/* ==========================================================================
   DBDBD 2026 - Dutch-Belgian DataBase Day
   Official Stylesheet matching DBDBD 2025 (University of Antwerp) aesthetic,
   tailored for Delft University of Technology (TU Delft / Delft Data).
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Roboto+Slab:wght@400;500;600;700;800&family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  /* Brand Colors */
  --tudelft-cyan: #00A6D6;
  --tudelft-navy: #0C2340;
  --theme-dark: #293241;
  --theme-slate: #475671;
  --theme-red: #e72939;
  --theme-bg-soft: #fbfbfc;
  --theme-bg-subtle: #f3f4f7;
  --theme-border: #e2e8f0;
  --theme-text: #2d3748;
  --theme-text-muted: #64748b;
  --theme-white: #ffffff;

  /* Callout / Alert Theme (Matching 2025 notice card) */
  --notice-bg: #f7f3ff;
  --notice-border: #c7b7ff;
  --notice-text: #463f5f;
  --notice-accent: #7b5ce6;
  --notice-shadow: rgba(90, 70, 160, 0.08);

  /* Typography */
  --font-serif: 'Roboto Slab', Georgia, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* Layout */
  --container-max-width: 1140px;
  --header-height: 86px;
  --border-radius-sm: 6px;
  --border-radius-md: 10px;
  --border-radius-lg: 14px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 28px rgba(12, 35, 64, 0.09);
  --transition: all 0.22s ease-in-out;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  color: var(--theme-text);
  background-color: #f7f5f0; /* Warm Dutch linen canvas tone */
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  position: relative;
}

a {
  color: var(--tudelft-cyan);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: #00779b;
  text-decoration: underline;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  color: var(--theme-dark);
  font-weight: 700;
  line-height: 1.35;
}

h1 {
  font-size: clamp(1.85rem, 3.2vw, 2.45rem);
  margin-bottom: 0.6rem;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.35rem, 2.2vw, 1.75rem);
  margin-bottom: 0.8rem;
}

h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1.15rem;
  color: #334155;
  font-size: 1.025rem;
}

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

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* ==========================================================================
   Header & Navigation (Blocksy style)
   ========================================================================== */

.site-header {
  background-color: var(--theme-white);
  border-bottom: 1px solid #eef2f6;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.site-branding {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  text-decoration: none;
}

.site-branding:hover {
  text-decoration: none;
}

.site-logo {
  width: 58px;
  height: 58px;
  object-fit: contain;
  border-radius: 50%;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
}

.brand-title-wrap {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--tudelft-navy);
  letter-spacing: -0.01em;
  line-height: 1.15;
}

.brand-subtitle {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--tudelft-cyan);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* Desktop Navigation */
.nav-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 0.5rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 0.95rem;
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--theme-dark);
  text-decoration: none;
  border-radius: var(--border-radius-sm);
  transition: var(--transition);
}

.nav-link:hover {
  color: var(--tudelft-cyan);
  background-color: #f0f8fc;
  text-decoration: none;
}

.nav-link.active {
  color: var(--tudelft-cyan);
  background-color: #e6f6fb;
  font-weight: 700;
}

.home-icon-link {
  font-size: 1.2rem;
  padding: 0.4rem 0.6rem;
}

/* Dropdown Menu */
.has-dropdown > .nav-link::after {
  content: '';
  display: inline-block;
  width: 7px;
  height: 7px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg) translateY(-2px);
  margin-left: 0.3rem;
  transition: transform 0.2s ease;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 190px;
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
  list-style: none;
  padding: 0.5rem 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.2s ease;
  z-index: 1050;
}

.has-dropdown:hover .dropdown-menu,
.has-dropdown:focus-within .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-item a {
  display: block;
  padding: 0.55rem 1.1rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--theme-dark);
  text-decoration: none;
  transition: var(--transition);
}

.dropdown-item a:hover {
  background-color: #f1f5f9;
  color: var(--tudelft-cyan);
  text-decoration: none;
}

/* Mobile Hamburger Toggle */
.mobile-nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 6px;
  color: var(--theme-dark);
}

.mobile-nav-toggle svg {
  display: block;
  width: 24px;
  height: 24px;
}

.mobile-nav-toggle:focus {
  outline: 2px solid var(--tudelft-cyan);
}

/* Mobile Drawer */
.mobile-drawer {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(12, 35, 64, 0.45);
  backdrop-filter: blur(3px);
  z-index: 2000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.mobile-drawer.is-open {
  opacity: 1;
  visibility: visible;
}

