/* ==========================================================================
   Design System — flomue.com
   Modern light-mode academic portfolio
   ========================================================================== */

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Colors */
  --color-bg: #fafbff;
  --color-bg-alt: #f0f2f9;
  --color-surface: #ffffff;
  --color-text: #1a1d2e;
  --color-text-secondary: #5a5f7a;
  --color-text-muted: #8a8fa8;
  --color-accent: #6366f1;
  --color-accent-light: #818cf8;
  --color-accent-dark: #4f46e5;
  --color-accent-bg: rgba(99, 102, 241, 0.08);
  --color-border: #e2e5f1;
  --color-border-light: #eef0f7;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.75rem;
  --font-size-5xl: 3.5rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(26, 29, 46, 0.04);
  --shadow-md: 0 4px 12px rgba(26, 29, 46, 0.06);
  --shadow-lg: 0 8px 30px rgba(26, 29, 46, 0.08);
  --shadow-xl: 0 16px 48px rgba(26, 29, 46, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --content-width: 900px;
  --content-width-wide: 1100px;
  --header-height: 72px;
}

/* ---------- Reset & Base ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
  padding-top: var(--header-height);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

h1,
h2,
h3,
h4 {
  line-height: 1.3;
  font-weight: 700;
  letter-spacing: -0.02em;
}

h1 {
  font-size: var(--font-size-4xl);
}

h2 {
  font-size: var(--font-size-2xl);
}

h3 {
  font-size: var(--font-size-xl);
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  z-index: 1000;
  background: rgba(250, 251, 255, 0.75);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-base);
}

.site-header.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: var(--content-width-wide);
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
  transition: color var(--transition-fast);
}

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

.nav-right {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}


.nav-links {
  list-style: none;
  display: flex;
  gap: var(--space-8);
  margin-right: auto;
  margin-left: var(--space-8);
}

.nav-link {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  position: relative;
  padding: var(--space-2) 0;
  letter-spacing: 0.01em;
  text-transform: lowercase;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  border-radius: 1px;
  transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-accent);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
  transition: all var(--transition-base);
}

/* ---------- Hero Section ---------- */
.hero {
  padding: var(--space-24) 0 var(--space-16);
  max-width: var(--content-width);
  margin: 0 auto;
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

.hero-inner {
  display: flex;
  align-items: flex-start;
  gap: var(--space-16);
}

.hero-content {
  flex: 1;
}

.hero-image-wrapper {
  flex-shrink: 0;
}

.hero-image {
  width: 220px;
  height: 220px;
  border-radius: var(--radius-full);
  object-fit: cover;
  border: 4px solid var(--color-surface);
  box-shadow: var(--shadow-lg), 0 0 0 1px var(--color-border-light);
  transition: transform var(--transition-slow), box-shadow var(--transition-slow);
}

.hero-image:hover {
  transform: scale(1.03);
  box-shadow: var(--shadow-xl), 0 0 0 1px var(--color-accent-bg);
}

.hero-name {
  font-size: var(--font-size-5xl);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--space-4);
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: var(--space-8);
  display: flex;
  flex-wrap: nowrap;
  gap: var(--space-3);
  white-space: nowrap;
}

.hero-subtitle span {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.hero-subtitle span::before {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: var(--radius-full);
  background: var(--color-accent-light);
}

.hero-subtitle span:first-child::before {
  display: none;
}

.hero-bio {
  font-size: var(--font-size-lg);
  line-height: 1.8;
  color: var(--color-text-secondary);
  max-width: 620px;
}

.hero-bio a {
  font-weight: 600;
}

/* Research keyword badges */
.keyword-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-8);
}

.keyword-badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-2) var(--space-4);
  background: var(--color-accent-bg);
  color: var(--color-accent-dark);
  font-size: var(--font-size-sm);
  font-weight: 500;
  border-radius: var(--radius-full);
  border: 1px solid rgba(99, 102, 241, 0.12);
  transition: all var(--transition-fast);
}

.keyword-badge:hover {
  background: rgba(99, 102, 241, 0.14);
  transform: translateY(-1px);
}

/* ---------- Research Focus Cards ---------- */
.research-focus {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-3);
  margin-top: var(--space-10);
}

.research-card {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
}

.research-card-icon {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--color-accent-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
}

.research-card-icon svg {
  width: 16px;
  height: 16px;
}

.research-card-body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.research-card-title {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.research-card-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  line-height: 1.45;
}

