/* ==========================================================================
   HEADER / NAVIGATION BAR
   Sticky, 76px, backdrop-blurred. Desktop full nav -> tablet compact ->
   mobile hamburger + slide drawer.
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: var(--header-height);
  background: var(--header-bg);
  backdrop-filter: blur(var(--header-blur)) saturate(180%);
  -webkit-backdrop-filter: blur(var(--header-blur)) saturate(180%);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--duration-theme) var(--ease-in-out),
    background-color var(--duration-theme) var(--ease-in-out),
    border-color var(--duration-theme) var(--ease-in-out);
}

/* Elevation appears only once the page scrolls, keeping the top of page flat. */
.site-header.is-scrolled {
  box-shadow: var(--shadow-md);
}

.header-container {
  width: 100%;
  height: 100%;
  padding: 0 var(--space-10);
  display: grid;
  /* The two outer tracks are equal-width by construction (same fr unit), so
     the auto-sized center track always sits at the header's true midpoint —
     regardless of how wide the logo is versus the action cluster. */
  grid-template-columns: minmax(0, 1fr) minmax(0, max-content) minmax(0, 1fr);
  align-items: center;
  gap: var(--space-6);
}

/* ---- Left: Alphanso logo --------------------------------------------------- */
.brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--text-primary);
  flex-shrink: 0;
  justify-self: start;
  min-width: 0;
  border-radius: var(--radius-md);
  transition: opacity var(--duration-hover) var(--ease-out);
}

.brand:hover {
  opacity: 0.82;
}

.brand-logo {
  height: 30px;
  width: auto;
  flex-shrink: 0;
  display: block;
}

/* Light/dark logo swap, same pattern as the theme toggle's sun/moon icons. */
.brand-logo-dark {
  display: none;
}

[data-theme="dark"] .brand-logo-light {
  display: none;
}

[data-theme="dark"] .brand-logo-dark {
  display: block;
}

/* ---- Center: client title -------------------------------------------------- */
.header-title {
  justify-self: center;
  width: 100%;
  min-width: 0;
  overflow: hidden;
  text-align: center;
}

.header-title-text {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  letter-spacing: -0.02em;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: block;
}

/* ---- Right: actions ------------------------------------------------------- */
.header-actions {
  display: flex;
  align-items: center;
  justify-self: end;
  justify-content: flex-end;
  gap: var(--space-3);
  min-width: 0;
}

.theme-toggle {
  position: relative;
  width: 40px;
  height: 40px;
  display: inline-grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background-color var(--duration-hover) var(--ease-out),
    color var(--duration-hover) var(--ease-out),
    border-color var(--duration-hover) var(--ease-out);
}

.theme-toggle:hover {
  background: var(--hover);
  color: var(--text-primary);
}

/* Sun and moon are stacked; the active one rotates into place. */
.theme-toggle svg {
  position: absolute;
  width: 18px;
  height: 18px;
  transition: opacity var(--duration-theme) var(--ease-in-out),
    transform var(--duration-theme) var(--ease-in-out);
}

.theme-toggle .icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.theme-toggle .icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.6);
}

[data-theme="dark"] .theme-toggle .icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.6);
}

[data-theme="dark"] .theme-toggle .icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

/* ---- Buttons -------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 10px var(--space-4);
  font-family: inherit;
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  line-height: 1;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--duration-hover) var(--ease-out),
    color var(--duration-hover) var(--ease-out),
    border-color var(--duration-hover) var(--ease-out),
    transform var(--duration-hover) var(--ease-out),
    box-shadow var(--duration-hover) var(--ease-out);
}

.btn:active {
  transform: scale(0.985);
}

.btn:disabled,
.btn[aria-disabled="true"] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.btn-ghost {
  color: var(--text-secondary);
  background: transparent;
}

.btn-ghost:hover:not(:disabled) {
  background: var(--hover);
  color: var(--text-primary);
}

.btn-secondary {
  color: var(--text-primary);
  background: transparent;
  border-color: var(--border-strong);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--hover);
}

.btn-primary {
  color: var(--btn-primary-text);
  background: var(--btn-primary-bg);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
  background: var(--btn-primary-hover);
  transform: scale(1.03);
  box-shadow: var(--shadow-md);
}

.btn-danger {
  color: var(--danger);
  background: var(--danger-soft);
}

.btn-danger:hover:not(:disabled) {
  background: var(--danger);
  color: var(--text-inverse);
}

.btn-sm {
  padding: 7px var(--space-3);
  font-size: var(--text-sm);
}

.btn-icon svg {
  width: 16px;
  height: 16px;
}

/* ---- Focus ring (WCAG 2.4.7) --------------------------------------------- */
.brand:focus-visible,
.btn:focus-visible,
.theme-toggle:focus-visible,
.nav-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* Only show focus rings for keyboard users. */
.btn:focus:not(:focus-visible),
.theme-toggle:focus:not(:focus-visible) {
  outline: none;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: var(--space-4);
  z-index: calc(var(--z-header) + 1);
  padding: var(--space-3) var(--space-4);
  background: var(--btn-primary-bg);
  color: var(--btn-primary-text);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  text-decoration: none;
  transition: top var(--duration-hover) var(--ease-out);
}

.skip-link:focus {
  top: var(--space-3);
}

/* ---- Mobile drawer trigger ------------------------------------------------ */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}

.nav-toggle:hover {
  background: var(--hover);
}

.nav-toggle svg {
  width: 20px;
  height: 20px;
}

.drawer-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(2px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--duration-theme) var(--ease-in-out),
    visibility var(--duration-theme);
  z-index: calc(var(--z-drawer) - 1);
}

.drawer-backdrop.is-open {
  opacity: 1;
  visibility: visible;
}

.mobile-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(340px, 86vw);
  padding: var(--space-6);
  background: var(--bg-elevated);
  border-left: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  transform: translateX(100%);
  transition: transform var(--duration-theme) var(--ease-in-out);
  z-index: var(--z-drawer);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

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

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-4);
}

.drawer-close {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}

.drawer-close:hover {
  background: var(--hover);
}

.drawer-close svg {
  width: 18px;
  height: 18px;
}

.drawer-actions {
  margin-top: auto;
  padding-top: var(--space-6);
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */

/* Tablet: compact header padding. */
@media (max-width: 1100px) {
  .header-container {
    padding: 0 var(--space-6);
  }
}

/* Mobile: hamburger + slide drawer. */
@media (max-width: 860px) {
  .header-container {
    padding: 0 var(--space-4);
    gap: var(--space-3);
  }

  .brand-logo {
    height: 24px;
  }

  .header-title-text {
    font-size: var(--text-base);
  }

  .header-actions .btn-cta {
    display: none;
  }

  .nav-toggle {
    display: grid;
  }
}

/* Very narrow phones: the title still fits, just tighter. */
@media (max-width: 400px) {
  .brand-logo {
    height: 20px;
  }

  .header-title-text {
    font-size: var(--text-sm);
  }
}

/* Respect a user's reduced-motion preference across the whole header. */
@media (prefers-reduced-motion: reduce) {
  .site-header,
  .theme-toggle svg,
  .mobile-drawer,
  .drawer-backdrop,
  .btn {
    transition-duration: 0.01ms !important;
  }

  .btn-primary:hover:not(:disabled) {
    transform: none;
  }
}