:root {
  --bg: #05070c;
  --bg2: #08101d;
  --panel: rgba(12,18,32,.84);
  --panel2: rgba(16,24,42,.92);
  --line: rgba(137,165,255,.14);
  --line2: rgba(45,226,255,.26);
  --text: #eef4ff;
  --muted: #98a8c9;
  --cyan: #2de2ff;
  --blue: #4f7cff;
  --green: #35f2a0;
  --red: #ff4f6d;
  --amber: #ffb84d;
  --purple: #b76cff;
  --radius: 24px;
  --shadow: 0 28px 70px rgba(0,0,0,.42);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 12% 0%, rgba(45,226,255,.10), transparent 26%),
    radial-gradient(circle at 84% 8%, rgba(183,108,255,.10), transparent 28%),
    radial-gradient(circle at 50% 120%, rgba(79,124,255,.12), transparent 42%),
    linear-gradient(180deg, #04070d, #05070c);
  min-height: 100vh;
  overflow-x: hidden;
}
body::before {
  content:"";
  position: fixed;
  inset:0;
  pointer-events:none;
  background-image: linear-gradient(rgba(255,255,255,.018) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.018) 1px, transparent 1px);
  background-size: 54px 54px;
  mask-image: radial-gradient(circle at center, black 38%, transparent 95%);
}
.noise {
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .05;
  background-image: radial-gradient(rgba(255,255,255,.55) .5px, transparent .5px);
  background-size: 7px 7px;
  z-index: 1;
}
.ambient {
  position: fixed;
  border-radius: 999px;
  filter: blur(90px);
  opacity: .28;
  pointer-events:none;
  z-index: 0;
}
.ambient-a { width: 360px; height: 360px; left: -120px; top: 90px; background: rgba(45,226,255,.18); }
.ambient-b { width: 440px; height: 440px; right: -140px; top: 240px; background: rgba(183,108,255,.18); }
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 16px 26px;
  background: rgba(5,7,12,.76);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line);
}
.brand { display:flex; align-items:center; gap: 13px; text-decoration:none; color:inherit; }
.brand-mark {
  width:18px; height:18px; border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #fff, var(--cyan) 35%, var(--blue) 68%);
  box-shadow: 0 0 24px rgba(45,226,255,.5);
}
.brand strong { display:block; font-size: 1rem; }
.brand small { color: var(--muted); }
.nav { display:flex; gap: 16px; flex-wrap: wrap; }
.nav a { color: var(--muted); text-decoration:none; font-size: .94rem; }
.nav a:hover, .nav a.active { color: var(--text); }
.topbar-actions { display:flex; gap: 10px; flex-wrap:wrap; }
main { position:relative; z-index:2; width:min(1440px, calc(100% - 32px)); margin:0 auto; padding: 28px 0 86px; }
.panel {
  background: linear-gradient(180deg, rgba(15,22,38,.86), rgba(8,12,22,.86));
  border:1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.eyebrow {
  margin:0;
  letter-spacing:.18em;
  text-transform:uppercase;
  color: var(--cyan);
  font-size:.75rem;
  font-weight: 900;
}
.btn, .icon-btn, .mini-btn {
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap: 8px;
  border-radius: 16px;
  border:1px solid transparent;
  min-height: 46px;
  padding: 12px 17px;
  color: var(--text);
  background: rgba(255,255,255,.04);
  text-decoration:none;
  font-weight: 800;
  cursor:pointer;
  transition:.25s ease;
}
.btn:hover, .icon-btn:hover, .mini-btn:hover { transform: translateY(-1px); border-color: rgba(45,226,255,.32); }
.btn.primary { background: linear-gradient(135deg, var(--blue), var(--cyan)); box-shadow: 0 18px 42px rgba(79,124,255,.22); }
.btn.ghost { border-color: rgba(255,255,255,.09); }
.btn.soft { background: linear-gradient(135deg, rgba(183,108,255,.28), rgba(45,226,255,.16)); border-color: rgba(183,108,255,.26); }
.section { margin-top: 34px; }
.section-heading { margin-bottom: 20px; }
.section-heading h2 { margin: 8px 0 10px; font-size: clamp(1.8rem, 3vw, 2.7rem); line-height: 1.06; }
.section-heading p:last-child { color: var(--muted); max-width: 980px; line-height: 1.72; }
.lead { color: var(--muted); font-size: 1.08rem; line-height: 1.74; }
.footer-note { margin-top: 30px; padding: 18px 20px; color: var(--muted); }
.hidden { display:none !important; }
.popup-overlay {
  position: fixed;
  inset: 0;
  z-index: 80;
  display:flex;
  align-items:center;
  justify-content:center;
  padding: 20px;
  background: rgba(2,5,10,.74);
  backdrop-filter: blur(12px);
}
.popup-panel { width:min(900px, 100%); max-height: 88vh; overflow:auto; padding: 22px 22px 26px; }
.popup-close {
  float:right;
  width:42px;
  height:42px;
  border-radius:50%;
  border:1px solid var(--line);
  background: rgba(255,255,255,.04);
  color: var(--text);
  font-size:1.55rem;
  cursor:pointer;
}
.popup-content { clear:both; }
.popup-content h3 { font-size: 1.7rem; margin: 8px 0 12px; }
.popup-content p, .popup-content li { color: var(--muted); line-height: 1.72; }
.popup-equation {
  margin: 18px 0;
  padding: 16px 18px;
  border-radius: 18px;
  background: rgba(4,9,15,.78);
  border: 1px solid rgba(45,226,255,.16);
  color: #c1fff7;
  font-weight: 900;
}
canvas { width:100%; height:auto; display:block; border-radius: 20px; background: radial-gradient(circle at 50% 35%, rgba(79,124,255,.06), rgba(3,5,10,.88)); border:1px solid rgba(255,255,255,.07); }
@media(max-width: 1180px) {
  .nav { display:none; }
}
@media(max-width: 720px) {
  .topbar { flex-wrap:wrap; padding:14px 16px; }
  main { width:min(100% - 18px, 100%); }
}