/**
 * Material Design 3 — Motion System
 * CMS — Course Management System
 *
 * MD3 motion principles:
 * - Meaningful motion (not decorative)
 * - Consistent easing curves
 * - Appropriate durations
 * - Smooth transitions
 * - Respects user preferences (reduced motion)
 */

/* ============================================================
   MD3 MOTION — EASING CURVES
   ============================================================ */
:root {
    --md3-ease-standard: cubic-bezier(0.2, 0, 0, 1);
    --md3-ease-standard-accelerate: cubic-bezier(0.3, 0, 1, 1);
    --md3-ease-standard-decelerate: cubic-bezier(0, 0, 0, 1);
    --md3-ease-emphasized: cubic-bezier(0.2, 0, 0, 1);
    --md3-ease-emphasized-accelerate: cubic-bezier(0.3, 0, 0.8, 0.15);
    --md3-ease-emphasized-decelerate: cubic-bezier(0.05, 0.7, 0.1, 1);
    --md3-ease-linear: cubic-bezier(0, 0, 1, 1);
}

/* ============================================================
   MD3 MOTION — DURATIONS
   ============================================================ */
:root {
    --md3-duration-short1: 50ms;
    --md3-duration-short2: 100ms;
    --md3-duration-short3: 150ms;
    --md3-duration-short4: 200ms;
    --md3-duration-medium1: 250ms;
    --md3-duration-medium2: 300ms;
    --md3-duration-medium3: 350ms;
    --md3-duration-medium4: 400ms;
    --md3-duration-long1: 450ms;
    --md3-duration-long2: 500ms;
    --md3-duration-long3: 550ms;
    --md3-duration-long4: 600ms;
    --md3-duration-extra-long1: 700ms;
    --md3-duration-extra-long2: 800ms;
    --md3-duration-extra-long3: 900ms;
    --md3-duration-extra-long4: 1000ms;
}

/* ============================================================
   MD3 MOTION — PAGE TRANSITIONS
   ============================================================ */
@keyframes md3-fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes md3-fade-out {
    from { opacity: 1; }
    to { opacity: 0; }
}

@keyframes md3-slide-in-right {
    from { transform: translateX(100%); }
    to { transform: translateX(0); }
}

@keyframes md3-slide-in-left {
    from { transform: translateX(-100%); }
    to { transform: translateX(0); }
}

@keyframes md3-slide-in-up {
    from { transform: translateY(100%); }
    to { transform: translateY(0); }
}

@keyframes md3-slide-in-down {
    from { transform: translateY(-100%); }
    to { transform: translateY(0); }
}

@keyframes md3-scale-in {
    from { transform: scale(0.8); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

@keyframes md3-scale-out {
    from { transform: scale(1); opacity: 1; }
    to { transform: scale(0.8); opacity: 0; }
}

@keyframes md3-rotate-in {
    from { transform: rotate(-90deg) scale(0.8); opacity: 0; }
    to { transform: rotate(0) scale(1); opacity: 1; }
}

/* ============================================================
   MD3 MOTION — COMPONENT ANIMATIONS
   ============================================================ */

/* Card entrance */
@keyframes md3-card-enter {
    from {
        opacity: 0;
        transform: translateY(16px) scale(0.96);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Dialog entrance */
@keyframes md3-dialog-enter {
    from {
        opacity: 0;
        transform: scale(0.8) translateY(24px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

/* Dialog exit */
@keyframes md3-dialog-exit {
    from {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
    to {
        opacity: 0;
        transform: scale(0.8) translateY(24px);
    }
}

/* Snackbar entrance */
@keyframes md3-snackbar-enter {
    from {
        opacity: 0;
        transform: translateY(100%) scale(0.9);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Navigation drawer entrance */
@keyframes md3-drawer-enter {
    from { transform: translateX(-100%); }
    to { transform: translateX(0); }
}

/* Navigation drawer exit */
@keyframes md3-drawer-exit {
    from { transform: translateX(0); }
    to { transform: translateX(-100%); }
}

/* FAB entrance */
@keyframes md3-fab-enter {
    from {
        opacity: 0;
        transform: scale(0.5) rotate(-45deg);
    }
    to {
        opacity: 1;
        transform: scale(1) rotate(0);
    }
}

/* List item stagger */
@keyframes md3-list-item-enter {
    from {
        opacity: 0;
        transform: translateX(-16px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Progress bar indeterminate */
@keyframes md3-progress-indeterminate {
    0% { transform: translateX(-100%); }
    50% { transform: translateX(0); }
    100% { transform: translateX(100%); }
}

/* Shimmer loading effect */
@keyframes md3-shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* Pulse animation */
@keyframes md3-pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* Spin animation */
@keyframes md3-spin {
    to { transform: rotate(360deg); }
}

