/* =================================================================
   Design tokens
   ================================================================= */

:root {
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, "Cascadia Mono",
    "Courier New", monospace;

  --bg: #F4F5F7;
  --surface: #FFFFFF;
  --surface-raised: #E9EBEE;
  --text: #1A1D22;
  --text-muted: #4A4F58;
  --text-subtle: #5B6270;
  --accent: #47566B;
  --accent-hover: #33415A;
  --accent-contrast: #F4F5F7;
  --accent-soft: #EBEEF3;
  --border: #D6DAE0;
  --border-strong: #B3BAC4;
  --shadow-sm: none;
  --shadow: none;
  --shadow-lg: none;
  --radius: 0;
  --radius-sm: 0;
  --radius-lg: 0;
  --max-width: 1200px;
  --nav-height: 4rem;
}

[data-theme="dark"] {
  --bg: #1A1D23;
  --surface: #232830;
  --surface-raised: #3A414D;
  --text: #E4E8ED;
  --text-muted: #C9CFD8;
  --text-subtle: #A5ACB8;
  --accent: #9FB3CD;
  --accent-hover: #C6D4E6;
  --accent-contrast: #1A1D23;
  --accent-soft: #3A414D;
  --border: #3A414D;
  --border-strong: #4A5261;
}

/* =================================================================
   Base
   ================================================================= */

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 1.1rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

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

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

h1, h2, h3, h4 {
  font-family: var(--font-mono);
  line-height: 1.3;
  margin-top: 0;
  font-weight: 700;
}

p {
  margin: 0 0 1rem;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 1000;
  background: var(--accent);
  color: var(--bg);
  padding: 0.5rem 1rem;
}

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

/* =================================================================
   Navigation
   ================================================================= */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--surface);
  color: var(--text);
  border-bottom: 1px solid var(--border);
  height: var(--nav-height);
}

.nav-container {
  position: relative;
  max-width: none;
  margin: 0 auto;
  padding: 0 1rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.nav-brand,
.theme-toggle {
  position: relative;
  z-index: 2;
}

.nav-brand {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--text);
  font-size: 1rem;
  border-bottom: none;
  white-space: nowrap;
}

.nav-brand:hover {
  color: var(--accent-hover);
  border-bottom: none;
}

.nav-menu {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  transform: translateX(-50%);
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.nav-menu ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: nowrap;
  white-space: nowrap;
}

.nav-menu ul li {
  margin: 0;
  color: var(--text-muted);
  font-size: 1rem;
}

.nav-menu ul li a.nav-link {
  font-family: var(--font-mono);
  color: var(--text-muted);
  font-size: 1rem;
  padding: 0.35rem 0.6rem;
  border-bottom: none;
  transition: background-color 0.15s ease, color 0.15s ease;
  display: inline-block;
}

.nav-menu ul li a.nav-link:hover {
  background-color: var(--accent-hover);
  color: var(--bg);
  border-bottom: none;
}

.nav-menu ul li a.nav-link.active {
  background-color: var(--accent-hover);
  color: var(--bg);
  font-weight: 700;
}

.nav-menu ul li a.nav-link.active:hover {
  color: var(--bg);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 0;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
  padding: 0;
  flex-shrink: 0;
}

.theme-toggle:hover {
  border-color: var(--accent);
  background: var(--surface-raised);
}

.theme-toggle .moon-icon,
[data-theme="dark"] .theme-toggle .sun-icon {
  display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
  display: block;
}

.theme-toggle .sun-icon {
  display: block;
}

/* =================================================================
   Layout
   ================================================================= */

.site-main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  min-width: 0;
}

/* =================================================================
   About section (about page only)
   ================================================================= */

.about-section {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(220px, 280px);
  gap: 2.5rem;
  align-items: start;
  margin-bottom: 3.5rem;
  padding: 2rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.about-bio {
  min-width: 0;
}

.about-bio > *:last-child {
  margin-bottom: 0;
}

.about-hero {
  text-align: center;
}

.hero-avatar {
  width: 140px;
  height: 140px;
  margin: 0 auto 1.25rem;
  border-radius: 50%;
  overflow: hidden;
  border: 1px solid var(--border);
}

.hero-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-name {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.hero-role {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
}

.hero-location {
  color: var(--text-subtle);
  font-size: 0.85rem;
  margin-bottom: 1.25rem;
}

.hero-contact {
  display: flex;
  flex-direction: row;
  gap: 1rem;
  justify-content: center;
}

/* =================================================================
   Sections
   ================================================================= */

.content-section {
  margin-bottom: 3.5rem;
}

.section-header,
.page-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.section-title,
.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 0.4rem;
  display: inline-block;
}

.section-link {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
  border-bottom: 1px solid var(--accent);
  padding-bottom: 0.1rem;
}

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

.empty-state {
  color: var(--text-subtle);
  font-style: italic;
}

.community-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.community-box ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--text-muted);
}

.community-box li {
  margin-bottom: 0.5rem;
}

.community-box li:last-child {
  margin-bottom: 0;
}

/* =================================================================
   Landing page
   ================================================================= */

.landing section {
  margin-bottom: 3.5rem;
}

.landing section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text);
  border-bottom: 2px solid var(--accent);
  padding-bottom: 0.4rem;
  display: inline-block;
}

.landing section p {
  color: var(--text-muted);
}

.landing section ul {
  padding-left: 1.25rem;
  color: var(--text-muted);
}

.landing section li {
  margin-bottom: 0.5rem;
}

/* =================================================================
   Cards
   ================================================================= */

