/* Header layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: radial-gradient(circle at top left, rgba(21, 24, 32, 0.96), rgba(5, 6, 8, 0.98));
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

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

/* Branding */
.site-header__branding {
  display: flex;
  align-items: center;
}

.site-header__logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-size: var(--font-size-sm);
}

.site-header__logo::after {
  content: none;
}

.site-header__logo-mark {
  width: 26px;
  height: 26px;
  border-radius: 999px;
  background: radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.35), transparent 55%), linear-gradient(135deg, var(--color-primary) 0%, #b31237 45%, #050608 100%);
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.18), 0 10px 25px rgba(0, 0, 0, 0.85);
  position: relative;
  overflow: hidden;
}

.site-header__logo-mark::after {
  content: "IS";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.55rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.site-header__logo-text {
  font-weight: 600;
}

/* Navigation */
.site-header__nav {
  display: flex;
}

.site-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

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

.site-header__nav-link {
  position: relative;
  font-size: var(--font-size-sm);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  padding: 0.4rem 0;
}

.site-header__nav-link::after {
  height: 1px;
}

.site-header__nav-link:hover,
.site-header__nav-link:focus-visible {
  color: #ffffff;
}

.site-header__nav-link--button {
  padding: 0.45rem 1.4rem;
  border-radius: var(--radius-full);
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: radial-gradient(circle at top left, rgba(255, 255, 255, 0.1), transparent 55%), linear-gradient(135deg, var(--color-primary) 0%, #b31237 45%, #050608 100%);
  color: #ffffff;
  box-shadow: var(--shadow-sm);
}

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

.site-header__nav-link--button:hover,
.site-header__nav-link--button:focus-visible {
  border-color: rgba(255, 255, 255, 0.5);
  box-shadow: var(--shadow-md);
}

/* Toggle (mobile) */
.site-header__toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  padding: 0.3rem 0.55rem;
  border-radius: var(--radius-full);
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(5, 6, 8, 0.85);
  color: var(--color-text);
}

.site-header__toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

.site-header__toggle-box {
  position: relative;
  width: 20px;
  height: 16px;
}

.site-header__toggle-line {
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 999px;
  background: #ffffff;
  transform-origin: center;
  transition: transform var(--transition-normal), opacity var(--transition-fast), top var(--transition-normal), bottom var(--transition-normal);
}

.site-header__toggle-line--top {
  top: 0;
}

.site-header__toggle-line--middle {
  top: 50%;
  transform: translateY(-50%);
}

.site-header__toggle-line--bottom {
  bottom: 0;
}

.site-header__toggle-text {
  font-size: var(--font-size-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

/* Toggle active */
.site-header--menu-open .site-header__toggle-line--top {
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
}

.site-header--menu-open .site-header__toggle-line--middle {
  opacity: 0;
}

.site-header--menu-open .site-header__toggle-line--bottom {
  bottom: 50%;
  transform: translateY(50%) rotate(-45deg);
}

/* Responsive */
@media (max-width: 900px) {
  .site-header__inner {
    padding-top: var(--space-2);
    padding-bottom: var(--space-2);
  }

  .site-header__toggle {
    display: inline-flex;
  }

  .site-header__nav {
    position: fixed;
    inset: 0 0 auto 0;
    top: 56px;
    background: radial-gradient(circle at top left, rgba(21, 24, 32, 0.98), rgba(5, 6, 8, 0.98));
    border-top: 1px solid rgba(255, 255, 255, 0.04);
    transform: translateY(-110%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-normal), opacity var(--transition-normal);
  }

  .site-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-4) var(--container-padding-x) var(--space-6);
    gap: var(--space-3);
  }

  .site-header__nav-item--accent {
    margin-left: 0;
    margin-top: var(--space-3);
  }

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

  .site-header__nav-link--button {
    width: 100%;
    text-align: center;
    justify-content: center;
  }

  .site-header--menu-open .site-header__nav {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  body.site-header--lock-scroll {
    overflow: hidden;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header__nav {
    transition: none;
  }
}