/* CSS RESET (minimal) */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin:0; font-family: system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,sans-serif; line-height:1.4; background:#0f1115; color:#1d2330; }
body.light { background:#f6f7f9; color:#1d2330; }
body.dark { background:#0f1115; color:#e5e9f0; }

:root {
  --accent:#0070f3;
  --accent-rgb:0 112 243;
  --bg-panel:#ffffff;
  --bg-panel-alt:#f8fafc;
  --border:#e2e8f0;
  --text-muted:#64748b;
  --radius:10px;
  --shadow:0 4px 16px -4px rgba(0 112 243 / 0.1),0 2px 4px -2px rgba(0 112 243 / 0.06);
  --gradient:linear-gradient(135deg,#0070f3 0%,#0ea5e9  .brand h1 {
    font-size: 1rem;
  }
  
  .brand-logo {
    height: 1.75rem;
  }%,#3b82f6 100%);
}
body.dark {
  --bg-panel:#1e293b;
  --bg-panel-alt:#0f172a;
  --border:#334155;
  --text-muted:#94a3b8;
  --shadow:0 4px 18px -4px rgba(0 112 243 / 0.3);
}

.skip-link { position:absolute; left:-999px; top:auto; width:1px; height:1px; overflow:hidden; }
.skip-link:focus { left:1rem; top:1rem; width:auto; height:auto; background:var(--accent); color:#fff; padding:.5rem 1rem; border-radius:4px; z-index:1000; }

/* Header */
.site-header { position:sticky; top:0; z-index:50; backdrop-filter:saturate(180%) blur(14px); background:rgba(var(--accent-rgb)/0.06); border-bottom:1px solid var(--border); display:flex; flex-wrap:wrap; align-items:center; gap:1rem; padding:.75rem clamp(1rem,2vw,2rem); }
.brand { flex:1 1 auto; min-width:200px; display:flex; align-items:center; gap:clamp(0.5rem, 1.5vw, 0.75rem); }
.brand-logo { height:clamp(1.5rem, 2.5vw, 2rem); width:auto; object-fit:contain; flex-shrink:0; }
.brand-text { flex:1; }
.brand h1 { font-size:clamp(1.15rem,3.2vw,1.75rem); margin:0; background:var(--gradient); -webkit-background-clip:text; background-clip:text; font-weight:600; letter-spacing:.5px; }

.brand .tagline { display:block; font-size:.7rem; font-weight:500; text-transform:uppercase; letter-spacing:1.5px; color:var(--text-muted); margin-top:.1rem; }
.header-actions { display:flex; align-items:center; gap:.75rem; }

.search-wrapper { position:relative; display:flex; align-items:center; }
#searchInput { padding:.55rem .75rem; padding-right:2.2rem; border:1px solid var(--border); background:var(--bg-panel); color:inherit; border-radius:2rem; min-width:260px; font-size:.9rem; box-shadow:none; outline:none; transition:border-color .25s, background .25s; }
#searchInput:focus { border-color:var(--accent); box-shadow:0 0 0 3px rgba(var(--accent-rgb)/0.25); }
#clearSearch { position:absolute; right:.35rem; background:transparent; border:none; font-size:1.1rem; cursor:pointer; color:var(--text-muted); padding:.25rem .4rem; border-radius:50%; line-height:1; }
#clearSearch:hover { background:var(--bg-panel-alt); }

.icon-btn { background:var(--bg-panel); color:inherit; border:1px solid var(--border); border-radius:2rem; padding:.55rem .95rem; cursor:pointer; display:inline-flex; align-items:center; gap:.35rem; font-size:.8rem; font-weight:500; letter-spacing:.5px; text-transform:uppercase; transition:background .25s,border-color .25s,color .25s; }
.icon-btn:hover, .icon-btn:focus-visible { background:var(--accent); color:#fff; border-color:var(--accent); outline:none; }

/* Tabs */
.tabs { display:flex; justify-content:flex-start; gap:.5rem; padding:.5rem clamp(1rem,2vw,2rem); background:linear-gradient(to right,var(--bg-panel),var(--bg-panel-alt)); border-bottom:1px solid var(--border); position:sticky; top:64px; z-index:40; }
.tab { background:var(--bg-panel-alt); border:1px solid var(--border); color:inherit; padding:.55rem 1.1rem; font-size:.8rem; border-radius:2rem; cursor:pointer; letter-spacing:.5px; font-weight:500; text-transform:uppercase; transition:all .25s; }
.tab.active, .tab:hover { background:var(--accent); color:#fff; border-color:var(--accent); }

