/* ==========================================================================
   Site theme — adapted from the layout of babakint.github.io
   (originally derived from github.com/Maeevee/MyPortfolio, MIT licence).
   Single stylesheet; no icon fonts, no external CSS beyond the Inter webfont.
   ========================================================================== */

:root {
  /* --- Raw palette: neutral greys --- */
  --grey-900: #1c1f23;  /* near-black — headings, dark surfaces */
  --grey-800: #2f343a;  /* charcoal — nav bar */
  --grey-600: #4a5158;  /* slate — links and accents */
  --grey-500: #6b727a;  /* muted body text */
  --grey-300: #d4d8dc;  /* borders and dividers */
  --grey-100: #f4f5f6;  /* page background */

  /* --- Semantic roles --- */
  --bg-page:          var(--grey-100);
  --bg-card:          #ffffff;
  --text-body:        #33383e;
  --text-muted:       var(--grey-500);
  --color-link:       var(--grey-600);
  --color-link-hover: var(--grey-900);
  --color-accent:     var(--grey-600);
  --color-border:     var(--grey-300);
  --color-navbar:     var(--grey-800);
  --color-heading:    var(--grey-900);

  /* --- Typography --- */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-body: 17px;
  --font-weight-body: 300;

  /* --- Layout --- */
  --content-max: 1060px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-page);
  color: var(--text-body);
  font-family: var(--font-body);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  transition: background-color 0.3s, color 0.3s;
}

p, li {
  font-size: var(--font-size-body);
  line-height: 1.7;
}

/* Inline links sit at body weight and are marked with an underline rather
   than bold. Navigation, pills, buttons, and card links opt out below. */
a {
  color: var(--color-link);
  font-weight: inherit;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

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

h1 { font-size: 22px; }
h2 { font-size: 42px; color: var(--color-heading); }
h3 { font-size: 26px; }
h4 { font-size: 18px; margin-bottom: 5px; }

/* ==========================================================================
   Header / navigation
   ========================================================================== */

header {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  padding: 10px 24px;
  min-height: 64px;
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  background-color: var(--color-navbar);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

header .site-id h1 {
  font-size: 18px;
  font-weight: 600;
  display: inline;
}

header .site-id h1 a {
  color: #ffffff;
  font-weight: 600;
  text-decoration: none;
}

header .site-id h1 a:hover {
  color: #ffffff;
  text-decoration: none;
  opacity: 0.85;
}

nav {
  display: flex;
  gap: 6px;
  align-items: center;
}

nav a {
  padding: 6px 20px;
  color: rgba(255, 255, 255, 0.85);
  font-size: 17px;
  font-weight: 500;
  border-radius: 4px;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

nav a:hover {
  color: #ffffff;
  background-color: rgba(255, 255, 255, 0.1);
  text-decoration: none;
}

nav a.active {
  font-weight: 600;
  color: #ffffff;
  background-color: rgba(255, 255, 255, 0.14);
}

/* ==========================================================================
   Main
   ========================================================================== */

/* `main` is the single width constraint; the blocks inside it just fill it.
   Using max-width rather than a percentage plus min-width keeps narrow
   desktop widths from overflowing horizontally. */
main {
  width: 100%;
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 48px 24px 50px;
}

.heading,
.section,
.page-title,
.projects-container,
.pub-group,
.prose {
  width: 100%;
  margin-left: auto;
  margin-right: auto;
}

/* --- Bio block --- */

.heading {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--color-border);
}

.photo {
  width: 220px;
  height: 220px;
  min-width: 220px;
  min-height: 220px;
  border-radius: 50%;
  background-position: center;
  background-size: cover;
  flex-shrink: 0;
}

.bio {
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: 100%;
}

.bio h2 {
  font-size: 40px;
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 4px;
}

.bio p {
  margin: 0;
}

.interests {
  font-size: 15px;
  color: var(--text-muted);
}

/* --- Text link row (no icons) --- */

.link-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 4px;
}

.link-row a {
  display: inline-block;
  padding: 7px 16px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-accent);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: transparent;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.link-row a:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: #ffffff;
  text-decoration: none;
}