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}

.card-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem;
  transition: border-color 0.15s ease, background-color 0.15s ease, box-shadow 0.15s ease;
}

.card:hover {
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}

.card-body {
  position: relative;
}

.card-title {
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.card-title a {
  position: relative;
  z-index: 2;
  color: var(--text);
  border-bottom: none;
}

.card-title a:hover {
  color: var(--accent-hover);
  border-bottom: none;
}

.card-tagline,
.card-abstract {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 0.75rem;
  line-height: 1.55;
}

.card-authors {
  color: var(--text-subtle);
  font-size: 0.85rem;
  margin-bottom: 0.25rem;
}

.author-highlight {
  text-decoration: underline;
  text-decoration-color: var(--accent);
  text-underline-offset: 2px;
}

.card-venue {
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.75rem;
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 0.75rem;
}

.tag {
  font-family: var(--font-mono);
  display: inline-block;
  padding: 0.15rem 0.55rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  letter-spacing: 0.02em;
  font-weight: 500;
  text-decoration: none;
}

a.tag:hover {
  background: var(--accent);
  color: var(--accent-contrast, var(--bg));
  border-color: var(--accent);
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.4rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-subtle);
}

.card-footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.card-action {
  margin-left: auto;
  font-weight: 500;
  font-size: 0.75rem;
  color: var(--accent);
  border-bottom: none;
  padding: 0.1rem 0.4rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.card-action:hover {
  color: var(--accent-hover);
  border-color: var(--accent);
  border-bottom: 1px solid var(--accent);
}

.card-details {
  font-weight: 500;
  font-size: 0.75rem;
  color: var(--accent);
  white-space: nowrap;
}

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

/* Project card specific */

.project-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 180px;
}

.project-card .card-footer {
  margin-top: auto;
}

/* =================================================================
   Detail pages
   ================================================================= */

.detail-page {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem;
}

.detail-header {
  margin-bottom: 1.5rem;
}

.detail-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.detail-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0;
  line-height: 1.3;
}

.detail-repo-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.detail-repo {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.75rem;
  background: var(--surface-raised);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 500;
  border-bottom: none;
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}

.detail-repo:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--surface);
  border-bottom: none;
}

.detail-meta {
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  font-size: 0.9rem;
}

.detail-authors {
  margin: 0;
  width: 100%;
  font-weight: 500;
  color: var(--text);
}

.detail-venue {
  margin: 0;
}

.detail-year {
  font-family: var(--font-mono);
  display: inline-block;
  background: var(--surface-raised);
  padding: 0.1rem 0.55rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.8rem;
}

.detail-projects {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-left: auto;
}

.related-list {
  list-style: disc;
  padding-left: 1.25rem;
  margin: 0;
}

.related-list li {
  margin-bottom: 0.4rem;
}

.related-list a {
  text-decoration: none;
}

.related-list a:hover {
  text-decoration: underline;
}

.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.detail-resources {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.resource-button {
  display: inline-flex;
  align-items: center;
  padding: 0.55rem 0.95rem;
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 0.85rem;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.resource-button:hover {
  background: var(--accent);
  color: var(--bg);
  border-color: var(--accent);
  border-bottom: 1px solid var(--accent);
}

.detail-section {
  margin-bottom: 2rem;
}

.detail-section h2 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text);
}

.detail-section p {
  color: var(--text-muted);
}

.detail-section .prose {
  color: var(--text-muted);
}

.detail-section .prose p {
  margin-bottom: 1rem;
}

.detail-section .prose ul {
  padding-left: 1.25rem;
  margin-bottom: 1rem;
}

.detail-section .prose li {
  margin-bottom: 0.5rem;
}

.back-link {
  margin-top: 2rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
  font-weight: 500;
}

/* =================================================================
   Code blocks + copy button
   ================================================================= */

.code-block {
  position: relative;
  background: var(--surface-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.code-block pre {
  margin: 0;
  padding: 1.25rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.5;
  color: var(--text);
  background: transparent;
}

.code-block code {
  font-family: var(--font-mono);
}

.copy-button {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.65rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.copy-button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.copy-button.copied {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
}

.copy-button.copied svg {
  stroke: var(--bg);
}

/* =================================================================
   Footer
   ================================================================= */

.site-footer {
  text-align: center;
  padding: 2rem 1rem;
  border-top: 1px solid var(--border);
  color: var(--text-subtle);
  font-size: 0.82rem;
}

.site-footer a {
  color: var(--text-muted);
}

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

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

@media (max-width: 1080px) {
  .site-nav {
    height: auto;
    padding: 0.75rem 0;
  }

  .nav-container {
    flex-wrap: nowrap;
    gap: 0.5rem;
  }

  .nav-menu {
    position: static;
    transform: none;
    flex: 1;
    min-width: 0;
    overflow-x: auto;
    -ms-overflow-style: none;
    scrollbar-width: none;
  }

  .nav-menu::-webkit-scrollbar {
    display: none;
  }

  .nav-menu ul {
    justify-content: flex-start;
    flex-wrap: nowrap;
  }

  .nav-menu ul li a.nav-link {
    padding: 0.35rem 0.5rem;
    font-size: 0.95rem;
  }
}

@media (max-width: 900px) {
  .site-main {
    padding: 1.5rem 1rem;
  }

  .about-section {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 1.5rem;
  }

  .hero-name {
    font-size: 1.6rem;
  }

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

  .detail-page {
    padding: 1.25rem;
  }
}

@media (max-width: 480px) {
  .hero-avatar {
    width: 120px;
    height: 120px;
  }

  .hero-name {
    font-size: 1.4rem;
  }

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