.reader-canvas {
    width: 100%;
    height: 100%;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 2rem 0;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;

    /* Dedicated Scrollbar Styling */
    scrollbar-width: thin;
    scrollbar-color: rgba(0, 255, 153, 0.2) transparent;
}

.reader-canvas::-webkit-scrollbar {
    width: 6px;
}

.reader-canvas::-webkit-scrollbar-track {
    background: transparent;
}

.reader-canvas::-webkit-scrollbar-thumb {
    background-color: rgba(0, 255, 153, 0.2);
    border-radius: 20px;
    border: 3px solid transparent;
}

.reader-canvas:hover::-webkit-scrollbar-thumb {
    background-color: rgba(0, 255, 153, 0.5);
}

.reader-canvas.theme-dark {
    background-color: #121214;
}

.reader-canvas.theme-light {
    background-color: #f4f1ea;
    /* Warm light beige/gray background */
}

.reader-flow-container {
    max-width: 680px;
    margin: 2rem auto;
    min-height: calc(100vh - 180px);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    position: relative;
    padding: 3rem 4rem 15rem 4rem;
    /* Large padding-bottom for reachability, plus comfortable side margins */
    border-radius: 12px;
    box-sizing: border-box;
    transition: background-color 0.3s, box-shadow 0.3s, border-color 0.3s;
}

.theme-dark .reader-flow-container {
    background-color: #1a1a1e;
    border: 1px solid rgba(255, 255, 255, 0.03);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.2);
}

.theme-light .reader-flow-container {
    background-color: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.04);
    box-shadow: 0 4px 20px rgba(139, 130, 115, 0.12);
}

.block-wrapper {
    transition: all 0.5s ease;
    border-radius: 8px;
    padding: 8px;
    border: 1px solid transparent;
}

/* Typographic refinement for TextSegmentBlock */
::deep .nexus-ebook {
    font-family: 'Merriweather', serif !important;
    line-height: 1.65 !important;
    letter-spacing: -0.01em !important;
    font-size: 1.15rem;
    font-weight: 400;
    text-align: left !important;
    color: #e4e4e7;
    /* Off-white with light gray tint */
}

.theme-light ::deep .nexus-ebook {
    color: #292524;
    /* Warm charcoal for legibility */
}

/* Callout Box styling for legacy blockquote segments */
::deep .nexus-ebook blockquote {
    background-color: rgba(255, 255, 255, 0.02);
    border-left: 4px solid var(--nexus-neon);
    padding: 1rem 1.25rem;
    margin: 1.5rem 0 1.5rem 0;
    border-radius: 0 8px 8px 0;
    font-size: 1.05rem;
    color: #e2e8f0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.theme-light ::deep .nexus-ebook blockquote {
    background-color: rgba(245, 158, 11, 0.04);
    border-left: 4px solid #f59e0b;
    color: #44403c;
}


/* Technical Code Block Container */
::deep .nexus-ebook pre {
    background-color: #2d2d2d;
    /* Dark theme for code for better contrast */
    color: #e0e0e0;
    padding: 1.25rem;
    border-radius: 8px;
    margin: 2rem 0;
    overflow-x: auto;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
    border-left: 4px solid var(--nexus-neon);
    /* Nexus neon accent */

    /* Dedicated Scrollbar for Code */
    scrollbar-width: thin;
    scrollbar-color: rgba(0, 255, 153, 0.3) transparent;
}

::deep .nexus-ebook pre::-webkit-scrollbar {
    height: 4px;
}

::deep .nexus-ebook pre::-webkit-scrollbar-thumb {
    background: rgba(0, 255, 153, 0.3);
    border-radius: 10px;
}

/* Monospace Typography Contrast */
::deep .nexus-ebook code {
    font-family: 'JetBrains Mono', 'Cascadia Code', 'Consolas', monospace !important;
    font-variant-ligatures: contextual;
    line-height: 1.5;
    tab-size: 4;
    font-size: 0.9rem;
}

/* Inline Code Highlight */
::deep .nexus-ebook p code {
    background-color: rgba(0, 0, 0, 0.05);
    color: #d63384;
    /* Classic differentiator for inline code */
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9em;
    border: none;
}

.theme-dark ::deep .nexus-ebook p code {
    background-color: rgba(255, 255, 255, 0.1);
    color: #ff79c6;
}

.block-wrapper.highlighted {
    background: rgba(0, 243, 255, 0.08);
    box-shadow: 0 0 20px rgba(0, 243, 255, 0.15);
    border-color: #00f3ff;
    transform: scale(1.01);
}

.ai-sparkle-trigger {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(18, 18, 18, 0.6);
    border: 1px solid rgba(0, 255, 153, 0.3);
    border-radius: 20px;
    cursor: pointer;
    margin: 1rem 0;
    transition: all 0.3s ease;
    position: relative;
}

