/* ============================================================
   FSE Layout — nav, container, sections, footer
   Depends on fse-variables.css, fse-base.css
   ============================================================ */

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

.fse-container {
    width: 100%;
    max-width: var(--fse-container-max);
    margin: 0 auto;
    padding: 0 var(--fse-space-5);
}

.fse-container-narrow {
    width: 100%;
    max-width: var(--fse-container-narrow);
    margin: 0 auto;
    padding: 0 var(--fse-space-5);
}

/* ---------- Sticky nav ---------- */

.fse-nav {
    position: sticky;
    top: 0;
    z-index: var(--fse-z-nav);
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid var(--fse-border-subtle);
    height: var(--fse-nav-height);
    display: flex;
    align-items: center;
}

.fse-nav-inner {
    width: 100%;
    max-width: var(--fse-container-max);
    margin: 0 auto;
    padding: 0 var(--fse-space-5);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--fse-space-6);
}

.fse-brand {
    display: inline-flex;
    align-items: center;
    gap: var(--fse-space-2);
    font-weight: var(--fse-font-weight-bold);
    font-size: var(--fse-font-size-lg);
    color: var(--fse-text-primary);
    letter-spacing: var(--fse-letter-spacing-tight);
    text-decoration: none;
}

.fse-brand:hover {
    color: var(--fse-text-primary);
    text-decoration: none;
}

.fse-brand-mark {
    width: 28px;
    height: 28px;
    border-radius: var(--fse-radius-md);
    background: var(--fse-gradient-accent);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--fse-text-inverse);
    font-size: var(--fse-font-size-sm);
    font-weight: var(--fse-font-weight-bold);
    box-shadow: var(--fse-shadow-accent);
}

.fse-nav-links {
    display: flex;
    align-items: center;
    gap: var(--fse-space-6);
    list-style: none;
    margin: 0;
    padding: 0;
}

.fse-nav-links a {
    color: var(--fse-text-body);
    font-weight: var(--fse-font-weight-medium);
    font-size: var(--fse-font-size-sm);
    padding: var(--fse-space-2) 0;
    position: relative;
    text-decoration: none;
    transition: color var(--fse-transition-fast);
}

.fse-nav-links a:hover,
.fse-nav-links a.is-active {
    color: var(--fse-text-primary);
    text-decoration: none;
}

.fse-nav-links a.is-active::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -6px;
    height: 2px;
    border-radius: var(--fse-radius-pill);
    background: var(--fse-gradient-accent);
}

.fse-nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: var(--fse-radius-md);
    align-items: center;
    justify-content: center;
    background: transparent;
    color: var(--fse-text-primary);
    border: 1px solid var(--fse-border-default);
    transition: background var(--fse-transition-fast), border-color var(--fse-transition-fast);
}

.fse-nav-toggle:hover {
    background: var(--fse-surface-muted);
    border-color: var(--fse-border-strong);
}

.fse-nav-toggle-bars {
    display: inline-flex;
    flex-direction: column;
    gap: 4px;
}

.fse-nav-toggle-bars span {
    display: block;
    width: 18px;
    height: 2px;
    background: currentColor;
    border-radius: var(--fse-radius-pill);
}

/* ---------- Section rhythm ---------- */

.fse-section {
    padding: var(--fse-space-11) 0;
}

.fse-section-tight {
    padding: var(--fse-space-9) 0;
}

.fse-section-loose {
    padding: var(--fse-space-12) 0;
}

.fse-section-header {
    text-align: center;
    max-width: 760px;
    margin: 0 auto var(--fse-space-8) auto;
}

.fse-section-header p {
    font-size: var(--fse-font-size-lg);
    color: var(--fse-text-muted);
}

.fse-section-dark {
    background: var(--fse-surface-inverse);
    color: var(--fse-text-inverse);
}

.fse-section-dark h1,
.fse-section-dark h2,
.fse-section-dark h3,
.fse-section-dark h4,
.fse-section-dark h5,
.fse-section-dark h6 {
    color: var(--fse-text-inverse);
}

.fse-section-dark p {
    color: var(--fse-color-ink-1);
}

.fse-section-dark .fse-eyebrow {
    color: var(--fse-color-accent-300);
}

.fse-section-dark .fse-timeline-item p,
.fse-section-dark .fse-timeline-item h4 {
    color: var(--fse-color-ink-1);
}

.fse-anchor-rule {
    border-top: 1px solid var(--fse-border-subtle);
    border-bottom: 1px solid var(--fse-border-subtle);
    padding: var(--fse-space-7) var(--fse-space-5);
    margin: 0;
    text-align: center;
    background: var(--fse-surface-muted);
}

.fse-anchor-rule p {
    margin: 0;
    font-family: var(--fse-font-mono);
    font-size: var(--fse-font-size-md);
    font-weight: var(--fse-font-weight-semibold);
    color: var(--fse-text-primary);
    letter-spacing: var(--fse-letter-spacing-wide);
}

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

.fse-footer {
    background: var(--fse-color-navy-900);
    color: var(--fse-color-ink-2);
    padding: var(--fse-space-8) 0;
    margin-top: var(--fse-space-11);
}

.fse-footer-inner {
    max-width: var(--fse-container-max);
    margin: 0 auto;
    padding: 0 var(--fse-space-5);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--fse-space-5);
    flex-wrap: wrap;
}

.fse-footer-brand {
    font-weight: var(--fse-font-weight-semibold);
    color: var(--fse-text-inverse);
    letter-spacing: var(--fse-letter-spacing-tight);
}

.fse-footer-meta {
    font-size: var(--fse-font-size-sm);
    color: var(--fse-color-ink-3);
}

.fse-footer-meta a {
    color: var(--fse-color-accent-300);
}

.fse-footer-meta a:hover {
    color: var(--fse-color-accent-100);
}

/* ---------- Mobile breakpoints ---------- */

@media (max-width: 860px) {
    .fse-nav-toggle {
        display: inline-flex;
    }

    .fse-nav-links {
        position: fixed;
        top: var(--fse-nav-height);
        left: 0;
        right: 0;
        flex-direction: column;
        gap: 0;
        background: var(--fse-surface-card);
        border-bottom: 1px solid var(--fse-border-subtle);
        box-shadow: var(--fse-shadow-md);
        padding: var(--fse-space-4) var(--fse-space-5);
        transform: translateY(-12px);
        opacity: 0;
        pointer-events: none;
        transition: opacity var(--fse-transition-base), transform var(--fse-transition-base);
    }

    .fse-nav.is-open .fse-nav-links {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .fse-nav-links li {
        width: 100%;
    }

    .fse-nav-links a {
        display: block;
        padding: var(--fse-space-3) 0;
        font-size: var(--fse-font-size-md);
        border-bottom: 1px solid var(--fse-border-subtle);
    }

    .fse-nav-links li:last-child a {
        border-bottom: none;
    }

    .fse-nav-links a.is-active::after {
        display: none;
    }
}

@media (max-width: 640px) {
    .fse-section {
        padding: var(--fse-space-9) 0;
    }

    .fse-section-loose {
        padding: var(--fse-space-10) 0;
    }

    .fse-footer-inner {
        flex-direction: column;
        text-align: center;
    }

    h1 { font-size: var(--fse-font-size-4xl); }
    h2 { font-size: var(--fse-font-size-3xl); }
    h3 { font-size: var(--fse-font-size-xl); }
}