/* Filter panel */
.filter-panel { position:fixed; inset:0 0 0 auto; width: min(380px,100%); background:var(--bg-panel); border-left:1px solid var(--border); transform:translateX(110%); transition:transform .45s cubic-bezier(.65,.05,.36,1); z-index:100; display:flex; flex-direction:column; box-shadow:-2px 0 16px -4px rgba(0 0 0 / .25); }
.filter-panel.open { transform:translateX(0); }
.filters { padding:1rem 1.25rem 2rem; overflow-y:auto; font-size:.85rem; }
.filters-header { display:flex; align-items:center; justify-content:space-between; margin-bottom:.5rem; }
.filters h2 { font-size:1.05rem; margin:0; }
.filters fieldset { border:1px solid var(--border); border-radius:.75rem; margin:1rem 0; padding:.6rem .9rem 1rem; background:var(--bg-panel-alt); }
.filters legend { padding:0 .4rem; font-weight:600; font-size:.7rem; text-transform:uppercase; letter-spacing:1px; color:var(--text-muted); }
.filters label { display:flex; gap:.45rem; align-items:center; font-weight:500; line-height:1.1; margin:.35rem 0; cursor:pointer; }
.tracks-list { display:grid; grid-template-columns:repeat(auto-fill,minmax(130px,1fr)); gap:.35rem .65rem; }
.filters-footer { display:flex; gap:.75rem; justify-content:flex-end; margin-top:.5rem; }
.filters button { font-size:.75rem; }
.filters button.primary { background:var(--accent); color:#fff; border:1px solid var(--accent); }
.filters button.primary:hover { filter:brightness(1.1); }

/* Main layout */
.main { max-width:1400px; margin:0 auto; padding:1.5rem clamp(1rem,3vw,2.5rem) 4rem; }
.agenda-section { display:none; }
.agenda-section.active { display:block; }

/* Timeline */
.timeline { display:flex; flex-direction:column; gap:1.25rem; }
.timeslot { display:grid; grid-template-columns:130px 1fr; gap:1.25rem; align-items:stretch; }
.time-col { text-align:right; padding-top:.35rem; font-size:.75rem; font-weight:600; color:var(--accent); letter-spacing:.5px; }
.slot-time { display:inline-block; background:var(--bg-panel-alt); padding:.35rem .55rem; border-radius:1rem; border:1px solid var(--border); box-shadow:var(--shadow); min-width:110px; }
.sessions-col { display:grid; gap:.9rem; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); }

/* Session Cards */
.session-card { position:relative; display:flex; flex-direction:column; gap:.55rem; background:var(--bg-panel); border:1px solid var(--border); padding:.85rem .95rem 1rem; border-radius:var(--radius); box-shadow:var(--shadow); min-height:160px; animation:fadeIn .5s ease; outline:none; }
.session-card:focus-visible { box-shadow:0 0 0 3px rgba(var(--accent-rgb)/.5), var(--shadow); }
.session-header { display:flex; gap:.55rem; align-items:flex-start; justify-content:space-between; }
.session-title { font-size:.95rem; line-height:1.25; margin:0; font-weight:600; }
.type-badge { background:var(--accent); color:#fff; padding:.25rem .5rem; font-size:.6rem; text-transform:uppercase; letter-spacing:1px; font-weight:600; border-radius:6px; box-shadow:0 0 0 1px rgba(255 255 255 / .2) inset; white-space:nowrap; }
.type-badge.demo { background:#0ea5e9; }
.type-badge.handson { background:#10b981; }
.type-badge.concur { background:#8b5cf6; }
.type-badge.academia { background:#f97316; }
.type-badge.break { background:#64748b; }
.session-meta { display:flex; flex-direction:column-reverse; gap:.35rem; font-size:.7rem; color:var(--text-muted); }
.track-badge { display:inline-flex; align-items:center; gap:.35rem; background:var(--bg-panel-alt); border:1px solid var(--border); padding:.25rem .55rem; border-radius:1rem; font-weight:500; font-size:.65rem; letter-spacing:.5px; text-transform:uppercase; max-width:100%; }
.speakers { font-size:.7rem; line-height:1.2; font-weight:500; }

