/* ==========================================================================
   Theme — change colors and fonts here.
   ========================================================================== */
:root {
  --font: "Inter", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  --bg: #ffffff;
  --text: #000000;
  --muted: #525252;
  --link: #2563eb;          /* blue */
  --link-hover: #f97316;    /* orange */
  --border: #e5e5e5;
  --placeholder-bg: #fafafa;
  --card-hover-bg: #f0f9ff;
  --card-hover-border: #e0f2fe;
  --card-shadow: rgba(0, 0, 0, .06);
  --figure-bg: #ffffff;     /* background behind paper images */

  --page-width: 56rem;
  --photo-width: 180px;          /* publication image column */
  --intro-photo-width: 280px;    /* profile photo column (tablet & desktop) */
  --intro-photo-focus: 50% 25%;  /* which part of the photo stays visible: x y */
}

/* Dark theme colors. Used when the visitor's system is in dark mode (unless they
   picked light with the button), or when they picked dark with the button. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1115;
    --text: #e6e6e6;
    --muted: #a1a1aa;
    --link: #60a5fa;
    --link-hover: #fb923c;
    --border: #2a2d33;
    --placeholder-bg: #171a1f;
    --card-hover-bg: #151b26;
    --card-hover-border: #1f2a3a;
    --card-shadow: rgba(0, 0, 0, .4);
    --figure-bg: #f4f4f5;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f1115;
  --text: #e6e6e6;
  --muted: #a1a1aa;
  --link: #60a5fa;
  --link-hover: #fb923c;
  --border: #2a2d33;
  --placeholder-bg: #171a1f;
  --card-hover-bg: #151b26;
  --card-hover-border: #1f2a3a;
  --card-shadow: rgba(0, 0, 0, .4);
  --figure-bg: #f4f4f5;
  color-scheme: dark;
}
:root[data-theme="light"] { color-scheme: light; }

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color .2s ease, color .2s ease;
}

h1, h2, h3, p, ul { margin: 0; }
ul { padding: 0; list-style: none; }
img { display: block; max-width: 100%; height: auto; }
strong { font-weight: 600; }

a {
  color: var(--link);
  text-decoration: none;
  transition: color .15s cubic-bezier(.4, 0, .2, 1);
}
a:hover { color: var(--link-hover); }
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
  border-radius: 2px;
}

/* Long URLs or words never cause sideways scrolling on phones */
.page { overflow-wrap: anywhere; }

/* ==========================================================================
   Layout
   ========================================================================== */
.page {
  position: relative;
  width: 100%;
  max-width: var(--page-width);
  margin: 0 auto;
  padding: 4rem 1.5rem;
}

/* ---------- Theme button ---------- */
.theme-toggle {
  position: absolute;
  top: 1.25rem;
  right: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition: color .15s, border-color .15s;
}
.theme-toggle:hover { color: var(--link-hover); border-color: var(--link-hover); }
/* Light theme shows the moon (switch to dark); dark theme shows the sun. */
.theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* ---------- Header ---------- */
.intro {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: 2rem;
  margin-bottom: 4rem;
}
.intro-photo-wrap { max-width: 220px; }
.intro-photo {
  width: 100%;
  aspect-ratio: 4 / 5;
  border-radius: .75rem;
  object-fit: cover;
  object-position: var(--intro-photo-focus);
}
.intro-name {
  font-size: 1.875rem;
  line-height: 2.25rem;
  font-weight: 400;
  letter-spacing: -.025em;
}
.intro-bio {
  margin-top: 1rem;
  max-width: 48rem;
  font-size: .875rem;
  line-height: 1.75rem;
}
.intro-bio p + p { margin-top: .75rem; }
.intro-links {
  margin-top: 1rem;
  row-gap: .5rem;
  font-size: .875rem;
}

/* "Link / Link / Link" rows */
.links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  column-gap: .75rem;
}
.links .sep { color: var(--text); }

/* ---------- Sections ---------- */
.section { margin-bottom: 3.5rem; }
.section-title {
  margin-bottom: 1.25rem;
  font-size: 1.25rem;
  line-height: 1.75rem;
  font-weight: 500;
  letter-spacing: -.025em;
}

/* ---------- Timeline (news, talks) ---------- */
.timeline-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0 1.25rem;
  font-size: .875rem;
  line-height: 1.5rem;
}
.timeline-item + .timeline-item { margin-top: .75rem; }
.timeline-date { font-weight: 500; }

/* ---------- Plain list (service) ---------- */
.plain-list {
  font-size: .875rem;
  line-height: 1.5rem;
}
.plain-list li + li { margin-top: .25rem; }

/* ---------- Roles (academic service) ---------- */
.roles {
  font-size: .875rem;
  line-height: 1.5rem;
}
.roles-row + .roles-row { margin-top: .5rem; }
.roles-row strong { font-weight: 600; margin-right: .5em; }