/* ---------- Affiliation Logos ---------- */
.affiliation-logos {
  margin-top: var(--space-8);
  display: flex;
  align-items: center;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.affiliation-logos-label {
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.affiliation-logos-row {
  display: flex;
  align-items: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}

.affiliation-logo-link {
  display: inline-flex;
  align-items: center;
  opacity: 0.7;
  transition: opacity var(--transition-fast), transform var(--transition-fast), filter var(--transition-fast);
  filter: grayscale(20%);
}

.affiliation-logo-link:hover {
  opacity: 1;
  transform: translateY(-2px);
  filter: grayscale(0%);
}

.affiliation-logo {
  height: 36px;
  width: auto;
  max-width: 180px;
  object-fit: contain;
  display: block;
}

/* ---------- Sections ---------- */
.section {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: var(--space-16) var(--space-6);
}

.section-wide {
  max-width: var(--content-width-wide);
}

.section-header {
  margin-bottom: var(--space-10);
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--color-text);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 48px;
  height: 3px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  border-radius: 2px;
}

.section-description {
  margin-top: var(--space-4);
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
}

/* ---------- Publication Cards ---------- */
.pub-year-group {
  margin-bottom: var(--space-12);
}

.pub-year-label {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-accent-light);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-border-light);
  position: sticky;
  top: var(--header-height);
  background: var(--color-bg);
  z-index: 10;
  padding-top: var(--space-4);
}

.pub-card {
  display: flex;
  gap: var(--space-6);
  padding: var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
  transition: all var(--transition-base);
  position: relative;
}

.pub-card:hover {
  border-color: var(--color-border);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.pub-card-image {
  flex-shrink: 0;
  width: 100px;
  height: 100px;
  border-radius: var(--radius-md);
  object-fit: cover;
  background: var(--color-bg-alt);
}

.pub-card-content {
  flex: 1;
  min-width: 0;
}

.pub-card-title {
  font-size: var(--font-size-base);
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: var(--space-2);
  color: var(--color-text);
}

.pub-card-link-overlay {
  color: inherit;
  text-decoration: none;
}

.pub-card-link-overlay::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1;
}

.pub-card-link-overlay:hover {
  color: var(--color-accent);
}

.pub-card-title a {
  color: inherit;
}

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

.pub-card-authors {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
  line-height: 1.5;
}

.pub-card-authors .highlight-author {
  font-weight: 600;
  color: var(--color-text);
}

.pub-card-venue {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  font-style: italic;
  margin-bottom: var(--space-3);
}

.venue-short-badge {
  display: inline-block;
  background: var(--color-accent-bg);
  color: var(--color-accent-dark);
  padding: 1px var(--space-2);
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: var(--font-size-xs);
  font-style: normal;
  vertical-align: middle;
  margin-right: var(--space-1);
  letter-spacing: 0.02em;
}

.pub-card-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  position: relative;
  z-index: 2;
}

.pub-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  background: var(--color-surface);
  transition: all var(--transition-fast);
}

.pub-link:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-bg);
}

.pub-link svg {
  width: 12px;
  height: 12px;
}

/* Publication search / filter */
.pub-search-wrapper {
  margin-bottom: var(--space-8);
  position: relative;
}

.pub-search {
  width: 100%;
  padding: var(--space-4) var(--space-6);
  padding-left: var(--space-12);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  color: var(--color-text);
  transition: all var(--transition-fast);
  outline: none;
}

.pub-search:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-bg);
}

.pub-search-icon {
  position: absolute;
  left: var(--space-5);
  top: 26px;
  /* align with input center, input padding-top + border + font/2 approx */
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: var(--color-text-muted);
  pointer-events: none;
}

.pub-count {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
  margin-left: var(--space-2);
  display: block;
}

/* ---------- Latest Publications (Homepage) ---------- */
.latest-pubs {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--space-6) var(--space-16);
}

.latest-pubs-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: var(--space-8);
}

.view-all-link {
  font-size: var(--font-size-sm);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.view-all-link::after {
  content: '→';
  transition: transform var(--transition-fast);
}

.view-all-link:hover::after {
  transform: translateX(4px);
}

/* ---------- Teaching Page ---------- */
.teaching-semester {
  margin-bottom: var(--space-12);
}

.teaching-semester-label {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--color-border-light);
}

.course-card {
  padding: var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
  transition: all var(--transition-base);
}

.course-card:hover {
  border-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.course-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.course-meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}