.mobile-drawer-content {
  position: absolute;
  top: 0;
  right: 0;
  width: 82%;
  max-width: 320px;
  height: 100%;
  background: var(--theme-white);
  box-shadow: -5px 0 25px rgba(0, 0, 0, 0.15);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  overflow-y: auto;
}

.mobile-drawer.is-open .mobile-drawer-content {
  transform: translateX(0);
}

.mobile-drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--theme-border);
  margin-bottom: 1rem;
}

.close-drawer-btn {
  background: none;
  border: none;
  font-size: 1.6rem;
  color: var(--theme-dark);
  cursor: pointer;
  padding: 0.2rem 0.5rem;
}

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.mobile-nav-link {
  display: block;
  padding: 0.75rem 0.85rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--theme-dark);
  border-radius: var(--border-radius-sm);
  text-decoration: none;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
  background: #f0f8fc;
  color: var(--tudelft-cyan);
}

.mobile-sub-link {
  padding-left: 1.8rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: #475569;
}

/* ==========================================================================
   Hero & Page Header
   ========================================================================== */

.hero-section {
  padding: 2.8rem 0 1.5rem 0;
  position: relative;
  z-index: 2;
}

@media (min-width: 992px) {
  .hero-section > .container {
    background: var(--theme-white);
    border: 1px solid var(--theme-border);
    border-radius: var(--border-radius-md);
    padding: 2.4rem;
    box-shadow: 0 4px 20px rgba(12, 35, 64, 0.08), 0 1px 3px rgba(0, 0, 0, 0.05);
    margin-top: 1.5rem;
    margin-bottom: 2.5rem;
  }
}

.entry-header {
  margin-bottom: 1.6rem;
}

.page-title {
  font-size: clamp(2rem, 3.4vw, 2.8rem);
  font-weight: 800;
  color: var(--theme-dark);
  line-height: 1.25;
}

.page-subtitle {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 500;
  color: #556270;
  margin-top: 0.35rem;
  font-style: italic;
}

/* 2025-style Highlight Notice Card */
.notice-card {
  border: 2px solid var(--notice-border);
  background: var(--notice-bg);
  color: var(--notice-text);
  padding: 1.3rem 1.6rem;
  border-radius: 12px;
  font-family: var(--font-sans);
  margin: 1.8rem 0;
  box-shadow: 0 2px 6px var(--notice-shadow);
  line-height: 1.6;
}

.notice-title {
  font-size: 1.15rem;
  font-weight: 700;
  display: block;
  margin-bottom: 0.5rem;
  color: #3b2c68;
}

.notice-card p {
  margin: 0.45rem 0;
  color: var(--notice-text);
  font-size: 0.98rem;
}

.notice-card a {
  color: var(--notice-accent);
  font-weight: 600;
  text-decoration: underline;
}

.notice-card a:hover {
  color: #5231c5;
}

.notice-card hr {
  border: none;
  border-top: 1px solid #e2d9ff;
  margin: 1rem 0;
}

/* Hero Banner Image */
.hero-image-wrap {
  margin: 1.8rem 0 2.2rem 0;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  position: relative;
  background-color: #0c2340;
}

.hero-image {
  width: 100%;
  max-height: 480px;
  object-fit: cover;
  display: block;
  transition: transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.hero-image-wrap:hover .hero-image {
  transform: scale(1.015);
}

.image-caption {
  position: absolute;
  bottom: 0;
  right: 0;
  background: rgba(12, 35, 64, 0.7);
  backdrop-filter: blur(4px);
  color: #ffffff;
  font-size: 0.75rem;
  padding: 0.35rem 0.8rem;
  border-top-left-radius: 8px;
}

/* Date Highlight Badge */
.date-highlight-bar {
  margin: 1.8rem 0 1.5rem 0;
  padding: 0.85rem 1.3rem;
  background: linear-gradient(135deg, #0c2340 0%, #1e3a61 100%);
  color: #ffffff;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
  box-shadow: 0 4px 14px rgba(12, 35, 64, 0.15);
}

.date-highlight-bar h2 {
  font-size: 1.25rem;
  font-weight: 700;
  color: #ffffff;
  margin: 0;
  letter-spacing: 0.01em;
}

.blinking-dot {
  width: 10px;
  height: 10px;
  background-color: #39e5b6;
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 10px #39e5b6;
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

