header {
  position: sticky;
  top: 0;
  z-index: 50;
}
header::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  backdrop-filter: saturate(160%) blur(10px);
  background: linear-gradient(180deg, rgba(12,18,40,.75), rgba(12,18,40,.35));
  border-bottom: 1px solid var(--stroke);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--txt);
}

.logo {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: conic-gradient(from 210deg, var(--brand-2), var(--brand), var(--brand-3));
  box-shadow: 0 8px 24px rgba(34,211,238,.25);
}

.brand b { font-weight: 800; letter-spacing: .2px }
.brand-tld { opacity: .75 }

.tag {
  font-size: 12px;
  padding: 2px 8px;
  border: 1px solid var(--stroke);
  border-radius: 999px;
  color: var(--muted);
}

.cta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 12px;
  background: linear-gradient(180deg, rgba(255,255,255,.15), rgba(255,255,255,.05));
  border: 1px solid var(--stroke);
  color: var(--txt);
  font-weight: 600;
}

.cta.primary {
  background: linear-gradient(180deg, rgba(34,211,238,.25), rgba(255,255,255,.06));
  border-color: rgba(34,211,238,.35);
}

.cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(34,211,238,.12);
  transition: .24s;
}

.cta.login {
  background: transparent;
  border-color: rgba(255,255,255,.2);
  font-weight: 500;
}

/* ── Hamburger button ── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  background: none;
  border: 1px solid var(--stroke);
  border-radius: 8px;
  cursor: pointer;
}
.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--txt);
  border-radius: 2px;
  transition: transform .3s, opacity .3s;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Mobile nav ── */
@media (max-width: 768px) {
  .hamburger { display: flex; }
  .tag { display: none; }

  nav {
    display: none;
    flex-direction: column;
    gap: 8px;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    padding: 16px;
    background: linear-gradient(180deg, rgba(12,18,40,.95), rgba(12,18,40,.92));
    backdrop-filter: saturate(160%) blur(14px);
    border-bottom: 1px solid var(--stroke);
  }
  nav.open { display: flex; }
  nav .cta { width: 100%; justify-content: center; }
}