/* ==========================================================================
   Tokens
   ========================================================================== */
:root {
    color-scheme: light;

    --font-display: "Space Grotesk", system-ui, sans-serif;
    --font-body: "Plus Jakarta Sans", system-ui, -apple-system, sans-serif;

    --color-bg: #fafaf9;
    --color-surface: #ffffff;
    --color-text: #1c1c1f;
    --color-text-muted: #6b6b76;
    --color-border: rgba(28, 28, 31, 0.08);
    --color-accent: #2563eb;
    --color-accent-strong: #1d4ed8;
    --color-accent-soft: rgba(37, 99, 235, 0.1);

    --color-ink-bg: #1c1c1f;
    --color-ink-text: #ffffff;
    --color-nav-bg: rgba(255, 255, 255, 0.72);
    --color-overlay-bg: rgba(250, 250, 249, 0.98);
    --color-success-text: #067a55;
    --color-danger-text: #b42318;

    --radius-lg: 1.5rem;
    --radius-md: 1rem;
    --radius-sm: 0.6rem;
    --radius-pill: 999px;

    --shadow-soft: 0 1px 2px rgba(20, 20, 30, 0.04), 0 12px 32px -12px rgba(20, 20, 30, 0.12);
    --shadow-lift: 0 24px 48px -20px rgba(20, 20, 30, 0.22);

    --container-width: 1120px;
    --section-pad-y: 6rem;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        color-scheme: dark;

        --color-bg: #0f0f12;
        --color-surface: #18181c;
        --color-text: #f2f2f4;
        --color-text-muted: #9a9aa3;
        --color-border: rgba(255, 255, 255, 0.09);
        --color-accent: #5b8def;
        --color-accent-strong: #7aa2f7;
        --color-accent-soft: rgba(91, 141, 239, 0.16);

        --color-ink-bg: #f2f2f4;
        --color-ink-text: #0f0f12;
        --color-nav-bg: rgba(15, 15, 18, 0.72);
        --color-overlay-bg: rgba(15, 15, 18, 0.97);
        --color-success-text: #34d399;
        --color-danger-text: #f87171;

        --shadow-soft: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -12px rgba(0, 0, 0, 0.5);
        --shadow-lift: 0 24px 48px -20px rgba(0, 0, 0, 0.6);
    }
}

:root[data-theme="dark"] {
    color-scheme: dark;

    --color-bg: #0f0f12;
    --color-surface: #18181c;
    --color-text: #f2f2f4;
    --color-text-muted: #9a9aa3;
    --color-border: rgba(255, 255, 255, 0.09);
    --color-accent: #5b8def;
    --color-accent-strong: #7aa2f7;
    --color-accent-soft: rgba(91, 141, 239, 0.16);

    --color-ink-bg: #f2f2f4;
    --color-ink-text: #0f0f12;
    --color-nav-bg: rgba(15, 15, 18, 0.72);
    --color-overlay-bg: rgba(15, 15, 18, 0.97);

    --shadow-soft: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -12px rgba(0, 0, 0, 0.5);
    --shadow-lift: 0 24px 48px -20px rgba(0, 0, 0, 0.6);
}

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

html { scroll-behavior: smooth; }

body {
    margin: 0;
    font-family: var(--font-body);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
    font-family: var(--font-display);
    line-height: 1.15;
    margin: 0 0 0.6em;
    letter-spacing: -0.01em;
}

p { margin: 0 0 1em; }

a { color: inherit; text-decoration: none; }

img { max-width: 100%; display: block; }

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

.container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ==========================================================================
   Header / Nav
   ========================================================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    padding: 1rem 1.25rem 0;
}

.nav-pill {
    max-width: var(--container-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    padding: 0.6rem 0.6rem 0.6rem 1.4rem;
    background: var(--color-nav-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-pill);
    box-shadow: var(--shadow-soft);
}

.nav-brand {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 1.05rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link {
    padding: 0.5rem 0.9rem;
    border-radius: var(--radius-pill);
    font-size: 0.92rem;
    font-weight: 500;
    color: var(--color-text-muted);
    transition: background-color 0.25s ease, color 0.25s ease;
}

.nav-link:hover { color: var(--color-text); background: var(--color-accent-soft); }
.nav-link.is-active { color: var(--color-accent-strong); background: var(--color-accent-soft); }

.nav-toggle-input { display: none; }

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    width: 40px;
    height: 40px;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-pill);
    cursor: pointer;
}

.nav-toggle span {
    width: 18px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

/* ==========================================================================
   Theme toggle
   ========================================================================== */
.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.15rem;
    height: 2.15rem;
    border-radius: 50%;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    color: var(--color-text);
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    transition: background-color 0.25s ease, transform 0.25s cubic-bezier(0.32, 0.72, 0, 1);
}

