.so-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: linear-gradient(135deg, rgba(240, 253, 244, 0.94), rgba(255, 255, 255, 0.96));
  border-bottom: 1px solid rgba(220, 252, 231, 0.9);
}

.so-header__inner {
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

.so-header__brand {
  display: flex;
  align-items: center;
}

.so-header__logo-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  padding-block: 0.25rem;
}

.so-header__logo-mark {
  width: 36px;
  height: 36px;
  border-radius: 16px;
  background: radial-gradient(circle at 20% 0, #bbf7d0, #22c55e);
  box-shadow: 0 12px 30px rgba(22, 163, 74, 0.45);
  position: relative;
}

.so-header__logo-mark::before,
.so-header__logo-mark::after {
  content: "";
  position: absolute;
  border-radius: inherit;
}

.so-header__logo-mark::before {
  inset: 4px;
  border: 1px solid rgba(240, 253, 244, 0.9);
}

.so-header__logo-mark::after {
  inset: 11px 8px 9px 8px;
  border-radius: 999px;
  background: rgba(240, 253, 244, 0.9);
}

.so-header__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.so-header__title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-heading);
}

.so-header__subtitle {
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.so-header__nav {
  display: flex;
  align-items: center;
}

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

.so-header__nav-link {
  position: relative;
  font-size: 0.85rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gray-700);
  padding-block: 0.35rem;
  white-space: nowrap;
}

.so-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.2rem;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, #22c55e, #d97706);
  opacity: 0;
  transform: scaleX(0.5);
  transform-origin: center;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.so-header__nav-link:hover::after {
  opacity: 1;
  transform: scaleX(1);
}

.so-header__nav-item--highlight .so-header__nav-link {
  padding-inline: 1.3rem;
  padding-block: 0.55rem;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(21, 128, 61, 0.3);
  background: radial-gradient(circle at 0 0, rgba(240, 253, 244, 0.9), transparent 55%),
    rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow-soft);
}

.so-header__nav-item--highlight .so-header__nav-link::after {
  display: none;
}

.so-header__nav-link--cta {
  color: var(--color-primary);
}

.so-header__nav-link--cta:hover {
  color: var(--color-primary);
}

.so-header__toggle {
  display: none;
}

@media (min-width: 901px) and (max-width: 1150px) {
  .so-header__nav-list {
    gap: var(--space-3);
  }

  .so-header__nav-link {
    font-size: 0.78rem;
    letter-spacing: 0.1em;
  }

  .so-header__nav-item--highlight .so-header__nav-link {
    padding-inline: 1rem;
  }
}

@media (max-width: 900px) {
  .so-header__inner {
    height: auto;
    padding-block: 0.85rem;
  }

  .so-header__toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .so-header__nav {
    position: absolute;
    inset-inline: 0;
    top: 100%;
    background: linear-gradient(135deg, rgba(240, 253, 244, 0.98), rgba(255, 255, 255, 0.98));
    border-bottom: 1px solid rgba(220, 252, 231, 0.9);
    box-shadow: 0 18px 40px rgba(15, 23, 42, 0.16);
    transform-origin: top;
    transform: scaleY(0.96);
    opacity: 0;
    pointer-events: none;
    visibility: hidden;
    transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
  }

  .so-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: 0.75rem 1.25rem 1.1rem;
    gap: 0.4rem;
  }

  .so-header__nav-item--highlight {
    width: 100%;
  }

  .so-header__nav-item--highlight .so-header__nav-link {
    width: 100%;
    text-align: center;
  }

  .so-header__nav-link {
    font-size: 0.8rem;
    padding-block: 0.35rem;
  }

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

@media (max-width: 640px) {
  .so-header__title {
    font-size: 0.98rem;
  }

  .so-header__subtitle {
    display: none;
  }
}

.so-header__nav-link:focus-visible {
  outline: 2px solid var(--color-accent-gold);
  outline-offset: 4px;
  border-radius: 999px;
}

.so-header__toggle[aria-expanded="true"] .nav-toggle-bar:first-child {
  transform: translateY(3px) rotate(42deg);
}

.so-header__toggle[aria-expanded="true"] .nav-toggle-bar:last-child {
  transform: translateY(-3px) rotate(-42deg);
}

.so-header__toggle .nav-toggle-bar {
  transition: transform var(--transition-fast), background var(--transition-fast);
}

.so-header__toggle:focus-visible {
  outline: 2px solid var(--color-accent-gold);
  outline-offset: 3px;
}

/* checklist: hamburger X */
.nav-toggle {
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}
.nav-toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  border-radius: 999px;
  background: currentColor;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

@media (max-width: 900px) {
  .so-header__nav {
    background: #ffffff;
    max-height: calc(100vh - 5rem);
    overflow-y: auto;
    overscroll-behavior: contain;
  }
  .so-header__nav-item {
    width: 100%;
  }
  .so-header__nav-link {
    display: flex;
    align-items: center;
    min-height: 44px;
  }
  .so-header__nav-item--highlight .so-header__nav-link {
    justify-content: center;
  }
}