/* ==========================================================================
   Header / Navigation
   ========================================================================== */

.site-header {
  position: fixed;
  inset-inline: 0;
  top: 0;
  z-index: 900;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: rgba(7, 11, 26, 0.55);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-base), background var(--transition-base), height var(--transition-base);
}

.site-header.is-scrolled {
  border-color: var(--border-color);
  background: rgba(7, 11, 26, 0.85);
  height: 68px;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

/* ---- Logo ---- */
.logo {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  isolation: isolate;
}
.logo__mark {
  width: 48px;
  height: 48px;
  flex-shrink: 0;
  object-fit: contain;
  mix-blend-mode: screen;
  filter: drop-shadow(0 0 10px rgba(45, 111, 255, 0.24));
  -webkit-mask-image: radial-gradient(ellipse 50% 50% at center, #000 70%, rgba(0, 0, 0, 0.94) 78%, rgba(0, 0, 0, 0.58) 87%, rgba(0, 0, 0, 0.16) 94%, transparent 100%);
  mask-image: radial-gradient(ellipse 50% 50% at center, #000 70%, rgba(0, 0, 0, 0.94) 78%, rgba(0, 0, 0, 0.58) 87%, rgba(0, 0, 0, 0.16) 94%, transparent 100%);
}
.logo__text {
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  line-height: 1.1;
}
.logo__text span {
  display: block;
  font-size: 0.62rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.14em;
  margin-top: 2px;
}

/* ---- Nav links ---- */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}
.nav-links a {
  font-weight: 600;
  font-size: 0.96rem;
  color: var(--text-secondary);
  position: relative;
  padding-block: 0.4rem;
  transition: color var(--transition-fast);
}
.nav-links a::after {
  content: "";
  position: absolute;
  bottom: 0;
  right: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-fast);
}
.nav-links a:hover,
.nav-links a.is-active { color: var(--text-primary); }
.nav-links a:hover::after,
.nav-links a.is-active::after { width: 100%; }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

/* ---- Mobile toggle ---- */
.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: rgba(255,255,255,0.04);
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text-primary);
  position: relative;
  transition: background var(--transition-fast);
}
.nav-toggle span::before,
.nav-toggle span::after {
  content: "";
  position: absolute;
  width: 18px;
  height: 2px;
  background: var(--text-primary);
  transition: transform var(--transition-fast);
}
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after { top: 6px; }

.nav-toggle[aria-expanded="true"] span { background: transparent; }
.nav-toggle[aria-expanded="true"] span::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span::after { transform: translateY(-6px) rotate(-45deg); }

/* ---- Page top padding (offset fixed header) ---- */
main { padding-top: var(--header-height); }