.theme-toggle:hover { background: var(--color-accent-soft); }
.theme-toggle:active { transform: scale(0.92); }

.theme-toggle-icon-sun { display: none; }
.theme-toggle-icon-moon { display: block; }

:root[data-theme="dark"] .theme-toggle-icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle-icon-moon { display: none; }

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.75rem 0.75rem 0.75rem 1.35rem;
    border-radius: var(--radius-pill);
    font-weight: 600;
    font-size: 0.95rem;
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform 0.25s cubic-bezier(0.32, 0.72, 0, 1), box-shadow 0.25s ease, background-color 0.25s ease;
}

.btn:active { transform: scale(0.98); }

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

.btn-primary:hover { box-shadow: var(--shadow-lift); }

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border);
}

.btn-secondary:hover { background: var(--color-accent-soft); }

.btn-small { padding: 0.5rem 0.5rem 0.5rem 1.1rem; font-size: 0.85rem; }

.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.8rem;
    height: 1.8rem;
    border-radius: 50%;
    background: color-mix(in srgb, var(--color-ink-text) 18%, transparent);
    font-size: 0.9rem;
}

.btn-secondary .btn-icon,
.btn-small .btn-icon {
    background: var(--color-accent-soft);
    color: var(--color-accent-strong);
    width: 1.5rem;
    height: 1.5rem;
}

/* ==========================================================================
   Eyebrow / section heading
   ========================================================================== */
.eyebrow {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    border-radius: var(--radius-pill);
    background: var(--color-accent-soft);
    color: var(--color-accent-strong);
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.14em;
    margin-bottom: 1rem;
}

.section {
    padding: var(--section-pad-y) 0;
}

.section-head {
    max-width: 640px;
    margin: 0 0 3rem;
}

.section-head p { color: var(--color-text-muted); font-size: 1.05rem; }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
    padding: 4rem 0 5rem;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 3rem;
    align-items: center;
}

.hero h1 {
    font-size: clamp(2.4rem, 4.5vw, 3.6rem);
}

.hero-lead {
    font-size: 1.15rem;
    color: var(--color-text-muted);
    max-width: 46ch;
}

.hero-actions {
    display: flex;
    gap: 0.9rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.hero-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 2rem;
}

.tag {
    padding: 0.35rem 0.75rem;
    border-radius: var(--radius-pill);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

.hero-card {
    background: var(--color-ink-bg);
    color: var(--color-ink-text);
    border-radius: var(--radius-lg);
    padding: 0.5rem;
    box-shadow: var(--shadow-lift);
}

.hero-card-inner {
    border-radius: calc(var(--radius-lg) - 0.4rem);
    padding: 2rem;
    background: linear-gradient(160deg, color-mix(in srgb, var(--color-ink-text) 6%, transparent), transparent);
    box-shadow: inset 0 1px 1px color-mix(in srgb, var(--color-ink-text) 12%, transparent);
}

.hero-card-inner .stat {
    display: flex;
    justify-content: space-between;
    padding: 0.9rem 0;
    border-bottom: 1px solid color-mix(in srgb, var(--color-ink-text) 12%, transparent);
    font-size: 0.95rem;
}

.hero-card-inner .stat:last-child { border-bottom: none; }
.hero-card-inner .stat span:last-child { color: color-mix(in srgb, var(--color-ink-text) 60%, transparent); }

/* ==========================================================================
   Cards / grids
   ========================================================================== */
.grid {
    display: grid;
    gap: 1.5rem;
}

.grid-skills { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.grid-projects { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }

.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1.75rem;
    box-shadow: var(--shadow-soft);
    transition: transform 0.35s cubic-bezier(0.32, 0.72, 0, 1), box-shadow 0.35s ease;
}

.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lift); }

.skill-card h3 {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
}

.skill-card ul { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.project-card { display: flex; flex-direction: column; height: 100%; }

.project-card .project-year { color: var(--color-text-muted); font-size: 0.85rem; }

.project-card h3 { font-size: 1.3rem; margin-top: 0.3rem; }

.project-card p { color: var(--color-text-muted); flex-grow: 1; }

.project-card .tag-row { display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 1rem 0 1.4rem; }

.project-card .card-link {
    font-weight: 600;
    color: var(--color-accent-strong);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

.badge-featured {
    align-self: flex-start;
    background: var(--color-ink-bg);
    color: var(--color-ink-text);
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 0.25rem 0.6rem;
    border-radius: var(--radius-pill);
    margin-bottom: 0.9rem;
}

/* ==========================================================================
   Timeline (About page)
   ========================================================================== */
.timeline {
    position: relative;
    padding-left: 2rem;
    border-left: 2px solid var(--color-border);
}

