/* ================================================== 
   Design System
   ================================================== */
:root {
    --bg-main: #09090b;
    --bg-secondary: #18181b;
    --bg-tertiary: #27272a;
    --text-primary: #fafafa;
    --text-muted: #a1a1aa;
    --text-dim: #52525b;

    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --accent-glow: rgba(99, 102, 241, 0.35);
    --accent-soft: rgba(99, 102, 241, 0.12);
    --danger: #e11d48;

    --glass-bg: rgba(24, 24, 27, 0.65);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

    --topbar-height: 60px;
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --page-shadow: 2px 0 12px rgba(0, 0, 0, 0.15), inset -2px 0 8px rgba(0, 0, 0, 0.05);
    --page-shadow-left: -2px 0 12px rgba(0, 0, 0, 0.15), inset 2px 0 8px rgba(0, 0, 0, 0.05);
}

[data-theme="light"] {
    --bg-main: #f1f5f9;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e2e8f0;
    --text-primary: #0f172a;
    --text-muted: #64748b;
    --text-dim: #94a3b8;
    --glass-bg: rgba(255, 255, 255, 0.72);
    --glass-border: rgba(0, 0, 0, 0.06);
    --page-shadow: 2px 0 12px rgba(0, 0, 0, 0.08), inset -2px 0 6px rgba(0, 0, 0, 0.03);
    --page-shadow-left: -2px 0 12px rgba(0, 0, 0, 0.08), inset 2px 0 6px rgba(0, 0, 0, 0.03);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    overflow: hidden;
    overscroll-behavior: none;
    transition: background-color 0.4s, color 0.4s;
}

.hidden {
    display: none !important;
}

/* Screens */
.screen-container {
    position: fixed;
    inset: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background: var(--bg-main);
    z-index: 100;
    overflow-y: auto;
    padding: 40px 20px;
    animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

/* Splash */
#splash-screen {
    position: fixed;
    inset: 0;
    background: linear-gradient(145deg, #09090b 0%, #1a1027 50%, #09090b 100%);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.8s ease;
}

.splash-title {
    font-family: 'Syne', sans-serif;
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, #6366f1, #a78bfa, #6366f1);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: gradientShift 3s ease infinite;
    letter-spacing: -1px;
}

.splash-subtitle {
    font-family: 'Inter', sans-serif;
    font-size: 0.85rem;
    color: var(--text-dim);
    margin-top: 6px;
    letter-spacing: 4px;
    text-transform: uppercase;
}

@keyframes gradientShift {

    0%,
    100% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }
}

.splash-loader {
    margin-top: 36px;
    width: 180px;
    height: 3px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 4px;
    overflow: hidden;
    position: relative;
    margin-left: auto;
    margin-right: auto;
}

.loader-bar {
    width: 40%;
    height: 100%;
    background: linear-gradient(90deg, var(--accent), #a78bfa);
    box-shadow: 0 0 16px var(--accent-glow);
    border-radius: 4px;
    animation: loading 1.2s infinite ease-in-out;
}

@keyframes loading {
    0% {
        transform: translateX(-100%);
    }

    100% {
        transform: translateX(350%);
    }
}

.powered-by {
    position: absolute;
    bottom: 24px;
    right: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 10000;
}

.powered-by span {
    font-family: 'Inter', sans-serif;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.6);
    font-weight: 500;
}

.powered-by img {
    height: 32px;
    width: auto;
}


/* Shared Brand */
.upload-brand {
    font-family: 'Syne', sans-serif;
    font-size: 2.2rem;
    font-weight: 800;
    background: linear-gradient(135deg, #6366f1, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-align: center;
}

.upload-tagline {
    color: var(--text-muted);
    font-size: 0.95rem;
    text-align: center;
    margin-top: 8px;
    margin-bottom: 30px;
}

/* Auth Card */
.auth-card {
    width: 100%;
    max-width: 400px;
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--glass-shadow);
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.input-group {
    position: relative;
    display: flex;
    align-items: center;
}

.input-group i {
    position: absolute;
    left: 16px;
    color: var(--text-dim);
}

.input-group input {
    width: 100%;
    padding: 14px 14px 14px 44px;
    border-radius: 10px;
    border: 1px solid var(--glass-border);
    background: var(--bg-main);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    outline: none;
    transition: all var(--transition-fast);
}

