/**
 * Page Transitions CSS
 * Smooth enter/exit animations for SPA navigation
 * 
 * @layer transitions
 */

/* ========================================
   Page Transition States
   ======================================== */

.page {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

/* Exit transition - fade out and slide up */
.page--exit {
  opacity: 0;
  transform: translateY(-10px);
  pointer-events: none;
}

/* Enter transition - start state (fade in from below) */
.page--enter {
  opacity: 0;
  transform: translateY(20px);
}

/* Enter transition - active state */
.page--enter-active {
  opacity: 1;
  transform: translateY(0);
}

/* Loading state */
.page--loading {
  opacity: 0.5;
}

.page__loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  gap: 1rem;
  color: var(--text-secondary, #888);
}


/* ========================================
   Nav Toggle Transitions
   ======================================== */

.nav__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s ease, background-color 0.2s ease;
}

.nav__toggle:hover {
  background-color: var(--surface-hover, rgba(255, 255, 255, 0.1));
}

.nav__toggle:active {
  transform: scale(0.95);
}

.nav__toggle svg {
  transition: transform 0.3s ease;
}

.nav-collapsed .nav__toggle svg {
  transform: rotate(180deg);
}


/* ========================================
   Navigation Transitions
   ======================================== */

.site__nav {
  transition: width 0.3s ease, transform 0.3s ease;
}

.site__nav--collapsed {
  width: 60px !important;
}

@media (max-width: 768px) {
  .site__nav {
    transform: translateX(0);
    transition: transform 0.3s ease;
  }
  
  .site__nav--collapsed {
    transform: translateX(-100%);
    width: var(--nav-width) !important;
  }
}

.nav__item {
  transition: background-color 0.2s ease, color 0.2s ease, padding 0.3s ease;
}

.nav__label {
  transition: opacity 0.2s ease, max-width 0.3s ease;
  white-space: nowrap;
  overflow: hidden;
}

.site__nav--collapsed .nav__label {
  opacity: 0;
  max-width: 0;
}

.nav__icon {
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

.nav__item:hover .nav__icon {
  transform: scale(1.1);
}


/* ========================================
   External Link Indicator
   ======================================== */

.nav__external {
  display: inline-flex;
  align-items: center;
  margin-left: auto;
  opacity: 0.5;
  transition: opacity 0.2s ease;
}

.nav__item:hover .nav__external {
  opacity: 1;
}

.nav__item--external::after {
  content: '';
}


/* ========================================
   Footer Link Transitions
   ======================================== */

.footer__social-link {
  transition: transform 0.2s ease, opacity 0.2s ease;
  opacity: 0.7;
}

.footer__social-link:hover {
  transform: translateY(-2px);
  opacity: 1;
}

.footer__link {
  transition: color 0.2s ease;
}


/* ========================================
   Error State
   ======================================== */

.site__error {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 2rem;
  text-align: center;
  background: var(--surface-base, #1a1a2e);
  color: var(--text-primary, #fff);
}

.error__icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.7; transform: scale(0.95); }
}

.site__error h1 {
  margin: 0 0 0.5rem 0;
  font-size: 1.5rem;
}

.site__error p {
  margin: 0 0 1.5rem 0;
  color: var(--text-secondary, #888);
}

.error__retry {
  padding: 0.75rem 2rem;
  font-size: 1rem;
  font-weight: 500;
  color: white;
  background: var(--primary, #6366f1);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.error__retry:hover {
  background: var(--primary-hover, #5558e3);
  transform: translateY(-1px);
}

.error__retry:active {
  transform: translateY(0);
}


/* ========================================
   Screen Reader Only (Accessibility)
   ======================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}


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

@media (prefers-reduced-motion: reduce) {
  .page,
  .page--exit,
  .page--enter,
  .page--enter-active,
  .site__nav,
  .nav__item,
  .nav__icon,
  .nav__toggle svg,
  .footer__social-link {
    transition: none !important;
    animation: none !important;
  }
  
  .page--enter {
    opacity: 1;
    transform: none;
  }
}