/* --- CSS DESIGN SYSTEM --- */

:root {
    /* Colors */
    --color-bg-dark: #0f1812;
    --color-bg-light: #18261d;
    --color-primary: #c5a059;
    --color-primary-glow: rgba(197, 160, 89, 0.4);
    --color-primary-light: #dfba73;
    --color-text-main: #f3f5f4;
    --color-text-muted: #a4b3a8;
    --color-glass-bg: rgba(15, 24, 18, 0.75);
    --color-glass-border: rgba(197, 160, 89, 0.15);
    --color-shadow: rgba(0, 0, 0, 0.5);
    
    /* Layout & Sizing */
    --header-height: 64px;
    --footer-height: 110px;
    --sidebar-width: 320px;
    --transition-speed: 0.3s;
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    
    /* Fonts */
    --font-heading: 'Outfit', 'Inter', sans-serif;
    --font-body: 'Inter', sans-serif;
}

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

body {
    background-color: var(--color-bg-dark);
    background-image: radial-gradient(circle at center, var(--color-bg-light) 0%, var(--color-bg-dark) 100%);
    color: var(--color-text-main);
    font-family: var(--font-body);
    height: 100vh;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
}

/* App Layout Container */
.app-container {
    display: grid;
    grid-template-rows: var(--header-height) 1fr var(--footer-height);
    height: 100vh;
    position: relative;
}

/* Header Styles */
.app-header {
    background: var(--color-glass-bg);
    border-bottom: 1px solid var(--color-glass-border);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px;
    z-index: 100;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.header-left {
    display: flex;
    align-items: center;
}

.brand-logo {
    height: 38px;
    width: auto;
    object-fit: contain;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.5));
}

.header-center h1 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--color-primary-light);
    letter-spacing: 0.5px;
    text-align: center;
}

.header-right {
    display: flex;
    gap: 12px;
}

/* Button & Icon Styles */
.icon-btn {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--color-text-muted);
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-md);
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all var(--transition-speed) ease;
}

.icon-btn:hover {
    color: var(--color-text-main);
    border-color: var(--color-primary);
    background: rgba(197, 160, 89, 0.08);
    box-shadow: 0 0 10px var(--color-primary-glow);
    transform: translateY(-2px);
}

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

.icon-btn.active {
    color: var(--color-primary-light);
    border-color: var(--color-primary);
    background: rgba(197, 160, 89, 0.15);
    box-shadow: inset 0 0 5px rgba(197, 160, 89, 0.3);
}

/* Sidebar / Thumbnails Panel */
.sidebar {
    position: absolute;
    top: 0;
    left: calc(-1 * var(--sidebar-width));
    width: var(--sidebar-width);
    height: 100%;
    background: rgba(10, 18, 13, 0.95);
    border-right: 1px solid var(--color-glass-border);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 500;
    display: flex;
    flex-direction: column;
    transition: left var(--transition-speed) cubic-bezier(0.1, 0.9, 0.2, 1);
    box-shadow: 10px 0 30px rgba(0, 0, 0, 0.5);
}

.sidebar.open {
    left: 0;
}

.sidebar-header {
    height: var(--header-height);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.sidebar-header h2 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-primary-light);
}

.close-btn {
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    font-size: 1.25rem;
    cursor: pointer;
    transition: color var(--transition-speed);
}

.close-btn:hover {
    color: var(--color-primary-light);
}

.thumbnail-grid {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

/* Custom Scrollbar for Sidebar & Grid */
.thumbnail-grid::-webkit-scrollbar {
    width: 6px;
}

.thumbnail-grid::-webkit-scrollbar-track {
    background: transparent;
}

.thumbnail-grid::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
}

.thumbnail-grid::-webkit-scrollbar-thumb:hover {
    background: var(--color-primary);
}

.thumb-item {
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 6px;
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    position: relative;
    transition: all var(--transition-speed) ease;
}

.thumb-img-container {
    aspect-ratio: 1.41;
    overflow: hidden;
    background: #000;
    border: 2px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--border-radius-sm);
    transition: border-color var(--transition-speed) ease;
}

.thumb-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.75;
    transition: opacity var(--transition-speed) ease, transform var(--transition-speed) ease;
}

.thumb-item:hover img {
    opacity: 1;
    transform: scale(1.05);
}

.thumb-item:hover .thumb-img-container {
    border-color: rgba(197, 160, 89, 0.5);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
}