/* Section dividers */
.section-divider {
  border: none;
  height: 1px;
  background: linear-gradient(90deg, transparent, #cbd5e1, transparent);
  margin: 3rem 0;
}

/* ==========================================================================
   News & Announcements Grid
   ========================================================================== */

.section-title {
  font-size: 1.65rem;
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--theme-dark);
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.3rem;
  margin-top: 1rem;
}

.news-card {
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-md);
  padding: 1.3rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.news-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: #cbd5e1;
}

.news-icon-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.6rem;
}

.news-icon {
  font-size: 1.4rem;
}

.news-tag {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.2rem 0.55rem;
  border-radius: 20px;
  background: #f1f5f9;
  color: #475569;
}

.news-card h3 {
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--theme-dark);
  margin-bottom: 0.45rem;
}

.news-card p {
  font-size: 0.94rem;
  color: var(--theme-text-muted);
  flex-grow: 1;
  margin-bottom: 0.8rem;
}

.news-link {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--tudelft-cyan);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.news-link:hover {
  color: #00779b;
}

/* ==========================================================================
   Content Sections (Common to subpages)
   ========================================================================== */

.content-box {
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-md);
  padding: 2.2rem;
  margin-bottom: 2rem;
  box-shadow: 0 4px 20px rgba(12, 35, 64, 0.08), 0 1px 3px rgba(0, 0, 0, 0.05);
}

.page-main-content {
  padding: 2.5rem 0 4rem 0;
  position: relative;
  z-index: 2;
}

/* Important Dates Card */
.dates-table-wrap {
  margin: 1.5rem 0;
  overflow-x: auto;
}

.dates-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--theme-white);
  border-radius: var(--border-radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.dates-table th, 
.dates-table td {
  padding: 0.95rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--theme-border);
  font-size: 0.98rem;
}

.dates-table th {
  background-color: #f8fafc;
  color: var(--theme-dark);
  font-weight: 700;
  font-family: var(--font-serif);
}

.dates-table tr:last-child td {
  border-bottom: none;
}

.dates-table tr:hover td {
  background-color: #fafbfc;
}

.badge {
  display: inline-block;
  padding: 0.25rem 0.65rem;
  border-radius: 4px;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.badge-primary {
  background-color: #e0f2fe;
  color: #0369a1;
}

.badge-success {
  background-color: #dcfce7;
  color: #15803d;
}

.badge-warning {
  background-color: #fef3c7;
  color: #b45309;
}

.badge-alert {
  background-color: #fee2e2;
  color: #b91c1c;
}

/* Call to Action Button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  font-size: 0.96rem;
  font-weight: 600;
  border-radius: var(--border-radius-sm);
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: var(--transition);
}

.btn-primary {
  background-color: var(--tudelft-cyan);
  color: #ffffff;
  box-shadow: 0 3px 8px rgba(0, 166, 214, 0.25);
}

.btn-primary:hover {
  background-color: #008eb7;
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: #f1f5f9;
  color: var(--theme-dark);
  border: 1px solid var(--theme-border);
}

.btn-secondary:hover {
  background-color: #e2e8f0;
  color: var(--theme-dark);
  text-decoration: none;
}

/* Topic List */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.2rem;
  margin: 1.5rem 0;
}

.topic-item {
  background: #f8fafc;
  border: 1px solid #edf2f7;
  border-radius: var(--border-radius-sm);
  padding: 1.1rem;
  transition: var(--transition);
}

.topic-item:hover {
  border-color: #cbd5e1;
  background: #f1f5f9;
}

.topic-item strong {
  display: block;
  font-family: var(--font-serif);
  color: var(--theme-dark);
  margin-bottom: 0.35rem;
  font-size: 1.05rem;
}

.topic-item p {
  font-size: 0.92rem;
  color: #556270;
  margin-bottom: 0;
}

/* ==========================================================================
   Speakers & Program
   ========================================================================== */

.speaker-card {
  display: flex;
  gap: 1.6rem;
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-md);
  padding: 1.6rem;
  margin-bottom: 1.6rem;
  box-shadow: var(--shadow-sm);
  align-items: flex-start;
}

.speaker-avatar {
  width: 110px;
  height: 110px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 3px solid var(--tudelft-cyan);
  background-color: #e2e8f0;
}

.speaker-info h3 {
  font-size: 1.35rem;
  color: var(--theme-dark);
  margin-bottom: 0.25rem;
}