.input-group input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-soft);
}

.btn-primary {
    padding: 14px;
    border-radius: 10px;
    border: none;
    background: var(--accent);
    color: white;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-top: 8px;
}

.btn-primary:hover {
    background: var(--accent-hover);
    box-shadow: 0 4px 20px var(--accent-glow);
    transform: translateY(-2px);
}

.error-text {
    color: var(--danger);
    font-size: 0.85rem;
    text-align: center;
    margin-top: 8px;
}

/* Dashboard */
#dashboard-screen {
    align-items: flex-start;
}

.dashboard-wrapper {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
}

.dash-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--glass-border);
}

.dash-title {
    font-family: 'Syne', sans-serif;
    font-size: 1.8rem;
    font-weight: 700;
}

.dash-subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-top: 4px;
}

.btn-secondary {
    padding: 8px 16px;
    border-radius: 8px;
    border: 1px solid var(--glass-border);
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    gap: 8px;
    align-items: center;
    font-weight: 500;
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
}

.dash-stats {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 20px;
    margin-bottom: 30px;
}

.stat-box {
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 700;
}

.stat-value span {
    color: var(--accent);
}

.dash-drop-zone {
    background: var(--accent-soft);
    border: 2px dashed var(--accent);
    border-radius: 16px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 12px;
    cursor: pointer;
    color: var(--accent);
    transition: var(--transition-fast);
    text-align: center;
}

.dash-drop-zone:hover,
.dash-drop-zone.dragover {
    background: var(--accent);
    color: white;
}

.dash-drop-zone i {
    font-size: 2rem;
}

.dash-drop-zone.disabled {
    background: var(--bg-tertiary);
    border-color: var(--glass-border);
    color: var(--text-dim);
    cursor: not-allowed;
}

.dash-drop-zone.disabled:hover {
    background: var(--bg-tertiary);
    color: var(--text-dim);
}

.dash-msg {
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 0.9rem;
    text-align: center;
}

.dash-msg.error {
    background: rgba(225, 29, 72, 0.1);
    color: var(--danger);
    border: 1px solid var(--danger);
}

/* File Grid */
.file-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    padding-bottom: 40px;
}

.file-card {
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    transition: transform var(--transition-fast);
}

.file-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--glass-shadow);
    border-color: var(--accent-soft);
}

.file-icon {
    width: 48px;
    height: 48px;
    background: rgba(225, 29, 72, 0.1);
    color: var(--danger);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.file-info {
    flex: 1;
    overflow: hidden;
}

.file-name {
    font-weight: 600;
    font-size: 1rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 4px;
}

.file-date {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.file-actions {
    display: flex;
    gap: 10px;
    margin-top: auto;
    border-top: 1px solid var(--glass-border);
    padding-top: 16px;
}

.btn-view {
    flex: 1;
    padding: 10px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition-fast);
}

.btn-view:hover {
    background: var(--accent-hover);
}

.btn-delete {
    padding: 10px 14px;
    background: transparent;
    color: var(--danger);
    border: 1px solid var(--danger);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-delete:hover {
    background: var(--danger);
    color: white;
}

#dashboard-loading {
    text-align: center;
    color: var(--accent);
    padding: 20px;
    font-weight: 500;
}

/* App Viewer & Top Bar */
#app {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

#top-bar {
    height: var(--topbar-height);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px;
    z-index: 100;
    flex-shrink: 0;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.book-title {
    font-family: 'Syne', sans-serif;
    font-weight: 700;
    font-size: 1.1rem;
    max-width: 250px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

#page-indicator {
    font-variant-numeric: tabular-nums;
    color: var(--text-muted);
    font-size: 0.9rem;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    padding: 6px 18px;
    border-radius: 20px;
    border: 1px solid var(--glass-border);
}

.nav-right {
    display: flex;
    gap: 8px;
}

.icon-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    width: 38px;
    height: 38px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    font-size: 0.9rem;
}

.icon-btn:hover {
    background: var(--accent);
    color: white;
    border-color: transparent;
    box-shadow: 0 4px 16px var(--accent-glow);
}

/* Book Stage & Flipbook */
#book-stage {
    flex: 1;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.book-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    gap: 20px;
    width: 100%;
    justify-content: center;
    perspective: 2500px;
}