.thumb-item.active .thumb-img-container {
    border-color: var(--color-primary);
    box-shadow: 0 0 10px var(--color-primary-glow);
}

.thumb-item.active img {
    opacity: 1;
}

.thumb-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    text-align: center;
    font-weight: 500;
    transition: color var(--transition-speed);
}

.thumb-item:hover .thumb-label, .thumb-item.active .thumb-label {
    color: var(--color-text-main);
}

/* Main Content Styles */
.main-content {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    padding: 20px;
    overflow: hidden;
}

/* Navigation Arrow Overlays */
.nav-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(15, 24, 18, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.5);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.25rem;
    z-index: 100; /* Overlaid on top of book pages */
    backdrop-filter: blur(4px);
    opacity: 0.15; /* Highly transparent by default */
    transition: all var(--transition-speed) ease;
}

.nav-arrow.prev {
    left: 16px;
}

.nav-arrow.next {
    right: 16px;
}

/* Fade in arrows when hovering over the viewport container */
.book-viewport:hover .nav-arrow {
    opacity: 0.6;
    background: rgba(15, 24, 18, 0.5);
}

.nav-arrow:hover {
    opacity: 1 !important;
    background: var(--color-primary) !important;
    border-color: var(--color-primary-light);
    color: #fff;
    box-shadow: 0 0 15px var(--color-primary-glow);
    transform: translateY(-50%) scale(1.1);
}

.nav-arrow:active {
    transform: translateY(-50%) scale(1.0);
}

/* Viewport containing page flip book */
.book-viewport {
    flex: 1;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: visible;
}

.book-zoom-container {
    display: flex;
    justify-content: center;
    align-items: center;
    transition: transform 0.2s cubic-bezier(0.1, 0.9, 0.2, 1);
    transform-origin: center center;
    width: 100%;
    height: 100%;
}

/* Flipbook specific classes */
.flip-book {
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6);
    background: #000;
    transition: opacity 0.3s ease;
    opacity: 0; /* will fade in once loaded */
    display: none; /* initialized by js */
}

.flip-book.loaded {
    opacity: 1;
}

.page-container {
    width: 100%;
    height: 100%;
    background-color: #0f1612;
    position: relative;
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.5);
    overflow: hidden;
}

.page-img {
    width: 100%;
    height: 100%;
    object-fit: fill;
    user-select: none;
    -webkit-user-drag: none;
}

/* Footer / Controls Styles */
.app-footer {
    background: var(--color-glass-bg);
    border-top: 1px solid var(--color-glass-border);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 10px 24px 15px 24px;
    z-index: 100;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.3);
}

/* Scrub Bar Styling */
.scrub-container {
    width: 100%;
    position: relative;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
}

.page-slider {
    -webkit-appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: rgba(255, 255, 255, 0.1);
    outline: none;
    cursor: pointer;
    position: relative;
    z-index: 5;
    transition: height 0.1s ease;
}

.page-slider:hover {
    height: 8px;
}

/* Slider progress highlights */
.slider-progress {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    height: 6px;
    background: var(--color-primary);
    border-radius: 3px 0 0 3px;
    pointer-events: none;
    z-index: 4;
}

.page-slider:hover ~ .slider-progress {
    height: 8px;
}

/* Slider Thumb customizations */
.page-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--color-primary-light);
    border: 2px solid var(--color-bg-dark);
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.5);
    cursor: pointer;
    transition: transform var(--transition-speed) ease, background-color var(--transition-speed);
}

.page-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    background: #fff;
    box-shadow: 0 0 10px var(--color-primary-light);
}

.page-slider::-moz-range-thumb {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--color-primary-light);
    border: 2px solid var(--color-bg-dark);
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.5);
    cursor: pointer;
    transition: transform var(--transition-speed) ease;
}

.page-slider::-moz-range-thumb:hover {
    transform: scale(1.2);
    background: #fff;
}

/* Footer Control Row */
.footer-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.divider {
    width: 1px;
    height: 24px;
    background: rgba(255, 255, 255, 0.1);
    margin: 0 4px;
}

/* Page Input Group */
.page-indicator {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.page-indicator input {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--color-text-main);
    width: 44px;
    height: 32px;
    text-align: center;
    border-radius: var(--border-radius-sm);
    font-size: 0.9rem;
    font-family: var(--font-body);
    font-weight: 600;
    outline: none;
    -moz-appearance: textfield;
}