.course-description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ---------- Single Publication Page ---------- */
.pub-single {
  max-width: var(--content-width-wide);
  margin: 0 auto;
  padding: var(--space-8) var(--space-6) var(--space-16);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.back-link:hover {
  color: var(--color-accent);
  border-color: var(--color-border);
  box-shadow: var(--shadow-md);
  transform: translateX(-2px);
}

.back-link svg {
  width: 16px;
  height: 16px;
}

.pub-single-header {
  margin-bottom: var(--space-8);
  border-bottom: 2px solid var(--color-border-light);
  padding-bottom: var(--space-6);
}

.pub-single-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: var(--space-4);
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.pub-single-authors {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
  line-height: 1.6;
}

.pub-single-authors .highlight-author {
  font-weight: 700;
  color: var(--color-text);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.pub-single-venue {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--font-size-base);
}

.venue-badge {
  background: var(--color-accent-bg);
  color: var(--color-accent-dark);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: var(--font-size-sm);
}

.venue-year {
  color: var(--color-text-muted);
  font-weight: 500;
}

.pub-single-venue-full {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-2);
}

.pub-single-grid {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: var(--space-10);
  align-items: start;
}

@media (max-width: 900px) {
  .pub-single-grid {
    grid-template-columns: 1fr;
    grid-template-areas:
      "sidebar"
      "main";
  }

  .pub-single-main {
    grid-area: main;
  }

  .pub-single-sidebar {
    grid-area: sidebar;
    margin-bottom: var(--space-8);
  }
}

.pub-single-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-10);
}

.pub-action-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-sm);
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.pub-action-btn svg {
  width: 18px;
  height: 18px;
}

.pub-action-btn.primary {
  background: var(--color-accent);
  color: white;
  border: 1px solid var(--color-accent);
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.3);
}

.pub-action-btn.primary:hover {
  background: var(--color-accent-dark);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
  transform: translateY(-1px);
}

.pub-action-btn.secondary {
  background: var(--color-surface);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.pub-action-btn.secondary:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-bg);
  transform: translateY(-1px);
}

.pub-single-abstract {
  margin-bottom: var(--space-12);
  background: var(--color-surface);
  padding: var(--space-8);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-sm);
}

.pub-single-abstract h2 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-4);
  color: var(--color-text);
}

.pub-single-abstract p {
  color: var(--color-text-secondary);
  line-height: 1.8;
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-4);
}

.pub-single-abstract p:last-child {
  margin-bottom: 0;
}

.pub-single-sidebar {
  position: sticky;
  top: calc(var(--header-height) + var(--space-8));
}

.pub-single-thumbnail-wrapper {
  border-radius: var(--radius-md);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  border: 6px solid var(--color-surface);
  background: var(--color-surface);
  margin-bottom: var(--space-8);
  transform: rotate(2deg) translateY(0);
  transition: all var(--transition-base);
  max-width: 240px;
}

.pub-single-thumbnail-wrapper:hover {
  transform: rotate(0deg) translateY(-4px);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.15);
  z-index: 10;
}

.pub-single-thumbnail {
  width: 100%;
  max-height: 280px;
  border-radius: 2px;
  object-fit: cover;
  display: block;
}

.sidebar-heading {
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
  font-weight: 700;
}

.keyword-badges.small .keyword-badge {
  font-size: var(--font-size-xs);
  padding: var(--space-1) var(--space-3);
}

.pub-single-videos {
  margin-top: var(--space-10);
}

.video-wrapper {
  margin-bottom: var(--space-10);
  background: #000;
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.video-wrapper h3 {
  font-size: var(--font-size-lg);
  color: white;
  padding: var(--space-4) var(--space-6);
  margin: 0;
  background: rgba(0, 0, 0, 0.8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.video-container {
  position: relative;
  padding-bottom: 56.25%;
  /* 16:9 ratio */
  height: 0;
  overflow: hidden;
  background: var(--color-bg-alt);
}

.gdpr-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-6);
  z-index: 2;
  border-bottom: 2px solid var(--color-border-light);
}

.gdpr-content {
  max-width: 480px;
}

.gdpr-content .play-icon {
  width: 48px;
  height: 48px;
  color: var(--color-accent);
  margin-bottom: var(--space-4);
  opacity: 0.8;
}

.gdpr-content p {
  font-size: var(--font-size-base);
  color: var(--color-text);
  margin-bottom: var(--space-4);
  line-height: 1.5;
}

.gdpr-content .gdpr-details {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.gdpr-content a {
  color: var(--color-accent);
  text-decoration: underline;
}

