/* ─── Tokens (Light Theme Only) ──────────────────── */
:root {
    --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

    --bg: #ffffff;
    --surface: #f9f9f9;
    --surface2: #f0f0f0;
    --text: rgba(0, 0, 0, 0.90);
    --muted: rgba(0, 0, 0, 0.60);
    --faint: rgba(0, 0, 0, 0.30);
    --border: rgba(0, 0, 0, 0.12);
    --border-h: rgba(0, 0, 0, 0.25);
    --nav-blur: rgba(255, 255, 255, 0.80);

    --brand-grad: linear-gradient(135deg, #4f46e5 0%, #0891b2 100%);
    --brand-glow: rgba(79, 70, 229, 0.1);

    --r: 8px;
    --max: 1020px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: var(--sans);
    background: var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    letter-spacing: -0.01em;
    position: relative;
}

/* Subtle Engineering Grid Background */
.bg-pattern {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-image: radial-gradient(var(--border) 1px, transparent 1px);
    background-size: 24px 24px;
    mask-image: linear-gradient(to bottom, black 0%, transparent 70%);
    -webkit-mask-image: linear-gradient(to bottom, black 0%, transparent 70%);
    z-index: -1;
    pointer-events: none;
}

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

.mono {
    font-family: var(--mono);
}

/* Responsive Container Padding */
.w {
    max-width: var(--max);
    margin: 0 auto;
    padding: 0 24px;
}

@media (max-width: 640px) {
    .w {
        padding: 0 16px;
    }
}

/* Text Gradient */
.text-gradient {
    background: var(--brand-grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
}

/* Pulsing Status Dot */
.status-dot {
    display: inline-block;
    width: 8px;
    height: 8px;
    background: #10b981;
    border-radius: 50%;
    box-shadow: 0 0 10px #10b981;
    margin-right: 8px;
    transform: translateY(-1px);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
    70% { box-shadow: 0 0 0 6px rgba(16, 185, 129, 0); }
    100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

/* ─── Navbar (Mobile Optimized) ──────────────────── */
.nav-wrap {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--nav-blur);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 0;
    flex-wrap: wrap;
    gap: 12px;
}

.brand {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.04em;
    color: var(--text);
}

/* Native App-Like Horizontal Scrolling for Mobile */
.nav-links {
    display: flex;
    gap: 4px;
    align-items: center;
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    order: 3;
    width: 100%;
    padding-bottom: 4px;
}

.nav-links::-webkit-scrollbar {
    display: none;
}

@media (min-width: 768px) {
    .nav-links {
        width: auto;
        order: 0;
        padding-bottom: 0;
        overflow-x: visible;
    }
}

.nav-links a {
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--muted);
    padding: 6px 12px;
    border-radius: 6px;
    transition: color .2s, background .2s;
}

.nav-links a:hover {
    color: var(--text);
    background: var(--surface2);
}

.nav-actions {
    display: flex;
    gap: 8px;
    align-items: center;
}

/* ─── Buttons ────────────────────────────────────── */
.btn-base {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.88rem;
    font-weight: 500;
    padding: 9px 18px;
    border-radius: var(--r);
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    transition: all .2s ease;
    white-space: nowrap;
}

.btn-base:hover {
    background: var(--surface2);
    border-color: var(--border-h);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--brand-glow);
}

.btn-solid {
    background: var(--text);
    color: var(--bg);
    border-color: var(--text);
    font-weight: 600;
}

.btn-solid:hover {
    background: var(--muted);
    border-color: var(--muted);
    color: var(--bg);
    transform: translateY(-1px);
}

.btn-ghost {
    border-color: transparent;
    background: transparent;
    color: var(--muted);
    padding-left: 8px;
    padding-right: 8px;
}

.btn-ghost:hover {
    background: var(--surface2);
    color: var(--text);
    transform: none;
}

/* Hide "Resume" text on very small phones to save space */
@media (max-width: 400px) {
    .hide-mobile {
        display: none;
    }
}

/* ─── Hero ───────────────────────────────────────── */
.hero {
    padding: 100px 0 80px;
    position: relative;
}

@media (min-width: 768px) {
    .hero {
        padding: 120px 0 90px;
    }
}

.hero-eyebrow {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--muted);
    margin-bottom: 22px;
    letter-spacing: 0.05em;
    display: flex;
    align-items: center;
}

.hero-title {
    font-size: clamp(2.6rem, 8vw, 4.4rem);
    font-weight: 700;
    letter-spacing: -0.05em;
    line-height: 1.05;
    margin: 0 0 20px;
    color: var(--text);
}

.hero-sub {
    font-size: 1.05rem;
    color: var(--muted);
    max-width: 58ch;
    line-height: 1.7;
    margin: 0 0 32px;
}

.hero-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* ─── Divider ────────────────────────────────────── */
.divider {
    border: none;
    border-top: 1px solid var(--border);
    margin: 0;
}

/* ─── Section wrapper ────────────────────────────── */
.section {
    padding: 60px 0;
}

@media (min-width: 768px) {
    .section {
        padding: 80px 0;
    }
}

.section-label {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--faint);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-heading {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.04em;
    margin: 0 0 30px;
    color: var(--text);
}

/* ─── Cards (Projects & Insights) ────────────────── */
.card-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

@media (min-width: 768px) {
    .card-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: 24px;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
    transition: transform .3s ease, border-color .3s ease, box-shadow .3s ease;
}

@media (min-width: 768px) {
    .card {
        padding: 32px;
    }
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--brand-grad);
    opacity: 0;
    transition: opacity .3s ease;
}

