/* Tokens */
:root {
  --bg: #ffffff;
  --bg-alt: #f7f7f7;
  --surface: #ffffff;
  --text: #111111;
  --muted: #555555;
  --border: #e5e5e5;
  --accent: #111111;
  --accent-hover: #000000;
  --on-accent: #ffffff;
  --radius: 6px;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;
  --space-9: 6.5rem;
  --wrap: 44rem;
  --header-h: 3.5rem;
  --font: "IBM Plex Sans", "Segoe UI", Helvetica, Arial, sans-serif;
  --ease: 160ms ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + var(--space-4));
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

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

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: -0.02em;
}

p,
dl,
ol,
ul {
  margin: 0;
}

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -4rem;
  z-index: 100;
  padding: var(--space-2) var(--space-4);
  background: var(--accent);
  color: var(--on-accent);
  border-radius: var(--radius);
}

.skip-link:focus {
  top: var(--space-2);
  color: var(--on-accent);
}

.wrap {
  width: min(var(--wrap), calc(100% - var(--space-6)));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(10px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
}

.logo {
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.02em;
  white-space: nowrap;
}

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

.site-nav {
  margin-left: auto;
}

.site-nav > ul {
  display: flex;
  gap: var(--space-5);
  list-style: none;
  padding: 0;
}

.social-bar {
  position: fixed;
  right: 1.25rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 40;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.45rem;
}

.social-bar::before,
.social-bar::after {
  content: "";
  width: 1px;
  height: 2.5rem;
  background: var(--text);
}

.icon-sprite {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}

.icon {
  width: 1.15rem;
  height: 1.15rem;
  fill: currentColor;
  display: block;
  flex-shrink: 0;
}

.social-bar a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  color: var(--bg);
  background: var(--text);
  border: 1.5px solid var(--text);
  text-decoration: none;
}

.social-bar .icon {
  width: 1.2rem;
  height: 1.2rem;
}

.social-bar a:hover,
.social-bar a:focus-visible,
.social-bar a:active {
  color: var(--text);
  background: var(--bg);
}

.site-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 500;
}

.site-nav a:hover,
.site-nav a[aria-current="true"] {
  color: var(--text);
}

.site-nav .nav-social {
  display: none;
}

.nav-toggle {
  display: none;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  cursor: pointer;
}

.nav-toggle-bar,
.nav-toggle-bar::before,
.nav-toggle-bar::after {
  display: block;
  width: 1rem;
  height: 1.5px;
  margin: auto;
  background: var(--text);
  border-radius: 1px;
  position: relative;
  transition: transform var(--ease), opacity var(--ease);
}

.nav-toggle-bar::before,
.nav-toggle-bar::after {
  content: "";
  position: absolute;
  left: 0;
}

.nav-toggle-bar::before {
  top: -5px;
}

.nav-toggle-bar::after {
  top: 5px;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar::after {
  top: 0;
  transform: rotate(-45deg);
}

/* Hero */
.hero {
  padding: var(--space-8) 0 var(--space-7);
}

.hero-inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.eyebrow {
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.hero-identity {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}

.portrait {
  width: 5.5rem;
  height: 5.5rem;
  object-fit: cover;
  border-radius: 50%;
  border: 1px solid var(--text);
  flex-shrink: 0;
}

.hero h1 {
  font-size: clamp(2.25rem, 6vw, 3.25rem);
}

.hero h1::after {
  content: "";
  display: block;
  width: 0;
  height: 2px;
  margin-top: 0.55rem;
  background: var(--text);
  animation: draw-bar 0.8s ease 0.2s forwards;
}

@keyframes draw-bar {
  to {
    width: 3.25rem;
  }
}

.title {
  margin-top: var(--space-2);
  font-size: clamp(1.05rem, 2.4vw, 1.25rem);
  font-weight: 500;
  color: var(--text);
}

.location {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  margin-top: var(--space-3);
  font-size: 0.9375rem;
  color: var(--muted);
}

.flag {
  width: 1.15rem;
  height: 0.7rem;
  border: 1px solid var(--border);
  flex-shrink: 0;
}

.lead {
  max-width: 38rem;
  color: var(--muted);
  font-size: 1.125rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.6rem 1.15rem;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 0.9375rem;
  text-decoration: none;
  transition: background-color var(--ease), color var(--ease), border-color var(--ease);
}

