/* ============================================
   SPARK - Layout
   Nav, page structure, Mana Reactor ambient layer
   ============================================ */

/* --- Mana Reactor Ambient Background ---
   This sits behind everything. JS updates --reactor-X vars (0 or 1).
   The radial gradients blend based on active mana colors.
   Transition is on body so the whole page shifts together. */

body {
  position: relative;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(ellipse at 30% 30%,
      rgba(255, 253, 224, calc(0.06 * var(--reactor-w))) 0%, transparent 60%),
    radial-gradient(ellipse at 70% 40%,
      rgba(77, 166, 255, calc(0.06 * var(--reactor-u))) 0%, transparent 60%),
    radial-gradient(ellipse at 50% 70%,
      rgba(138, 111, 173, calc(0.06 * var(--reactor-b))) 0%, transparent 60%),
    radial-gradient(ellipse at 25% 60%,
      rgba(255, 107, 90, calc(0.06 * var(--reactor-r))) 0%, transparent 60%),
    radial-gradient(ellipse at 75% 65%,
      rgba(74, 222, 128, calc(0.06 * var(--reactor-g))) 0%, transparent 60%),
    radial-gradient(ellipse at 50% 40%,
      rgba(107, 63, 160, 0.05) 0%, transparent 50%),
    radial-gradient(ellipse at 40% 50%,
      rgba(201, 120, 12, 0.03) 0%, transparent 50%),
    var(--void);
  transition: background 800ms ease;
  animation: ambient-breathe 6s ease-in-out infinite;
}

/* --- Navigation --- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(7, 6, 10, 0.9);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--surface-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--content-padding);
  z-index: 100;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}

.nav-brand--active .nav-title {
  color: var(--gold-bright);
}

.nav-logo {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--gradient-gold);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 13px;
  color: var(--void);
  transition: transform var(--duration-fast) var(--ease-spring);
}

.nav-logo:hover {
  transform: scale(1.08);
}

.nav-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--gold-bright);
}

.nav-links {
  display: flex;
  gap: 2px;
}

.nav-link {
  font-weight: 600;
  font-size: 11px;
  letter-spacing: 0.12em;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  color: var(--text-muted);
  transition: all var(--duration-base) var(--ease-out);
}

.nav-link:hover {
  color: var(--text);
}

.nav-link.active {
  color: var(--gold-bright);
  background: rgba(201, 120, 12, 0.1);
}

/* --- Page System --- */

.page {
  display: none;
  padding-top: var(--nav-height);
  min-height: 100dvh;
}

.page.active {
  display: block;
  animation: fade-in var(--duration-slow) var(--ease-out);
}

.page-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-10) var(--content-padding);
}

.page-header {
  margin-bottom: var(--space-8);
}

.page-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: var(--text-3xl);
  letter-spacing: 0.06em;
  color: var(--text);
}

.page-desc {
  color: var(--text-secondary);
  margin-top: var(--space-2);
}

/* --- Section Headers --- */

.section-header {
  margin-bottom: var(--space-6);
  border-bottom: 1px solid var(--surface-border);
  padding-bottom: var(--space-4);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  letter-spacing: 0.2em;
  color: var(--gold);
}

.section-desc {
  font-size: var(--text-sm);
  color: var(--text-muted);
  margin-top: var(--space-1);
}

/* --- Responsive --- */

@media (max-width: 640px) {
  .nav-title {
    display: none;
  }
}