/* The CV gets a filled treatment so it reads as the primary action. */
.link-row a.primary {
  background: var(--grey-800);
  border-color: var(--grey-800);
  color: #ffffff;
  position: relative;
  overflow: hidden;
  letter-spacing: 0.3px;
}

.link-row a.primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(120deg, transparent 0%, rgba(255, 255, 255, 0.25) 50%, transparent 100%);
  transition: left 0.5s ease;
}

.link-row a.primary:hover::before { left: 120%; }
.link-row a.primary:hover { filter: brightness(1.1); }

/* --- Generic section --- */

.section {
  padding-top: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--color-border);
}

.section:last-of-type { border-bottom: none; }

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 20px;
}

.section-header h3 {
  font-size: 26px;
  font-weight: 600;
  color: var(--color-heading);
}

.section-link {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-accent);
  white-space: nowrap;
  text-decoration: none;
}

/* --- News / updates list --- */

.updates ul {
  list-style-position: outside;
  padding-left: 22px;
  margin: 0;
}

.updates li {
  margin-bottom: 10px;
  line-height: 1.5;
}

.updates .date {
  font-variant-numeric: tabular-nums;
  color: var(--text-muted);
}

.hidden { display: none; }

.toggle-btn {
  background: none;
  border: none;
  color: var(--color-accent);
  cursor: pointer;
  padding: 8px 0 0;
  font-family: inherit;
  font-size: 1em;
  text-decoration: underline;
}

.toggle-btn:hover { color: var(--color-link-hover); }

/* ==========================================================================
   Research strip (home) — horizontally scrollable cards
   ========================================================================== */

.research-strip-scroll {
  display: flex;
  gap: 20px;
  overflow-x: auto;
  padding-bottom: 12px;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}

.research-strip-scroll::-webkit-scrollbar { height: 4px; }
.research-strip-scroll::-webkit-scrollbar-track { background: transparent; }
.research-strip-scroll::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 9999px;
}

.research-strip-card {
  flex: 0 0 260px;
  scroll-snap-align: start;
  background: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.research-strip-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.research-strip-card img {
  width: 100%;
  height: 150px;
  object-fit: cover;
  object-position: top;
  display: block;
  background: #e8ecef;
}

.research-strip-card-body {
  padding: 14px 16px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
}

.research-strip-venue {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
}

.research-strip-card-body h4 {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-heading);
  margin: 0;
  line-height: 1.3;
}

.research-strip-card-body p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
  margin: 0;
  flex: 1;
}

.research-strip-paper-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-accent);
  margin-top: 4px;
  text-decoration: none;
}

/* ==========================================================================
   Projects page — cards (no tags)
   ========================================================================== */

.page-title {
  margin: 0 auto 32px;
}

.page-title h2 {
  font-size: 34px;
  font-weight: 700;
}

.page-title p {
  margin-top: 10px;
  color: var(--text-muted);
}

.projects-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.12);
}

.project-image img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  display: block;
  background: #e8ecef;
}

.project-content {
  padding: 1.1rem 1.2rem 1.3rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  flex: 1;
}

.project-content h3 {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-heading);
  line-height: 1.3;
  margin: 0;
}

.project-content p {
  font-size: 15px;
  color: var(--text-muted);
  margin: 0;
  flex: 1;
}

.project-links {
  display: flex;
  gap: 0.8rem;
  margin-top: 0.2rem;
}

.project-links a {
  padding: 0.45rem 1rem;
  border-radius: 4px;
  background: var(--color-accent);
  color: #ffffff;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: opacity 0.3s ease;
}

.project-links a:hover {
  opacity: 0.85;
  text-decoration: none;
  color: #ffffff;
}

/* ==========================================================================
   Publications
   ========================================================================== */

.pub-group {
  margin: 0 auto 40px;
}

.pub-group > h3 {
  font-size: 24px;
  font-weight: 600;
  color: var(--color-heading);
  padding-bottom: 8px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--color-border);
}

