/* =============================================================================
   ANIMATIONS — "Paper Slide" and Micro-interactions
   ============================================================================= */

/* =============================================================================
   1. PAPER SLIDE — Signature animation for grading results
   ============================================================================= */

@keyframes paper-slide-in {
    0% {
        opacity: 0;
        transform: translateY(40px) scale(0.97);
    }
    60% {
        opacity: 1;
        transform: translateY(-8px) scale(1.01);
    }
    80% {
        transform: translateY(3px) scale(0.995);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.paper-slide {
    animation: paper-slide-in 0.6s var(--ease-spring) both;
}

/* Staggered paper slide for lists */
.paper-slide-stagger > * {
    opacity: 0;
    animation: paper-slide-in 0.5s var(--ease-spring) both;
}

.paper-slide-stagger > *:nth-child(1) { animation-delay: 0.05s; }
.paper-slide-stagger > *:nth-child(2) { animation-delay: 0.10s; }
.paper-slide-stagger > *:nth-child(3) { animation-delay: 0.15s; }
.paper-slide-stagger > *:nth-child(4) { animation-delay: 0.20s; }
.paper-slide-stagger > *:nth-child(5) { animation-delay: 0.25s; }
.paper-slide-stagger > *:nth-child(6) { animation-delay: 0.30s; }
.paper-slide-stagger > *:nth-child(7) { animation-delay: 0.35s; }
.paper-slide-stagger > *:nth-child(8) { animation-delay: 0.40s; }


/* =============================================================================
   2. FADE IN — General purpose
   ============================================================================= */

@keyframes fade-in {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fade-in 0.4s var(--ease-out) both;
}


/* =============================================================================
   3. SCALE IN — For modals and popovers
   ============================================================================= */

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

.scale-in {
    animation: scale-in 0.25s var(--ease-out) both;
}


/* =============================================================================
   4. SLIDE IN — For toast notifications
   ============================================================================= */

@keyframes slide-in-right {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slide-out-right {
    from {
        opacity: 1;
        transform: translateX(0);
    }
    to {
        opacity: 0;
        transform: translateX(100%);
    }
}

/* Toast transition classes for Alpine.js */
.toast-enter       { animation: slide-in-right 0.35s var(--ease-spring) both; }
.toast-enter-start { opacity: 0; transform: translateX(100%); }
.toast-enter-end   { opacity: 1; transform: translateX(0); }
.toast-leave       { animation: slide-out-right 0.25s var(--ease-out) both; }
.toast-leave-start { opacity: 1; transform: translateX(0); }
.toast-leave-end   { opacity: 0; transform: translateX(100%); }


/* =============================================================================
   5. PULSE — Loading/processing indicator
   ============================================================================= */

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

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


/* =============================================================================
   6. SPIN — For loading spinners
   ============================================================================= */

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

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--surface-container-high);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

.spinner-lg {
    width: 36px;
    height: 36px;
    border-width: 3px;
}


/* =============================================================================
   7. PROGRESS SHIMMER — For loading states
   ============================================================================= */

@keyframes shimmer {
    0% {
        background-position: -200% 0;
    }
    100% {
        background-position: 200% 0;
    }
}

.skeleton {
    background: linear-gradient(
        90deg,
        var(--surface-container-high) 25%,
        var(--surface-container) 37%,
        var(--surface-container-high) 63%
    );
    background-size: 200% 100%;
    animation: shimmer 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

.skeleton-text {
    height: 14px;
    margin-bottom: var(--space-2);
}

.skeleton-title {
    height: 24px;
    width: 60%;
    margin-bottom: var(--space-3);
}

.skeleton-card {
    height: 120px;
}


/* =============================================================================
   8. HOVER INTERACTIONS
   ============================================================================= */

/* Subtle lift on hover */
.hover-lift {
    transition: transform var(--duration-base) var(--ease-out),
                box-shadow var(--duration-base) var(--ease-out);
}

.hover-lift:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-ambient);
}

/* Scale on hover */
.hover-scale {
    transition: transform var(--duration-fast) var(--ease-spring);
}

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

/* Glow on hover (for primary buttons) */
.hover-glow {
    transition: box-shadow var(--duration-base) var(--ease-out);
}

.hover-glow:hover {
    box-shadow: 0 0 24px rgba(0, 91, 191, 0.20);
}


/* =============================================================================
   9. COUNT UP — For stat numbers
   ============================================================================= */

@keyframes count-up-reveal {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.count-up {
    animation: count-up-reveal 0.6s var(--ease-spring) both;
}


/* =============================================================================
   10. FLOATING PAPERS (Login Hero)
   ============================================================================= */

.floating-papers-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 400px;
}

.paper {
    position: absolute;
    width: 120px;
    height: 160px;
    background: var(--surface-container-lowest);
    border-radius: var(--radius-md);
    padding: var(--space-4);
    box-shadow: var(--shadow-elevated);
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    animation: float-paper 6s ease-in-out infinite, sway-paper 8s ease-in-out infinite;
    transform-origin: center;
}

.paper-line {
    height: 6px;
    background: var(--surface-container-high);
    border-radius: var(--radius-full);
}

.paper-check {
    margin-top: auto;
    align-self: flex-end;
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.paper-1 {
    top: 10%;
    left: 20%;
    z-index: 3;
    animation-delay: 0s, 0s;
    transform: rotate(-10deg);
}

.paper-2 {
    top: 30%;
    right: 15%;
    z-index: 2;
    animation-delay: -2s, -3s;
    transform: rotate(15deg) scale(0.9);
    opacity: 0.8;
}

.paper-3 {
    top: 50%;
    left: 30%;
    z-index: 1;
    animation-delay: -4s, -1s;
    transform: rotate(-5deg) scale(0.8);
    opacity: 0.6;
}

@keyframes float-paper {
    0%, 100% { transform: translateY(0) rotate(var(--angle, 0deg)) scale(var(--scale, 1)); }
    50% { transform: translateY(-30px) rotate(calc(var(--angle, 0deg) + 5deg)) scale(var(--scale, 1)); }
}

@keyframes sway-paper {
    0%, 100% { margin-left: 0; }
    50% { margin-left: 15px; }
}

.paper-1 { --angle: -10deg; --scale: 1; }
.paper-2 { --angle: 15deg; --scale: 0.9; }
.paper-3 { --angle: -5deg; --scale: 0.8; }

/* =============================================================================
   11. REDUCED MOTION
   ============================================================================= */

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}