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

:root {
  --bg:        #09090f;
  --surface:   #111118;
  --border:    rgba(255,255,255,.08);
  --text:      #f1f1f5;
  --muted:     #7c7c9a;
  --accent:    #6366f1;
  --sidebar-w: 240px;
  --radius:    14px;
  --ease:      cubic-bezier(.4,0,.2,1);
  font-family: 'Space Grotesk', system-ui, sans-serif;
}

html, body { height: 100%; overflow: hidden; background: var(--bg); color: var(--text); }

/* ── Hub ────────────────────────────────────────────────────────────── */
#hub {
  position: fixed; inset: 0;
  display: flex; flex-direction: column;
  overflow-y: auto;
  transition: opacity .35s var(--ease), transform .35s var(--ease);
}
#hub.leaving {
  opacity: 0;
  transform: scale(.97);
  pointer-events: none;
}

/* Background decorations */
.hub-bg { position: fixed; inset: 0; pointer-events: none; overflow: hidden; z-index: 0; }
.bg-orb {
  position: absolute; border-radius: 50%;
  filter: blur(120px); opacity: .18;
}
.bg-orb-a {
  width: 700px; height: 700px;
  background: radial-gradient(circle, #6366f1, transparent 70%);
  top: -200px; left: -150px;
}
.bg-orb-b {
  width: 600px; height: 600px;
  background: radial-gradient(circle, #0ea5e9, transparent 70%);
  bottom: -200px; right: -100px;
}
.bg-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
  background-size: 48px 48px;
}

/* Hub header */
.hub-header {
  position: relative; z-index: 1;
  padding: 28px 48px 0;
}
.hub-brand {
  display: flex; align-items: center; gap: 10px;
  color: var(--text);
}
.hub-brand svg { opacity: .85; flex-shrink: 0; }
.brand-name   { font-size: 1rem; font-weight: 700; letter-spacing: -.01em; }
.brand-sep    { color: var(--muted); font-weight: 400; }
.brand-section { font-size: 1rem; font-weight: 500; color: var(--muted); }

/* Hub main */
.hub-main {
  position: relative; z-index: 1;
  flex: 1;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: 48px 48px 64px;
  gap: 48px;
}
.hub-intro { text-align: center; }
.hub-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -.03em;
  line-height: 1.1;
  background: linear-gradient(135deg, #fff 40%, rgba(255,255,255,.5));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
  margin-bottom: 12px;
}
.hub-subtitle {
  font-size: 1rem;
  color: var(--muted);
  max-width: 480px;
  margin: 0 auto;
  line-height: 1.6;
}

/* Cards grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 360px));
  gap: 20px;
  width: 100%;
  max-width: 1200px;
  justify-content: center;
}

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 28px 24px;
  cursor: pointer;
  transition: transform .22s var(--ease), box-shadow .22s var(--ease), border-color .22s var(--ease);
  overflow: hidden;
  outline: none;
  text-align: left;
}
.card::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, var(--card-accent-faint, rgba(99,102,241,.08)), transparent 70%);
  pointer-events: none;
  transition: opacity .3s;
}
.card:hover, .card:focus-visible {
  transform: translateY(-4px);
  box-shadow: 0 20px 50px rgba(0,0,0,.4), 0 0 0 1px var(--card-accent, var(--accent));
  border-color: var(--card-accent, var(--accent));
}
.card:active { transform: translateY(-2px); }

.card-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 20px;
  background: color-mix(in srgb, var(--card-accent, var(--accent)) 15%, transparent);
  color: var(--card-accent, var(--accent));
}
.card-icon svg { width: 24px; height: 24px; }

.card-name {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--text);
  margin-bottom: 8px;
}
.card-desc {
  font-size: .875rem;
  color: var(--muted);
  line-height: 1.55;
}
.card-arrow {
  position: absolute; bottom: 22px; right: 22px;
  color: var(--card-accent, var(--accent));
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity .2s, transform .2s;
}
.card:hover .card-arrow, .card:focus-visible .card-arrow {
  opacity: 1; transform: translateX(0);
}

/* ── Viewer ─────────────────────────────────────────────────────────── */
#viewer {
  position: fixed; inset: 0;
  display: flex;
  opacity: 0;
  transform: scale(1.02);
  transition: opacity .35s var(--ease), transform .35s var(--ease);
  pointer-events: none;
}
#viewer.visible {
  opacity: 1; transform: scale(1);
  pointer-events: auto;
}
#viewer.hidden { display: none; }

/* Sidebar */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: #0d0d14;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 0;
  overflow: hidden;
}
.sidebar-top {
  padding: 20px 16px 16px;
  border-bottom: 1px solid var(--border);
  display: flex; flex-direction: column; gap: 16px;
}
.btn-back {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(255,255,255,.05);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 8px;
  padding: 7px 12px;
  font-size: .8rem; font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background .18s, color .18s, border-color .18s;
  width: fit-content;
}
.btn-back:hover {
  background: rgba(255,255,255,.1);
  color: var(--text);
  border-color: rgba(255,255,255,.18);
}
.sidebar-brand {
  display: flex; align-items: center; gap: 8px;
  color: var(--text); font-size: .85rem; font-weight: 700;
}
.sidebar-brand svg { opacity: .7; }

.sidebar-nav {
  flex: 1;
  padding: 12px 10px;
  display: flex; flex-direction: column; gap: 4px;
  overflow-y: auto;
}
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background .18s, color .18s;
  border: none; background: transparent;
  color: var(--muted);
  font-family: inherit; font-size: .85rem; font-weight: 500;
  text-align: left;
  width: 100%;
}
.nav-item:hover { background: rgba(255,255,255,.06); color: var(--text); }
.nav-item.active {
  background: color-mix(in srgb, var(--item-accent, var(--accent)) 18%, transparent);
  color: var(--item-accent, var(--accent));
}
.nav-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--item-accent, var(--accent));
  flex-shrink: 0;
  opacity: .5;
  transition: opacity .18s;
}
.nav-item.active .nav-dot { opacity: 1; }
.nav-label { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.sidebar-footer {
  padding: 12px 16px;
  border-top: 1px solid var(--border);
  min-height: 40px;
}
.active-label {
  font-size: .7rem;
  font-family: 'JetBrains Mono', monospace;
  color: var(--muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  display: block;
}

/* Iframe wrap */
.viewer-frame-wrap {
  flex: 1;
  position: relative;
  background: var(--bg);
}
#pres-frame {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  border: none;
}
.frame-loader {
  position: absolute; inset: 0; z-index: 2;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg);
  transition: opacity .3s;
}
.frame-loader.done { opacity: 0; pointer-events: none; }
.spinner {
  width: 36px; height: 36px;
  border: 3px solid rgba(255,255,255,.1);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Utilities ──────────────────────────────────────────────────────── */
.hidden { display: none !important; }

@media (max-width: 600px) {
  .hub-header { padding: 20px 20px 0; }
  .hub-main   { padding: 32px 20px 48px; }
  .sidebar    { width: 200px; }
  :root       { --sidebar-w: 200px; }
}