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

.breadcrumbs {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: .4rem;
    margin-bottom: 1.1rem;
    font-size: .875rem;
    color: var(--ink-400);
}

.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);
}

.breadcrumbs [aria-current="page"] {
    color: var(--ink-700);
    font-weight: 550;
}

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

.site-footer {
    margin-top: auto;
    background: var(--glass);
    -webkit-backdrop-filter: var(--blur);
    backdrop-filter: var(--blur);
    border-top: 1px solid var(--glass-border);
}

.site-footer__inner {
    display: grid;
    grid-template-columns: minmax(220px, 1.4fr) repeat(auto-fit, minmax(150px, 1fr));
    gap: clamp(1.25rem, 1rem + 1.5vw, 2.5rem);
    padding-block: clamp(1.75rem, 1.4rem + 1.5vw, 2.75rem);
}

.site-footer__brand p {
    margin: .5rem 0 0;
    max-width: 34ch;
    font-size: .9rem;
    color: var(--ink-500);
}

.site-footer__col h3 {
    margin: 0 0 .6rem;
    font-size: .78rem;
    font-weight: 700;
    letter-spacing: .09em;
    text-transform: uppercase;
    color: var(--ink-400);
}

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

.site-footer__col li {
    margin-bottom: .35rem;
}

.site-footer__col a {
    color: var(--ink-700);
    font-size: .9rem;
    text-decoration: none;
}

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

.site-footer__bar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: .75rem;
    padding-block: 1rem;
    border-top: 1px solid var(--hairline);
    font-size: .85rem;
    color: var(--ink-400);
}

.site-footer__bar p {
    margin: 0;
}