.btn-play-video {
  background: var(--color-accent);
  color: white;
  border: none;
  padding: var(--space-2) var(--space-6);
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-top: var(--space-2);
}

.btn-play-video:hover {
  background: var(--color-accent-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* ---------- Imprint ---------- */
.imprint-content {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: var(--space-16) var(--space-6);
}

.imprint-content h1 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-8);
}

.imprint-content h2 {
  font-size: var(--font-size-xl);
  margin-top: var(--space-10);
  margin-bottom: var(--space-4);
}

.imprint-content h3 {
  font-size: var(--font-size-lg);
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
}

.imprint-content p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
}

.imprint-content ul {
  color: var(--color-text-secondary);
  margin-left: var(--space-6);
  margin-bottom: var(--space-4);
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-10) 0;
  margin-top: auto;
}

.footer-container {
  max-width: var(--content-width-wide);
  margin: 0 auto;
  padding: 0 var(--space-6);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer-links {
  display: flex;
  gap: var(--space-5);
}

.footer-links a {
  color: var(--color-text-muted);
  transition: color var(--transition-fast), transform var(--transition-fast);
  display: inline-flex;
}

.footer-links a:hover {
  color: var(--color-accent);
  transform: translateY(-2px);
}

.footer-meta {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.footer-imprint {
  color: var(--color-text-muted);
  font-weight: 500;
}

.footer-logos {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.footer-logo {
  height: 28px;
  width: auto;
  max-width: 140px;
  object-fit: contain;
  display: block;
  opacity: 0.55;
  filter: grayscale(30%);
  transition: opacity var(--transition-fast), filter var(--transition-fast), transform var(--transition-fast);
}

.footer-logos .affiliation-logo-link:hover .footer-logo {
  opacity: 0.9;
  filter: grayscale(0%);
  transform: translateY(-2px);
}

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

/* ---------- Animations ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.stagger>* {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 400ms ease, transform 400ms ease;
}

.stagger>*.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2.5rem;
    --font-size-4xl: 2rem;
    --font-size-3xl: 1.5rem;
    --header-height: 64px;
  }

  .hero-inner {
    flex-direction: column-reverse;
    align-items: center;
    gap: var(--space-8);
    text-align: center;
  }

  .hero-image {
    width: 160px;
    height: 160px;
  }

  .hero-subtitle {
    justify-content: center;
    flex-wrap: wrap;
    white-space: normal;
  }

  .hero-bio {
    max-width: 100%;
  }

  .research-focus {
    grid-template-columns: repeat(2, 1fr);
    margin-top: var(--space-8);
  }

  .affiliation-logos {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-4);
  }

  .keyword-badges {
    justify-content: center;
  }

  .pub-card {
    flex-direction: column;
  }

  .pub-card-image {
    width: 100%;
    height: 160px;
  }

  /* Mobile nav */
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--header-height);
    right: 0;
    width: 260px;
    height: calc(100vh - var(--header-height));
    flex-direction: column;
    background: rgba(250, 251, 255, 0.97);
    backdrop-filter: blur(20px);
    padding: var(--space-8) var(--space-6);
    gap: var(--space-4);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    border-left: 1px solid var(--color-border-light);
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .nav-link {
    font-size: var(--font-size-base);
    padding: var(--space-3) 0;
  }

  .latest-pubs-header {
    flex-direction: column;
    gap: var(--space-3);
  }

  .footer-container {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  :root {
    --font-size-5xl: 2rem;
    --font-size-4xl: 1.75rem;
  }

  .hero {
    padding-top: var(--space-16);
  }

  .hero-image {
    width: 130px;
    height: 130px;
  }

  .research-focus {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }

  .research-card {
    padding: var(--space-3);
  }
}

/* ---------- Utility ---------- */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}
/* ---------- BibTeX Modal ---------- */
.bibtex-modal {
  position: fixed;
  inset: 0;
  z-index: 1001;
  display: flex;
  align-items: center;
  justify-content: center;
}

.bibtex-modal[hidden] { display: none; }

.bibtex-modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(4px);
}

.bibtex-modal-box {
  position: relative;
  z-index: 1;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2);
  width: min(640px, 92vw);
  max-height: 80vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.bibtex-modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}

.bibtex-modal-title {
  font-weight: 600;
  font-size: var(--font-size-base);
  color: var(--color-text);
}

.bibtex-modal-close {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  line-height: 1;
  color: var(--color-text-muted);
  padding: 0 var(--space-1);
  transition: color var(--transition-fast);
}