.speaker-affiliation {
  font-size: 0.95rem;
  color: var(--theme-text-muted);
  font-weight: 500;
  margin-bottom: 0.65rem;
}

.speaker-talk-title {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--tudelft-navy);
  margin-bottom: 0.6rem;
}

/* Schedule Timeline Table */
.schedule-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  background: var(--theme-white);
  box-shadow: var(--shadow-sm);
  border-radius: var(--border-radius-md);
  overflow: hidden;
}

.schedule-table th,
.schedule-table td {
  padding: 1rem 1.2rem;
  border-bottom: 1px solid var(--theme-border);
}

.schedule-table th {
  background-color: #f8fafc;
  font-family: var(--font-serif);
  color: var(--theme-dark);
  font-weight: 700;
}

.schedule-table .time-col {
  width: 130px;
  font-weight: 700;
  color: var(--tudelft-cyan);
  white-space: nowrap;
}

.schedule-break {
  background-color: #fbfbfc;
  font-style: italic;
  color: #64748b;
}

.schedule-session-header {
  background-color: #f1f5f9;
  border-top: 2px solid #cbd5e1;
  border-bottom: 1px solid #e2e8f0;
}

.schedule-session-header td {
  padding: 0.9rem 1.2rem;
}

.session-header-title {
  font-family: var(--font-serif);
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--tudelft-navy);
  letter-spacing: -0.2px;
}

.session-header-details {
  font-size: 0.88rem;
  font-weight: normal;
  color: var(--theme-text-muted);
  margin-left: 0.4rem;
}

.schedule-keynote-row {
  background-color: #f0fdfa;
}

.schedule-paper-row {
  background-color: #ffffff;
}

.schedule-paper-row td {
  padding-top: 0.45rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid #f1f5f9;
}

.schedule-paper-row:hover td {
  background-color: #fafbfc;
}

.paper-entry {
  padding-left: 0.65rem;
  border-left: 2px solid #e2e8f0;
}

.schedule-paper-row .paper-title,
.paper-entry .paper-title,
.paper-title {
  font-family: var(--font-sans);
  font-size: 0.76rem;
  font-weight: 400; /* strictly regular weight, subordinate to session header */
  color: #334155;
  line-height: 1.35;
}

.schedule-paper-row .paper-authors,
.paper-entry .paper-authors,
.paper-authors {
  font-size: 0.72rem;
  color: #64748b;
  font-style: italic; /* author names in italics */
  margin-top: 0.1rem;
  line-height: 1.3;
}

.paper-authors em {
  font-style: italic;
  color: #475569;
}

.paper-authors .paper-affiliation {
  font-style: normal;
  color: #94a3b8;
}

.paper-links {
  white-space: nowrap;
  vertical-align: middle;
  text-align: right;
}

.abstract-link {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--tudelft-cyan);
  text-decoration: none;
  padding: 0.14rem 0.48rem;
  background: rgba(0, 166, 214, 0.08);
  border: 1px solid rgba(0, 166, 214, 0.25);
  border-radius: 4px;
  display: inline-block;
  margin-top: 0.15rem;
  line-height: 1.2;
  transition: var(--transition);
}

.abstract-link:hover {
  background: var(--tudelft-cyan);
  color: #ffffff;
  border-color: var(--tudelft-cyan);
  text-decoration: none;
}

.slides-link {
  font-size: 0.72rem;
  font-weight: 600;
  color: #475569;
  text-decoration: none;
  padding: 0.14rem 0.48rem;
  background: rgba(100, 116, 139, 0.08);
  border: 1px solid rgba(100, 116, 139, 0.25);
  border-radius: 4px;
  display: inline-block;
  margin-top: 0.15rem;
  margin-left: 0.3rem;
  line-height: 1.2;
  transition: var(--transition);
}

.slides-link:hover {
  background: #475569;
  color: #ffffff;
  border-color: #475569;
  text-decoration: none;
}

.poster-item {
  line-height: 1.6;
}



/* ==========================================================================
   Accepted Papers List
   ========================================================================== */

.paper-search-wrap {
  margin-bottom: 1.8rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.paper-search-input {
  flex-grow: 1;
  min-width: 260px;
  padding: 0.75rem 1rem;
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  outline: none;
  transition: var(--transition);
}

.paper-search-input:focus {
  border-color: var(--tudelft-cyan);
  box-shadow: 0 0 0 3px rgba(0, 166, 214, 0.15);
}

