/* ==========================================================================
   BJJ Concepts Reader - app.css
   Mobile-first design / Book-style reader
   ========================================================================== */

/* --------------------------------------------------------------------------
   Custom Properties
   -------------------------------------------------------------------------- */
:root {
    /* Brand */
    --color-primary: #1f1f1f;
    --color-primary-light: #333333;
    --color-accent: #a41311;
    --color-accent-hover: #88100e;
    --color-accent-soft: rgba(233, 69, 96, 0.1);

    /* Surfaces */
    --color-bg: #fafaf9;
    --color-surface: #ffffff;
    --color-surface-hover: #f5f4f1;
    --color-surface-active: #eeedea;
    --color-border: #e5e4e0;
    --color-border-light: #f0efec;

    /* Text */
    --color-text: #1c1c1c;
    --color-text-secondary: #5a5a5a;
    --color-text-tertiary: #8a8a8a;
    --color-text-inverse: #ffffff;

    /* Section colors - black & red (instructor belt) */
    --color-blueprint: #1a1a1a;
    --color-level1: #a41311;
    --color-level2: #a41311;
    --color-level3: #a41311;
    --color-level4: #a41311;
    --color-level5: #a41311;
    --color-level6: #a41311;
    --color-level7: #a41311;
    --color-fieldguide: #1a1a1a;

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-serif: 'Merriweather', Georgia, serif;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Layout */
    --topbar-height: 3.5rem;
    --bottombar-height: 3.5rem;
    --sidebar-width: 18rem;
    --content-max-width: 65rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);

    /* Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    color-scheme: light dark;
}

[data-theme="dark"] {
    --color-bg: #161616;
    --color-surface: #1f1f1f;
    --color-surface-hover: #2a2a2a;
    --color-surface-active: #333333;
    --color-border: #2e2e2e;
    --color-border-light: #252525;
    --color-text: #e8e6e1;
    --color-text-secondary: #a8a49e;
    --color-text-tertiary: #6b6762;
    --color-text-inverse: #ffffff;
    --color-primary: #1a1a1a;
    --color-primary-light: #2a2a2a;
    --color-accent: #e05553;
    --color-accent-hover: #cc3f3d;
    --color-accent-soft: rgba(224, 85, 83, 0.15);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
    color-scheme: dark;
}

/* --------------------------------------------------------------------------
   Reset & Base
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100dvh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --------------------------------------------------------------------------
   Top Bar
   -------------------------------------------------------------------------- */
.reader__topbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--topbar-height);
    padding: 0 var(--space-md);
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
}

.reader__topbar-left {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    min-width: 0;
}

.reader__topbar-title {
    font-weight: 600;
    font-size: 1.0625rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    letter-spacing: -0.01em;
}

.reader__topbar-right {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

/* --------------------------------------------------------------------------
   Icon Buttons
   -------------------------------------------------------------------------- */
.reader__icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    border: none;
    border-radius: var(--radius-full);
    background: transparent;
    color: inherit;
    cursor: pointer;
    touch-action: manipulation;
    transition: background-color var(--transition-fast);
    flex-shrink: 0;
}

.reader__icon-btn:hover {
    background-color: rgba(255, 255, 255, 0.12);
}

.reader__icon-btn:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.reader__icon-btn .material-symbols-outlined {
    font-size: 1.5rem;
}

/* Hidden on mobile - search lives in bottom bar on small screens */
.reader__icon-btn--search {
    display: none;
}

/* --------------------------------------------------------------------------
   Sidebar
   -------------------------------------------------------------------------- */
.reader__sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 200;
    width: var(--sidebar-width);
    max-width: 85vw;
    background-color: var(--color-surface);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    transform: translateX(-100%);
    transition: transform var(--transition-base);
    overflow: hidden;
}

.reader__sidebar.is-open {
    transform: translateX(0);
}

.reader__sidebar-overlay {
    position: fixed;
    inset: 0;
    z-index: 199;
    background-color: rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-base), visibility var(--transition-base);
}

.reader__sidebar-overlay.is-visible {
    opacity: 1;
    visibility: visible;
}

.reader__sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) var(--space-md) var(--space-sm);
    flex-shrink: 0;
}

