.header {
  position: fixed;
  inset-inline: 0;
  top: 0;
  z-index: 50;
  transition: all .3s ease;
  background: transparent;
}
.header.scrolled {
  background-color: rgba(var(--color-bg-elevated), .65);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  border-bottom: 1px solid rgba(var(--color-border), .8);
  box-shadow: var(--shadow-card);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
}

.logo-link {
  position: relative;
  display: block;
  height: 2.25rem;
  width: 170px;
}
@media (min-width: 640px) { .logo-link { width: 200px; } }
.logo-link img {
  position: absolute;
  inset: 0;
  height: 100%;
  width: auto;
  object-fit: contain;
  object-position: left center;
}
.logo-light { opacity: 1; }
.logo-dark { opacity: 0; }
html.dark .logo-light { opacity: 0; }
html.dark .logo-dark { opacity: 1; }

.nav-desktop {
  display: none;
  align-items: center;
  gap: 1.75rem;
}
@media (min-width: 1024px) { .nav-desktop { display: flex; } }
.nav-desktop a {
  font-size: .875rem;
  font-weight: 500;
  color: var(--ink-600);
  transition: color .2s ease;
}
html.dark .nav-desktop a { color: var(--ink-200); }
.nav-desktop a:hover { color: var(--brand); }

.header-actions {
  display: none;
  align-items: center;
  gap: .75rem;
}
@media (min-width: 1024px) { .header-actions { display: flex; } }

.header-actions-mobile {
  display: flex;
  align-items: center;
  gap: .5rem;
}
@media (min-width: 1024px) { .header-actions-mobile { display: none; } }

/* Icon buttons (theme toggle, mobile menu trigger) */
.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 2.25rem;
  width: 2.25rem;
  border-radius: 999px;
  border: 1px solid rgba(var(--color-border), .8);
  color: var(--ink-600);
  transition: all .2s ease;
}
html.dark .icon-btn { color: var(--ink-200); }
.icon-btn:hover { border-color: var(--brand); color: var(--brand); }
.icon-btn svg { width: 16px; height: 16px; }

/* Language switcher */
.lang-switcher { position: relative; }
.lang-trigger {
  display: flex;
  align-items: center;
  gap: .4rem;
  border-radius: 999px;
  border: 1px solid rgba(var(--color-border), .8);
  padding: .45rem .9rem;
  font-size: .875rem;
  font-weight: 600;
  color: var(--ink-700);
  transition: all .2s ease;
}
html.dark .lang-trigger { color: var(--ink-100); }
.lang-trigger:hover { border-color: var(--brand); color: var(--brand); }
.lang-trigger svg:first-child { width: 16px; height: 16px; }
.lang-trigger .chev { width: 14px; height: 14px; transition: transform .2s ease; }
.lang-trigger[aria-expanded="true"] .chev { transform: rotate(180deg); }

.lang-menu {
  position: absolute;
  right: 0;
  top: calc(100% + .5rem);
  width: 160px;
  border-radius: .85rem;
  overflow: hidden;
  background-color: rgba(var(--color-bg-elevated), .9);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  border: 1px solid rgba(var(--color-border), .8);
  box-shadow: var(--shadow-card);
  display: none;
}
.lang-menu.open { display: block; }
.lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: .65rem 1rem;
  font-size: .875rem;
  text-align: left;
  color: var(--ink-700);
  transition: background-color .15s ease;
}
html.dark .lang-option { color: var(--ink-200); }
.lang-option:hover { background-color: rgba(38,181,216,.1); }
.lang-option.active { color: var(--brand); font-weight: 600; }
.lang-option svg { width: 16px; height: 16px; }

/* Mobile menu */
.mobile-menu {
  display: none;
  height: calc(100dvh - 4.5rem);
  overflow-y: auto;
  padding: 2rem 1.5rem;
  background-color: rgba(var(--color-bg-elevated), .85);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  border-bottom: 1px solid rgba(var(--color-border), .8);
}
.mobile-menu.open { display: block; }
@media (min-width: 1024px) { .mobile-menu { display: none !important; } }

.mobile-nav { display: flex; flex-direction: column; gap: .25rem; }
.mobile-nav a {
  padding: .85rem .75rem;
  border-radius: .6rem;
  font-size: 1rem;
  font-weight: 500;
  color: var(--ink-700);
  transition: all .15s ease;
}
html.dark .mobile-nav a { color: var(--ink-100); }
.mobile-nav a:hover { background-color: rgba(38,181,216,.1); color: var(--brand); }

.mobile-ctas {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: .75rem;
}