.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: linear-gradient(to bottom, rgba(5, 7, 18, 0.96), rgba(5, 7, 18, 0.85), transparent);
  border-bottom: 1px solid rgba(148, 163, 184, 0.25);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-3);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
}

.site-header__logo-mark {
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 30%;
  background: radial-gradient(circle at 30% 20%, #ffffff 0, #8b9dff 22%, #6173ff 45%, #111827 72%);
  box-shadow: 0 0 22px rgba(97, 115, 255, 0.6);
}

.site-header__brand-text {
  display: flex;
  flex-direction: column;
}

.site-header__brand-name {
  font-family: var(--font-display);
  font-size: var(--font-size-xl);
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.site-header__brand-tagline {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.site-header__nav {
  display: flex;
}

.site-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-header__nav-link {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  padding-block: 0.35rem;
  position: relative;
}

.site-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.45rem;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(to right, var(--color-primary), var(--color-success));
  opacity: 0;
  transform: scaleX(0.5);
  transform-origin: center;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.site-header__nav-link:hover::after,
.site-header__nav-link:focus-visible::after,
.site-header__nav-link--active::after {
  opacity: 1;
  transform: scaleX(1);
}

.site-header__nav-link--cta {
  padding-inline: var(--space-4);
  padding-block: 0.5rem;
  border-radius: var(--radius-pill);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-strong) 100%);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.18);
  box-shadow: var(--shadow-glow-primary);
}

.site-header__nav-link--cta::after {
  display: none;
}

.site-header__nav-item--cta {
  margin-left: var(--space-2);
}

.site-header__menu-toggle {
  display: none;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(148, 163, 184, 0.5);
  background: rgba(15, 23, 42, 0.96);
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 0.25rem;
  cursor: pointer;
}

.site-header__menu-toggle-bar {
  width: 1.3rem;
  height: 2px;
  border-radius: 999px;
  background: #e5e7eb;
  transition: transform var(--transition-base), opacity var(--transition-base), width var(--transition-base);
}

.site-header__menu-toggle.is-open .site-header__menu-toggle-bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.site-header__menu-toggle.is-open .site-header__menu-toggle-bar:nth-child(2) {
  opacity: 0;
  width: 0;
}

.site-header__menu-toggle.is-open .site-header__menu-toggle-bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

@media (max-width: 880px) {
  .site-header__menu-toggle {
    display: inline-flex;
  }

  .site-header__nav {
    position: absolute;
    inset-inline: 0;
    top: 100%;
    background: radial-gradient(circle at top, rgba(15, 23, 42, 0.98) 0, rgba(5, 7, 18, 0.98) 52%, rgba(5, 7, 18, 0.98) 100%);
    border-bottom: 1px solid rgba(148, 163, 184, 0.35);
    transform-origin: top;
    transform: scaleY(0.9);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
  }

  .site-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-4);
    gap: var(--space-3);
  }

  .site-header__nav-link {
    font-size: var(--font-size-base);
  }

  .site-header__nav-link--cta {
    width: 100%;
    text-align: center;
  }

  .site-header__nav-item--cta {
    width: 100%;
    margin-left: 0;
    margin-top: var(--space-2);
  }

  .site-header__nav--open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: scaleY(1);
  }
}

@media (max-width: 520px) {
  .site-header__brand-tagline {
    display: none;
  }
}