.timeline-item {
    position: relative;
    padding-bottom: 2.75rem;
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-item::before {
    content: "";
    position: absolute;
    left: -2.45rem;
    top: 0.35rem;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--color-accent);
    box-shadow: 0 0 0 4px var(--color-accent-soft);
}

.timeline-item .period {
    font-size: 0.82rem;
    color: var(--color-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.timeline-item h3 { margin: 0.3rem 0 0.15rem; font-size: 1.2rem; }

.timeline-item .organization { color: var(--color-accent-strong); font-weight: 600; margin-bottom: 0.6rem; }

.timeline-item p { color: var(--color-text-muted); }

/* ==========================================================================
   Project detail
   ========================================================================== */
.project-detail-head { max-width: 720px; }

.project-meta { display: flex; flex-wrap: wrap; gap: 0.6rem; margin: 1.5rem 0 2rem; }

.project-body { max-width: 720px; font-size: 1.05rem; color: var(--color-text); }

.project-body p { color: var(--color-text-muted); }

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--color-text-muted);
    font-weight: 500;
    margin-bottom: 2rem;
}

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

/* ==========================================================================
   Reveal-on-scroll
   ========================================================================== */
[data-reveal] {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.8s cubic-bezier(0.32, 0.72, 0, 1), transform 0.8s cubic-bezier(0.32, 0.72, 0, 1);
}

[data-reveal].is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
    border-top: 1px solid var(--color-border);
    margin-top: 4rem;
    padding: 3rem 0;
}

.footer-inner {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    text-align: center;
}

.footer-name { font-family: var(--font-display); font-weight: 600; margin-bottom: 0.2rem; }

.footer-tagline { color: var(--color-text-muted); font-size: 0.9rem; }

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.25rem;
    margin: 1.25rem 0;
    font-size: 0.9rem;
}

.footer-links a { color: var(--color-text-muted); }
.footer-links a:hover { color: var(--color-accent-strong); }

.footer-copy { color: var(--color-text-muted); font-size: 0.8rem; margin: 0; }

/* ==========================================================================
   Empty state
   ========================================================================== */
.empty-state {
    text-align: center;
    padding: 4rem 1rem;
    color: var(--color-text-muted);
}

/* ==========================================================================
   Flash messages
   ========================================================================== */
.flash-message {
    margin: 2rem auto 0;
    max-width: 640px;
    padding: 1rem 1.4rem;
    border-radius: var(--radius-md);
    font-weight: 500;
    border: 1px solid var(--color-border);
}

.flash-success { background: rgba(16, 185, 129, 0.1); color: var(--color-success-text); border-color: rgba(16, 185, 129, 0.25); }
.flash-error { background: rgba(220, 38, 38, 0.08); color: var(--color-danger-text); border-color: rgba(220, 38, 38, 0.25); }

/* ==========================================================================
   Contact form
   ========================================================================== */
.contact-layout {
    display: grid;
    grid-template-columns: 0.8fr 1.2fr;
    gap: 3rem;
    align-items: start;
}

.contact-info h2 { font-size: 1.4rem; }
.contact-info p { color: var(--color-text-muted); }

.contact-info-list { display: flex; flex-direction: column; gap: 1rem; margin-top: 1.5rem; }

.contact-info-list a { font-weight: 600; color: var(--color-accent-strong); }

.form-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-soft);
}

.form-row { margin-bottom: 1.25rem; }

.form-row label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.4rem;
}

.form-row input[type="text"],
.form-row input[type="email"],
.form-row textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    font-family: var(--font-body);
    font-size: 0.98rem;
    color: var(--color-text);
    transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.form-row input:focus,
.form-row textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-soft);
}

.form-row textarea { resize: vertical; min-height: 140px; }

.form-errors { color: var(--color-danger-text); font-size: 0.85rem; margin-top: 0.4rem; }

.form-honeypot { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }

.form-submit { margin-top: 0.5rem; }

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 860px) {
    .hero-grid { grid-template-columns: 1fr; }
    .hero-card { order: -1; }
    .contact-layout { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    :root { --section-pad-y: 3.5rem; }

    .nav-toggle { display: flex; }

    .nav-links {
        position: fixed;
        inset: 0;
        z-index: 40;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 1.25rem;
        background: var(--color-overlay-bg);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        opacity: 0;
        pointer-events: none;
        transform: translateY(-12px);
        transition: opacity 0.35s ease, transform 0.35s ease;
    }

    .nav-link { font-size: 1.2rem; }

    .nav-toggle-input:checked ~ .nav-links {
        opacity: 1;
        pointer-events: auto;
        transform: translateY(0);
    }

    .nav-toggle-input:checked ~ .nav-toggle span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
    .nav-toggle-input:checked ~ .nav-toggle span:nth-child(2) { opacity: 0; }
    .nav-toggle-input:checked ~ .nav-toggle span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

    .container { padding: 0 1.1rem; }
}