/* ============================================
   ANIMATIONS.CSS - Motion Design System
   ============================================ */

/* ============================================
   KEYFRAMES - Animation Definitions
   ============================================ */

/* Fade In/Out */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

/* Slide Animations */
@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideOutDown {
  from {
    opacity: 1;
    transform: translateY(0);
  }
  to {
    opacity: 0;
    transform: translateY(20px);
  }
}

/* Scale Animations */
@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes scaleOut {
  from {
    opacity: 1;
    transform: scale(1);
  }
  to {
    opacity: 0;
    transform: scale(0.95);
  }
}

/* Shimmer Animation for Skeletons */
@keyframes shimmer {
  0% {
    background-position: -200% 0;
  }
  100% {
    background-position: 200% 0;
  }
}

/* Pulse Animation */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

/* Spin Animation */
@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

/* Bounce Animation */
@keyframes bounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-4px);
  }
}

/* Ripple Effect */
@keyframes ripple {
  0% {
    transform: scale(0);
    opacity: 0.4;
  }
  100% {
    transform: scale(4);
    opacity: 0;
  }
}

/* Shake Animation (for errors) */
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  10%, 30%, 50%, 70%, 90% { transform: translateX(-4px); }
  20%, 40%, 60%, 80% { transform: translateX(4px); }
}

/* Progress Bar Animation */
@keyframes progressIndeterminate {
  0% {
    transform: translateX(-100%);
  }
  50% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(100%);
  }
}

/* Page Transition Keyframes */
@keyframes pageEnter {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pageExit {
  from {
    opacity: 1;
    transform: translateY(0);
  }
  to {
    opacity: 0;
    transform: translateY(-10px);
  }
}

/* ============================================
   PAGE TRANSITIONS
   ============================================ */

.page-transition-enter {
  animation: pageEnter 400ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.page-transition-exit {
  animation: pageExit 300ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* ============================================
   CARD ANIMATIONS
   ============================================ */

.card {
  transition: transform 200ms cubic-bezier(0.4, 0, 0.2, 1),
              box-shadow 200ms cubic-bezier(0.4, 0, 0.2, 1),
              border-color 150ms ease;
}

.card--hover-lift:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card--hover-scale:hover {
  transform: scale(1.02);
}

.card--active:active {
  transform: scale(0.98);
}

/* Card Entry Animation */
.card-enter {
  animation: slideInUp 300ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* ============================================
   BUTTON ANIMATIONS
   ============================================ */

.btn {
  position: relative;
  overflow: hidden;
  transition: transform 100ms ease,
              background-color 150ms ease,
              border-color 150ms ease,
              box-shadow 150ms ease;
}

.btn:active:not(:disabled) {
  transform: scale(0.98);
}

/* Button Ripple Effect */
.btn--ripple {
  position: relative;
  overflow: hidden;
}

.btn--ripple::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 100px;
  height: 100px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  transform: translate(-50%, -50%) scale(0);
  opacity: 0;
  pointer-events: none;
}

.btn--ripple:active::after {
  animation: ripple 400ms ease-out;
}

/* Button Loading State */
.btn--loading {
  position: relative;
  color: transparent !important;
  pointer-events: none;
}

.btn--loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  margin-top: -10px;
  margin-left: -10px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

/* ============================================
   MODAL ANIMATIONS
   ============================================ */

.modal-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  opacity: 0;
  visibility: hidden;
  transition: opacity 300ms cubic-bezier(0.4, 0, 0.2, 1),
              visibility 300ms cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 900;
}

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

.modal {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.95);
  opacity: 0;
  visibility: hidden;
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1),
              opacity 300ms cubic-bezier(0.4, 0, 0.2, 1),
              visibility 300ms cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1000;
}

.modal--open {
  transform: translate(-50%, -50%) scale(1);
  opacity: 1;
  visibility: visible;
}

/* Modal Entry Animation */
.modal-enter {
  animation: scaleIn 300ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.modal-exit {
  animation: scaleOut 200ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* ============================================
   TOAST ANIMATIONS
   ============================================ */