.filter-btn {
  padding: 0.5rem 0.9rem;
  background: #ffffff;
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--theme-text-muted);
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--tudelft-cyan);
  color: #ffffff;
  border-color: var(--tudelft-cyan);
}

.paper-card {
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  padding: 1.25rem 1.4rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.paper-card:hover {
  border-color: #cbd5e1;
  box-shadow: var(--shadow-md);
}

.paper-card .paper-title {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--theme-dark);
  margin-bottom: 0.4rem;
}

.paper-card .paper-authors {
  font-size: 0.94rem;
  color: #475569;
  margin-bottom: 0.25rem;
}

.paper-affiliation {
  font-size: 0.86rem;
  color: var(--theme-text-muted);
  margin-bottom: 0.7rem;
}

.paper-abstract-toggle {
  background: none;
  border: none;
  color: var(--tudelft-cyan);
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
  padding: 0;
  text-decoration: underline;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.paper-abstract-toggle:hover {
  color: #00779b;
}

.paper-abstract-body {
  display: none;
  margin-top: 0.9rem;
  padding: 1rem;
  background-color: #f8fafc;
  border-left: 3px solid var(--tudelft-cyan);
  border-radius: 4px;
  font-size: 0.92rem;
  color: #334155;
}

.paper-abstract-body.is-open {
  display: block;
}

/* ==========================================================================
   Historical Archive (DBDBD in Previous Years)
   ========================================================================== */

.years-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.year-card {
  background: var(--theme-white);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  padding: 1.1rem 1.3rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  text-decoration: none;
  color: var(--theme-dark);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.year-card:hover {
  border-color: var(--tudelft-cyan);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}

.year-number {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--tudelft-navy);
}

.year-city {
  font-size: 0.95rem;
  font-weight: 600;
  color: #475569;
}

.year-country-flag {
  font-size: 1.2rem;
}

/* ==========================================================================
   Sponsors & Organizers (Bottom of Home)
   ========================================================================== */

.sponsors-section {
  padding: 2.5rem 0 3rem 0;
  background-color: #ffffff;
  border-top: 1px solid var(--theme-border);
  margin-top: 2rem;
}

.sponsors-heading {
  text-align: center;
  font-size: 1.25rem;
  font-family: var(--font-serif);
  color: var(--theme-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 2rem;
}

.sponsors-grid {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 3rem;
}

.sponsor-logo-item {
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  opacity: 0.9;
}

.sponsor-logo-item:hover {
  opacity: 1;
  transform: translateY(-2px);
}

.sponsor-logo-item img {
  max-height: 52px;
  width: auto;
  object-fit: contain;
}

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

.site-footer {
  background-color: var(--tudelft-navy);
  color: #ffffff;
  padding: 2.5rem 0 2rem 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 1.2rem;
}

.footer-contact {
  font-size: 1.05rem;
  font-family: var(--font-serif);
}

.footer-contact a {
  color: #7ce7ff;
  font-weight: 600;
  text-decoration: underline;
}

.footer-contact a:hover {
  color: #ffffff;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  list-style: none;
}

.footer-links a {
  color: #94a3b8;
  font-size: 0.9rem;
  text-decoration: none;
}

.footer-links a:hover {
  color: #ffffff;
}

.footer-copyright {
  font-size: 0.85rem;
  color: #64748b;
}

/* ==========================================================================
   Organizers Section
   ========================================================================== */

.organizers-section {
  padding: 2.5rem 0 3rem 0;
  background-color: var(--theme-white);
  border-top: 1px solid var(--theme-border);
}

.organizers-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.2rem 2rem;
  max-width: 920px;
  margin: 1.8rem auto 0 auto;
  text-align: center;
}

.organizer-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 1rem 0.5rem;
  border-radius: var(--border-radius-md);
  transition: var(--transition);
}

.organizer-card:hover {
  transform: translateY(-3px);
}

.organizer-photo {
  width: 110px;
  height: 110px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 0.8rem;
  border: 3px solid var(--tudelft-cyan);
  box-shadow: 0 4px 10px rgba(0, 166, 214, 0.18);
  background-color: #f1f5f9;
}

.organizer-name {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--theme-dark);
  margin-bottom: 0.2rem;
}

.organizer-group {
  font-size: 0.82rem;
  color: var(--tudelft-cyan);
  font-weight: 600;
  line-height: 1.3;
}