.card:hover {
    border-color: var(--border-h);
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.05);
}

.card:hover::before {
    opacity: 1;
}

.card-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 16px;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin: 0;
}

.card-stat {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--text);
    background: var(--surface2);
    border: 1px solid var(--border);
    padding: 4px 10px;
    border-radius: 6px;
    white-space: nowrap;
}

.card-body {
    font-size: 0.95rem;
    color: var(--muted);
    line-height: 1.7;
    flex: 1;
    margin: 0 0 24px;
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
}

.tag {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--text);
    background: var(--border);
    padding: 4px 10px;
    border-radius: 4px;
    letter-spacing: 0.02em;
    opacity: 0.8;
}

.card-actions {
    display: flex;
    gap: 10px;
    margin-top: auto;
}

/* ─── Code Block (architecture) ─────────────────── */
.code-block {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 16px;
    margin: 16px 0 24px;
    overflow-x: auto;
}

.code-block pre {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--muted);
    margin: 0;
    white-space: pre;
    line-height: 1.6;
}

/* ─── Timeline ───────────────────────────────────── */
.timeline {
    border-left: 1px dashed var(--border-h);
    padding-left: 24px;
    margin: 0;
}

@media (min-width: 768px) {
    .timeline {
        padding-left: 28px;
    }
}

.t-item {
    position: relative;
    padding-bottom: 36px;
}

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

.t-item::before {
    content: "";
    position: absolute;
    left: -29px;
    top: 6px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--bg);
    border: 2px solid var(--muted);
    transition: border-color .3s;
}

@media (min-width: 768px) {
    .t-item::before {
        left: -33px;
    }
}

.t-item:hover::before {
    border-color: #0891b2;
}

.t-date {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--faint);
    text-transform: uppercase;
    letter-spacing: 0.10em;
    margin-bottom: 8px;
    display: block;
}

.t-role {
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 4px;
    color: var(--text);
}

.t-org {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 12px;
}

.t-desc {
    font-size: 0.95rem;
    color: var(--muted);
    line-height: 1.7;
    margin: 0;
}

/* ─── Publications ───────────────────────────────── */
.pub-list {
    margin: 0;
    padding: 0;
    list-style: none;
}

.pub-item {
    padding: 24px 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    transition: background .3s;
}

@media (min-width: 768px) {
    .pub-item {
        padding: 28px 0;
        gap: 24px;
    }
}

.pub-item:first-child {
    padding-top: 0;
}

.pub-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.pub-title {
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 8px;
    color: var(--text);
}

.pub-meta {
    font-size: 0.9rem;
    color: var(--muted);
    line-height: 1.6;
    margin: 0;
}

.pub-actions {
    display: flex;
    gap: 10px;
    flex-shrink: 0;
    flex-wrap: wrap;
}

@media (max-width: 640px) {
    .pub-item {
        flex-direction: column;
    }
}

/* ─── Skills Grid ────────────────────────────────── */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    gap: 12px;
}

.skill-chip {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: 12px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text);
    background: var(--surface);
    transition: all .2s;
}

.skill-chip i {
    color: var(--muted);
    font-size: 1.1rem;
    transition: color .2s;
}

.skill-chip:hover {
    border-color: var(--border-h);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--brand-glow);
}

.skill-chip:hover i {
    color: #0891b2;
}

/* ─── Recruiter Box ──────────────────────────────── */
.recruiter-box {
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: 24px;
    background: var(--surface);
    position: relative;
    overflow: hidden;
}

.recruiter-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    width: 3px;
    background: var(--brand-grad);
}

.recruiter-box .label-sm {
    font-family: var(--mono);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--faint);
    margin-bottom: 12px;
}

.recruiter-box .big {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    color: var(--text);
}

.recruiter-box p {
    font-size: 0.95rem;
    color: var(--muted);
    margin: 0;
    line-height: 1.6;
}

/* ─── Footer ─────────────────────────────────────── */
footer {
    padding: 40px 0;
    border-top: 1px solid var(--border);
}

@media (min-width: 768px) {
    footer {
        padding: 56px 0;
    }
}

.footer-inner {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: flex-start;
    gap: 24px;
}

.footer-name {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 6px;
}

.footer-city {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--faint);
}

.footer-links {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    align-items: center;
}

.footer-links a {
    font-size: 0.9rem;
    color: var(--muted);
    display: flex;
    gap: 8px;
    align-items: center;
    padding: 8px 10px;
    border-radius: 6px;
    transition: all .2s;
}

.footer-links a:hover {
    color: var(--text);
    background: var(--surface2);
}

.footer-copy {
    width: 100%;
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--faint);
    padding-top: 24px;
    border-top: 1px solid var(--border);
    margin-top: 8px;
}

/* ─── Fade-in (Intersection Observer) ───────────── */
.io {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity .6s ease-out, transform .6s ease-out;
}

.io.in {
    opacity: 1;
    transform: translateY(0);
}

.io-d1 { transition-delay: .08s; }
.io-d2 { transition-delay: .16s; }
.io-d3 { transition-delay: .24s; }

@media (prefers-reduced-motion: reduce) {
    .io {
        transition: none;
        opacity: 1;
        transform: none;
    }

    .status-dot {
        animation: none;
        box-shadow: none;
    }
}

/* ─── Focus rings ────────────────────────────────── */
:focus-visible {
    outline: 2px solid var(--text);
    outline-offset: 3px;
    border-radius: 4px;
}