/**
 * Lydia Sierra — Personal Developer Portfolio
 * Header & Navigation Styles
 * Conforming to DESIGN_SPEC.md & Visual Mockup
 */

/* ==========================================================================
   Header Landmark & Bar Layout
   ========================================================================== */
/* State A — Initial position at the top (Light mode: original cream appearance) */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  background-color: rgba(248, 245, 242, 0.94);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border-subtle);
  padding-block: 1rem;
  transition:
    background-color var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
}

/* State B — Scrolled down: clearly visible translucent white glass (Light mode) */
.site-header.is-scrolled {
  background-color: rgb(255 255 255 / 82%);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: rgba(230, 225, 220, 0.85);
  box-shadow: 0 4px 20px rgba(46, 42, 39, 0.05), 0 1px 3px rgba(46, 42, 39, 0.03);
}

/* Dark mode: State A — at the top */
[data-theme="dark"] .site-header {
  background-color: rgba(24, 22, 20, 0.94);
  border-bottom-color: var(--color-border-subtle);
  box-shadow: none;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .site-header {
    background-color: rgba(24, 22, 20, 0.94);
    border-bottom-color: var(--color-border-subtle);
    box-shadow: none;
  }
}

/* Dark mode: State B — scrolled down: coordinated translucent dark glass */
[data-theme="dark"] .site-header.is-scrolled {
  background-color: rgb(24 22 20 / 82%);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: rgba(58, 52, 47, 0.85);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4), 0 1px 3px rgba(0, 0, 0, 0.25);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .site-header.is-scrolled {
    background-color: rgb(24 22 20 / 82%);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom-color: rgba(58, 52, 47, 0.85);
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4), 0 1px 3px rgba(0, 0, 0, 0.25);
  }
}

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

/* ==========================================================================
   Brand Wordmark
   ========================================================================== */
.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
  color: var(--color-text-main);
  white-space: nowrap;
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}

.brand-link:hover {
  opacity: 0.85;
  color: var(--color-text-main);
}

.brand-icon {
  color: var(--color-primary);
  flex-shrink: 0;
  width: 22px;
  height: 22px;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.375rem; /* ~22px */
  font-weight: 400;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--color-text-main);
  white-space: nowrap;
  flex-shrink: 0;
}

/* ==========================================================================
   Primary Navigation Menu
   ========================================================================== */
.nav-menu {
  display: block;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 0.5rem + 0.6vw, 1.5rem);
  margin: 0;
  padding: 0;
  list-style: none;
  white-space: nowrap;
}

.nav-list > li {
  list-style: none;
  display: inline-flex;
  align-items: center;
}

.nav-link {
  position: relative;
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  white-space: nowrap;
  padding: 0.35rem 0.25rem;
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-primary);
}

/* Active Page Indicator Underline — Stable, zero translation, zero layout shift */
.nav-link.active,
.nav-link[aria-current="page"] {
  color: var(--color-primary);
  font-weight: 500; /* Preserve font-weight to prevent baseline & width reflow */
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: var(--radius-full);
  opacity: 0;
  transition: opacity var(--transition-fast);
  pointer-events: none;
}

.nav-link.active::after,
.nav-link[aria-current="page"]::after {
  opacity: 1;
}

[data-theme="dark"] .nav-link:hover,
[data-theme="dark"] .nav-link.active,
[data-theme="dark"] .nav-link[aria-current="page"] {
  color: #9EC4A7;
}

[data-theme="dark"] .nav-link::after {
  background-color: #9EC4A7;
}

/* ==========================================================================
   Progressive Overflow Menu (Desktop & Tablet)
   ========================================================================== */
.nav-overflow-item {
  position: relative;
  display: inline-flex;
  align-items: center;
  list-style: none;
}

.nav-overflow-item[hidden] {
  display: none !important;
}

.nav-overflow-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.35rem 0.45rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-overflow-btn:hover,
.nav-overflow-btn:focus-visible {
  color: var(--color-primary);
  background-color: var(--color-surface-subtle);
}

.nav-overflow-btn.has-active {
  color: var(--color-primary);
}

.nav-overflow-btn.has-active::after {
  opacity: 1;
}

.nav-overflow-caret {
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.nav-overflow-btn[aria-expanded="true"] .nav-overflow-caret {
  transform: rotate(180deg);
}

.nav-overflow-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 150px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 0.35rem;
  list-style: none;
  z-index: 1010;
  display: flex;
  flex-direction: column;
  gap: 2px;
  animation: fadeInDropdown 150ms ease-out;
}

