/* ==========================================================================
   Advanced Modern Animations and Transitions
   ========================================================================== */

/* Smooth Gradient Animation */
@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* Gentle Floating Animation */
@keyframes gentleFloat {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    33% { transform: translateY(-8px) rotate(1deg); }
    66% { transform: translateY(-4px) rotate(-1deg); }
}

/* Soft Glow Effect */
@keyframes softGlow {
    0%, 100% { box-shadow: 0 0 20px rgba(38, 208, 206, 0.2); }
    50% { box-shadow: 0 0 35px rgba(38, 208, 206, 0.4); }
}

/* Smooth Scale Animation */
@keyframes smoothScale {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* Particle Effect */
@keyframes particles {
    0% { transform: translateY(0) rotate(0deg); opacity: 1; }
    100% { transform: translateY(-100px) rotate(360deg); opacity: 0; }
}

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

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

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

@keyframes slideInUp {
    from {
        transform: translateY(100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes slideInDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

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

@keyframes bounce {
    0%, 20%, 53%, 80%, 100% {
        animation-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
        transform: translate3d(0, 0, 0);
    }
    40%, 43% {
        animation-timing-function: cubic-bezier(0.755, 0.05, 0.855, 0.06);
        transform: translate3d(0, -30px, 0) scaleY(1.1);
    }
    70% {
        animation-timing-function: cubic-bezier(0.755, 0.05, 0.855, 0.06);
        transform: translate3d(0, -15px, 0) scaleY(1.05);
    }
    90% {
        transform: translate3d(0, -4px, 0) scaleY(0.95);
    }
}

@keyframes shake {
    10%, 90% {
        transform: translate3d(-1px, 0, 0);
    }
    20%, 80% {
        transform: translate3d(2px, 0, 0);
    }
    30%, 50%, 70% {
        transform: translate3d(-4px, 0, 0);
    }
    40%, 60% {
        transform: translate3d(4px, 0, 0);
    }
}

/* ==========================================================================
   Utility Animation Classes
   ========================================================================== */

.animate-gentle-float {
    animation: gentleFloat 6s ease-in-out infinite;
}

.animate-soft-glow {
    animation: softGlow 4s ease-in-out infinite;
}

.animate-smooth-scale {
    animation: smoothScale 8s ease-in-out infinite;
}

.hover-lift {
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.hover-lift:hover {
    transform: translateY(-12px);
}

.slide-in-left {
    animation: slideInLeft 0.6s ease-out forwards;
}

.slide-in-up {
    animation: slideInUp 0.6s ease-out forwards;
}

.slide-in-down {
    animation: slideInDown 0.6s ease-out forwards;
}

.scale-in {
    animation: scaleIn 0.3s ease-out forwards;
}

/* ==========================================================================
   Hover Effects
   ========================================================================== */

.hover-grow {
    transition: transform 0.3s ease;
}

.hover-grow:hover {
    transform: scale(1.05);
}

.hover-shrink {
    transition: transform 0.3s ease;
}

.hover-shrink:hover {
    transform: scale(0.95);
}

.hover-rotate {
    transition: transform 0.3s ease;
}

.hover-rotate:hover {
    transform: rotate(5deg);
}

.hover-float {
    transition: transform 0.3s ease;
}

.hover-float:hover {
    transform: translateY(-10px);
}

/* ==========================================================================
   Loading States
   ========================================================================== */

.loading-skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

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

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid var(--secondary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: inline-block;
}

/* ==========================================================================
   Micro-interactions
   ========================================================================== */

.book-card {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.book-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.book-card:hover .book-card__img {
    transform: scale(1.1);
}

.book-card__category {
    transition: all 0.3s ease;
}

.book-card:hover .book-card__category {
    transform: scale(1.1);
    background-color: var(--secondary-dark);
}

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

.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transition: width 0.6s, height 0.6s;
    transform: translate(-50%, -50%);
    z-index: 0;
}

.btn:active::after {
    width: 300px;
    height: 300px;
}

.btn > * {
    position: relative;
    z-index: 1;
}

/* ==========================================================================
   Scroll Animations
   ========================================================================== */

.scroll-fade-in {
    opacity: 0;
    transform: translateY(50px);
    transition: all 0.8s ease-out;
}

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

.scroll-slide-left {
    opacity: 0;
    transform: translateX(-50px);
    transition: all 0.8s ease-out;
}

.scroll-slide-left.visible {
    opacity: 1;
    transform: translateX(0);
}

.scroll-slide-right {
    opacity: 0;
    transform: translateX(50px);
    transition: all 0.8s ease-out;
}

.scroll-slide-right.visible {
    opacity: 1;
    transform: translateX(0);
}

.scroll-scale-in {
    opacity: 0;
    transform: scale(0.8);
    transition: all 0.8s ease-out;
}

.scroll-scale-in.visible {
    opacity: 1;
    transform: scale(1);
}

/* ==========================================================================
   Focus States for Accessibility
   ========================================================================== */

.btn:focus,
.form__input:focus,
.form__textarea:focus,
.nav__link:focus,
.filter-btn:focus {
    outline: 2px solid var(--secondary-color);
    outline-offset: 2px;
}

/* ==========================================================================
   Dark Mode Support (Future Enhancement)
   ========================================================================== */

@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #ffffff;
        --text-secondary: #b0bec5;
        --text-light: #78909c;
        --background-light: #121212;
        --background-gray: #1e1e1e;
        --background-dark: #000000;
        --border-color: #333333;
        --shadow-light: rgba(0, 0, 0, 0.3);
        --shadow-medium: rgba(0, 0, 0, 0.4);
        --shadow-heavy: rgba(0, 0, 0, 0.6);
    }

    .header {
        background-color: rgba(255, 255, 255, 0.98);
    }

    .book-card,
    .contact__form {
        background-color: #1e1e1e;
        border: 1px solid #333333;
    }

    .loading-skeleton {
        background: linear-gradient(90deg, #333333 25%, #404040 50%, #333333 75%);
        background-size: 200% 100%;
    }
}

/* ==========================================================================
   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;
    }

    .hero__book {
        transform: none !important;
    }

    .book-card:hover {
        transform: none !important;
    }

    .animate-pulse,
    .animate-spin,
    .animate-bounce {
        animation: none !important;
    }
}

/* ==========================================================================
   High Contrast Mode Support
   ========================================================================== */

@media (prefers-contrast: high) {
    :root {
        --primary-color: #000000;
        --secondary-color: #ff6600;
        --text-primary: #000000;
        --text-secondary: #333333;
        --background-light: #ffffff;
        --border-color: #000000;
    }

    .btn--primary {
        border: 2px solid #000000;
    }

    .book-card {
        border: 2px solid #000000;
    }

    .form__input,
    .form__textarea {
        border: 2px solid #000000;
    }
}