.reader__sidebar-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: -0.02em;
}

.reader__sidebar-close .material-symbols-outlined {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
}

/* TOC */
.reader__toc {
    flex: 1;
    overflow-y: auto;
    padding-bottom: var(--space-xl);
    -webkit-overflow-scrolling: touch;
}

.reader__toc-section {
    border-bottom: 1px solid var(--color-border-light);
}

.reader__toc-section:last-child {
    border-bottom: none;
}

.reader__toc-heading {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    border: none;
    background: none;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    font-weight: 700;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    text-align: left;
    transition: background-color var(--transition-fast);
}

.reader__toc-heading:hover {
    background-color: var(--color-surface-hover);
}

.reader__toc-heading:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: -2px;
}

.reader__toc-heading::before {
    content: '';
    width: 0.375rem;
    height: 0.375rem;
    border-radius: var(--radius-full);
    flex-shrink: 0;
}

.reader__toc-heading[data-section="blueprint"]::before { background-color: var(--color-blueprint); }
.reader__toc-heading[data-section="level-1"]::before { background-color: var(--color-level1); }
.reader__toc-heading[data-section="level-2"]::before { background-color: var(--color-level2); }
.reader__toc-heading[data-section="level-3"]::before { background-color: var(--color-level3); }
.reader__toc-heading[data-section="level-4"]::before { background-color: var(--color-level4); }
.reader__toc-heading[data-section="level-5"]::before { background-color: var(--color-level5); }
.reader__toc-heading[data-section="level-6"]::before { background-color: var(--color-level6); }
.reader__toc-heading[data-section="level-7"]::before { background-color: var(--color-level7); }
.reader__toc-heading[data-section="field-guide"]::before { background-color: var(--color-fieldguide); }

.reader__toc-heading .material-symbols-outlined {
    font-size: 1.125rem;
    margin-left: auto;
    transform: rotate(0deg);
    transition: transform var(--transition-fast);
}

.reader__toc-heading.is-expanded .material-symbols-outlined {
    transform: rotate(180deg);
}

.reader__toc-list {
    list-style: none;
    display: none;
}

.reader__toc-list.is-expanded {
    display: block;
}

.reader__toc-item {
    display: flex;
    align-items: center;
}

.reader__toc-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    width: 100%;
    padding: var(--space-sm) var(--space-md) var(--space-sm) calc(var(--space-md) + 1.25rem);
    border: none;
    background: none;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    color: var(--color-text);
    text-align: left;
    line-height: 1.4;
    transition: background-color var(--transition-fast), color var(--transition-fast);
    text-decoration: none;
}

.reader__toc-link:hover {
    background-color: var(--color-surface-hover);
    color: var(--color-accent);
}

.reader__toc-link:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: -2px;
}

.reader__toc-link.is-active {
    background-color: var(--color-accent-soft);
    color: var(--color-accent);
    font-weight: 600;
}

/* --------------------------------------------------------------------------
   Search Overlay
   -------------------------------------------------------------------------- */
.reader__search-overlay {
    position: fixed;
    inset: 0;
    z-index: 300;
    background-color: var(--color-bg);
    display: flex;
    flex-direction: column;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-fast), visibility var(--transition-fast);
}

.reader__search-overlay[hidden] {
    display: none;
}

.reader__search-overlay.is-open {
    display: flex;
    opacity: 1;
    visibility: visible;
}

.reader__search-bar {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    height: var(--topbar-height);
    padding: 0 var(--space-md);
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-shrink: 0;
}

.reader__search-bar-icon {
    color: var(--color-text-tertiary);
    font-size: 1.375rem;
    flex-shrink: 0;
}

.reader__search-input {
    flex: 1;
    border: none;
    outline: none;
    background: none;
    font-family: var(--font-sans);
    font-size: 1rem;
    color: var(--color-text);
    min-width: 0;
}

.reader__search-input::placeholder {
    color: var(--color-text-tertiary);
}

.reader__search-close .material-symbols-outlined {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
}

.reader__search-results {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-md);
    -webkit-overflow-scrolling: touch;
}

.reader__search-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-3xl) var(--space-lg);
    text-align: center;
    color: var(--color-text-tertiary);
}