.page-indicator input::-webkit-outer-spin-button,
.page-indicator input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.page-indicator input:focus {
    border-color: var(--color-primary);
    background: rgba(197, 160, 89, 0.05);
    box-shadow: 0 0 8px rgba(197, 160, 89, 0.2);
}

/* Zoom Value label */
.zoom-value {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-weight: 600;
    min-width: 48px;
    text-align: center;
}

/* Powered By Branding styling */
.powered-by {
    display: flex;
    align-items: center;
    gap: 8px;
}

.powered-text {
    font-family: var(--font-heading);
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--color-text-muted);
    font-weight: 600;
    opacity: 0.8;
}

.powered-logo {
    height: 24px;
    width: auto;
    object-fit: contain;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.3));
}

/* Tooltip implementation */
.tooltip {
    position: relative;
}

.tooltip::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    background: rgba(15, 24, 18, 0.95);
    border: 1px solid var(--color-glass-border);
    color: var(--color-text-main);
    padding: 6px 10px;
    font-size: 0.75rem;
    border-radius: var(--border-radius-sm);
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: all 0.15s ease;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
    z-index: 1000;
}

.tooltip:hover::after {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* --- RESPONSIVENESS AND COLLAPSIBLE VIEWS --- */

@media (max-width: 900px) {
    .header-center h1 {
        font-size: 1.1rem;
    }
    .powered-text {
        display: none; /* Hide "powered by" text on medium screens */
    }
}

@media (max-width: 768px) {
    .app-container {
        grid-template-rows: var(--header-height) 1fr calc(var(--footer-height) + 15px);
    }
    
    .nav-arrow {
        display: none; /* Hide navigation arrows on smaller devices */
    }
    
    .header-center h1 {
        display: none; /* Hide document title, keep logo */
    }
    
    .zoom-value, #btn-zoom-in, #btn-zoom-out, .divider {
        display: none; /* Hide zoom controls on mobile */
    }
    
    .footer-controls {
        flex-direction: column;
        gap: 12px;
        align-items: center;
    }
    
    .control-group.feature-controls {
        order: 1;
    }
    
    .control-group.navigation-controls {
        order: 2;
    }
    
    .powered-by {
        order: 3;
        margin-top: 4px;
    }
}

@media (max-width: 480px) {
    .sidebar {
        width: 100%;
        left: -100%;
    }
    .thumbnail-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* --- Cover Page Video Play Overlay --- */
.video-overlay-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: transparent;
    z-index: 5;
    pointer-events: none;
}

.video-play-btn {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: rgba(15, 24, 18, 0.45);
    border: 2px solid rgba(255, 255, 255, 0.55);
    color: #fff;
    font-size: 2rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: all 0.3s cubic-bezier(0.1, 0.9, 0.2, 1);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    pointer-events: auto;
}

.video-play-btn:hover {
    background: rgba(197, 160, 89, 0.85);
    border-color: var(--color-primary-light);
    transform: scale(1.08);
    box-shadow: 0 0 20px var(--color-primary-glow);
}

/* --- Video Modal Lightbox --- */
.video-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 2000; /* above everything including sidebars */
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.4s ease;
}

.video-modal.open {
    opacity: 1;
    pointer-events: auto;
}

.video-modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(8, 14, 10, 0.88);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.video-modal-content {
    position: relative;
    width: 90%;
    max-width: 1000px;
    aspect-ratio: 16/9;
    background: #000;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.8), 0 0 30px var(--color-primary-glow);
    border: 1px solid var(--color-glass-border);
    z-index: 2010;
    transform: scale(0.92);
    transition: transform 0.4s cubic-bezier(0.1, 0.9, 0.2, 1);
}

.video-modal.open .video-modal-content {
    transform: scale(1);
}

#modal-video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #000;
}

.video-modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.25);
    color: #fff;
    font-size: 1.25rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2020;
    transition: all 0.3s ease;
}

.video-modal-close:hover {
    background: var(--color-primary);
    border-color: var(--color-primary-light);
    transform: rotate(90deg);
}

/* --- Page 28 Hotspots --- */
.hotspots-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 10;
}

.hotspot {
    position: absolute;
    cursor: pointer;
    pointer-events: auto;
    background: transparent;
    border: 1px solid transparent;
    transition: all var(--transition-speed) ease;
    border-radius: var(--border-radius-sm);
}

.hotspot:hover {
    background: rgba(197, 160, 89, 0.18);
    border-color: var(--color-primary);
    box-shadow: 0 0 10px var(--color-primary-glow);
}