:root {
  --orange: #E77500;      /* Princeton orange */
  --black: #000000;
  --paper: #FFFFFF;
  --ink: #000000;
  --muted: #5C5C5C;
  --rule: #E2E2E2;
  --hero-bg: #000000;
  --hero-text: #FFFFFF;
  --hero-muted: #BDBDBD;
  --hero-accent: #E77500;
  --hero-line: rgba(255, 255, 255, 0.18);
  --hero-track: rgba(255, 255, 255, 0.06);

  --font: "Archivo", "Helvetica Neue", Arial, sans-serif;
  --wrap: 72rem;
  --gutter: clamp(1rem, 4vw, 2.5rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #141414;
    --ink: #F2F2F2;
    --muted: #A8A8A8;
    --rule: #2E2E2E;
  }
}

/* Personal mode: a warmer, lighter hero */

html[data-mode="personal"] .hero {
  --hero-bg: #F6F1EA;
  --hero-text: #141414;
  --hero-muted: #4D4D4D;
  --hero-accent: #A85400;
  --hero-line: rgba(0, 0, 0, 0.14);
  --hero-track: rgba(0, 0, 0, 0.04);
}

@media (prefers-color-scheme: dark) {
  html[data-mode="personal"] .hero {
    --hero-bg: #221D18;
    --hero-text: #F2F2F2;
    --hero-muted: #B8B0A6;
    --hero-accent: #E77500;
    --hero-line: rgba(255, 255, 255, 0.16);
    --hero-track: rgba(255, 255, 255, 0.05);
  }
}

html[data-mode="personal"] [data-only="professional"],
html:not([data-mode="personal"]) [data-only="personal"] {
  display: none;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration-color: var(--orange);
  text-decoration-thickness: 2px;
  text-underline-offset: 0.2em;
}

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

:focus-visible {
  outline: 3px solid var(--orange);
  outline-offset: 3px;
  border-radius: 2px;
}

.wrap {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  padding: 0.5rem 1rem;
  background: var(--orange);
  color: var(--black);
  font-weight: 600;
  z-index: 10;
}

.skip-link:focus {
  top: 1rem;
}

/* Hero */

.hero {
  background: var(--hero-bg);
  color: var(--hero-text);
  padding-bottom: clamp(3rem, 8vw, 6rem);
  border-bottom: 6px solid var(--orange);
  transition: background-color 0.35s ease, color 0.35s ease;
}

.topbar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem 2rem;
  padding-block: 1.5rem;
  font-size: 0.9375rem;
}

.topbar a {
  text-decoration: none;
}

.dept {
  color: var(--hero-muted);
}

.nav {
  grid-column: 3;
  justify-self: end;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav a:hover,
.dept a:hover {
  color: var(--hero-accent);
}

/* Professional / Personal toggle */

.mode-toggle {
  grid-column: 2;
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  padding: 4px;
  border: 1px solid var(--hero-line);
  border-radius: 999px;
  background: var(--hero-track);
}

.mode-toggle::before {
  content: "";
  position: absolute;
  inset: 4px auto 4px 4px;
  width: calc(50% - 4px);
  border-radius: 999px;
  background: var(--orange);
  transition: transform 0.35s cubic-bezier(0.2, 0.7, 0.1, 1);
}

html[data-mode="personal"] .mode-toggle::before {
  transform: translateX(100%);
}

.mode-toggle button {
  position: relative;
  padding: 0.4rem 1.1rem;
  border: 0;
  border-radius: 999px;
  background: none;
  color: var(--hero-muted);
  font: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.35s ease;
}

.mode-toggle button:hover {
  color: var(--hero-text);
}

.mode-toggle button[aria-pressed="true"] {
  color: var(--black);
}

.intro {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem clamp(2rem, 6vw, 5rem);
  align-items: center;
  margin-top: clamp(3rem, 8vw, 6rem);
}

.name {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 700;
  font-stretch: 112%;
  line-height: 1.05;
  letter-spacing: -0.01em;
}

.role {
  margin: 0.5rem 0 0;
  color: var(--hero-accent);
  font-size: clamp(1.125rem, 2.2vw, 1.375rem);
  font-weight: 500;
}