.reader__search-empty .material-symbols-outlined {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.4;
}

.reader__search-count {
    font-size: 0.8125rem;
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-md);
}

.reader__search-item {
    padding: var(--space-md);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-sm);
    cursor: pointer;
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.reader__search-item:hover {
    background-color: var(--color-surface-hover);
    border-color: var(--color-border);
}

.reader__search-item:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.reader__search-item-section {
    display: inline-block;
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-xs);
}

.reader__search-item-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--space-xs);
}

.reader__search-item-excerpt {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

.reader__search-item-excerpt mark {
    background-color: rgba(233, 69, 96, 0.15);
    color: var(--color-accent);
    border-radius: 2px;
    padding: 0 2px;
}

/* --------------------------------------------------------------------------
   Main Content Area
   -------------------------------------------------------------------------- */
.reader__main {
    padding-top: var(--topbar-height);
    padding-bottom: var(--bottombar-height);
    min-height: 100dvh;
}

/* --------------------------------------------------------------------------
   Home Screen
   -------------------------------------------------------------------------- */
.reader__home {
    padding: var(--space-xl) var(--space-md) var(--space-2xl);
    max-width: var(--content-max-width);
    margin: 0 auto;
}

.reader__home-hero {
    text-align: center;
    padding: var(--space-2xl) 0;
}

.reader__home-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text);
    line-height: 1.2;
    margin-bottom: var(--space-xs);
}

.reader__home-subtitle {
    font-size: 1.0625rem;
    font-weight: 300;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-lg);
}

.reader__home-desc {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
    max-width: 32rem;
    margin: 0 auto;
}

/* Home Actions */
.reader__home-actions {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    margin-bottom: var(--space-2xl);
}

.reader__btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: 0.875rem var(--space-lg);
    border: none;
    border-radius: var(--radius-lg);
    font-family: var(--font-sans);
    font-size: 0.9375rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color var(--transition-fast), transform var(--transition-fast);
    text-decoration: none;
}

.reader__btn:active {
    transform: scale(0.98);
}

.reader__btn:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.reader__btn .material-symbols-outlined {
    font-size: 1.25rem;
}

.reader__btn--primary {
    background-color: var(--color-accent);
    color: var(--color-text-inverse);
}

.reader__btn--primary:hover {
    background-color: var(--color-accent-hover);
}

.reader__btn--secondary {
    background-color: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.reader__btn--secondary:hover {
    background-color: var(--color-surface-hover);
}

.reader__btn--accent {
    background-color: transparent;
    color: var(--color-accent);
    border: 2px solid var(--color-accent);
}

.reader__btn--accent:hover {
    background-color: var(--color-accent);
    color: var(--color-text-inverse);
}

/* Home Section Cards */
.reader__home-sections {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.reader__section-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: border-color var(--transition-fast);
}

.reader__section-card:hover {
    border-color: var(--color-border);
}

.reader__section-card-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    cursor: pointer;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    font-family: var(--font-sans);
    transition: background-color var(--transition-fast);
}

.reader__section-card-header:hover {
    background-color: var(--color-surface-hover);
}

.reader__section-card-header:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: -2px;
}

.reader__section-card-dot {
    width: 0.625rem;
    height: 0.625rem;
    border-radius: var(--radius-full);
    flex-shrink: 0;
}

.reader__section-card-info {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 5px;
    height: 100%;
}

.reader__section-card-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-text);
}

.reader__section-card-count {
    font-size: 0.75rem;
    color: var(--color-text-tertiary);
    margin-top: auto;
}

.reader__section-card-header .material-symbols-outlined {
    font-size: 1.25rem;
    color: var(--color-text-tertiary);
    transform: rotate(0deg);
    transition: transform var(--transition-fast);
}

.reader__section-card-header.is-expanded .material-symbols-outlined {
    transform: rotate(180deg);
}

.reader__section-card-items {
    display: none;
    list-style: none;
    padding: 0 var(--space-md) var(--space-md);
    border-top: 1px solid var(--color-border-light);
}