.btn-primary {
  background: var(--accent);
  color: var(--on-accent);
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: var(--on-accent);
}

.btn-secondary {
  border: 1px solid var(--border);
  color: var(--text);
  background: transparent;
}

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

/* Sections */
.section {
  padding: var(--space-8) 0;
  border-top: 1px solid var(--border);
}

.section h2 {
  font-size: clamp(1.6rem, 3.5vw, 2rem);
  margin: var(--space-2) 0 var(--space-6);
}

/* About */
.about-grid {
  display: grid;
  gap: var(--space-4);
}

.about-grid p {
  color: var(--muted);
}


/* Skills */
.skill-list {
  display: grid;
  gap: 0;
}

.skill-list > div {
  display: grid;
  grid-template-columns: 12.5rem 1fr;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-top: 1px solid var(--border);
}

.skill-list > div:last-child {
  border-bottom: 1px solid var(--border);
}

.skill-list dt {
  font-weight: 600;
  font-size: 0.9375rem;
}

.skill-list dd {
  color: var(--muted);
}

/* Projects */
.project {
  display: grid;
  grid-template-columns: 2.75rem 1fr;
  gap: 0 var(--space-5);
  padding: var(--space-7) 0;
  border-top: 1px solid var(--border);
}

.project:last-child {
  border-bottom: 1px solid var(--border);
}

.project-index {
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--muted);
  padding-top: 0.4rem;
  font-variant-numeric: tabular-nums;
}

.project-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  margin-bottom: var(--space-3);
}

.project h3 {
  font-size: 1.25rem;
}

.project-org {
  font-size: 0.8125rem;
  color: var(--muted);
}

.project-org a {
  color: var(--muted);
  text-decoration: none;
}

.project-org a:hover {
  color: var(--text);
}

.project-problem {
  color: var(--text);
  font-weight: 500;
  max-width: 36rem;
}

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

.project-body > p + p {
  margin-top: var(--space-3);
}

.project-body strong {
  color: var(--text);
  font-weight: 600;
}

.project-metrics {
  color: var(--text) !important;
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.tech {
  margin-top: var(--space-4);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.project-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-top: var(--space-4);
  font-size: 0.875rem;
  font-weight: 500;
}

.project-links a {
  color: var(--text);
  text-decoration: none;
  border-bottom: 1px solid var(--text);
}

.project-links a:hover {
  color: var(--muted);
  border-color: var(--muted);
}

/* Experience */
.timeline {
  list-style: none;
  padding: 0;
  border-left: 1px solid var(--border);
}

.timeline > li {
  position: relative;
  padding: 0 0 var(--space-7) var(--space-5);
}

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

.timeline > li::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 0.45rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
}

.when {
  font-size: 0.8125rem;
  color: var(--muted);
  margin-bottom: var(--space-2);
}

.timeline h3 {
  font-size: 1.125rem;
}

.org {
  margin: var(--space-1) 0 var(--space-3);
  color: var(--muted);
}

.timeline ul {
  padding-left: 1.1rem;
  color: var(--muted);
}

.timeline strong {
  color: var(--text);
  font-weight: 600;
}

.timeline li + li {
  margin-top: var(--space-2);
}

.education {
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid var(--border);
}

.education h3 {
  font-size: 1.125rem;
  margin-bottom: var(--space-4);
}

.education p + p {
  margin-top: var(--space-3);
}

.education p {
  color: var(--muted);
}

.education strong {
  color: var(--text);
  font-weight: 600;
}

/* Research */
.subhead {
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin: var(--space-6) 0 var(--space-4);
}

.subhead:first-of-type {
  margin-top: 0;
}

.pub-list,
.artifact-list {
  padding-left: 1.15rem;
}

.pub-list li,
.artifact-list li {
  color: var(--muted);
}

.pub-list li + li,
.artifact-list li + li {
  margin-top: var(--space-4);
}

.pub-list a {
  color: var(--text);
  text-decoration: none;
}

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

.pub-list span {
  display: block;
  margin-top: var(--space-1);
  font-size: 0.875rem;
}

