.pdf-viewer-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto 4rem auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    background: transparent;
    padding: 2rem 1rem 4rem 1rem;
    overflow: hidden;
    position: relative;
}

.pdf-viewer-container.is-zoomed {
    touch-action: none;
}

/* Hide by default, only show in fullscreen */
.pdf-viewer-container:not(:fullscreen) {
    position: fixed;
    top: -9999px;
    left: -9999px;
    width: 1px;
    height: 1px;
    opacity: 0;
    pointer-events: none;
}

/* Vertical Mode Container tweaks */
.pdf-viewer-container.is-vertical {
    overflow-y: auto;
    overflow-x: hidden;
    padding-bottom: 6rem; /* Extra space for scrolling */
}

/* Fullscreen mode overrides */
.pdf-viewer-container:fullscreen {
    background: var(--bg-color);
    max-width: 100%;
    padding: 3rem 1rem 5rem 1rem;
    overflow: auto;
    display: flex;
    flex-direction: column;
}

.pdf-viewer-container:fullscreen .pdf-book-wrapper {
    max-width: none;
    flex: 1;
    min-height: 400px;
    height: 100%;
}

/* Unified Action Bar */
.pdf-action-bar {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    width: 100%;
    max-width: 1000px;
    margin-bottom: 2rem;
    gap: 1rem;
    position: sticky;
    top: 1rem;
    z-index: 100;
}

/* Fixed when fullscreen */
.pdf-viewer-container:fullscreen .pdf-action-bar {
    position: fixed;
    top: 1rem;
    right: 1rem;
    width: auto;
    background: var(--bg-color);
    padding: 0.5rem;
    border-radius: 50px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    border: 1px solid var(--border-color);
}

.zoom-controls {
    display: flex;
    align-items: center;
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
}

.zoom-controls button,
.fullscreen-btn {
    background: transparent;
    border: none;
    padding: 0.5rem 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    transition: background 0.3s ease, color 0.3s ease;
}

.zoom-controls button:hover,
.fullscreen-btn:hover {
    background: var(--text-primary);
    color: var(--bg-color);
}

#zoom-level {
    font-family: var(--font-sans);
    font-weight: 500;
    font-size: 0.9rem;
    padding: 0 0.5rem;
    min-width: 60px;
    text-align: center;
    color: var(--text-primary);
}

.fullscreen-btn {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
}

#btn-toggle-view {
    margin-right: 0 !important;
}

/* Book Wrapper */
.pdf-book-wrapper {
    position: relative;
    width: 100%;
    max-width: 1000px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: transform 0.3s ease;
    transform-origin: center center;
    z-index: 10;
    margin: auto;
    touch-action: none;
}

/* When zoomed and dragging */
.pdf-book-wrapper.is-zoomed,
.pdf-vertical-wrapper.is-zoomed {
    transition: none;
    cursor: grab;
}
.pdf-book-wrapper.is-dragging,
.pdf-vertical-wrapper.is-dragging {
    cursor: grabbing;
}

/* Removed box-shadow from pdf-book to prevent uncanny shadow on empty left page */
#pdf-book {
    background: transparent;
    width: 100%;
    height: 100%;
}

.pdf-page {
    background: white;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    border: 1px solid rgba(0,0,0,0.05);
    box-shadow: inset 0 0 10px rgba(0,0,0,0.02);
}

.pdf-page canvas {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    pointer-events: none;
}

/* Vertical Wrapper */
.pdf-vertical-wrapper {
    width: 100%;
    max-width: 1000px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
    z-index: 10;
    transition: transform 0.3s ease;
    transform-origin: top center;
}
.pdf-vertical-wrapper .pdf-page {
    width: 100% !important; /* Override inline width */
    height: auto !important; /* Override inline height */
    box-shadow: 0 10px 40px rgba(0,0,0,0.08); /* Shadow for vertical pages */
}
.pdf-vertical-wrapper .pdf-page canvas {
    width: 100%;
    height: auto;
}

/* Flip Zones */
.flip-zone {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 50%;
    z-index: 15;
}

.flip-zone-left {
    left: 0;
    cursor: w-resize; /* Fallback */
}
.flip-zone-left:hover {
    cursor: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='40' height='40' viewBox='0 0 40 40'%3E%3Cfilter id='shadow'%3E%3CfeDropShadow dx='0' dy='2' stdDeviation='3' flood-color='rgba(0,0,0,0.5)'/%3E%3C/filter%3E%3Ccircle cx='20' cy='20' r='16' fill='white' filter='url(%23shadow)'/%3E%3Cpath d='M22 14l-6 6 6 6' fill='none' stroke='black' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") 20 20, w-resize;
}

.flip-zone-right {
    right: 0;
    cursor: e-resize;
}

/* --- Thumbnail Button Styles --- */
.pdf-thumbnail-btn {
    position: relative;
    width: 100%;
    aspect-ratio: 1 / 1.414; /* A4 proportion approx */
    background: var(--bg-color);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.pdf-thumbnail-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.15);
}

.pdf-thumbnail-btn canvas {
    width: 100%;
    height: 100%;
    object-fit: cover;
    pointer-events: none;
}

.pdf-thumbnail-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3); /* Always slight tint to indicate interactivity */
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.4s ease;
}

.pdf-thumbnail-btn:hover .pdf-thumbnail-overlay {
    background: rgba(0, 0, 0, 0.6);
}

.view-work-text {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--bg-color);
    background: var(--text-primary);
    padding: 0.8rem 1.5rem;
    border-radius: 50px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    display: none; /* Hidden by default until loaded */
    pointer-events: none;
    transition: transform 0.2s ease, background 0.2s ease;
}

.pdf-thumbnail-btn:hover .view-work-text {
    transform: scale(1.05);
}

/* Skeleton/Spinner */
.thumbnail-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(255,255,255,0.2);
    border-top-color: #ffffff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.pdf-thumbnail-btn.is-loaded .view-work-text {
    display: block;
}

.pdf-thumbnail-btn.is-loaded .thumbnail-spinner {
    display: none;
}

.flip-zone-right:hover {
    cursor: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='40' height='40' viewBox='0 0 40 40'%3E%3Cfilter id='shadow'%3E%3CfeDropShadow dx='0' dy='2' stdDeviation='3' flood-color='rgba(0,0,0,0.5)'/%3E%3C/filter%3E%3Ccircle cx='20' cy='20' r='16' fill='white' filter='url(%23shadow)'/%3E%3Cpath d='M18 14l6 6-6 6' fill='none' stroke='black' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") 20 20, e-resize;
}

.pdf-book-wrapper.is-zoomed .flip-zone {
    display: none;
}

/* Page Counter at Bottom */
.pdf-page-num {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-primary);
    background: var(--bg-color);
    padding: 0.5rem 1.25rem;
    border-radius: 50px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    z-index: 50; /* Ensure it stays on top */
    pointer-events: none; /* Don't block interactions */
}

/* In vertical mode, if we want it fixed, position: fixed works well, but we can also use absolute relative to container if we prefer */
.pdf-viewer-container.is-vertical .pdf-page-num {
    position: fixed;
}

.pdf-loading {
    padding: 4rem;
    font-family: var(--font-sans);
    font-weight: 500;
    text-align: center;
    color: var(--text-primary);
    font-size: 1.25rem;
}