/* ── Engineering Board / SYS_INFRA theme ── */
:root {
    --bg: #0a0a0a;
    --bg-panel: #0f0f0f;
    --bg-elevated: #141414;

    --text-primary: #f0f0f0;
    --text-secondary: #c4c4c4;
    --text-muted: #a3a3a3;
    --text-dim: #8a8a8a;

    --border: #2a2a2a;
    --border-light: #3a3a3a;
    --grid-line: rgba(255, 255, 255, 0.04);

    --accent: #e5e5e5;
    --link: #93c5fd;

    /* Category accents (reference palette) */
    --cat-architecture: #9ca3af;
    --cat-performance: #a78bfa;
    --cat-reliability: #fb923c;
    --cat-data: #6366f1;
    --cat-security: #3b82f6;
    --cat-system: #4ade80;

    --font-display: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', 'Consolas', monospace;
    --font-pixel: 'Geist Pixel', 'JetBrains Mono', monospace;

    --nav-h: 56px;
    --max-w: 1120px;

    --ease: cubic-bezier(0.4, 0, 0.2, 1);
    --transition: 0.35s var(--ease);
    --transition-fast: 0.2s var(--ease);

    /* Sharp shapes — zero radius */
    --radius: 0;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

a { text-decoration: none; }

::selection {
    background: var(--text-primary);
    color: var(--bg);
}

:focus-visible {
    outline: 1px solid var(--accent);
    outline-offset: 2px;
}

.skip-link {
    position: absolute;
    left: 0.75rem;
    top: -100px;
    z-index: 400;
    padding: 0.65rem 1rem;
    background: var(--text-primary);
    color: var(--bg);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.skip-link:focus {
    top: 0.75rem;
    outline: none;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: var(--font-display);
    background: var(--bg);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* ── Engineering grid background ── */
.grid-bg {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background-color: var(--bg);
    background-image:
        linear-gradient(var(--grid-line) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
    background-size: 32px 32px;
}

.grid-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 70% 60% at 50% 30%, transparent 0%, var(--bg) 75%);
}

.page-shell {
    position: relative;
    min-height: 100vh;
}

/* ── Scroll reveal ── */
.reveal {
    opacity: 1;
    transform: none;
}

.reveal.visible {
    opacity: 1;
    transform: none;
}

@media (prefers-reduced-motion: no-preference) {
    .reveal {
        opacity: 1;
        transform: translateY(10px);
        transition: transform 0.55s var(--ease);
    }

    .reveal.visible {
        transform: translateY(0);
    }
}

.reveal-delay-1 { transition-delay: 0.08s; }
.reveal-delay-2 { transition-delay: 0.16s; }
.reveal-delay-3 { transition-delay: 0.24s; }
.reveal-delay-4 { transition-delay: 0.32s; }

/* ── Header ── */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 300;
    height: var(--nav-h);
    display: flex;
    align-items: center;
    background: rgba(10, 10, 10, 0.92);
    border-bottom: 1px solid var(--border);
    transition: background var(--transition);
}

header.scrolled {
    background: rgba(10, 10, 10, 0.98);
}

.nav-bar {
    width: 100%;
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 1rem;
}

.logo { justify-self: start; }

.logo h1 {
    font-family: var(--font-pixel);
    font-size: 0.95rem;
    font-weight: 400;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin: 0;
}

.logo a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.logo a:hover { color: var(--link); }

nav {
    display: flex;
    align-items: center;
    gap: 1.75rem;
    justify-self: center;
}

nav a {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-muted);
    text-decoration: none;
    letter-spacing: 0.02em;
    padding-bottom: 2px;
    border-bottom: 1px solid transparent;
    transition: color var(--transition-fast), border-color var(--transition-fast);
}

nav a:hover { color: var(--text-primary); }

nav a.active {
    color: var(--text-primary);
    border-bottom-color: var(--text-primary);
}

.header-status {
    justify-self: end;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.header-icons {
    display: flex;
    align-items: center;
    gap: 0.7rem;
}

.header-icons a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    color: var(--text-muted);
    font-size: 0.95rem;
    transition: color var(--transition-fast);
}

.header-icons a:hover { color: var(--text-primary); }

.header-icons svg {
    width: 0.9rem;
    height: 0.9rem;
    display: block;
    fill: currentColor;
}