.toast-container {
  position: fixed;
  bottom: calc(var(--bottom-nav-height) + var(--space-4));
  right: var(--space-4);
  left: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  z-index: 1000;
  pointer-events: none;
}

@media (min-width: 768px) {
  .toast-container {
    left: auto;
    width: 400px;
    max-width: 100%;
    bottom: var(--space-4);
  }
}

.toast {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  pointer-events: auto;
  animation: toastSlideIn 300ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes toastSlideIn {
  from {
    opacity: 0;
    transform: translateY(20px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes toastSlideOut {
  from {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  to {
    opacity: 0;
    transform: translateY(-20px) scale(0.95);
  }
}

.toast--exiting {
  animation: toastSlideOut 200ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* Toast Variants */
.toast--success {
  border-left: 4px solid var(--color-success);
}

.toast--error {
  border-left: 4px solid var(--color-danger);
}

.toast--warning {
  border-left: 4px solid var(--color-warning);
}

.toast--info {
  border-left: 4px solid var(--color-info);
}

/* ============================================
   SKELETON LOADING ANIMATIONS
   ============================================ */

.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-surface) 25%,
    var(--color-surface-hover) 50%,
    var(--color-surface) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: var(--radius-md);
}

.skeleton--text {
  height: 1em;
  margin-bottom: var(--space-2);
}

.skeleton--text:last-child {
  width: 80%;
}

.skeleton--title {
  height: 1.5em;
  width: 60%;
  margin-bottom: var(--space-3);
}

.skeleton--circle {
  border-radius: 50%;
}

.skeleton--card {
  height: 200px;
  border-radius: var(--radius-lg);
}

.skeleton--image {
  height: 150px;
  border-radius: var(--radius-md);
}

.skeleton--avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}

.skeleton--button {
  height: 44px;
  width: 120px;
  border-radius: var(--radius-md);
}

/* Skeleton Pulse Variant */
.skeleton--pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* ============================================
   LIST STAGGER ANIMATIONS
   ============================================ */

.stagger-list {
  --stagger-delay: 50ms;
}

.stagger-list > * {
  opacity: 0;
  animation: slideInUp 300ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.stagger-list > *:nth-child(1) { animation-delay: calc(var(--stagger-delay) * 0); }
.stagger-list > *:nth-child(2) { animation-delay: calc(var(--stagger-delay) * 1); }
.stagger-list > *:nth-child(3) { animation-delay: calc(var(--stagger-delay) * 2); }
.stagger-list > *:nth-child(4) { animation-delay: calc(var(--stagger-delay) * 3); }
.stagger-list > *:nth-child(5) { animation-delay: calc(var(--stagger-delay) * 4); }
.stagger-list > *:nth-child(6) { animation-delay: calc(var(--stagger-delay) * 5); }
.stagger-list > *:nth-child(7) { animation-delay: calc(var(--stagger-delay) * 6); }
.stagger-list > *:nth-child(8) { animation-delay: calc(var(--stagger-delay) * 7); }
.stagger-list > *:nth-child(9) { animation-delay: calc(var(--stagger-delay) * 8); }
.stagger-list > *:nth-child(10) { animation-delay: calc(var(--stagger-delay) * 9); }

/* ============================================
   LOADING SPINNER
   ============================================ */

.loading-spinner {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.loading-spinner__circle {
  width: 24px;
  height: 24px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.loading-spinner--sm .loading-spinner__circle {
  width: 16px;
  height: 16px;
  border-width: 1.5px;
}

.loading-spinner--lg .loading-spinner__circle {
  width: 40px;
  height: 40px;
  border-width: 3px;
}

.loading-spinner--primary .loading-spinner__circle {
  border-top-color: var(--color-primary);
}

.loading-spinner--success .loading-spinner__circle {
  border-top-color: var(--color-success);
}

.loading-spinner--danger .loading-spinner__circle {
  border-top-color: var(--color-danger);
}

/* ============================================
   PROGRESS BAR
   ============================================ */

.progress-bar {
  position: relative;
  height: 8px;
  background-color: var(--color-surface-hover);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  border-radius: var(--radius-full);
  transition: width 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

