/* ─── Reset & tokens ──────────────────────────────────────────────────────── */

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

* {
  margin: 0;
  padding: 0;
}

:root {
  /* Editorial dark palette. Light theme overrides below. */
  --bg: #0b0b0c;
  --bg-elev: #131316;
  --bg-card: #131418;
  --fg: #f5f5f4;
  --fg-mute: #a4a4a3;
  --fg-soft: #6f6f6e;
  --line: #232325;
  --line-soft: #18181a;
  --accent: #34d399;      /* emerald-400 */
  --accent-soft: #34d39922;
  --accent-line: #34d39933;
  --ring: #34d39955;

  --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-display: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', Menlo, monospace;

  --max: 1100px;
  --pad: clamp(1.25rem, 3vw, 2rem);
  --section-y: clamp(4rem, 8vw, 7rem);

  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;
  --r-xl: 24px;

  --ease: cubic-bezier(0.16, 1, 0.3, 1);

  color-scheme: dark;
}

html[data-theme='light'] {
  --bg: #fafaf9;
  --bg-elev: #ffffff;
  --bg-card: #ffffff;
  --fg: #0d0d0e;
  --fg-mute: #4f4f4e;
  --fg-soft: #7f7f7e;
  --line: #e7e5e4;
  --line-soft: #f1efee;
  --accent: #059669;      /* emerald-600 */
  --accent-soft: #05966915;
  --accent-line: #05966938;
  --ring: #05966955;
  color-scheme: light;
}

html {
  font-family: var(--font-sans);
  font-feature-settings: 'ss01', 'ss02', 'cv11';
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  background: var(--bg);
  color: var(--fg);
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

@supports (font-variation-settings: normal) {
  html {
    font-family: 'Inter var', system-ui, -apple-system, sans-serif;
  }
}

body {
  background: var(--bg);
  color: var(--fg);
  line-height: 1.55;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Soft grain on the background — small, low-opacity SVG noise. */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.04;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='240' height='240'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 160ms var(--ease);
}

a:hover {
  color: var(--accent);
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: 3px;
  border-radius: 4px;
}

button {
  font: inherit;
  color: inherit;
  background: transparent;
  border: 0;
  cursor: pointer;
}

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

em {
  font-style: normal;
  color: var(--fg);
}

/* Skip link */
.skip {
  position: absolute;
  top: 0;
  left: 0;
  padding: 0.5rem 1rem;
  background: var(--accent);
  color: #0b0b0c;
  font-weight: 600;
  transform: translateY(-200%);
  z-index: 100;
}

.skip:focus {
  transform: translateY(0);
}

/* ─── Nav ─────────────────────────────────────────────────────────────────── */

.nav {
  position: sticky;
  top: 0;
  z-index: 30;
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  background: color-mix(in oklab, var(--bg) 78%, transparent);
  border-bottom: 1px solid var(--line-soft);
}

.nav-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.875rem var(--pad);
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-mark {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  font-size: 0.82rem;
}

.mark-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.mark-text {
  text-transform: uppercase;
}

.nav-links {
  display: none;
  margin-left: auto;
  gap: 1.4rem;
  list-style: none;
  font-size: 0.875rem;
  color: var(--fg-mute);
}

.nav-links a:hover {
  color: var(--fg);
}

.theme-toggle {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--line);
  color: var(--fg-mute);
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background 160ms var(--ease);
}

.theme-toggle:hover {
  color: var(--fg);
  border-color: var(--accent-line);
  background: var(--accent-soft);
}

.theme-toggle svg {
  width: 16px;
  height: 16px;
}

@media (min-width: 760px) {
  .nav-links {
    display: flex;
  }
  .theme-toggle {
    margin-left: 0;
  }
}

/* ─── Hero ────────────────────────────────────────────────────────────────── */

.hero {
  position: relative;
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(3rem, 9vw, 6rem) var(--pad) clamp(3rem, 6vw, 5rem);
  z-index: 1;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fg-mute);
  margin-bottom: 1.5rem;
}

.eyebrow-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 2.2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 var(--accent-soft); }
  50% { box-shadow: 0 0 0 6px transparent; }
}

.hero-name {
  display: flex;
  align-items: center;
  gap: clamp(1rem, 3vw, 1.75rem);
  margin-bottom: 1.5rem;
}