/* Enhanced color variations for different session types */
.session-card { 
  /* Default lecture cards - enhanced blue tint */
  background: linear-gradient(145deg, #eff6ff, #f1f5f9);
  border-left: 4px solid #3b82f6;
}

.session-card.demo { 
  /* Demo Pod cards - enhanced sky blue tint */
  background: linear-gradient(145deg, #e0f2fe, #f0f9ff);
  border-left: 4px solid #0ea5e9;
}

.session-card.handson { 
  /* Hands On cards - enhanced emerald tint */
  background: linear-gradient(145deg, #ecfdf5, #f0fdf4);
  border-left: 4px solid #10b981;
}

.session-card.concur { 
  /* Concur cards - enhanced purple tint */
  background: linear-gradient(145deg, #faf5ff, #f3e8ff);
  border-left: 4px solid #8b5cf6;
}

.session-card.academia { 
  /* Academia cards - enhanced orange tint */
  background: linear-gradient(145deg, #fff7ed, #ffedd5);
  border-left: 4px solid #f97316;
}

.session-card.break { 
  /* Break cards - enhanced neutral gray */
  background: linear-gradient(145deg, #f1f5f9, #e2e8f0);
  border-left: 4px solid #64748b;
  grid-column: 1 / -1;
  max-width: none;
  text-align: center;
  padding: 1.5rem 2rem;
  min-height: auto;
}
.session-card.break .session-title { 
  color: var(--accent); 
  font-size: 1.1rem;
  line-height: 1.4;
  text-align: left;
}
.session-card.break .session-header {
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  text-align: left;
}
.session-card.break .type-badge { background: #64748b; }

.session-card.keynote { 
  /* Keynote cards - enhanced indigo tint */
  background: linear-gradient(145deg, #eef2ff, #f1f5f9);
  border-left: 4px solid #6366f1;
}

.session-card.registration { 
  /* Registration cards - enhanced amber tint */
  background: linear-gradient(145deg, #fef3c7, #fffbeb);
  border-left: 4px solid #f59e0b;
}

/* Full width cards for keynotes and registration */
.session-card.keynote,
.session-card.registration {
  grid-column: 1 / -1;
  max-width: none;
  text-align: center;
  padding: 1.5rem 2rem;
  min-height: auto;
}

.session-card.keynote .session-title,
.session-card.registration .session-title {
  font-size: 1.1rem;
  line-height: 1.4;
  text-align: left;
}

.session-card.keynote .session-header,
.session-card.registration .session-header {
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  text-align: left;
}

.session-card.keynote .speakers,
.session-card.registration .speakers {
  font-size: 0.85rem;
  line-height: 1.5;
  margin: 0.75rem 0;
  color: var(--text-muted);
  font-weight: 500;
  text-align: left;
}

.session-card.keynote .track-badge,
.session-card.registration .track-badge {
  font-size: 0.7rem;
  margin-top: auto;
  align-self: flex-start;
}

/* Empty state */
.empty-state { text-align:center; padding:3rem 1rem; font-weight:500; color:var(--text-muted); }

/* Sponsors Section */
.sponsors-section {
  background: linear-gradient(135deg, var(--bg-panel) 0%, var(--bg-panel-alt) 100%);
  border-top: 1px solid var(--border);
  margin-top: 4rem;
  padding: 3rem 0;
}

.sponsors-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1rem, 3vw, 2.5rem);
}

.sponsors-header {
  text-align: center;
  margin-bottom: 3rem;
}

.sponsors-header h2 {
  font-size: clamp(1.5rem, 4vw, 2.5rem);
  margin: 0 0 1rem;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.sponsors-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
  margin: 0;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
}

.sponsors-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
  align-items: center;
  justify-items: center;
}

.sponsor-item {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
  min-height: 120px;
  width: 100%;
  max-width: 280px;
}

.sponsor-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px -8px rgba(var(--accent-rgb) / 0.15);
  border-color: var(--accent);
}

.sponsor-logo {
  max-width: 100%;
  max-height: 80px;
  width: auto;
  height: auto;
  object-fit: contain;
  filter: grayscale(0.3) opacity(0.85);
  transition: filter 0.3s ease;
}

