/**
 * Mobile Navigation — Hamburger Menu & Drawer
 *
 * Clean, accessible mobile navigation that appears
 * on screens smaller than 640px.
 */

/* ========== Hamburger Button ========== */

.mobile-nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  z-index: var(--z-sticky);
  transition: background var(--duration-fast) var(--ease-out);
}

.mobile-nav__toggle:hover {
  background: var(--bg-hover);
}

.mobile-nav__toggle:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

.mobile-nav__bar {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 1px;
  transition:
    transform var(--duration-fast) var(--ease-out),
    opacity var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
}

/* Hamburger to X animation */
.mobile-nav__toggle--active .mobile-nav__bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.mobile-nav__toggle--active .mobile-nav__bar:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.mobile-nav__toggle--active .mobile-nav__bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ========== Overlay ========== */

.mobile-nav__overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: calc(var(--z-modal) - 1);
  opacity: 0;
  visibility: hidden;
  transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal);
}

.mobile-nav__overlay--visible {
  opacity: 1;
  visibility: visible;
}

/* ========== Drawer ========== */

.mobile-nav__drawer {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 280px;
  max-width: 85vw;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border);
  z-index: var(--z-modal);
  display: flex;
  flex-direction: column;
  transform: translateX(-100%);
  transition: transform var(--duration-normal) var(--ease-smooth);
  box-shadow: 4px 0 24px rgba(0, 0, 0, 0.2);
}

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

/* ========== Drawer Header ========== */

.mobile-nav__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4);
  border-bottom: 1px solid var(--border-dim);
}

.mobile-nav__brand {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
}

.mobile-nav__close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  border-radius: var(--radius);
  color: var(--text-tertiary);
  font-size: var(--text-xl);
  cursor: pointer;
  transition:
    color var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
}

.mobile-nav__close:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.mobile-nav__close:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* ========== Navigation Links ========== */

.mobile-nav__links {
  flex: 1;
  padding: var(--space-3);
  overflow-y: auto;
}

.mobile-nav__link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  min-height: 44px;
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  transition:
    color var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
}

.mobile-nav__link:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.mobile-nav__link--active {
  background: var(--accent-dim);
  color: var(--accent-primary);
}

.mobile-nav__link:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: -2px;
}

.mobile-nav__link-icon {
  font-size: var(--text-base);
  opacity: 0.7;
}

.mobile-nav__link--active .mobile-nav__link-icon {
  opacity: 1;
}

.mobile-nav__link-label {
  flex: 1;
}

/* ========== Footer ========== */

.mobile-nav__footer {
  padding: var(--space-4);
  border-top: 1px solid var(--border-dim);
}

.mobile-nav__version {
  font-size: var(--text-xs);
  color: var(--text-tertiary);
}

/* ========== Show on Mobile ========== */

@media (max-width: 640px) {
  .mobile-nav__toggle {
    display: flex;
  }

  /* Hide desktop nav on mobile when hamburger is active */
  .header__nav {
    display: none;
  }
}

/* ========== Light Mode ========== */

[data-theme="light"] .mobile-nav__overlay {
  background: rgba(0, 0, 0, 0.4);
}

[data-theme="light"] .mobile-nav__drawer {
  box-shadow: 4px 0 24px rgba(0, 0, 0, 0.1);
}

/* ========== Reduced Motion ========== */

@media (prefers-reduced-motion: reduce) {
  .mobile-nav__overlay,
  .mobile-nav__drawer,
  .mobile-nav__bar {
    transition: none;
  }

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