:root {
  --bg: #09090b;
  --surface: #111113;
  --border: #1e1e22;
  --text: #fafafa;
  --text-secondary: #71717a;
  --accent: #22d3ee;
  --accent-dim: rgba(34,211,238,0.12);
  --mono: 'JetBrains Mono', monospace;
  --sans: 'Space Grotesk', system-ui, sans-serif;
  --chat-accent: #10a37f;
  --chat-accent-shadow: rgba(16,163,127,0.4);
  --chat-accent-shadow-hover: rgba(16,163,127,0.6);
  --chat-accent-shadow-bright: rgba(16,163,127,0.8);
  --chat-accent-shadow-dim: rgba(16,163,127,0.3);
  --chat-accent-border: rgba(16,163,127,0.3);
  --chat-accent-border-dim: rgba(16,163,127,0.2);
  --chat-accent-border-focus: rgba(16,163,127,0.5);
  --chat-accent-glow: rgba(16,163,127,0.1);
  --chat-accent-bg: rgba(16,163,127,0.25);
  --chat-accent-bg-strong: rgba(16,163,127,0.8);
  --chat-bg: rgba(10,10,11,0.95);
  --chat-header-bg: rgba(0,0,0,0.3);
  --chat-input-bg: rgba(0,0,0,0.4);
  --chat-input-area-bg: rgba(0,0,0,0.2);
  --chat-text: rgba(255,255,255,0.9);
  --chat-text-dim: rgba(255,255,255,0.5);
  --chat-text-dimmer: rgba(255,255,255,0.3);
  --chat-text-hover-bg: rgba(255,255,255,0.1);
  --chat-input-border: rgba(255,255,255,0.1);
  --chat-msg-assistant-bg: rgba(255,255,255,0.05);
  --chat-msg-assistant-border: rgba(255,255,255,0.2);
  --chat-code-bg: rgba(255,255,255,0.1);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

/* -- NAV -- */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 40px; height: 56px;
  background: rgba(9,9,11,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-brand {
  font-family: var(--mono);
  font-weight: 700; font-size: 14px;
  letter-spacing: 0.04em;
  display: flex; align-items: center; gap: 8px;
}
.nav-brand .mit {
  background: #a31f34;
  color: white;
  font-size: 10px;
  padding: 2px 5px;
  font-weight: 700;
  letter-spacing: 0.08em;
}
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--text); }

/* -- HERO -- */
.hero {
  padding: 140px 40px 80px;
  max-width: 1100px;
  margin: 0 auto;
}
.hero-ascii {
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1.25;
  color: var(--text-secondary);
  white-space: pre;
  margin-bottom: 32px;
  opacity: 0.5;
}
.hero h1 {
  font-family: var(--sans);
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 300;
  line-height: 1.3;
  color: var(--text-secondary);
  max-width: 800px;
}
.hero h1 strong {
  color: var(--text);
  font-weight: 500;
}

/* -- CONTROL LOOP -- */
.control-loop {
  margin-top: 40px;
  max-width: 700px;
}
.control-loop svg {
  width: 100%;
  height: auto;
}
.control-loop text {
  font-family: var(--mono);
}

/* -- SECTIONS -- */
section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 60px 40px;
}
.section-label {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 32px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

/* -- RESEARCH GRID -- */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}
.research-card {
  background: var(--bg);
  padding: 28px 24px;
  transition: background 0.2s;
  cursor: default;
}
.research-card:hover { background: var(--surface); }
.research-card .num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent);
  margin-bottom: 12px;
}
.research-card h3 {
  font-size: 15px;
  font-weight: 500;
  margin-bottom: 10px;
  line-height: 1.4;
}
.research-card p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* -- TEAM TABLE -- */
.team-table { width: 100%; border-collapse: collapse; }
.team-table tr {
  border-bottom: 1px solid var(--border);
  transition: background 0.15s;
}
.team-table tr:hover { background: var(--surface); }
.team-table td {
  padding: 14px 0;
  vertical-align: top;
}
.team-table .role {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-secondary);
  width: 180px;
  letter-spacing: 0.02em;
  padding-right: 24px;
}
.team-table .names {
  font-size: 14px;
  color: var(--text);
  line-height: 1.8;
}
.team-table .names .count {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-secondary);
  margin-left: 4px;
}

/* -- NETWORK CTA -- */
.network-cta {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 32px;
  border: 1px solid var(--border);
  background: var(--surface);
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  text-decoration: none;
}
.network-cta:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
}
.network-cta:hover .arrow { color: var(--accent); }
.network-cta .cta-text h3 {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 4px;
}
.network-cta .cta-text p {
  font-size: 13px;
  color: var(--text-secondary);
}
.network-cta .arrow {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 20px;
  color: var(--text-secondary);
  transition: color 0.2s;
}