.bibtex-modal-close:hover { color: var(--color-text); }

.bibtex-modal-code {
  flex: 1;
  overflow: auto;
  padding: var(--space-5) var(--space-6);
  margin: 0;
  font-family: 'Courier New', Courier, monospace;
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg-alt);
  white-space: pre;
  border-radius: 0;
}

.bibtex-modal-footer {
  padding: var(--space-3) var(--space-6);
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: flex-end;
  flex-shrink: 0;
}

.bibtex-copy-btn {
  background: var(--color-accent);
  color: white;
  border: none;
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--font-size-sm);
  font-weight: 600;
  font-family: inherit;
  transition: background var(--transition-fast);
}

.bibtex-copy-btn:hover { background: var(--color-accent-dark); }
.bibtex-copy-btn.copied { background: #16a34a; }

/* button reset for pub-link and pub-action-btn used as <button> */
button.pub-link,
button.pub-action-btn {
  cursor: pointer;
  font-family: inherit;
  text-decoration: none;
}

/* ---------- Research Pillar Cards (home page) ---------- */
.research-pillars {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--space-6) var(--space-12);
}
.pillar-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}
.pillar-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-6) var(--space-5);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-top: 3px solid transparent;
  border-radius: var(--radius-xl);
  text-decoration: none;
  color: inherit;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}
.pillar-card:hover { transform: translateY(-4px); color: inherit; }
.pillar-card-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: var(--space-1);
}
.pillar-card-icon svg { width: 22px; height: 22px; }
.pillar-card-title {
  font-size: var(--font-size-base);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.3;
  min-height: 2.6em;
}
.pillar-card-desc { font-size: var(--font-size-xs); color: var(--color-text-secondary); line-height: 1.55; flex: 1; }
.pillar-card-cta { font-size: var(--font-size-xs); font-weight: 600; margin-top: var(--space-1); }

.pillar-card--indigo { border-top-color: var(--color-accent); }
.pillar-card--indigo .pillar-card-icon { background: var(--color-accent-bg); color: var(--color-accent); }
.pillar-card--indigo .pillar-card-cta { color: var(--color-accent); }
.pillar-card--indigo:hover { box-shadow: var(--shadow-lg), 0 0 0 1px rgba(99,102,241,0.15); }

.pillar-card--sky { border-top-color: #0ea5e9; }
.pillar-card--sky .pillar-card-icon { background: rgba(14,165,233,0.1); color: #0ea5e9; }
.pillar-card--sky .pillar-card-cta { color: #0284c7; }
.pillar-card--sky:hover { box-shadow: var(--shadow-lg), 0 0 0 1px rgba(14,165,233,0.15); }

.pillar-card--orange { border-top-color: #f97316; }
.pillar-card--orange .pillar-card-icon { background: rgba(249,115,22,0.1); color: #f97316; }
.pillar-card--orange .pillar-card-cta { color: #ea6c0a; }
.pillar-card--orange:hover { box-shadow: var(--shadow-lg), 0 0 0 1px rgba(249,115,22,0.15); }

.pillar-card--violet { border-top-color: #a855f7; }
.pillar-card--violet .pillar-card-icon { background: rgba(168,85,247,0.1); color: #a855f7; }
.pillar-card--violet .pillar-card-cta { color: #9333ea; }
.pillar-card--violet:hover { box-shadow: var(--shadow-lg), 0 0 0 1px rgba(168,85,247,0.15); }

/* ---------- Pillar filter buttons (publications page) ---------- */
.pillar-filters {
  display: flex; gap: var(--space-2); flex-wrap: wrap;
  margin-top: var(--space-4); margin-bottom: var(--space-6);
}
.pillar-filter-btn {
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm); font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.pillar-filter-btn:hover { border-color: var(--color-text); color: var(--color-text); }
.pillar-filter-btn--all.active { background: var(--color-text); color: var(--color-surface); border-color: var(--color-text); }
.pillar-filter-btn--indigo.active { background: var(--color-accent); color: #fff; border-color: var(--color-accent); }
.pillar-filter-btn--sky.active { background: #0ea5e9; color: #fff; border-color: #0ea5e9; }
.pillar-filter-btn--orange.active { background: #f97316; color: #fff; border-color: #f97316; }
.pillar-filter-btn--violet.active { background: #a855f7; color: #fff; border-color: #a855f7; }

@media (max-width: 768px) {
  .pillar-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 480px) {
  .pillar-grid { grid-template-columns: 1fr; }
}