.organizer-univ {
  font-size: 0.78rem;
  color: var(--theme-text-muted);
}

/* Session Talks Inside Program Schedule */
.session-talks {
  margin-top: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.session-talk-item {
  background: #f8fafc;
  border-left: 3px solid var(--tudelft-cyan);
  padding: 0.65rem 0.9rem;
  border-radius: 0 6px 6px 0;
  font-size: 0.92rem;
}

.session-talk-title {
  font-weight: 700;
  color: var(--theme-dark);
  margin-bottom: 0.15rem;
}

.session-talk-authors {
  color: #475569;
  font-size: 0.86rem;
}

.session-talk-authors span {
  color: var(--theme-text-muted);
}

/* Previous Years Bullet List */
.years-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.years-list li {
  display: flex;
  align-items: baseline;
  padding: 0.7rem 1rem;
  background: #ffffff;
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  transition: var(--transition);
  font-size: 1.02rem;
}

.years-list li:hover {
  background: #f8fafc;
  border-color: #cbd5e1;
  transform: translateX(4px);
}

.years-list li::before {
  content: "•";
  color: var(--tudelft-cyan);
  font-weight: bold;
  font-size: 1.3rem;
  margin-right: 0.85rem;
  line-height: 1;
}

.years-list a {
  font-weight: 600;
  color: var(--theme-dark);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.years-list a:hover {
  color: var(--tudelft-cyan);
  text-decoration: underline;
}

.years-list .year-badge {
  font-weight: 800;
  font-family: var(--font-serif);
  color: var(--tudelft-navy);
  margin-right: 0.4rem;
}

.years-list .city-name {
  color: #475569;
}

.years-list .country-flag {
  margin-left: auto;
  font-size: 1.1rem;
}

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

@media (max-width: 960px) {
  .nav-menu {
    display: none;
  }

  .mobile-nav-toggle {
    display: block;
  }

  .mobile-drawer {
    display: block;
  }

  .hero-section {
    padding-top: 2rem;
  }

  .speaker-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
}

@media (max-width: 640px) {
  .header-inner {
    height: 72px;
  }

  .site-logo {
    width: 46px;
    height: 46px;
  }

  .brand-title {
    font-size: 1.1rem;
  }

  .date-highlight-bar {
    width: 100%;
    flex-direction: column;
    text-align: center;
  }

  .content-box {
    padding: 1.4rem;
  }

  .sponsors-grid {
    gap: 1.8rem;
  }

  .organizers-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.6rem 1rem;
    max-width: 480px;
  }
}

@media (max-width: 440px) {
  .organizers-grid {
    grid-template-columns: 1fr;
    gap: 1.4rem;
  }
}

/* ==========================================================================
   Venue & Directions Styles
   ========================================================================== */
.venue-showcase-card {
  background: #ffffff;
  border: 1px solid var(--theme-border);
  border-left: 5px solid var(--tudelft-cyan);
  border-radius: var(--border-radius-md);
  padding: 1.6rem 1.8rem;
  margin: 1.5rem 0 2rem 0;
  box-shadow: var(--shadow-sm);
}

.venue-badge-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 0.8rem;
}

.venue-header-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(0, 166, 214, 0.12);
  color: #00779e;
  font-weight: 700;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 0.25rem 0.65rem;
  border-radius: 20px;
}

.venue-date-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--theme-bg-subtle);
  color: var(--theme-slate);
  font-weight: 600;
  font-size: 0.82rem;
  padding: 0.25rem 0.65rem;
  border-radius: 20px;
}

.venue-name {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--tudelft-navy);
  margin: 0 0 0.35rem 0;
  font-family: var(--font-serif);
}

.venue-address {
  font-size: 1.05rem;
  color: var(--theme-text);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.venue-description {
  font-size: 0.98rem;
  line-height: 1.65;
  color: var(--theme-text);
  margin-bottom: 1.3rem;
}

.venue-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn-venue {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.6rem 1.15rem;
  border-radius: 6px;
  font-size: 0.92rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s ease;
}

.btn-venue-primary {
  background: var(--tudelft-cyan);
  color: #ffffff;
  border: 1px solid transparent;
}
.btn-venue-primary:hover {
  background: #0087af;
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(0, 166, 214, 0.3);
}