.ai-sparkle-trigger:hover {
    background: rgba(0, 255, 153, 0.1);
    border-color: #00ff99;
    transform: translateY(-2px);
}

.sparkle-tooltip {
    font-size: 0.75rem;
    color: #fff;
    opacity: 0.7;
}

.neon-pulse {
    color: #00ff99;
    filter: drop-shadow(0 0 5px #00ff99);
    animation: pulse-small 2s infinite;
}

@keyframes pulse-small {
    0% {
        transform: scale(1);
        opacity: 1;
    }

    50% {
        transform: scale(1.1);
        opacity: 0.8;
    }

    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Chapter Loading Overlay and Spinners */
.loading-state.full-page {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    min-height: 400px;
    gap: 1.5rem;
    animation: fadeIn 0.4s ease-out;
}

.spinner-glow {
    width: 60px;
    height: 60px;
    border: 3px solid rgba(0, 255, 153, 0.1);
    border-radius: 50%;
    border-top-color: var(--nexus-neon, #00ff99);
    animation: spin 1s cubic-bezier(0.55, 0.055, 0.675, 0.19) infinite;
    box-shadow: 0 0 15px rgba(0, 255, 153, 0.2);
}

.spinner-glow.small {
    width: 36px;
    height: 36px;
    border-width: 2px;
}

.loading-text {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.1rem;
    letter-spacing: 0.5px;
    font-weight: 500;
}

.theme-light .loading-text {
    color: rgba(0, 0, 0, 0.7);
}

.chapter-loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
    background-color: rgba(15, 23, 42, 0.15);
    backdrop-filter: blur(2px);
    animation: fadeIn 0.3s ease-out;
}

.theme-light .chapter-loading-overlay {
    background-color: rgba(255, 255, 255, 0.2);
}

.loader-card {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    padding: 1.25rem 2rem;
    border-radius: 40px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25), 0 0 1px rgba(255, 255, 255, 0.1) inset;
    animation: scaleIn 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.loader-text {
    font-family: var(--nexus-font-sans, 'Inter', sans-serif);
    font-weight: 500;
    color: #ffffff;
    font-size: 0.95rem;
    letter-spacing: 0.2px;
}

.theme-light .loader-text {
    color: #0f172a;
}

.content-blurred {
    filter: blur(3px);
    opacity: 0.55;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

@keyframes scaleIn {
    from {
        transform: scale(0.9) translateY(10px);
        opacity: 0;
    }

    to {
        transform: scale(1) translateY(0);
        opacity: 1;
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

/* MOBILE READER UI OVERRIDES */
@media (max-width: 768px) {
    .reader-canvas {
        padding-top: 54px !important;
        padding-bottom: 80px !important;
        /* Ensure content is clear of bottom toolbar */
    }

    .reader-flow-container {
        padding-bottom: 4rem;
        /* Safe breathing room */
    }
}

.nexus-mobile-reader-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 50px;
    background: rgba(18, 18, 18, 0.75);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    padding: 0 1rem;
    z-index: 1000;
    box-sizing: border-box;
}

.theme-light .nexus-mobile-reader-header {
    background: rgba(249, 249, 249, 0.8);
    border-bottom-color: rgba(0, 0, 0, 0.08);
}

.nexus-mobile-escape-btn {
    background: none;
    border: none;
    display: flex;
    align-items: center;
    gap: 4px;
    color: var(--nexus-neon, #00FF99);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: 8px;
    transition: background-color 0.2s ease;
    margin-left: -8px;
}

.nexus-mobile-escape-btn:active {
    background-color: rgba(0, 255, 153, 0.08);
}

.nexus-mobile-chapter-navigation {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.25rem;
    height: 100%;
    min-width: 0;
}

.nexus-mobile-chapter-title {
    flex: 1;
    text-align: center;
    font-size: 0.8rem;
    font-weight: 600;
    color: #FFFFFF;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    padding: 0 0.5rem;
    min-width: 0;
}

.theme-light .nexus-mobile-chapter-title {
    color: #292524;
}

.theme-light .nexus-mobile-escape-btn {
    color: #78716c;
}

.theme-light .nexus-mobile-escape-btn:hover {
    color: #10b981;
    background-color: rgba(16, 185, 129, 0.05);
}

.theme-light .nexus-mobile-escape-btn:active {
    background-color: rgba(16, 185, 129, 0.08);
}

.nexus-chapter-nav-btn {
    background: none;
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    color: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 0;
}

.nexus-chapter-nav-btn:hover:not(:disabled) {
    color: var(--nexus-neon, #00FF99);
    background: rgba(255, 255, 255, 0.06);
}

.nexus-chapter-nav-btn:disabled {
    opacity: 0.2;
    cursor: not-allowed;
}

.theme-light .nexus-chapter-nav-btn {
    color: rgba(0, 0, 0, 0.5);
}

.theme-light .nexus-chapter-nav-btn:hover:not(:disabled) {
    background: rgba(0, 0, 0, 0.06);
}