.nav-overflow-menu[hidden] {
  display: none !important;
}

.nav-overflow-menu li {
  list-style: none;
  width: 100%;
}

.nav-overflow-menu .nav-link {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 0.45rem 0.75rem;
  font-size: var(--text-xs);
  border-radius: var(--radius-xs);
  color: var(--color-text-main);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.nav-overflow-menu .nav-link::after {
  display: none;
}

.nav-overflow-menu .nav-link:hover,
.nav-overflow-menu .nav-link:focus-visible {
  background-color: var(--color-surface-subtle);
  color: var(--color-primary);
}

.nav-overflow-menu .nav-link.active {
  background-color: rgba(74, 93, 78, 0.08);
  color: var(--color-primary);
  font-weight: 600;
}

[data-theme="dark"] .nav-overflow-menu .nav-link.active {
  background-color: rgba(110, 142, 116, 0.15);
  color: #9EC4A7;
}

/* Mobile drawer actions hidden on desktop */
.nav-drawer-actions {
  display: none;
}

/* ==========================================================================
   Header Action Controls Group
   ========================================================================== */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
}

/* Mobile Navigation Toggle Button */
.nav-toggle {
  display: none; /* Hidden on desktop */
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-main);
  cursor: pointer;
  padding: 0.5rem;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast);
}

.nav-toggle:hover {
  background-color: var(--color-surface-subtle);
  border-color: var(--color-primary);
}

/* Accessible Hamburger Icon Bars */
.nav-toggle-icon {
  display: block;
  position: relative;
  width: 18px;
  height: 2px;
  background-color: currentColor;
  border-radius: 1px;
  transition: background-color var(--transition-fast);
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background-color: currentColor;
  border-radius: 1px;
  transition: transform var(--transition-fast), top var(--transition-fast);
}

.nav-toggle-icon::before {
  top: -6px;
}

.nav-toggle-icon::after {
  top: 6px;
}

/* Hamburger to X Transform when Expanded */
.nav-toggle[aria-expanded="true"] .nav-toggle-icon {
  background-color: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  top: 0;
  transform: rotate(-45deg);
}

/* ==========================================================================
   Responsive Header Breakpoint (Tablet & Mobile Stacking & Drawer Menu)
   ========================================================================== */
@media (max-width: 899px) {
  /* 3-Column Mobile Header Grid: Far-left hamburger, dead-center leaf icon, far-right language selector */
  .header-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: var(--space-2);
  }

  .nav-toggle {
    display: inline-flex;
    justify-self: start;
    order: 1;
  }

  .brand-link {
    justify-self: center;
    order: 2;
    margin: 0;
  }

  /* Show leaf SVG icon only on mobile; hide wordmark text */
  .brand-name {
    display: none;
  }

  .brand-icon {
    width: 26px;
    height: 26px;
  }

  .header-actions {
    justify-self: end;
    order: 3;
    gap: 0.5rem;
  }

  /* Standalone CV and theme toggle buttons are strictly hidden from top bar on mobile */
  .desktop-only-action {
    display: none !important;
  }

  .nav-overflow-item {
    display: none !important;
  }

  /* Slide-down mobile navigation drawer */
  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    width: 100%;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    padding: var(--space-4) var(--space-6);
    z-index: 999;
    transition:
      background-color var(--transition-base),
      border-color var(--transition-base);
  }

  .nav-menu.is-open {
    display: block;
    animation: slideDownNav 200ms cubic-bezier(0.16, 1, 0.3, 1);
  }

  @keyframes slideDownNav {
    from {
      opacity: 0;
      transform: translateY(-8px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
    white-space: normal;
  }

  .nav-list > li {
    display: block;
    width: 100%;
  }

  .nav-link {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    font-size: var(--text-base);
    border-radius: var(--radius-sm);
    min-height: 44px;
    width: 100%;
    color: var(--color-text-main);
  }

  .nav-link:hover,
  .nav-link:focus-visible {
    background-color: var(--color-surface-subtle);
    color: var(--color-primary);
  }

  .nav-link.active,
  .nav-link[aria-current="page"] {
    background-color: rgba(74, 93, 78, 0.08);
    color: var(--color-primary);
    font-weight: 600;
  }

  .nav-link.active::after,
  .nav-link[aria-current="page"]::after {
    display: none;
  }

  [data-theme="dark"] .nav-link.active,
  [data-theme="dark"] .nav-link[aria-current="page"] {
    background-color: rgba(110, 142, 116, 0.15);
    color: #9EC4A7;
  }

  /* Mobile Drawer Action Controls: Download CV & Theme Toggle housed inside drawer */
  .nav-drawer-actions {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    margin-top: var(--space-4);
    padding-top: var(--space-4);
    border-top: 1px solid var(--color-border-subtle);
  }