.book-nav {
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    z-index: 50;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.book-nav:hover {
    transform: scale(1.1);
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 20px var(--accent-glow);
}

.book-nav:disabled {
    opacity: 0.3;
    pointer-events: none;
}

#flipbook-container {
    position: relative;
    background-color: transparent;
    transform-style: preserve-3d;
    touch-action: none;
    transition: transform 0.3s ease;
}

.fb-spread {
    position: absolute;
    right: 0;
    width: 50%;
    height: 100%;
    transform-style: preserve-3d;
    transform-origin: left center;
}

.fb-face {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    background: #ffffff;
    overflow: hidden;
    color: #1a1a1a;
}

.fb-face-right {
    z-index: 2;
    transform: rotateY(0deg);
    border-radius: 0 6px 6px 0;
    box-shadow: var(--page-shadow);
}

.fb-face-left {
    z-index: 2;
    transform: rotateY(0deg);
    border-radius: 6px 0 0 6px;
    box-shadow: var(--page-shadow-left);
}

.page-img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #fafafa;
    display: block;
}

#flipbook-container::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 6px;
    transform: translateX(-50%);
    background: linear-gradient(90deg, rgba(0, 0, 0, 0.15) 0%, rgba(0, 0, 0, 0.05) 30%, rgba(0, 0, 0, 0.0) 50%, rgba(0, 0, 0, 0.05) 70%, rgba(0, 0, 0, 0.15) 100%);
    z-index: 100;
    pointer-events: none;
}

/* Thumbnails */
#thumbnail-dock {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 150;
    padding: 12px 24px 16px;
    background: linear-gradient(to top, var(--bg-main) 60%, transparent);
    display: flex;
    justify-content: center;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.3s ease, transform 0.3s ease;
}

#thumbnail-dock:hover,
#thumbnail-dock.show {
    opacity: 1;
    transform: translateY(0);
}

#app:not(.fullscreen) #thumbnail-dock {
    opacity: 0.4;
}

#app:not(.fullscreen) #thumbnail-dock:hover {
    opacity: 1;
}

.thumb-container {
    display: flex;
    gap: 8px;
    padding: 8px;
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    box-shadow: var(--glass-shadow);
    overflow-x: auto;
    max-width: 90vw;
    scrollbar-width: thin;
    scrollbar-color: var(--accent) transparent;
}

.thumb-item {
    flex-shrink: 0;
    width: 56px;
    height: 72px;
    border-radius: 6px;
    overflow: hidden;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all var(--transition-fast);
    position: relative;
    background: #f0f0f0;
}

.thumb-item.active {
    border-color: var(--accent);
    box-shadow: 0 0 16px var(--accent-glow);
}

.thumb-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.thumb-label {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    font-size: 0.55rem;
    text-align: center;
    padding: 2px 0;
    background: rgba(0, 0, 0, 0.5);
    color: white;
    font-weight: 600;
}

/* Viewer Loading */
#viewer-loading {
    position: absolute;
    inset: 0;
    background: var(--bg-main);
    z-index: 200;
    display: flex;
    justify-content: center;
    align-items: center;
}

.viewer-loader-content {
    text-align: center;
    width: 250px;
}

.viewer-loader-content i {
    font-size: 2rem;
    color: var(--accent);
    margin-bottom: 16px;
}

.loading-track {
    width: 100%;
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 6px;
    overflow: hidden;
    margin-top: 16px;
}

.loading-fill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent), #a78bfa);
    transition: width 0.3s ease;
}

/* Responsiveness */
@media (max-width: 850px) {
    .dash-stats {
        grid-template-columns: 1fr;
    }

    .fb-spread {
        width: 100%;
        right: auto;
    }

    #flipbook-container::before {
        display: none;
    }

    .book-nav {
        width: 38px;
        height: 38px;
    }
}

@media (max-width: 500px) {
    .nav-right {
        gap: 4px;
    }

    .icon-btn {
        width: 32px;
        height: 32px;
        font-size: 0.8rem;
    }
}

#app.fullscreen #top-bar {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to bottom, var(--bg-main) 50%, transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

#app.fullscreen #top-bar:hover {
    opacity: 1;
}

#app.fullscreen #book-stage {
    height: 100vh;
}