/* ---------- Show more ---------- */
.more { margin-top: .75rem; }
.more > summary {
  display: inline-block;
  cursor: pointer;
  list-style: none;
  color: var(--link);
  font-size: .875rem;
  transition: color .15s;
}
.more > summary::-webkit-details-marker { display: none; }
.more > summary:hover { color: var(--link-hover); }
.more > summary::after { content: " ↓"; }
.more[open] > summary::after { content: " ↑"; }
.more .more-open, .more[open] .more-closed { display: none; }
.more[open] .more-open { display: inline; }
.more[open] > summary { margin-bottom: .75rem; }

/* Second "Show less" at the end of the expanded list */
.more-collapse {
  margin-top: .75rem;
  padding: 0;
  border: 0;
  background: none;
  font: inherit;
  font-size: .875rem;
  color: var(--link);
  cursor: pointer;
  transition: color .15s;
}
.more-collapse:hover { color: var(--link-hover); }
.more-collapse::after { content: " ↑"; }

/* ---------- Publications ---------- */
.papers > * + * { margin-top: 1rem; }

.paper-card {
  display: grid;
  grid-template-columns: 1fr;
  align-items: center;
  gap: 1.5rem;
  padding: 1rem;
  border: 1px solid transparent;
  border-radius: .75rem;
  transition: background-color .18s ease, border-color .18s ease, box-shadow .18s ease, transform .18s ease;
}
@media (hover: hover) {
  .paper-card:hover {
    background-color: var(--card-hover-bg);
    border-color: var(--card-hover-border);
    box-shadow: 0 6px 18px var(--card-shadow);
    transform: translateY(-2px) scale(1.01);
  }
}
.paper-media { align-self: center; }
.paper-media--empty { display: none; }   /* no image: hide placeholder on phones */
.paper-zoom {
  display: block;
  width: 100%;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: zoom-in;
}
.paper-img {
  width: 100%;
  aspect-ratio: 5 / 4;
  padding: .5rem;
  border: 1px solid var(--border);
  border-radius: .375rem;
  background: var(--figure-bg);
  object-fit: contain;
}
/* image_wide: true -> figure spans the full card width above the text */
.paper-card--wide .paper-img { aspect-ratio: auto; height: auto; }

.paper-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--placeholder-bg);
  color: var(--muted);
  font-size: .875rem;
  text-align: center;
}
.paper-body {
  display: flex;
  flex-direction: column;
  gap: .125rem;
}
.paper-title {
  font-size: 1.125rem;
  line-height: 1.25;
  font-weight: 500;
}
.paper-meta, .paper-links {
  font-size: .875rem;
  line-height: 1.25;
}
.paper-title + .paper-meta { margin-top: .25rem; }
.paper-meta a { color: inherit; }
.paper-meta a:hover { color: var(--link-hover); }
.paper-links { margin-top: .25rem; }
.paper-desc {
  margin-top: .75rem;
  font-size: .875rem;
  line-height: 1.5rem;
}

/* ---------- Footer ---------- */
.footer {
  display: flex;
  flex-wrap: wrap;
  gap: .25rem .5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .8125rem;
}

/* ---------- Image zoom ---------- */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: rgba(0, 0, 0, .75);
  cursor: zoom-out;
}
.lightbox[hidden] { display: none; }
.lightbox-img {
  max-width: 90vw;
  max-height: 90vh;
  padding: .5rem;
  border-radius: .5rem;
  background: var(--figure-bg);
  object-fit: contain;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, .1), 0 8px 10px -6px rgba(0, 0, 0, .1);
}

/* ==========================================================================
   Tablet & desktop (≥ 640px)
   ========================================================================== */
@media (min-width: 640px) {
  .page { padding: 5rem 2rem; }
  .theme-toggle { top: 1.75rem; right: 2rem; }

  /* Photo column stretches to the full height of the bio and links */
  .intro {
    grid-template-columns: var(--intro-photo-width) minmax(0, 1fr);
    align-items: stretch;
  }
  .intro-photo-wrap {
    position: relative;
    max-width: none;
    min-height: 300px;
  }
  .intro-photo {
    position: absolute;
    inset: 0;
    height: 100%;
    aspect-ratio: auto;
  }
  .intro-name { font-size: 2.25rem; line-height: 2.5rem; }
  .intro-bio { font-size: 1rem; }
  .intro-links { font-size: .95rem; }

  .section-title { font-size: 1.4rem; }

  .timeline-item { grid-template-columns: 6.5rem minmax(0, 1fr); font-size: 1rem; }
  .plain-list, .roles { font-size: 1rem; }
  .more > summary, .more-collapse { font-size: 1rem; }

  .paper-card { grid-template-columns: var(--photo-width) minmax(0, 1fr); }
  .paper-card--wide { grid-template-columns: minmax(0, 1fr); gap: 1rem; }
  .paper-media--empty { display: block; }
  .paper-title { font-size: 1.25rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}