:root {
    --bg-dark: #f8f9fa;
    --bg-card: #ffffff;
    --primary: #5856d6;
    --primary-glow: rgba(88, 86, 214, 0.15);
    --text-main: #111827;
    --text-muted: #6b7280;
    --border: #e5e7eb;
    --success: #34c759;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    overflow-x: hidden;
}

/* Library Layout */
.navbar {
    height: 64px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 40px;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    color: #111827;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
}

.logo span {
    color: var(--primary);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 40px 20px;
}

.section-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-main);
    border-left: 4px solid var(--primary);
    padding-left: 12px;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.book-card {
    background-color: var(--bg-card);
    border-radius: 16px;
    border: 1px solid var(--border);
    overflow: hidden;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.book-card:hover {
    transform: translateY(-6px);
    border-color: var(--primary);
    box-shadow: 0 10px 25px rgba(88, 86, 214, 0.1);
}

.book-cover-placeholder {
    height: 280px;
    background: linear-gradient(135deg, #f3f4f6, #e5e7eb);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
    text-align: center;
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--border);
}

.book-cover-placeholder .book-icon {
    font-size: 48px;
    margin-bottom: 16px;
    filter: drop-shadow(0 4px 6px rgba(0,0,0,0.1));
}

.book-cover-placeholder .book-title-cover {
    font-size: 16px;
    font-weight: 700;
    color: #1f2937;
    line-height: 1.3;
}

.book-info {
    padding: 20px;
}

.book-title {
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 6px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    color: var(--text-main);
}

.book-chapters-count {
    font-size: 13px;
    color: var(--text-muted);
}

/* Modal Drawer */
.drawer-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.4);
    z-index: 1000;
    display: none;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.drawer {
    position: fixed;
    top: 0;
    right: -450px;
    width: 450px;
    height: 100%;
    background-color: var(--bg-card);
    border-left: 1px solid var(--border);
    z-index: 1001;
    box-shadow: -5px 0 25px rgba(0,0,0,0.1);
    transition: right 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
}

.drawer.open {
    right: 0;
}

.drawer-header {
    padding: 24px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.drawer-title {
    font-size: 18px;
    font-weight: 700;
}

.close-btn {
    background: none;
    border: none;
    color: var(--text-main);
    cursor: pointer;
    font-size: 20px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.close-btn:hover {
    background: #f3f4f6;
}

.drawer-body {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
}

.chapters-list {
    list-style: none;
}

.chapter-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px;
    border-radius: 12px;
    border: 1px solid var(--border);
    margin-bottom: 12px;
    cursor: pointer;
    transition: all 0.2s;
    background: #ffffff;
}

.chapter-item:hover {
    border-color: var(--primary);
    background: rgba(88, 86, 214, 0.05);
}

.chapter-item .ch-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.chapter-item .ch-number {
    font-weight: 700;
    color: var(--primary);
    background: rgba(88, 86, 214, 0.1);
    width: 28px;
    height: 28px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
}

.chapter-item .ch-title {
    font-weight: 500;
    font-size: 14px;
    color: var(--text-main);
}

.chapter-item .ch-badge {
    font-size: 11px;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 4px;
    background: #f3f4f6;
    color: var(--text-muted);
}

.chapter-item .ch-badge.ch-pdf {
    background: rgba(52, 199, 89, 0.1);
    color: var(--success);
}

/* Secure E-Reader Styles */
.viewer-layout {
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

.viewer-header {
    height: 56px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    background: #ffffff;
}

.viewer-header .left-section {
    display: flex;
    align-items: center;
    gap: 12px;
}

.viewer-header .back-btn {
    background: transparent;
    border: none;
    cursor: pointer;
    color: #374151;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6px;
    border-radius: 50%;
    transition: background-color 0.2s;
}

.viewer-header .back-btn:hover {
    background-color: #f3f4f6;
}

.viewer-header .book-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #111827;
}

/* Tab Bar container */
.viewer-tabs-container {
    display: flex;
    justify-content: center;
    border-bottom: 1px solid var(--border);
    background-color: #ffffff;
}

.viewer-tabs {
    display: flex;
    gap: 28px;
}

.viewer-tab-btn {
    background: transparent;
    border: none;
    padding: 12px 4px;
    font-size: 0.9rem;
    font-weight: 500;
    color: #6b7280;
    cursor: pointer;
    position: relative;
    transition: color 0.2s;
}

.viewer-tab-btn:hover {
    color: #111827;
}

.viewer-tab-btn.active {
    color: #111827;
    font-weight: 600;
}

.viewer-tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 3px;
    background-color: #000000;
    border-radius: 3px 3px 0 0;
}

/* Control Bar (Dropdown & Video button) */
.viewer-control-bar {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 14px;
    padding: 12px 16px;
    background-color: #ffffff;
    border-bottom: 1px solid var(--border);
}

.viewer-control-bar .dropdown-wrapper {
    position: relative;
    width: 240px;
}

.viewer-control-bar .section-dropdown {
    width: 100%;
    appearance: none;
    -webkit-appearance: none;
    background-color: #f3f4f6;
    border: none;
    border-radius: 8px;
    padding: 8px 16px;
    font-family: inherit;
    font-size: 0.85rem;
    font-weight: 500;
    color: #374151;
    cursor: pointer;
    outline: none;
}

.viewer-control-bar .dropdown-arrow {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
    color: #4b5563;
    display: flex;
    align-items: center;
}

.viewer-control-bar .video-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    background-color: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 20px;
    padding: 6px 14px;
    font-family: inherit;
    font-size: 0.85rem;
    font-weight: 500;
    color: #111827;
    cursor: pointer;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    transition: background-color 0.2s;
}

.viewer-control-bar .video-btn:hover {
    background-color: #f9fafb;
    border-color: #d1d5db;
}

.viewer-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
    background: #f3f4f6;
}

.viewer-body {
    flex: 1;
    overflow-y: auto;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 24px 0 80px;
    position: relative;
    scroll-behavior: smooth;
}

/* Protected Canvas container */
.canvas-wrapper {
    position: relative;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border);
    background-color: #ffffff;
}

.canvas-shield {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    cursor: default;
    background: transparent;
}

/* Floating bottom navigator */
.bottom-navigator {
    position: absolute;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: #374151; /* Clean dark gray pill */
    padding: 6px 12px;
    border-radius: 30px;
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 50;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.nav-btn {
    background: none;
    border: none;
    color: #9ca3af;
    cursor: pointer;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s, background 0.2s;
}

.nav-btn:hover:not(:disabled) {
    color: #ffffff;
    background: rgba(255,255,255,0.1);
}

.nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.page-indicator {
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.2px;
    color: #ffffff;
    min-width: 80px;
    text-align: center;
    user-select: none;
}

/* Toast Messages */
.toast-msg {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: rgba(31, 41, 55, 0.95);
    color: white;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
    z-index: 9999;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease;
}

.toast-msg.show {
    opacity: 1;
    transform: translateY(0);
}