.sponsor-item:hover .sponsor-logo {
  filter: grayscale(0) opacity(1);
}

/* Dark mode adjustments for sponsors */
body.dark .sponsor-logo {
  filter: grayscale(0.3) opacity(0.75) brightness(1.1);
}

body.dark .sponsor-item:hover .sponsor-logo {
  filter: grayscale(0) opacity(0.95) brightness(1.2);
}

/* Footer Image */
.footer-image-container {
  width: 100%;
  margin-top: 2rem;
  overflow: hidden;
}

.footer-image {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

/* Footer */
.site-footer { text-align:center; margin-top:1rem; padding:2.5rem 1rem 3rem; font-size:.75rem; color:var(--text-muted); }

/* Utilities */
.sr-only { position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; clip:rect(0,0,0,0); white-space:nowrap; border:0; }

/* Enhanced focus indicators */
.session-card:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Loading state */
.loading {
  display: inline-block;
  position: relative;
}

.loading::after {
  content: '';
  position: absolute;
  width: 1rem;
  height: 1rem;
  border: 2px solid transparent;
  border-top: 2px solid var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-left: 0.5rem;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Error state */
.error-state {
  padding: 2rem;
  text-align: center;
  color: var(--text-muted);
}

.error-state h2 {
  color: #dc2626;
  margin-bottom: 1rem;
}

/* Improved session cards */
.session-card:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 25px -8px rgba(0 0 0 / 0.2);
  border-color: var(--accent);
}

/* Better spacing for speakers */
.speakers:empty {
  display: none;
}

/* Filter panel overlay for mobile */
@media (max-width: 768px) {
  .filter-panel::before {
    content: '';
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    z-index: -1;
  }
  
  .filter-panel.open::before {
    opacity: 1;
    visibility: visible;
  }
}

/* Dark mode adjustments */
body.dark .tab { background:#1e2430; }
body.dark .tab.active { background:var(--accent); }

/* Enhanced dark mode card colors */
body.dark .session-card {
  /* Default lecture cards - enhanced dark blue */
  background: linear-gradient(145deg, #1e3a8a, #1e293b);
  border-left: 4px solid #3b82f6;
}

body.dark .session-card.demo {
  /* Demo Pod cards - enhanced dark sky blue */
  background: linear-gradient(145deg, #0c4a6e, #1e293b);
  border-left: 4px solid #0ea5e9;
}

body.dark .session-card.handson {
  /* Hands On cards - enhanced dark emerald */
  background: linear-gradient(145deg, #064e3b, #1e293b);
  border-left: 4px solid #10b981;
}

body.dark .session-card.concur {
  /* Concur cards - enhanced dark purple */
  background: linear-gradient(145deg, #581c87, #1e293b);
  border-left: 4px solid #8b5cf6;
}

body.dark .session-card.academia {
  /* Academia cards - enhanced dark orange */
  background: linear-gradient(145deg, #9a3412, #1e293b);
  border-left: 4px solid #f97316;
}

body.dark .session-card.break { 
  background: linear-gradient(145deg, #374151, #1f2937); 
  border-left: 4px solid #6b7280;
  grid-column: 1 / -1;
  max-width: none;
  text-align: center;
  padding: 1.5rem 2rem;
  min-height: auto;
}

body.dark .session-card.keynote {
  /* Keynote cards - enhanced dark indigo */
  background: linear-gradient(145deg, #312e81, #1e293b);
  border-left: 4px solid #6366f1;
}

body.dark .session-card.registration {
  /* Registration cards - enhanced dark amber */
  background: linear-gradient(145deg, #92400e, #1e293b);
  border-left: 4px solid #f59e0b;
}

/* Animations */
@keyframes fadeIn { from { opacity:0; transform:translateY(6px);} to { opacity:1; transform:translateY(0);} }

/* Responsive Design */
@media (max-width: 1200px) {
  .sessions-col { 
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); 
  }
}

@media (max-width: 1000px) { 
  .sessions-col { 
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); 
  }
  .timeslot { 
    grid-template-columns: 120px 1fr; 
  }
}

@media (max-width: 768px) {
  .site-header { 
    position: static; 
    padding: 1rem; 
    flex-direction: column;
    gap: 1rem;
  }
  