.progress-bar--indeterminate .progress-bar__fill {
  width: 50%;
  animation: progressIndeterminate 1.5s ease-in-out infinite;
}

.progress-bar--sm {
  height: 4px;
}

.progress-bar--lg {
  height: 12px;
}

/* ============================================
   INPUT ANIMATIONS
   ============================================ */

.form-input,
.form-select,
.form-textarea {
  transition: border-color 150ms ease,
              box-shadow 150ms ease,
              transform 100ms ease;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  transform: translateY(-1px);
}

/* Input Shake (for validation errors) */
.form-input--error {
  animation: shake 400ms ease-in-out;
  border-color: var(--color-danger) !important;
}

/* ============================================
   NAVIGATION ANIMATIONS
   ============================================ */

.nav-item {
  position: relative;
  transition: background-color 150ms ease,
              color 150ms ease;
}

.nav-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%) scaleY(0);
  width: 3px;
  height: 60%;
  background-color: var(--color-primary);
  border-radius: 0 var(--radius-full) var(--radius-full) 0;
  transition: transform 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-item--active::before {
  transform: translateY(-50%) scaleY(1);
}

/* Bottom Nav Item */
.bottom-nav__item {
  transition: color 150ms ease,
              transform 100ms ease;
}

.bottom-nav__item:active {
  transform: scale(0.95);
}

/* ============================================
   BADGE ANIMATIONS
   ============================================ */

.badge {
  transition: transform 150ms ease;
}

.badge--pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* ============================================
   HOVER EFFECTS
   ============================================ */

/* Link Hover Animation */
.link-hover {
  position: relative;
  text-decoration: none;
}

.link-hover::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: currentColor;
  transition: width 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

.link-hover:hover::after {
  width: 100%;
}

/* Icon Button Hover */
.icon-btn {
  transition: transform 150ms ease,
              background-color 150ms ease;
}

.icon-btn:hover {
  transform: scale(1.1);
}

.icon-btn:active {
  transform: scale(0.95);
}

/* ============================================
   FADE IN SECTIONS
   ============================================ */

.fade-in-section {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 400ms cubic-bezier(0.4, 0, 0.2, 1),
              transform 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-in-section--visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   REDUCED MOTION SUPPORT
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  .skeleton {
    animation: none;
    background: var(--color-surface-hover);
  }
  
  .loading-spinner__circle {
    animation: none;
    border-top-color: var(--color-primary);
  }
  
  .progress-bar--indeterminate .progress-bar__fill {
    animation: none;
    width: 100%;
  }
  
  .btn--ripple::after {
    display: none;
  }
  
  .card--hover-lift:hover,
  .card--hover-scale:hover {
    transform: none;
  }
  
  .page-transition-enter,
  .page-transition-exit,
  .toast,
  .toast--exiting,
  .modal-enter,
  .modal-exit,
  .stagger-list > * {
    animation: none;
    opacity: 1;
    transform: none;
  }
  
  .fade-in-section {
    opacity: 1;
    transform: none;
  }
}

/* ============================================
   UTILITY ANIMATION CLASSES
   ============================================ */

/* Animation Durations */
.animate-fast { animation-duration: 150ms; }
.animate-normal { animation-duration: 300ms; }
.animate-slow { animation-duration: 500ms; }

/* Animation Delays */
.delay-100 { animation-delay: 100ms; }
.delay-200 { animation-delay: 200ms; }
.delay-300 { animation-delay: 300ms; }
.delay-400 { animation-delay: 400ms; }
.delay-500 { animation-delay: 500ms; }

/* Animation Fill Modes */
.animate-forwards { animation-fill-mode: forwards; }
.animate-backwards { animation-fill-mode: backwards; }
.animate-both { animation-fill-mode: both; }

/* Animation Iteration */
.animate-infinite { animation-iteration-count: infinite; }
.animate-once { animation-iteration-count: 1; }

/* Animation Timing Functions */
.ease-linear { animation-timing-function: linear; }
.ease-in { animation-timing-function: ease-in; }
.ease-out { animation-timing-function: ease-out; }
.ease-in-out { animation-timing-function: ease-in-out; }
.ease-spring { animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1); }