/* Bounce animation */
@keyframes md3-bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

/* ============================================================
   MD3 MOTION — UTILITY CLASSES
   ============================================================ */
.md3-animate-fade-in {
    animation: md3-fade-in var(--md3-duration-medium2) var(--md3-ease-standard) forwards;
}

.md3-animate-fade-out {
    animation: md3-fade-out var(--md3-duration-medium2) var(--md3-ease-standard) forwards;
}

.md3-animate-slide-in-right {
    animation: md3-slide-in-right var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-slide-in-left {
    animation: md3-slide-in-left var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-slide-in-up {
    animation: md3-slide-in-up var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-slide-in-down {
    animation: md3-slide-in-down var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-scale-in {
    animation: md3-scale-in var(--md3-duration-medium2) var(--md3-ease-emphasized) forwards;
}

.md3-animate-scale-out {
    animation: md3-scale-out var(--md3-duration-medium2) var(--md3-ease-emphasized) forwards;
}

.md3-animate-card-enter {
    animation: md3-card-enter var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-dialog-enter {
    animation: md3-dialog-enter var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-snackbar-enter {
    animation: md3-snackbar-enter var(--md3-duration-medium2) var(--md3-ease-emphasized) forwards;
}

.md3-animate-fab-enter {
    animation: md3-fab-enter var(--md3-duration-medium3) var(--md3-ease-emphasized) forwards;
}

.md3-animate-list-item-enter {
    animation: md3-list-item-enter var(--md3-duration-short4) var(--md3-ease-standard) forwards;
}

.md3-animate-pulse {
    animation: md3-pulse 2s var(--md3-ease-standard) infinite;
}

.md3-animate-spin {
    animation: md3-spin 1s var(--md3-ease-linear) infinite;
}

.md3-animate-bounce {
    animation: md3-bounce 1s var(--md3-ease-standard) infinite;
}

/* ============================================================
   MD3 MOTION — STAGGER DELAYS
   ============================================================ */
.md3-stagger-1 { animation-delay: 50ms; }
.md3-stagger-2 { animation-delay: 100ms; }
.md3-stagger-3 { animation-delay: 150ms; }
.md3-stagger-4 { animation-delay: 200ms; }
.md3-stagger-5 { animation-delay: 250ms; }
.md3-stagger-6 { animation-delay: 300ms; }
.md3-stagger-7 { animation-delay: 350ms; }
.md3-stagger-8 { animation-delay: 400ms; }

/* ============================================================
   MD3 MOTION — LOADING SKELETON
   ============================================================ */
.md3-skeleton {
    background: linear-gradient(
        90deg,
        var(--md3-surface-container) 25%,
        var(--md3-surface-container-high) 50%,
        var(--md3-surface-container) 75%
    );
    background-size: 200% 100%;
    animation: md3-shimmer 1.5s var(--md3-ease-linear) infinite;
    border-radius: var(--md3-shape-corner-small);
}

.md3-skeleton--text {
    height: 16px;
    margin-bottom: 8px;
}

.md3-skeleton--title {
    height: 24px;
    width: 60%;
    margin-bottom: 16px;
}

.md3-skeleton--circle {
    width: 48px;
    height: 48px;
    border-radius: 50%;
}

.md3-skeleton--card {
    height: 120px;
    border-radius: var(--md3-shape-corner-medium);
}

/* ============================================================
   MD3 MOTION — INTERACTION STATES
   ============================================================ */
.md3-ripple {
    position: relative;
    overflow: hidden;
}

.md3-ripple::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle, currentColor 10%, transparent 10.01%);
    background-repeat: no-repeat;
    background-position: 50%;
    transform: scale(10, 10);
    opacity: 0;
    transition: transform 0.5s, opacity 1s;
    pointer-events: none;
}

.md3-ripple:active::after {
    transform: scale(0, 0);
    opacity: 0.12;
    transition: 0s;
}

/* ============================================================
   MD3 MOTION — REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
    .md3-animate-fade-in,
    .md3-animate-fade-out,
    .md3-animate-slide-in-right,
    .md3-animate-slide-in-left,
    .md3-animate-slide-in-up,
    .md3-animate-slide-in-down,
    .md3-animate-scale-in,
    .md3-animate-scale-out,
    .md3-animate-card-enter,
    .md3-animate-dialog-enter,
    .md3-animate-snackbar-enter,
    .md3-animate-fab-enter,
    .md3-animate-list-item-enter,
    .md3-animate-pulse,
    .md3-animate-spin,
    .md3-animate-bounce {
        animation: none !important;
    }

    .md3-skeleton {
        animation: none !important;
        background: var(--md3-surface-container-high);
    }

    .md3-ripple::after {
        display: none;
    }
}