.hamburger {
    display: none;
    cursor: pointer;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    width: 44px;
    height: 44px;
    color: var(--text-primary);
    font-family: var(--font-mono);
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

/* ── Typography ── */
.eyebrow,
.section-label {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    font-weight: 500;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 0.65rem;
}

.page-heading,
.section-title {
    font-family: var(--font-pixel);
    font-size: clamp(2rem, 4.5vw, 2.75rem);
    font-weight: 400;
    letter-spacing: 0.02em;
    text-transform: uppercase;
    line-height: 1.1;
}

.page-subheading {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--text-muted);
    margin-top: 0.65rem;
    letter-spacing: 0.02em;
}

.page-header {
    margin-bottom: 2.5rem;
}

.page-header.centered { text-align: center; }

/* Category labels */
.cat {
    font-family: var(--font-mono);
    font-size: 0.625rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.cat-architecture { color: var(--cat-architecture); }
.cat-performance  { color: var(--cat-performance); }
.cat-reliability  { color: var(--cat-reliability); }
.cat-data         { color: var(--cat-data); }
.cat-security     { color: var(--cat-security); }
.cat-system       { color: var(--cat-system); }

/* ── Tags (#hash style) ── */
.tag {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    padding: 0.35rem 0.65rem;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    color: var(--text-muted);
    transition: color var(--transition-fast), border-color var(--transition-fast);
}

.tag::before { content: '#'; opacity: 0.45; margin-right: 1px; }

.tag--plain::before { content: none; margin: 0; }

.tag:hover {
    color: var(--text-primary);
    border-color: var(--border-light);
}

/* ── Connect block ── */
.connect-container {
    max-width: 560px;
    margin: 0 auto;
    padding: 2rem;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    text-align: center;
}

.connect-heading {
    font-family: var(--font-pixel);
    font-size: clamp(1.125rem, 2vw, 1.35rem);
    font-weight: 400;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 0.85rem;
}

.connect-text {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--text-secondary);
    line-height: 1.75;
    margin-bottom: 1.5rem;
}

.connect-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.65rem;
}

.connect-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 0.65rem 1.15rem;
    min-height: 44px;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.connect-btn:hover {
    color: var(--bg);
    background: var(--text-primary);
    border-color: var(--text-primary);
}

.connect-btn--primary {
    color: var(--bg);
    background: var(--text-primary);
    border-color: var(--text-primary);
}

.resume-link {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-secondary);
    text-decoration: underline;
    text-underline-offset: 0.22em;
    text-decoration-thickness: 1px;
    transition: color var(--transition-fast);
}

.resume-link:hover { color: var(--text-primary); }

/* ── Footer ── */
footer {
    position: relative;
    z-index: 10;
    padding: 1.25rem 1.5rem;
    border-top: 1px solid var(--border);
    background: rgba(10, 10, 10, 0.95);
}

footer.fixed-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
}

.footer-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
}

footer p {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    color: var(--text-dim);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.footer-links {
    display: flex;
    gap: 1.25rem;
}

.footer-links a {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    color: var(--text-dim);
    text-decoration: none;
    letter-spacing: 0.03em;
    transition: color var(--transition-fast);
}

.footer-links a:hover { color: var(--text-primary); }

/* ── Overlay (below header bar, above page content) ── */
.overlay {
    display: none;
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    z-index: 200;
}

.overlay.active {
    display: block;
}

body.menu-open {
    overflow: hidden;
}

@media (max-width: 900px) {
    .nav-bar {
        grid-template-columns: 1fr auto;
    }

    nav { display: none; }

    .header-icons { gap: 0.45rem; }

    .header-status {
        display: flex;
        justify-self: end;
    }

    .hamburger {
        display: flex;
        align-items: center;
        justify-content: center;
        justify-self: end;
        position: relative;
        z-index: 320;
        cursor: pointer;
    }

    nav.active {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: var(--nav-h);
        left: 0;
        right: 0;
        z-index: 310;
        background: var(--bg-panel);
        border-bottom: 1px solid var(--border);
        padding: 1rem 1.5rem;
        gap: 0.75rem;
        box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
    }

    nav.active a {
        display: block;
        padding: 0.65rem 0;
        font-size: 0.8125rem;
    }
}