.site-header {
  position: fixed;
  top: var(--progress-height);
  left: 0;
  right: 0;
  z-index: 110;
  transition: background var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast),
    transform var(--transition-fast);
}

.site-header.is-scrolled {
  background: rgba(10, 22, 40, 0.7);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 12px 30px rgba(6, 14, 28, 0.32);
}

.site-header__inner {
  width: var(--container);
  height: calc(var(--nav-height) + var(--safe-top));
  margin-inline: auto;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 1.5rem;
  align-items: center;
  position: relative;
  padding-top: var(--safe-top);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.9rem;
}

.brand__mark {
  width: 56px;
  height: 72px;
  display: block;
  flex-shrink: 0;
  background: url("../assets/images/logo/mark-only.png") center / contain no-repeat;
  filter: drop-shadow(0 8px 18px rgba(66, 165, 245, 0.25));
}

.brand__mark > * {
  display: none;
}

.brand__book {
  opacity: 0.85;
}

.brand__wing {
  transform-origin: 60% 56%;
  animation: wingFlap 4s ease-in-out infinite;
}

.brand__type {
  display: grid;
  gap: 0.1rem;
}

.brand__title {
  font-family: var(--font-display);
  font-size: 1.65rem;
  letter-spacing: 0.02em;
}

.brand__subtitle {
  font-family: var(--font-tamil);
  font-size: 0.7rem;
  color: rgba(227, 234, 244, 0.72);
  letter-spacing: 0.08em;
}

.page-light .site-header:not(.is-scrolled) .brand__title,
.page-light .site-header:not(.is-scrolled) .site-nav__link {
  color: var(--color-sky-deep);
}

.page-light .site-header:not(.is-scrolled) .brand__subtitle {
  color: rgba(10, 22, 40, 0.68);
}

.page-light .site-header:not(.is-scrolled) .hamburger {
  border-color: rgba(10, 22, 40, 0.12);
  background: rgba(10, 22, 40, 0.04);
}

.page-light .site-header:not(.is-scrolled) .hamburger span {
  background: var(--color-sky-deep);
}

.site-nav {
  position: relative;
  z-index: 2;
  display: flex;
  justify-content: center;
  min-width: 0;
}

.site-nav__list {
  display: inline-flex;
  align-items: center;
  gap: 1.35rem;
  width: 100%;
  justify-content: center;
  flex-wrap: nowrap;
  padding: 0.5rem 1rem;
  margin: 0;
  list-style: none;
}

.site-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 50px;
  padding-inline: 0.12rem;
  white-space: nowrap;
  color: rgba(227, 234, 244, 0.94);
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  text-shadow: 0 1px 10px rgba(3, 12, 24, 0.22);
  transition: color var(--transition-fast), transform var(--transition-fast), text-shadow var(--transition-fast);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  bottom: 0.5rem;
  left: 0;
  width: 100%;
  height: 2.5px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--color-sky-bright), var(--color-wing-gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-fast);
}

.site-nav__link:hover,
.site-nav__link[aria-current="page"] {
  color: var(--color-white);
  text-shadow: 0 1px 14px rgba(66, 165, 245, 0.18);
  transform: translateY(-1px);
}

.site-nav__link:hover::after,
.site-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-actions {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.hamburger {
  display: none;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.04);
}

.hamburger span {
  display: block;
  width: 18px;
  height: 2px;
  margin-inline: auto;
  background: var(--color-white);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.hamburger span + span {
  margin-top: 4px;
}

.site-header.menu-open .hamburger span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.site-header.menu-open .hamburger span:nth-child(2) {
  opacity: 0;
}

.site-header.menu-open .hamburger span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 105;
  display: grid;
  place-items: center;
  align-content: start;
  overflow-y: auto;
  padding:
    calc(var(--nav-height) + var(--safe-top) + 1.5rem)
    max(1.25rem, calc(1.25rem + var(--safe-right)))
    max(1.5rem, calc(1.5rem + var(--safe-bottom)))
    max(1.25rem, calc(1.25rem + var(--safe-left)));
  background: linear-gradient(180deg, rgba(10, 22, 40, 0.96), rgba(7, 17, 31, 1));
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--transition-fast), visibility var(--transition-fast);
}

.mobile-menu.is-open {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.mobile-menu__list {
  display: grid;
  gap: 1rem;
  width: min(420px, 100%);
  padding: 0;
  margin: 0;
  list-style: none;
}

.mobile-menu__link,
.mobile-menu__cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 60px;
  padding: 0 0 0.25rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--color-white);
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 8vw, 3rem);
  opacity: 0;
  transform: translateY(18px);
}

.mobile-menu.is-open .mobile-menu__link,
.mobile-menu.is-open .mobile-menu__cta {
  animation: fadeStagger 600ms cubic-bezier(0.16, 1, 0.3, 1) forwards;
  animation-delay: calc(var(--index, 0) * 100ms);
}

.mobile-menu__meta {
  margin-top: 2rem;
  text-align: center;
  color: rgba(227, 234, 244, 0.66);
}

@media (max-width: 1360px) {
  .site-header__inner {
    gap: 1rem;
  }

  .brand__title {
    font-size: 1.5rem;
  }

  .site-nav__list {
    gap: 0.95rem;
    padding-inline: 0.5rem;
  }

  .site-nav__link {
    font-size: 0.97rem;
  }

  .nav-actions .btn {
    min-height: 46px;
    padding-inline: 1rem;
  }
}

@media (max-width: 1280px) {
  .site-header__inner {
    grid-template-columns: 1fr auto auto;
  }

  .site-nav,
  .nav-actions .btn {
    display: none;
  }

  .hamburger {
    display: inline-grid;
    place-items: center;
  }

  .brand__title {
    font-size: 1.35rem;
  }

  .brand__subtitle {
    font-size: 0.62rem;
  }
}

@media (max-width: 640px) {
  .site-header__inner {
    gap: 0.75rem;
  }

  .brand {
    gap: 0.7rem;
    min-width: 0;
  }

  .brand__mark {
    width: 44px;
    height: 58px;
  }

  .brand__title {
    font-size: 1.1rem;
  }

  .brand__subtitle {
    font-size: 0.56rem;
  }

  .mobile-menu__link,
  .mobile-menu__cta {
    font-size: clamp(1.55rem, 8vw, 2.4rem);
  }
}

@media (max-width: 420px) {
  .site-header__inner {
    grid-template-columns: minmax(0, 1fr) auto auto;
  }

  .brand__title {
    font-size: 1rem;
  }

  .brand__subtitle {
    letter-spacing: 0.05em;
  }
}