  .btn-drawer-cv {
    width: 100%;
    justify-content: center;
  }

  .btn-theme-drawer {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.65rem;
    width: 100%;
    min-height: 44px;
    padding: 0.65rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background-color: var(--color-surface-subtle);
    color: var(--color-text-main);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 500;
    cursor: pointer;
    transition:
      background-color var(--transition-fast),
      border-color var(--transition-fast),
      color var(--transition-fast);
  }

  .btn-theme-drawer:hover,
  .btn-theme-drawer:focus-visible {
    background-color: var(--color-surface);
    border-color: var(--color-primary);
    color: var(--color-primary);
  }

  [data-theme="dark"] .btn-theme-drawer:hover,
  [data-theme="dark"] .btn-theme-drawer:focus-visible {
    color: #9EC4A7;
  }

  .theme-icon-slot {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary);
  }

  [data-theme="dark"] .theme-icon-slot {
    color: #9EC4A7;
  }
}

@media (prefers-reduced-motion: reduce) {
  .nav-menu.is-open {
    animation: none;
  }
}

/* ==========================================================================
   Language Selector Component
   ========================================================================== */
.lang-selector-wrapper {
  position: relative;
}

.lang-selector-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  height: 38px;
  min-height: 38px;
  padding: 0.4rem 0.65rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-main);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.lang-selector-btn:hover {
  background-color: var(--color-surface-subtle);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.lang-selector-btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.lang-icon {
  color: var(--color-primary);
  flex-shrink: 0;
}

[data-theme="dark"] .lang-icon {
  color: #9EC4A7;
}

.lang-current-code {
  font-family: var(--font-mono);
  font-weight: 600;
  letter-spacing: 0.04em;
  font-size: 0.75rem;
}

.lang-caret {
  color: var(--color-text-muted);
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.lang-selector-btn[aria-expanded="true"] .lang-caret {
  transform: rotate(180deg);
}

/* Dropdown Menu */
.lang-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 145px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 0.35rem;
  list-style: none;
  z-index: 1010;
  display: flex;
  flex-direction: column;
  gap: 2px;
  animation: fadeInDropdown 150ms ease-out;
}

.lang-menu[hidden] {
  display: none !important;
}

@keyframes fadeInDropdown {
  from {
    opacity: 0;
    transform: translateY(-4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.45rem 0.65rem;
  border-radius: var(--radius-xs);
  cursor: pointer;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-main);
  user-select: none;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast);
}

.lang-option:hover {
  background-color: var(--color-surface-subtle);
  color: var(--color-primary);
}

.lang-option:focus {
  background-color: var(--color-surface-subtle);
  color: var(--color-primary);
  outline: 2px solid var(--color-primary);
  outline-offset: -2px;
}

[data-theme="dark"] .lang-option:focus {
  outline-color: #9EC4A7;
}

@media (forced-colors: active) {
  .lang-option:focus {
    outline: 2px solid Highlight;
  }
}

.lang-option.selected {
  color: var(--color-primary);
  font-weight: 600;
  background-color: rgba(74, 93, 78, 0.08);
}

[data-theme="dark"] .lang-option.selected {
  background-color: rgba(110, 142, 116, 0.15);
  color: #9EC4A7;
}

.lang-option-code {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-text-muted);
  font-weight: 600;
  padding: 0.1rem 0.35rem;
  border-radius: var(--radius-xs);
  background-color: rgba(46, 42, 39, 0.05);
}

[data-theme="dark"] .lang-option-code {
  background-color: rgba(245, 242, 238, 0.08);
  color: var(--color-text-muted);
}

.lang-option.selected .lang-option-code {
  color: var(--color-primary);
}

[data-theme="dark"] .lang-option.selected .lang-option-code {
  color: #9EC4A7;
}

.lang-option-name {
  flex-grow: 1;
}

.lang-check {
  color: var(--color-primary);
  opacity: 0;
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}

.lang-option.selected .lang-check {
  opacity: 1;
}

[data-theme="dark"] .lang-check {
  color: #9EC4A7;
}

@media (max-width: 480px) {
  .header-container {
    gap: var(--space-2);
  }

  .brand-name {
    font-size: 1.15rem;
  }

  .header-actions {
    gap: 0.4rem;
  }

  .header-actions .btn-sm {
    padding-inline: 0.55rem;
  }

  .header-actions .btn-sm span {
    font-size: var(--text-xs);
  }

  .lang-selector-btn {
    padding: 0.35rem 0.5rem;
    gap: 0.25rem;
  }
}