.reader__section-card-items.is-expanded {
    display: block;
}

.reader__section-card-link {
    display: block;
    padding: var(--space-sm) 0;
    font-size: 0.875rem;
    color: var(--color-text);
    text-decoration: none;
    cursor: pointer;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    font-family: var(--font-sans);
    transition: color var(--transition-fast);
    line-height: 1.4;
}

.reader__section-card-link:hover {
    color: var(--color-accent);
}

.reader__section-card-link:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   Document View
   -------------------------------------------------------------------------- */
.reader__document {
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: var(--space-lg) var(--space-md) var(--space-xl);
}

.reader__document-meta {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--color-border-light);
}

.reader__document-section {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-tertiary);
}

.reader__document-number {
    font-size: 0.75rem;
    color: var(--color-text-tertiary);
}

.reader__bookmark-btn {
    margin-left: auto;
    color: var(--color-text-tertiary);
    transition: color var(--transition-fast), transform var(--transition-fast);
}

.reader__bookmark-btn:hover {
    color: var(--color-accent);
}

.reader__bookmark-btn.is-bookmarked {
    color: var(--color-accent);
}

.reader__bookmark-btn.is-bookmarked .material-symbols-outlined {
    font-variation-settings: 'FILL' 1;
}

/* Heading-level bookmark buttons */
.reader__heading-bookmark {
    flex-shrink: 0;
    margin-left: auto;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.125rem;
    color: var(--color-text-tertiary);
    transition: color var(--transition-fast);
}

.reader__heading-bookmark:hover {
    color: var(--color-accent);
}

.reader__heading-bookmark.is-bookmarked {
    color: var(--color-accent);
}

.reader__heading-bookmark.is-bookmarked .material-symbols-outlined {
    font-variation-settings: 'FILL' 1;
}

.reader__heading-bookmark .material-symbols-outlined {
    font-size: 1.125rem;
}

/* Markdown Body Styles */
.reader__document-body {
    font-family: var(--font-serif);
    font-size: 1rem;
    line-height: 1.8;
    color: var(--color-text);
}

.reader__document-body h1 {
    font-family: var(--font-serif);
    font-size: 1.75rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.reader__document-body h2 {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-sans);
    font-size: 1.3125rem;
    font-weight: 700;
    line-height: 1.3;
    margin-top: var(--space-2xl);
    margin-bottom: var(--space-md);
    color: var(--color-text);
    scroll-margin-top: calc(var(--topbar-height) + var(--space-md));
}

.reader__document-body h3 {
    font-family: var(--font-sans);
    font-size: 1.0625rem;
    font-weight: 600;
    line-height: 1.4;
    margin-top: var(--space-xl);
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

.reader__document-body h4 {
    font-family: var(--font-sans);
    font-size: 0.9375rem;
    font-weight: 600;
    line-height: 1.4;
    margin-top: var(--space-lg);
    margin-bottom: var(--space-sm);
    color: var(--color-text-secondary);
}

.reader__document-body p {
    margin-bottom: var(--space-md);
}

.reader__document-body ul,
.reader__document-body ol {
    margin-bottom: var(--space-md);
    padding-left: var(--space-lg);
}

.reader__document-body li {
    margin-bottom: var(--space-xs);
}

.reader__document-body li > ul,
.reader__document-body li > ol {
    margin-top: var(--space-xs);
    margin-bottom: 0;
}

.reader__document-body strong {
    font-weight: 700;
}

.reader__document-body em {
    font-style: italic;
}

.reader__document-body blockquote {
    margin: var(--space-lg) 0;
    padding: var(--space-md) var(--space-lg);
    border-left: 3px solid var(--color-accent);
    background-color: var(--color-surface);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-style: italic;
    color: var(--color-text-secondary);
}

.reader__document-body blockquote p:last-child {
    margin-bottom: 0;
}

.reader__document-body code {
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.875em;
    background-color: var(--color-surface-hover);
    padding: 0.125rem 0.375rem;
    border-radius: var(--radius-sm);
}

.reader__document-body pre {
    margin: var(--space-lg) 0;
    padding: var(--space-md);
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    border-radius: var(--radius-md);
    overflow-x: auto;
    font-size: 0.875rem;
    line-height: 1.6;
    -webkit-overflow-scrolling: touch;
}

