.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding-block: 1.5rem;
  transition: padding var(--dur-fast) var(--ease-premium),
    background var(--dur-fast) var(--ease-premium),
    box-shadow var(--dur-fast) var(--ease-premium),
    border-color var(--dur-fast) var(--ease-premium);
  border-bottom: 1px solid transparent;
}

.site-header.is-scrolled {
  padding-block: 1rem;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  border-bottom-color: var(--color-line);
  box-shadow: 0 8px 30px -20px rgba(20, 25, 27, 0.25);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex-shrink: 0;
}

.brand__mark {
  width: 30px;
  height: auto;
}

.brand__word {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-ink);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.brand__word em {
  font-style: italic;
  color: var(--color-brand);
  font-weight: 500;
}

.nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav a {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-ink);
  position: relative;
  padding-block: 0.3rem;
  white-space: nowrap;
}

.nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 0;
  height: 1px;
  background: var(--color-brand);
  transition: right var(--dur-fast) var(--ease-premium);
}

.nav a:hover {
  color: var(--color-brand);
}

.nav a:hover::after {
  right: 0;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex-shrink: 0;
}

.site-header__actions .btn {
  padding: 0.75rem 1.3rem;
  font-size: var(--fs-caption);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 26px;
}

.nav-toggle span {
  height: 1.5px;
  width: 100%;
  background: var(--color-ink);
  transition: transform var(--dur-fast) var(--ease-premium), opacity var(--dur-fast);
}

@media (max-width: 1150px) {
  .nav {
    position: fixed;
    inset: 0 0 0 30%;
    background: var(--color-bg);
    flex-direction: column;
    justify-content: center;
    gap: 2.2rem;
    transform: translateX(100%);
    transition: transform var(--dur-med) var(--ease-premium);
    box-shadow: -20px 0 60px -30px rgba(0,0,0,0.25);
  }

  .nav.is-open {
    transform: translateX(0);
  }

  .nav a {
    font-size: 1.35rem;
    font-family: var(--font-display);
  }

  .site-header__actions .btn-primary {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-toggle.is-active span:nth-child(1) {
    transform: translateY(6.5px) rotate(45deg);
  }
  .nav-toggle.is-active span:nth-child(2) {
    opacity: 0;
  }
  .nav-toggle.is-active span:nth-child(3) {
    transform: translateY(-6.5px) rotate(-45deg);
  }
}