.hero-avatar {
  flex-shrink: 0;
  width: clamp(72px, 12vw, 112px);
  height: clamp(72px, 12vw, 112px);
  border-radius: 18px;
  object-fit: cover;
  border: 2px solid var(--accent-line);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.28);
}

.hero-title {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(2.4rem, 7vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.035em;
}

.hero-title .line {
  display: block;
}

.hero-title .accent {
  background: linear-gradient(180deg, var(--fg) 0%, var(--fg-mute) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lede {
  max-width: 38rem;
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  color: var(--fg-mute);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.05rem;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  border: 1px solid var(--line);
  transition: all 160ms var(--ease);
}

.btn svg {
  width: 14px;
  height: 14px;
}

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

.btn-primary:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0b0c;
  transform: translateY(-1px);
}

.btn-ghost {
  color: var(--fg-mute);
}

.btn-ghost:hover {
  color: var(--fg);
  border-color: var(--fg-mute);
}

.btn-lg {
  padding: 0.95rem 1.5rem;
  font-size: 1rem;
}

.hero-meta {
  margin-top: clamp(2.5rem, 5vw, 4rem);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line-soft);
}

.meta-card {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding: 0.5rem 0;
}

.meta-k {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-soft);
}

.meta-v {
  font-size: 0.92rem;
  color: var(--fg);
}

/* ─── Generic section ─────────────────────────────────────────────────────── */

.section {
  position: relative;
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--section-y) var(--pad);
  z-index: 1;
}

.section + .section {
  border-top: 1px solid var(--line-soft);
}

.section-head {
  margin-bottom: clamp(2rem, 4vw, 3.5rem);
  max-width: 44rem;
}

.section-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fg-soft);
  margin-bottom: 1rem;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--fg);
}

.section-sub {
  margin-top: 1rem;
  color: var(--fg-mute);
  font-size: 1rem;
  max-width: 36rem;
}

/* ─── About ───────────────────────────────────────────────────────────────── */

.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.prose + .prose {
  margin-top: 1.1rem;
}

.prose {
  color: var(--fg-mute);
  font-size: 1.02rem;
  line-height: 1.75;
  max-width: 38rem;
}

.quick {
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--bg-card);
}

.quick-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fg-soft);
  margin-bottom: 1rem;
}

.quick-list {
  display: grid;
  gap: 0.9rem;
}

.quick-list div {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 0.9rem;
}

.quick-list dt {
  color: var(--fg-soft);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.quick-list dd {
  color: var(--fg);
}

@media (min-width: 880px) {
  .about-grid {
    grid-template-columns: 1.4fr 1fr;
    gap: 3.5rem;
  }
}

/* ─── Timeline ────────────────────────────────────────────────────────────── */

.timeline {
  list-style: none;
  display: grid;
  gap: 1.5rem;
  position: relative;
}

.timeline-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--bg-card);
  transition: border-color 200ms var(--ease), transform 200ms var(--ease);
}

.timeline-item:hover {
  border-color: var(--accent-line);
  transform: translateY(-1px);
}

.t-meta {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.t-dates {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

.t-co {
  font-size: 0.95rem;
  color: var(--fg-mute);
}

.t-body h3 {
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: 0.5rem;
}

.t-body p,
.t-body li {
  color: var(--fg-mute);
  font-size: 0.95rem;
  line-height: 1.65;
}

.t-body ul {
  margin: 0.5rem 0 0 1.1rem;
  display: grid;
  gap: 0.35rem;
}

.t-body strong {
  color: var(--fg);
  font-weight: 500;
}

@media (min-width: 820px) {
  .timeline-item {
    grid-template-columns: 200px 1fr;
    gap: 2rem;
    padding: 1.8rem 2rem;
  }
}

/* ─── Research ────────────────────────────────────────────────────────────── */

.research-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.paper {
  position: relative;
  padding: 1.75rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--bg-card);
  transition: border-color 200ms var(--ease), transform 200ms var(--ease);
  overflow: hidden;
}

.paper::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(120% 80% at 0% 0%, var(--accent-soft), transparent 50%);
  pointer-events: none;
  opacity: 0.5;
}

.paper-quiet::before {
  display: none;
}

.paper:hover {
  border-color: var(--accent-line);
  transform: translateY(-1px);
}