.scholar {
  margin-top: var(--space-5);
  font-weight: 500;
}

/* Contact */
.contact-inner h2 {
  margin: var(--space-5) 0 var(--space-5);
}

.email-display {
  display: block;
  color: var(--text);
  text-decoration: none;
  line-height: 0.95;
}

.email-display span {
  display: block;
  font-size: clamp(2.4rem, 9vw, 5rem);
  font-weight: 600;
  letter-spacing: -0.05em;
}

.email-display span:last-child {
  width: fit-content;
  padding-bottom: 0.12em;
  background-image: linear-gradient(currentColor, currentColor);
  background-size: 0 3px;
  background-repeat: no-repeat;
  background-position: left bottom;
  transition: background-size 0.35s ease;
}

.email-display:hover span:last-child,
.email-display:focus-visible span:last-child {
  background-size: 100% 3px;
}

.contact-note {
  margin-bottom: var(--space-3);
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text);
}

.contact-inner .lead {
  max-width: 28rem;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3) var(--space-5);
  list-style: none;
  padding: 0;
  margin-bottom: var(--space-6);
}

.contact-links a,
.nav-social a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
}

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

.site-footer {
  padding: var(--space-6) 0;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.875rem;
}

.social-bar a {
  opacity: 0;
  transform: translateX(12px);
  animation: slide-in 0.5s ease forwards;
}

.social-bar a:nth-child(1) { animation-delay: 0.35s; }
.social-bar a:nth-child(2) { animation-delay: 0.43s; }
.social-bar a:nth-child(3) { animation-delay: 0.51s; }
.social-bar a:nth-child(4) { animation-delay: 0.59s; }
.social-bar a:nth-child(5) { animation-delay: 0.67s; }
.social-bar a:nth-child(6) { animation-delay: 0.75s; }

.social-bar::before,
.social-bar::after {
  transform: scaleY(0);
  animation: draw-y 0.55s ease 0.3s forwards;
}

.social-bar::before {
  transform-origin: bottom;
}

.social-bar::after {
  transform-origin: top;
}

.social-bar a {
  transition: background-color var(--ease), color var(--ease), transform var(--ease);
}

.social-bar a:hover {
  transform: translateY(-2px);
}

.btn {
  transition: background-color var(--ease), color var(--ease), border-color var(--ease), transform var(--ease);
}

.btn:hover {
  transform: translateY(-1px);
}

@keyframes slide-in {
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes draw-y {
  to {
    transform: scaleY(1);
  }
}

/* Tablet and below: hamburger + stacked skills */
@media (max-width: 880px) {
  :root {
    --space-8: 3.5rem;
    --space-9: 4.5rem;
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .site-nav {
    display: none;
    margin-left: 0;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: var(--space-4) var(--space-5) var(--space-5);
  }

  .social-bar {
    display: none;
  }

  .site-nav.is-open .nav-social {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3) var(--space-4);
    list-style: none;
    padding: var(--space-4) 0 0;
    margin-top: var(--space-3);
    border-top: 1px solid var(--border);
  }

  .site-nav > ul {
    flex-direction: column;
    gap: 0;
  }

  .site-nav.is-open {
    display: block;
  }

  .site-nav a {
    display: block;
    padding: 0.7rem 0;
    font-size: 1.0625rem;
  }

  .site-nav.is-open .nav-social a {
    display: inline-flex;
  }

  .skill-list > div {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }

  .project {
    grid-template-columns: 2rem 1fr;
    gap: 0 var(--space-4);
  }
}

@media (max-width: 560px) {
  .hero-identity {
    align-items: flex-start;
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .hero-actions {
    width: 100%;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 1rem;
  }

  .wrap {
    width: calc(100% - var(--space-5));
  }

  .hero {
    padding-top: var(--space-6);
  }

  .lead {
    font-size: 1.05rem;
  }

  .email-display span {
    word-break: break-word;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .social-bar a,
  .social-bar::before,
  .social-bar::after,
  .hero h1::after {
    animation: none;
    opacity: 1;
    transform: none;
  }

  .hero h1::after {
    width: 3.25rem;
  }

  .btn,
  .social-bar a,
  .nav-toggle-bar,
  .nav-toggle-bar::before,
  .nav-toggle-bar::after {
    transition: none;
  }
}