/* public/css/flipbook.css */
.flipbook-container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 12px;
    margin: 40px auto 0 auto;
    box-shadow: 0 4px 15px rgba(0,0,0,0.02);
    max-width: 950px;
    padding: 2.5rem 1.5rem;
    text-align: center;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.flipbook-title {
    color: #ff5d01;
    font-weight: 800;
    margin-bottom: 0.5rem;
    font-size: 2.5rem;
}

.stage-wrapper {
    perspective: 2000px;
    margin: 2rem auto;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 500px;
    overflow: visible;
}

.book-viewport {
    position: relative;
    width: 600px;
    height: 400px;
    transform-style: preserve-3d;
    transition: transform 0.2s ease-out;
    transform: scale(var(--zoom-factor, 1)); 
    cursor: grab;
}

.book-viewport:active {
    cursor: grabbing;
}

.flip-page {
    position: absolute;
    width: 50%;
    height: 100%;
    top: 0;
    transform-style: preserve-3d;
    transform-origin: left center;
    transition: transform 0.8s cubic-bezier(0.25, 1, 0.5, 1), z-index 0.1s;
    user-select: none;
}

.flip-page.left-side {
    left: 0;
    transform-origin: right center;
}

.flip-page.right-side {
    left: 50%;
    transform-origin: left center;
}

.page-face {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    backface-visibility: hidden;
    background: #fff;
    box-shadow: inset 3px 0 10px rgba(0,0,0,0.05), 0 2px 5px rgba(0,0,0,0.1);
    border-radius: 2px 4px 4px 2px;
}

.page-face.back {
    transform: rotateY(180deg);
}

.page-face canvas {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.flip-page.flipped {
    transform: rotateY(-180deg);
    pointer-events: none;
}

.nav-controls {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.zoom-panel {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: #f1f3f5;
    padding: 0.4rem 1rem;
    border-radius: 20px;
    margin: 0 1rem;
}

.zoom-slider {
    accent-color: #ff5d01;
    cursor: pointer;
    width: 120px;
}

.btn-nav {
    background: #212529;
    color: white;
    border: none;
    padding: 0.5rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
}

.btn-nav:disabled {
    background: #eaecf1;
    color: #a3a6b5;
    cursor: not-allowed;
}

/* Floating Fullscreen HUD Styles */
.fs-controls-hud {
    display: none;
    position: absolute;
    bottom: 25px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(33, 37, 41, 0.9);
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    gap: 1rem;
    align-items: center;
    z-index: 100000;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
}

.btn-hud {
    background: #343a40;
    color: white;
    border: 1px solid #495057;
    padding: 0.4rem 1.2rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-hud:hover {
    background: #ff5d01;
    border-color: #ff5d01;
}

.btn-exit-fs {
    background: #dc3545;
    border-color: #dc3545;
}

/* Fullscreen Staging State Engine Activations */
:fullscreen .stage-wrapper {
    background: #111111 !important;
    width: 100vw;
    height: 100vh;
    margin: 0 !important;
    position: relative;
}

:fullscreen .fs-controls-hud {
    display: flex !important;
}

:-webkit-full-screen .stage-wrapper {
    background: #111111 !important;
    width: 100vw;
    height: 100vh;
    margin: 0 !important;
}

:-webkit-full-screen .fs-controls-hud {
    display: flex !important;
}

/* Anti-aliasing engine parameters for high-magnification scales */
.page-face canvas {
    image-rendering: -webkit-optimize-contrast;
    image-rendering: crisp-edges;
    image-rendering: high-quality;
}

/* Accessibility button interactive highlights */
.btn-zoom-adjust {
    font-size: 0.85rem;
    transition: transform 0.1s ease;
    user-select: none;
}
.btn-zoom-adjust:active {
    transform: scale(1.2);
}