.sda-header {
  position: sticky;
  top: 0;
  z-index: 40;
  width: 100%;
  backdrop-filter: blur(14px);
  background: linear-gradient(to bottom, rgba(252, 251, 250, 0.92), rgba(252, 251, 250, 0.85));
  border-bottom: 1px solid var(--color-border-subtle);
}

.sda-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
  gap: var(--space-4);
}

.sda-header__brand {
  display: flex;
  align-items: center;
  min-width: 0;
}

.sda-header__logo-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
}

.sda-header__logo-mark {
  width: 34px;
  height: 34px;
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  background: radial-gradient(circle at 0 0, #f6efe4 0, #f0e2cf 45%, #c25e00 100%);
  color: #fff;
  border: 1px solid rgba(0, 0, 0, 0.12);
  box-shadow: 0 8px 20px rgba(119, 63, 10, 0.4);
}

.sda-header__text-group {
  display: flex;
  flex-direction: column;
}

.sda-header__title {
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-text);
  white-space: nowrap;
}

.sda-header__subtitle {
  font-family: var(--font-mono);
  font-size: var(--font-size-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

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

.sda-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}

.sda-header__nav-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  padding-bottom: 0.15rem;
}

.sda-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 1px;
  background-color: var(--color-primary);
  transition: width var(--transition-base);
}

.sda-header__nav-link:hover,
.sda-header__nav-link:focus-visible {
  color: var(--color-text);
}

.sda-header__nav-link:hover::after,
.sda-header__nav-link:focus-visible::after {
  width: 100%;
}

.sda-header__nav-item--accent .sda-header__nav-link {
  padding: 0.4rem 1.1rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-border-subtle);
  background: linear-gradient(135deg, #fffdf9, #f6efe4);
}

.sda-header__nav-link--accent {
  color: var(--color-text);
}

.sda-header__nav-item--accent .sda-header__nav-link::after {
  display: none;
}

.sda-header__nav-item--accent .sda-header__nav-link:hover,
.sda-header__nav-item--accent .sda-header__nav-link:focus-visible {
  border-color: var(--color-primary);
  box-shadow: 0 8px 20px rgba(119, 63, 10, 0.14);
}

.sda-header__nav-toggle {
  position: relative;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: 999px;
  border: 1px solid var(--color-border-subtle);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: var(--shadow-soft-inner);
  color: var(--color-text);
  display: none;
}

.sda-header__nav-toggle-bar {
  width: 18px;
  height: 1.5px;
  border-radius: 999px;
  background-color: var(--color-neutral-800);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.sda-header__nav-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.sda-header__nav-toggle[aria-expanded="true"] .sda-header__nav-toggle-bar:first-child {
  transform: translateY(3px) rotate(45deg);
}

.sda-header__nav-toggle[aria-expanded="true"] .sda-header__nav-toggle-bar:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

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

  .sda-header__nav {
    position: absolute;
    inset: calc(100% + 2px) var(--space-5) auto var(--space-5);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-subtle);
    background: radial-gradient(circle at top left, rgba(244, 232, 210, 0.48), transparent 55%), #ffffff;
    box-shadow: var(--shadow-elevated);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
  }

  .sda-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-4);
    gap: var(--space-2);
  }

  .sda-header__nav-link {
    padding: 0.45rem 0.25rem;
    width: 100%;
  }

  .sda-header__nav-item--accent .sda-header__nav-link {
    width: 100%;
    justify-content: center;
    margin-top: var(--space-2);
  }

  .sda-header__nav--open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
}

@media (max-width: 520px) {
  .sda-header__title {
    font-size: var(--font-size-sm);
    letter-spacing: 0.18em;
  }

  .sda-header__subtitle {
    display: none;
  }
}

body.sda-nav-open {
  overflow: hidden;
}

.sda-header__nav-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(8, 6, 4, 0.26);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
  z-index: 30;
}

.sda-header__nav-backdrop--visible {
  opacity: 1;
  visibility: visible;
}