* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #1a1a2e;
    --secondary-color: #16213e;
    --accent-color: #0f3460;
    --highlight-color: #e94560;
    --text-color: #eaeaea;
    --text-muted: #a0a0a0;
    --border-color: #2a2a4a;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    min-height: 100vh;
    color: var(--text-color);
    overflow: hidden;
}

/* Container */
.flipbook-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-height: 100vh;
}

.flipbook-container.fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 9999;
    background: var(--primary-color);
}

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 2rem;
    background: #ffffff;
    border-bottom: 1px solid #e5e5e5;
    gap: 1rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.header-logo {
    display: flex;
    align-items: center;
    flex-shrink: 0;
}

.header-logo img {
    height: 50px;
    width: auto;
    max-width: 180px;
    object-fit: contain;
    transition: transform 0.2s ease;
}

.header-logo:hover img {
    transform: scale(1.05);
}

.header-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1a1a2e;
    flex: 1;
    text-align: center;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.page-indicator {
    font-size: 0.9rem;
    color: #ffffff;
    background: var(--highlight-color);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 500;
}

/* Flipbook Wrapper */
.flipbook-wrapper {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    position: relative;
    overflow: hidden;
}

.flipbook {
    position: relative;
    background: transparent;
    box-shadow: var(--shadow);
}

/* Page Styles */
.page {
    background: white;
    overflow: hidden;
}

.page-content {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: white;
}

.page-content img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.page-content canvas {
    max-width: 100%;
    max-height: 100%;
}

/* Hard covers */
.page.hard {
    background: var(--accent-color);
}

.page.hard .page-content {
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--secondary-color) 100%);
    color: white;
    flex-direction: column;
    gap: 1rem;
}

/* Loading Overlay */
.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(26, 26, 46, 0.95);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    z-index: 100;
    transition: opacity 0.3s ease;
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--highlight-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Controls */
.controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    padding: 1rem 2rem;
    background: var(--secondary-color);
    border-top: 1px solid var(--border-color);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.control-btn {
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 8px;
    background: var(--accent-color);
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.2s ease;
}

.control-btn:hover {
    background: var(--highlight-color);
    transform: translateY(-2px);
}

.control-btn:active {
    transform: translateY(0);
}

.control-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.zoom-level {
    min-width: 60px;
    text-align: center;
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Thumbnail Bar */
.thumbnail-bar {
    position: fixed;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    z-index: 50;
}

.thumbnail-toggle {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 80px;
    border: none;
    border-radius: 0 8px 8px 0;
    background: var(--accent-color);
    color: var(--text-color);
    cursor: pointer;
    transition: all 0.3s ease;
}

.thumbnail-toggle:hover {
    background: var(--highlight-color);
}

.thumbnails {
    position: absolute;
    left: -200px;
    top: 50%;
    transform: translateY(-50%);
    width: 180px;
    max-height: 400px;
    overflow-y: auto;
    background: var(--secondary-color);
    border-radius: 0 8px 8px 0;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: left 0.3s ease;
    box-shadow: var(--shadow);
}

.thumbnails.open {
    left: 40px;
}

.thumbnail {
    width: 100%;
    min-height: 120px;
    height: auto;
    border: 2px solid transparent;
    border-radius: 4px;
    overflow: hidden;
    cursor: pointer;
    transition: all 0.2s ease;
    background: white;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.thumbnail:hover {
    border-color: var(--highlight-color);
    transform: scale(1.05);
}

.thumbnail.active {
    border-color: var(--highlight-color);
}

.thumbnail img,
.thumbnail canvas {
    width: 100%;
    height: auto;
    min-height: 100px;
    max-height: 160px;
    object-fit: contain;
    display: block;
}

/* Page Flip Shadows */
.stf__wrapper {
    box-shadow: var(--shadow);
}

/* Mobile Styles */
@media (max-width: 768px) {
    .header {
        padding: 0.5rem 1rem;
        gap: 0.5rem;
    }
    
    .header-logo img {
        height: 40px;
        max-width: 140px;
    }
    
    .header-title {
        font-size: 1rem;
    }
    
    .flipbook-wrapper {
        padding: 1rem;
    }
    
    .controls {
        flex-wrap: wrap;
        gap: 1rem;
        padding: 0.75rem 1rem;
    }
    
    .control-btn {
        width: 40px;
        height: 40px;
    }
    
    .thumbnail-bar {
        display: none;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 0.5rem 0.75rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .header-logo img {
        height: 35px;
        max-width: 120px;
    }
    
    .header-title {
        font-size: 0.85rem;
        order: 3;
        width: 100%;
        text-align: center;
        margin-top: 0.25rem;
    }
    
    .header-controls {
        order: 2;
    }
    
    .page-indicator {
        font-size: 0.75rem;
        padding: 0.35rem 0.7rem;
    }
    
    .controls {
        gap: 0.5rem;
    }
    
    .control-group {
        gap: 0.25rem;
    }
    
    .control-btn {
        width: 36px;
        height: 36px;
        font-size: 0.9rem;
    }
    
    .zoom-level {
        display: none;
    }
}

/* Touch feedback */
@media (hover: none) {
    .control-btn:hover {
        background: var(--accent-color);
        transform: none;
    }
    
    .control-btn:active {
        background: var(--highlight-color);
    }
}

/* Scrollbar Styles */
.thumbnails::-webkit-scrollbar {
    width: 6px;
}

.thumbnails::-webkit-scrollbar-track {
    background: var(--primary-color);
    border-radius: 3px;
}

.thumbnails::-webkit-scrollbar-thumb {
    background: var(--accent-color);
    border-radius: 3px;
}

.thumbnails::-webkit-scrollbar-thumb:hover {
    background: var(--highlight-color);
}