  .brand {
    text-align: center;
    min-width: auto;
    gap: 0.5rem;
  }
  
  .brand-logo {
    height: 1.75rem;
  }
  
  .header-actions {
    justify-content: center;
    width: 100%;
    flex-wrap: wrap;
  }
  
  .tabs { 
    top: 0; 
    padding: 1rem;
  }
  
  .main { 
    padding: 1.5rem 1rem 3rem; 
  }
  
  #searchInput { 
    min-width: 200px; 
    width: 100%;
    max-width: 300px;
  }
  
  .search-wrapper {
    flex-grow: 1;
    max-width: 300px;
  }
  
  .sessions-col { 
    grid-template-columns: 1fr;
  }
  
  .timeslot { 
    grid-template-columns: 100px 1fr; 
    gap: 1rem;
  }
  
  .slot-time { 
    min-width: 85px; 
  }
  
  .filter-panel {
    width: 100%;
  }
  
  .filters-footer {
    position: sticky;
    bottom: 0;
    background: var(--bg-panel);
    padding: 1rem 0 0;
    border-top: 1px solid var(--border);
    margin-top: 1rem;
  }

  /* Sponsors responsive adjustments */
  .sponsors-section {
    padding: 2rem 0;
    margin-top: 2rem;
  }
  
  .sponsors-header {
    margin-bottom: 2rem;
  }
  
  .sponsors-grid {
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1.5rem;
  }
  
  .sponsor-item {
    padding: 1rem;
    min-height: 100px;
  }
  
  .sponsor-logo {
    max-height: 60px;
  }
}

@media (max-width: 560px) {
  .site-header {
    padding: 0.75rem;
  }
  
  .brand h1 {
    font-size: 1.25rem;
  }
  
  .brand-logo {
    height: 1.5rem;
  }
  
  .header-actions {
    gap: 0.5rem;
  }
  
  .tabs {
    padding: 0.75rem;
    gap: 0.25rem;
  }
  
  .tab {
    padding: 0.5rem 0.8rem;
    font-size: 0.75rem;
  }
  
  .timeslot { 
    grid-template-columns: 1fr; 
    gap: 0.5rem;
  }
  
  .time-col { 
    text-align: left; 
  }
  
  .slot-time { 
    margin-bottom: 0.5rem; 
    display: inline-block;
  }
  
  #searchInput {
    min-width: auto;
    width: 100%;
    font-size: 1rem; /* Prevent zoom on iOS */
  }
  
  .session-card {
    min-height: auto;
    padding: 1rem;
  }
  
  .session-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .type-badge {
    align-self: flex-start;
  }
  
  .filters {
    padding: 1rem;
  }
  
  .tracks-list {
    grid-template-columns: 1fr;
  }

  /* Sponsors mobile adjustments */
  .sponsors-section {
    padding: 1.5rem 0;
  }
  
  .sponsors-header h2 {
    font-size: 1.5rem;
  }
  
  .sponsors-subtitle {
    font-size: 0.9rem;
    padding: 0 1rem;
  }
  
  .sponsors-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
  }
  
  .sponsor-item {
    padding: 0.75rem;
    min-height: 80px;
  }
  
  .sponsor-logo {
    max-height: 50px;
  }

  /* Full width cards mobile adjustments */
  .session-card.keynote,
  .session-card.registration {
    padding: 1rem;
    font-size: 0.9rem;
  }

  .session-card.keynote .session-title,
  .session-card.registration .session-title {
    font-size: 1rem;
  }
}

@media (max-width: 400px) {
  .brand h1 {
    font-size: 1.1rem;
  }
  
  .brand-logo {
    height: 1.25rem;
  }
  
  .main {
    padding: 1rem 0.5rem 2rem;
  }
  
  .session-card {
    padding: 0.75rem;
  }
  
  .session-title {
    font-size: 0.9rem;
  }

  /* Sponsors very small screens */
  .sponsors-container {
    padding: 0 1rem;
  }
  
  .sponsors-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  
  .sponsor-item {
    max-width: 100%;
    padding: 1rem;
    min-height: 90px;
  }
  
  .sponsor-logo {
    max-height: 55px;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .session-card {
    border-width: 2px;
  }
  
  .type-badge {
    border: 1px solid currentColor;
  }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}