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

.pub-item {
  display: grid;
  grid-template-columns: 76px 1fr;
  gap: 18px;
  padding: 14px 0;
  border-bottom: 1px solid rgba(176, 180, 191, 0.35);
}

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

.pub-year {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
  padding-top: 2px;
}

.pub-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-heading);
  line-height: 1.4;
  display: block;
  text-decoration: none;
}

a.pub-title:hover { text-decoration: underline; color: var(--color-accent); }

.pub-venue {
  font-size: 14px;
  color: var(--text-muted);
  font-style: italic;
  margin-top: 3px;
}

.pub-excerpt {
  font-size: 14px;
  color: var(--text-muted);
  margin-top: 5px;
}

/* ==========================================================================
   Prose (CV, publication detail pages, and other markdown content)
   ========================================================================== */

.prose {
  margin: 0 auto;
}

.prose h1 { font-size: 32px; display: block; }
.prose h2 { font-size: 26px; margin: 28px 0 12px; }
.prose h3 { font-size: 20px; margin: 22px 0 10px; }
.prose p, .prose li { margin-bottom: 10px; }
.prose ul, .prose ol { padding-left: 24px; margin-bottom: 14px; }
.prose img { max-width: 100%; height: auto; }
.prose hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 28px 0;
}
.prose .center { display: block; margin: 16px auto; }

/* Images side by side, stacking on narrow screens. */
.figure-row {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 20px;
  margin: 24px 0;
}

.figure-row img {
  flex: 1 1 280px;
  min-width: 0;
  width: 100%;
  height: auto;
  display: block;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: #ffffff;
}

/* ==========================================================================
   Footer + theme toggle
   ========================================================================== */

.footer {
  text-align: center;
  padding: 1rem;
  color: var(--text-muted);
}

.footer p, .footer a { font-size: 11px; margin: 0; }

#theme-toggle {
  position: fixed;
  bottom: 20px;
  right: 20px;
  padding: 10px 16px;
  background-color: #000000;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  z-index: 200;
}

#theme-toggle:hover {
  background-color: var(--grey-600);
  opacity: 0.85;
}

/* ==========================================================================
   Dark mode
   ========================================================================== */

body.dark-mode {
  --bg-page:          #16191c;
  --bg-card:          #21262b;
  --text-body:        #e3e6e8;
  --text-muted:       #a2a9b0;
  --color-link:       #b8c0c8;
  --color-link-hover: #ffffff;
  --color-accent:     #b8c0c8;
  --color-border:     rgba(255, 255, 255, 0.16);
  --color-heading:    #eceef0;
  --color-navbar:     #21262b;
}

body.dark-mode .link-row a:hover,
body.dark-mode .project-links a {
  color: #16191c;
}

body.dark-mode .link-row a.primary,
body.dark-mode .link-row a.primary:hover {
  background: #e3e6e8;
  border-color: #e3e6e8;
  color: #16191c;
}

body.dark-mode #theme-toggle {
  background-color: #3a4148;
}

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (max-width: 1180px) {
  .projects-container { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  main { padding: 36px 20px 40px; }

  .heading {
    flex-direction: column;
    align-items: center;
    gap: 28px;
  }

  .bio h2 { font-size: 32px; }
}

@media (max-width: 768px) {
  .projects-container { grid-template-columns: 1fr; }

  .photo {
    width: 200px;
    height: 200px;
    min-width: 200px;
    min-height: 200px;
  }

  .pub-item {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .research-strip-card { flex: 0 0 220px; }

  .section-header { flex-direction: column; align-items: flex-start; gap: 6px; }
}

@media (max-width: 560px) {
  header {
    flex-direction: column;
    align-items: flex-start;
    padding: 12px 16px;
    gap: 8px;
  }

  header .site-id h1 { font-size: 15px; display: block; }

  nav { flex-wrap: wrap; gap: 4px; width: 100%; }
  nav a { font-size: 14px; padding: 4px 10px; }

  .bio h2 { font-size: 28px; }

  .photo {
    width: 170px;
    height: 170px;
    min-width: 170px;
    min-height: 170px;
  }
}