.paper-head {
  position: relative;
  margin-bottom: 1rem;
}

.paper-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  padding: 0.25rem 0.55rem;
  border: 1px solid var(--accent-line);
  border-radius: 4px;
  margin-bottom: 0.85rem;
}

.paper h3 {
  font-size: 1.18rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  line-height: 1.35;
}

.paper p {
  position: relative;
  color: var(--fg-mute);
  font-size: 0.96rem;
  line-height: 1.7;
}

.paper em {
  color: var(--fg);
}

.paper code {
  font-family: var(--font-mono);
  font-size: 0.86em;
  padding: 0.1em 0.35em;
  border-radius: 4px;
  background: var(--bg-elev);
  border: 1px solid var(--line);
}

.metrics {
  position: relative;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line-soft);
}

.metrics li {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.m-val {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--fg);
}

.m-key {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-soft);
}

@media (min-width: 880px) {
  .research-grid {
    grid-template-columns: 1fr 1fr;
  }
  .paper-quiet,
  .paper-wide {
    grid-column: span 2;
  }
}

/* ─── Publications ────────────────────────────────────────────────────────── */

.pubs {
  list-style: none;
  display: grid;
  gap: 1.25rem;
}

.pub {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  padding: 1.5rem 0;
  border-top: 1px solid var(--line-soft);
}

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

.pub-meta {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-soft);
}

.pub-body h3 {
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: 0.4rem;
  line-height: 1.4;
}

.pub-body p {
  color: var(--fg-mute);
  font-size: 0.95rem;
  line-height: 1.65;
}

.pub-body a {
  display: inline-block;
  margin-top: 0.5rem;
  font-size: 0.86rem;
  color: var(--accent);
}

.pub-body a:hover {
  color: var(--fg);
}

@media (min-width: 760px) {
  .pub {
    grid-template-columns: 200px 1fr;
    gap: 2rem;
  }
}

/* ─── Stack ───────────────────────────────────────────────────────────────── */

.stack-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.stack-card {
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--bg-card);
  transition: border-color 200ms var(--ease);
}

.stack-card:hover {
  border-color: var(--accent-line);
}

.stack-card h3 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.85rem;
}

.stack-card ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.stack-card li {
  font-size: 0.82rem;
  padding: 0.3rem 0.6rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--fg-mute);
  white-space: nowrap;
}

/* ─── Open source ─────────────────────────────────────────────────────────── */

.os-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.os-card {
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--bg-card);
}

.os-card h3 {
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: 0.5rem;
}

.os-card h3 a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--fg);
  transition: color 160ms var(--ease);
}

.os-card h3 a:hover {
  color: var(--accent);
}

.link-arrow {
  width: 14px;
  height: 14px;
  opacity: 0.6;
  transition: transform 160ms var(--ease), opacity 160ms var(--ease);
}

.os-card h3 a:hover .link-arrow {
  opacity: 1;
  transform: translate(2px, -2px);
}

.os-card p {
  color: var(--fg-mute);
  font-size: 0.95rem;
  line-height: 1.65;
}

@media (min-width: 760px) {
  .os-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* ─── Contact ─────────────────────────────────────────────────────────────── */

.contact-actions {
  margin-top: 1rem;
}

/* ─── Footer ──────────────────────────────────────────────────────────────── */

.foot {
  position: relative;
  border-top: 1px solid var(--line-soft);
  margin-top: clamp(4rem, 8vw, 6rem);
  z-index: 1;
}

.foot-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.5rem var(--pad);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--fg-soft);
  letter-spacing: 0.04em;
}

.foot-mark {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}

.foot-host {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--fg-soft);
}

.foot-host svg {
  width: 12px;
  height: 12px;
  color: var(--accent);
}

@media (min-width: 600px) {
  .foot-inner {
    flex-direction: row;
    align-items: center;
  }
}

/* ─── Reveal-on-scroll ────────────────────────────────────────────────────── */

.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 700ms var(--ease), transform 700ms var(--ease);
}

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

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .eyebrow-dot {
    animation: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* ─── Mobile polish ───────────────────────────────────────────────────────── */

@media (max-width: 480px) {
  .nav-mark .mark-text { display: none; }
  .nav-links {
    display: none;       /* keep the page calm at narrow widths */
  }
}