.affiliation {
  margin: 0.25rem 0 0;
  color: var(--hero-text);
  font-size: clamp(1rem, 1.8vw, 1.125rem);
  font-weight: 500;
}

.lede {
  max-width: 36em;
  margin: 1.5rem 0 0;
  color: var(--hero-muted);
  font-size: 1.1875rem;
  line-height: 1.55;
}

.portrait {
  display: block;
  width: clamp(9rem, 18vw, 13rem);
  height: auto;
  aspect-ratio: 1;
  margin: 8px;
  border-radius: 50%;
  object-fit: cover;
  outline: 2px solid var(--hero-accent);
  outline-offset: 6px;
}

/* Sections */

.section {
  display: grid;
  grid-template-columns: minmax(10rem, 3fr) 9fr;
  gap: 1rem clamp(2rem, 5vw, 4rem);
  padding-block: clamp(3rem, 7vw, 5rem);
}

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

.section-title {
  margin: 0;
  font-size: 1.375rem;
  font-weight: 800;
  font-stretch: 118%;
  line-height: 1.2;
}

.section-body {
  min-width: 0;
}

.prose p {
  max-width: 38em;
  margin: 0 0 1.1em;
}

.prose p:last-child {
  margin-bottom: 0;
}

/* Timeline */

.timeline {
  max-width: 38em;
  margin: 2rem 0 0;
  border-top: 1px solid var(--rule);
}

.timeline > div {
  display: grid;
  grid-template-columns: 9rem 1fr;
  gap: 0.25rem 1.5rem;
  padding-block: 0.75rem;
  border-bottom: 1px solid var(--rule);
}

.timeline dt {
  color: var(--muted);
  font-size: 0.9375rem;
  font-variant-numeric: tabular-nums;
}

.timeline dd {
  margin: 0;
  font-weight: 600;
}

/* Services */

.services {
  margin: 0;
}

.services > div {
  display: grid;
  grid-template-columns: minmax(12rem, 1fr) 2fr;
  gap: 0.25rem 2rem;
  padding-block: 1rem;
}

.services > div:first-child {
  padding-top: 0;
}

.services dt {
  font-weight: 650;
}

.services dd {
  max-width: 34em;
  margin: 0;
  color: var(--muted);
}

/* Projects */

.projects {
  margin: 0;
  padding: 0;
  list-style: none;
}

.project {
  padding-block: 1.5rem;
}

.project:first-child {
  padding-top: 0;
}

.project + .project {
  border-top: 1px solid var(--rule);
}

.project h3 {
  margin: 0 0 0.4rem;
  font-size: 1.25rem;
  font-weight: 700;
  font-stretch: 112%;
  line-height: 1.25;
}

.project h3 a {
  text-decoration: none;
}

.project h3 a:hover {
  text-decoration: underline;
  text-decoration-color: var(--orange);
}

.project p {
  max-width: 38em;
  margin: 0;
}

.project .stack {
  margin-top: 0.4rem;
  color: var(--muted);
  font-size: 0.9375rem;
}

/* Contact */

.contact {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 1.75rem 2rem;
  margin: 0;
}

.contact dt {
  color: var(--muted);
  font-size: 0.9375rem;
}

.contact dd {
  margin: 0.25rem 0 0;
  font-weight: 500;
}

/* Footer */

.footer {
  background: var(--black);
  color: var(--hero-muted);
  font-size: 0.9375rem;
}

.footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 2rem;
  padding-block: 2rem;
}

.footer p {
  margin: 0;
}

.footer a {
  text-decoration: none;
}

.footer a:hover {
  color: var(--orange);
}

/* Small screens */

@media (max-width: 960px) {
  .topbar {
    grid-template-columns: 1fr;
    justify-items: start;
  }

  .mode-toggle,
  .nav {
    grid-column: auto;
    justify-self: start;
  }
}

@media (max-width: 720px) {
  .intro {
    grid-template-columns: 1fr;
  }

  .portrait {
    grid-row: 1;
    width: 8rem;
  }

  .section {
    grid-template-columns: 1fr;
  }

  .services > div,
  .timeline > div {
    grid-template-columns: 1fr;
  }
}

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

  .hero,
  .mode-toggle::before,
  .mode-toggle button {
    transition: none;
  }
}