/**
 * ANIMATIONS.CSS - Lightweight Micro-Interactions
 * GPU-accelerated, no layout shift, no blink
 * Optimized for performance (~8KB vs 21KB before)
 */

/* ============================================
   CSS Variables for Animation Control
   ============================================ */
:root {
    --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-out-back: cubic-bezier(0.34, 1.56, 0.64, 1);
    --ease-spring: cubic-bezier(0.175, 0.885, 0.32, 1.275);
    
    --duration-fast: 0.15s;
    --duration-normal: 0.3s;
    --duration-slow: 0.5s;
}

/* ============================================
   Core Keyframes (Only what's needed)
   ============================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

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

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

/* ============================================
   Hover Transitions (No animation on load)
   ============================================ */

/* Logo - No Animation (Brand stability) */
.logo {
    /* Intentionally static - brand elements should not animate */
}

/* Back Button */
.back-btn {
    transition: all var(--duration-normal) var(--ease-out-expo);
}
.back-btn:hover {
    transform: translateX(-4px);
    color: var(--primary, #4a90d9);
}

/* ============================================
   Card Hover Effects (NO load animation)
   ============================================ */
.tool-card, .img-card, .result-item {
    transition: transform var(--duration-fast) ease,
                box-shadow var(--duration-fast) ease;
}

.tool-card:hover, .img-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.result-item:hover {
    transform: translateX(8px);
    background: rgba(74, 144, 217, 0.05);
}

/* ============================================
   Button Animations
   ============================================ */
button, .btn, [class*="btn-"] {
    position: relative;
    overflow: hidden;
    transition: all var(--duration-normal) var(--ease-out-expo);
}

/* Primary Button Hover */
.btn--primary:hover, .btn-primary:hover, 
[class*="btn-download"]:hover, [class*="btn-convert"]:hover,
[class*="btn-resize"]:hover, [class*="btn-compress"]:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

.btn--primary:active, .btn-primary:active {
    opacity: 0.9;
}

/* Icon Button Animation */
.icon-btn:hover, [class*="btn-zoom"]:hover, 
[class*="btn-rotate"]:hover, [class*="btn-flip"]:hover {
    opacity: 0.7;
}

/* Disabled State */
button:disabled, .btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
}

/* ============================================
   Dropzone Animations
   ============================================ */
.dropzone, .upload-area, [class*="drop"] {
    transition: border-color var(--duration-fast) ease;
}

.dropzone:hover, .upload-area:hover {
    border-color: var(--primary, #4a90d9);
}

.dropzone.dragover, .drag-over {
    border-color: var(--primary, #4a90d9);
    background: rgba(74, 144, 217, 0.02);
}

.dropzone svg, .upload-area svg {
    transition: opacity var(--duration-fast) ease;
}
.dropzone:hover svg, .upload-area:hover svg {
    opacity: 0.8;
}

/* ============================================
   Input & Slider Animations
   ============================================ */
input[type="text"], input[type="number"], textarea, select {
    transition: all var(--duration-fast) var(--ease-out-expo);
}

input:focus, textarea:focus, select:focus {
    box-shadow: 0 0 0 4px rgba(74, 144, 217, 0.15);
}

input[type="range"]::-webkit-slider-thumb {
    transition: all var(--duration-fast) var(--ease-out-back);
}
input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* ============================================
   Tab & Toggle Hover
   ============================================ */
.tab, [class*="tab-"], .mode, .preset, .format-btn, 
.platform-btn, .bg-btn, .orient-btn, .size-btn {
    transition: opacity var(--duration-fast) ease;
}

.tab:hover, .preset:hover, .format-btn:hover, 
.platform-btn:hover, .bg-btn:hover {
    opacity: 0.8;
}

/* ============================================
   Processing States
   ============================================ */
.processing {
    transition: opacity var(--duration-normal) var(--ease-out-expo);
}

.progress-bar, [class*="progress-bar"] {
    transition: width var(--duration-fast) var(--ease-out-expo);
}

.spinner, [class*="spinner"] {
    animation: spin 1s linear infinite;
}

/* ============================================
   Footer Links
   ============================================ */
footer a, .footer a {
    transition: all var(--duration-fast) var(--ease-out-expo);
}

footer a:hover, .footer a:hover {
    color: var(--primary, #4a90d9);
}

/* ============================================
   Bug Report Button
   ============================================ */
.bug-report-btn {
    transition: opacity var(--duration-fast) ease !important;
}

.bug-report-btn:hover {
    opacity: 0.7 !important;
}

/* ============================================
   Skeleton Loading
   ============================================ */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 4px;
}

/* ============================================
   Accessibility - Focus Visible
   ============================================ */
:focus-visible {
    outline: 2px solid var(--primary, #4a90d9);
    outline-offset: 2px;
}

/* Skip link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary, #4a90d9);
    color: white;
    padding: 8px 16px;
    z-index: 1000;
    font-weight: 600;
    border-radius: 0 0 8px 0;
    transition: top 0.3s;
}
.skip-link:focus {
    top: 0;
}

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