.btn-venue-secondary {
  background: var(--theme-bg-subtle);
  color: var(--tudelft-navy);
  border: 1px solid var(--theme-border);
}
.btn-venue-secondary:hover {
  background: #ffffff;
  border-color: var(--tudelft-cyan);
  color: #00779e;
  transform: translateY(-1px);
}

/* Directions Grid */
.directions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0 2.2rem 0;
}

.direction-card {
  background: #ffffff;
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-md);
  padding: 1.4rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

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

.direction-card.featured-mode {
  border-top: 4px solid var(--tudelft-cyan);
  background: linear-gradient(180deg, #f7fdff 0%, #ffffff 60px);
}

.direction-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.4rem;
}

.direction-title-wrap {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.direction-icon {
  font-size: 1.6rem;
  line-height: 1;
}

.direction-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--tudelft-navy);
  margin: 0;
}

.direction-time-badge {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  background: rgba(0, 166, 214, 0.12);
  color: #00779e;
  padding: 0.2rem 0.6rem;
  border-radius: 12px;
  margin: 0.35rem 0 0.75rem 0;
  width: fit-content;
}

.direction-body {
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--theme-text);
  flex-grow: 1;
}

.direction-body p {
  margin: 0.45rem 0;
}

.direction-body ul {
  padding-left: 1.2rem;
  margin: 0.4rem 0;
}

.direction-body li {
  margin-bottom: 0.3rem;
}

.direction-body strong {
  color: var(--tudelft-navy);
}

/* Map Embed */
.map-embed-box {
  margin: 1.8rem 0;
  border-radius: var(--border-radius-md);
  overflow: hidden;
  border: 1px solid var(--theme-border);
  box-shadow: var(--shadow-sm);
  background: #f8fafc;
}

.map-embed-box iframe {
  display: block;
  width: 100%;
  height: 380px;
  border: none;
}

.map-embed-bar {
  padding: 0.75rem 1.2rem;
  background: #ffffff;
  border-top: 1px solid var(--theme-border);
  font-size: 0.88rem;
  color: var(--theme-text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.map-embed-bar a {
  color: #00779e;
  font-weight: 600;
  text-decoration: underline;
}

.map-embed-bar a:hover {
  color: var(--tudelft-cyan);
}

/* Venue practical cards */
.venue-facilities-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
  margin: 1.2rem 0;
}

.venue-facility-item {
  background: var(--theme-bg-soft);
  border: 1px solid var(--theme-border);
  border-radius: var(--border-radius-sm);
  padding: 1rem 1.2rem;
}

.venue-facility-item h4 {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--tudelft-navy);
  margin-bottom: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.venue-facility-item p {
  font-size: 0.88rem;
  color: var(--theme-text-muted);
  margin: 0;
  line-height: 1.45;
}

/* ==========================================================================
   Vermeer-Inspired Delft Flank Backgrounds
   Authentic Dutch Golden Age master oil paintings framing the sides of the
   page on wide desktop viewports (Oude Kerk on left, Nieuwe Kerk on right).
   ========================================================================== */

@media (min-width: 1200px) {
  /* Left Flank: Vermeer's Oude Kerk, canal boat, and historic Delft facades */
  body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: calc((100vw - var(--container-max-width)) / 2 + 35px);
    height: 100vh;
    background-image: url('../images/vermeer-left.jpg');
    background-position: left top;
    background-size: cover;
    background-repeat: no-repeat;
    z-index: 0;
    pointer-events: none;
    opacity: 0.95;
    box-shadow: inset -10px 0 20px -8px rgba(12, 35, 64, 0.25);
    mask-image: linear-gradient(to right, black calc(100% - 40px), transparent 100%);
    -webkit-mask-image: linear-gradient(to right, black calc(100% - 40px), transparent 100%);
  }

  /* Right Flank: Vermeer's Nieuwe Kerk, canal bridge, and stepped gables */
  body::after {
    content: "";
    position: fixed;
    top: 0;
    right: 0;
    width: calc((100vw - var(--container-max-width)) / 2 + 35px);
    height: 100vh;
    background-image: url('../images/vermeer-right.jpg');
    background-position: right top;
    background-size: cover;
    background-repeat: no-repeat;
    z-index: 0;
    pointer-events: none;
    opacity: 0.95;
    box-shadow: inset 10px 0 20px -8px rgba(12, 35, 64, 0.25);
    mask-image: linear-gradient(to left, black calc(100% - 40px), transparent 100%);
    -webkit-mask-image: linear-gradient(to left, black calc(100% - 40px), transparent 100%);
  }
}