/* -- POSITIONS -- */
.positions-list { display: flex; flex-direction: column; gap: 1px; background: var(--border); border: 1px solid var(--border); }
.position-row {
  display: flex; justify-content: space-between; align-items: center;
  padding: 18px 24px;
  background: var(--bg);
  transition: background 0.15s;
}
.position-row:hover { background: var(--surface); }
.position-row .title { font-size: 14px; font-weight: 500; }
.position-row .tag {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent);
  letter-spacing: 0.04em;
}
.position-row a {
  text-decoration: none; color: inherit; display: flex;
  justify-content: space-between; align-items: center; width: 100%;
}
.position-row a:hover .title { color: var(--accent); }
.position-category {
  font-size: 11px; font-family: var(--mono); color: var(--text-secondary);
  letter-spacing: 0.06em; text-transform: uppercase;
  padding: 10px 24px 6px; background: var(--bg);
}

/* -- CONTACT -- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}
.contact-grid p {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 8px;
}
.contact-grid strong { color: var(--text); font-weight: 500; }
.contact-grid a { color: var(--accent); }

/* -- FOOTER -- */
footer {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
footer span {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-secondary);
}

/* -- DATASETS LEADERBOARD -- */
.leaderboard-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 16px; flex-wrap: wrap; gap: 12px;
}
.leaderboard-tabs {
  display: flex; gap: 0; border: 1px solid var(--border); overflow: hidden;
}
.leaderboard-tabs button {
  font-family: var(--mono); font-size: 12px;
  background: var(--bg); color: var(--text-secondary);
  border: none; padding: 8px 16px; cursor: pointer;
  border-right: 1px solid var(--border);
  transition: background 0.15s, color 0.15s;
}
.leaderboard-tabs button:last-child { border-right: none; }
.leaderboard-tabs button:hover { background: var(--surface); color: var(--text); }
.leaderboard-tabs button.active { background: var(--accent-dim); color: var(--accent); }
.leaderboard-search {
  font-family: var(--mono); font-size: 13px;
  background: var(--surface); color: var(--text);
  border: 1px solid var(--border); padding: 8px 14px;
  width: 260px; outline: none; transition: border-color 0.2s;
}
.leaderboard-search:focus { border-color: var(--accent); }
.leaderboard-search::placeholder { color: var(--text-secondary); }
.leaderboard-table { width: 100%; border-collapse: collapse; }
.leaderboard-table thead th {
  font-family: var(--mono); font-size: 11px; font-weight: 500;
  color: var(--text-secondary); letter-spacing: 0.06em;
  text-transform: uppercase; text-align: left;
  padding: 10px 16px; border-bottom: 1px solid var(--border);
}
.leaderboard-table thead th:last-child { text-align: right; }
.leaderboard-table tbody tr {
  border-bottom: 1px solid var(--border);
  transition: background 0.12s; cursor: pointer;
}
.leaderboard-table tbody tr:hover { background: var(--surface); }
.leaderboard-table td { padding: 12px 16px; vertical-align: middle; }
.leaderboard-table .rank {
  font-family: var(--mono); font-size: 12px;
  color: var(--text-secondary); width: 40px;
}
.leaderboard-table .ds-name { font-size: 14px; font-weight: 500; }
.leaderboard-table .ds-source {
  font-family: var(--mono); font-size: 12px;
  color: var(--text-secondary); display: block; margin-top: 2px;
}
.leaderboard-table .ds-stat {
  font-family: var(--mono); font-size: 13px;
  color: var(--accent); text-align: right;
}
.leaderboard-table .ds-tag {
  font-family: var(--mono); font-size: 10px;
  padding: 2px 6px; letter-spacing: 0.04em;
  border: 1px solid var(--border); color: var(--text-secondary);
  display: inline-block; margin-right: 4px;
}
.leaderboard-count {
  font-family: var(--mono); font-size: 12px;
  color: var(--text-secondary); margin-top: 12px;
}

/* -- SCROLLING BANNER -- */
.hero-banner {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 32px;
  overflow: hidden;
}
.hero-banner .mit-badge {
  background: #a31f34;
  color: white;
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  padding: 3px 8px;
  letter-spacing: 0.08em;
  flex-shrink: 0;
  vertical-align: super;
}
.hero-banner .scroll-track {
  overflow: hidden;
  flex: 1;
  mask-image: linear-gradient(to right, transparent, black 32px, black calc(100% - 32px), transparent);
  -webkit-mask-image: linear-gradient(to right, transparent, black 32px, black calc(100% - 32px), transparent);
}
.hero-banner .scroll-inner {
  display: flex;
  gap: 0;
  white-space: nowrap;
  animation: scroll-left 28s linear infinite;
  width: max-content;
}
.hero-banner .scroll-inner:hover {
  animation-play-state: paused;
}
.hero-banner .assoc-item {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
  padding: 0 12px;
}
.hero-banner .assoc-sep {
  color: var(--accent);
  opacity: 0.4;
  font-size: 10px;
  padding: 0 4px;
  align-self: center;
}
@keyframes scroll-left {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

/* -- RESPONSIVE -- */
@media (max-width: 700px) {
  nav { padding: 0 20px; }
  .hero, section, footer { padding-left: 20px; padding-right: 20px; }
  .contact-grid { grid-template-columns: 1fr; gap: 24px; }
  .team-table .role { width: 120px; font-size: 11px; }
  .hero-ascii { font-size: 7px; }
  #ai-chat-popup { width: calc(100vw - 32px); right: 16px; }
}

/* -- AI CHAT WIDGET -- */
.chat-fab {
  position: fixed; bottom: 24px; right: 24px; z-index: 1000;
  width: 48px; height: 48px; border-radius: 50%;
  background: var(--chat-accent); border: none; cursor: pointer;
  box-shadow: 0 4px 16px var(--chat-accent-shadow);
  display: flex; align-items: center; justify-content: center;
  transition: transform 0.2s, box-shadow 0.2s;
}
.chat-fab:hover { transform: scale(1.1); box-shadow: 0 6px 24px var(--chat-accent-shadow-hover); }
.chat-fab svg { width: 22px; height: 22px; fill: white; }
@keyframes chat-sparkle {
  0%,100% { box-shadow: 0 4px 16px var(--chat-accent-shadow); }
  50% { box-shadow: 0 0 24px var(--chat-accent-shadow-bright), 0 0 48px var(--chat-accent-shadow-dim); }
}
.chat-fab.sparkle { animation: chat-sparkle 1.5s ease-in-out; }

#ai-chat-popup {
  position: fixed; bottom: 84px; right: 24px; z-index: 1001;
  width: 400px; max-height: 460px;
  background: var(--chat-bg); backdrop-filter: blur(12px);
  border: 1px solid var(--chat-accent-border); border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.5), 0 0 40px var(--chat-accent-glow);
  display: flex; flex-direction: column;
  font-family: var(--mono);
  transition: all 0.3s cubic-bezier(0.4,0,0.2,1);
  opacity: 1; transform: translateY(0);
}
#ai-chat-popup.hidden {
  opacity: 0; transform: translateY(20px); pointer-events: none;
}
.chat-header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--chat-accent-border-dim);
  display: flex; justify-content: space-between; align-items: center;
  background: var(--chat-header-bg); border-radius: 12px 12px 0 0;
}
.chat-header h3 {
  font-size: 13px; font-weight: 500; color: var(--chat-accent);
  font-family: var(--mono); letter-spacing: 0.5px;
}
.chat-header h3::before { content: '> '; opacity: 0.5; }
.chat-close {
  background: none; border: none; color: var(--chat-text-dim);
  cursor: pointer; font-size: 18px; width: 24px; height: 24px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 4px; transition: all 0.2s;
}
.chat-close:hover { background: var(--chat-text-hover-bg); color: #fff; }
.chat-messages {
  flex: 1; overflow-y: auto; padding: 12px 16px;
  max-height: 300px; font-size: 13px; line-height: 1.5;
}
.chat-message {
  margin-bottom: 10px; padding: 10px 12px; border-radius: 6px;
  font-size: 13px; color: var(--chat-text);
}
.chat-message.user {
  background: var(--chat-accent-bg); border-left: 2px solid var(--chat-accent); margin-left: 20px;
}
.chat-message.assistant {
  background: var(--chat-msg-assistant-bg); border-left: 2px solid var(--chat-msg-assistant-border); margin-right: 20px;
}
.chat-message.assistant a { color: var(--chat-accent); text-decoration: none; }
.chat-message.assistant a:hover { text-decoration: underline; }
.chat-message.assistant strong { color: #fff; }
.chat-message.assistant code {
  background: var(--chat-code-bg); padding: 2px 6px; border-radius: 4px; font-size: 12px;
}
.chat-message.assistant ul, .chat-message.assistant ol { margin: 6px 0; padding-left: 20px; }
.chat-message.assistant li { margin: 3px 0; }
.chat-input-area {
  padding: 12px 16px; border-top: 1px solid var(--chat-accent-border-dim);
  display: flex; gap: 8px; background: var(--chat-input-area-bg); border-radius: 0 0 12px 12px;
}
.chat-input-area input {
  flex: 1; padding: 10px 12px;
  background: var(--chat-input-bg); border: 1px solid var(--chat-input-border);
  border-radius: 6px; color: var(--chat-text);
  font-size: 13px; font-family: var(--mono);
}
.chat-input-area input::placeholder { color: var(--chat-text-dimmer); }
.chat-input-area input:focus {
  outline: none; border-color: var(--chat-accent-border-focus);
  box-shadow: 0 0 0 2px var(--chat-accent-glow);
}
.chat-input-area button {
  padding: 10px 14px; background: var(--chat-accent-bg-strong);
  border: none; border-radius: 6px; color: white; cursor: pointer;
  font-size: 12px; font-family: var(--mono); font-weight: 500; transition: all 0.2s;
}
.chat-input-area button:hover { background: var(--chat-accent); }