.reader__document-body pre code {
    background: none;
    padding: 0;
    color: inherit;
}

.reader__document-body hr {
    margin: var(--space-2xl) 0;
    border: none;
    border-top: 1px solid var(--color-border);
}

.reader__document-body table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-lg) 0;
    font-family: var(--font-sans);
    font-size: 0.875rem;
}

.reader__document-body th,
.reader__document-body td {
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    text-align: left;
}

.reader__document-body th {
    background-color: var(--color-surface-hover);
    font-weight: 600;
}

.reader__document-body a {
    color: var(--color-accent);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 2px;
    transition: color var(--transition-fast);
}

.reader__document-body a:hover {
    color: var(--color-accent-hover);
}

.reader__document-body a:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   Chapter Navigation
   -------------------------------------------------------------------------- */
.reader__chapter-nav {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    margin-top: var(--space-2xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--color-border);
}

.reader__chapter-btn {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background-color: var(--color-surface);
    cursor: pointer;
    font-family: var(--font-sans);
    text-align: left;
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
    text-decoration: none;
}

.reader__chapter-btn:hover {
    background-color: var(--color-surface-hover);
    border-color: var(--color-accent);
}

.reader__chapter-btn:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.reader__chapter-btn:disabled {
    opacity: 0.3;
    pointer-events: none;
}

.reader__chapter-btn .material-symbols-outlined {
    font-size: 1.25rem;
    color: var(--color-text-tertiary);
    flex-shrink: 0;
}

.reader__chapter-btn-text {
    flex: 1;
    min-width: 0;
}

.reader__chapter-btn-label {
    display: block;
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-tertiary);
    margin-bottom: 0.125rem;
}

.reader__chapter-btn-title {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.reader__chapter-btn--next {
    text-align: right;
}

.reader__chapter-btn--next .reader__chapter-btn-text {
    order: -1;
}

/* --------------------------------------------------------------------------
   Bottom Bar (Mobile)
   -------------------------------------------------------------------------- */
.reader__bottombar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-around;
    height: var(--bottombar-height);
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding-bottom: env(safe-area-inset-bottom, 0);
}

.reader__bottombar-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.125rem;
    border: none;
    background: none;
    color: var(--color-text-tertiary);
    cursor: pointer;
    padding: var(--space-xs) var(--space-sm);
    min-width: 3rem;
    font-family: var(--font-sans);
    transition: color var(--transition-fast);
}

.reader__document-body li::marker {
    color: currentColor;
}

.reader__bottombar-btn:hover,
.reader__bottombar-btn.is-active {
    color: var(--color-accent);
}

.reader__bottombar-btn:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: -2px;
    border-radius: var(--radius-sm);
}

.reader__bottombar-btn:disabled {
    opacity: 0.3;
    pointer-events: none;
}

.reader__bottombar-btn .material-symbols-outlined {
    font-size: 1.375rem;
}

.reader__bottombar-label {
    font-size: 0.625rem;
    font-weight: 500;
    letter-spacing: 0.02em;
}

/* --------------------------------------------------------------------------
   Loading / Error States
   -------------------------------------------------------------------------- */
.reader__loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-3xl) var(--space-lg);
    color: var(--color-text-tertiary);
}

.reader__loading-spinner {
    width: 2rem;
    height: 2rem;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: var(--radius-full);
    animation: spin 0.8s linear infinite;
    margin-bottom: var(--space-md);
}

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

.reader__error {
    text-align: center;
    padding: var(--space-3xl) var(--space-lg);
    color: var(--color-text-secondary);
}

.reader__error .material-symbols-outlined {
    font-size: 3rem;
    color: var(--color-accent);
    margin-bottom: var(--space-md);
}

.reader__error-text {
    font-size: 0.9375rem;
    margin-bottom: var(--space-md);
}

/* --------------------------------------------------------------------------
   DESKTOP - 768px+
   -------------------------------------------------------------------------- */
@media (min-width: 768px) {
    .reader__home-actions {
        flex-direction: row;
        justify-content: center;
    }

    .reader__chapter-nav {
        flex-direction: row;
    }

    .reader__chapter-btn {
        flex: 1;
    }
}

/* --------------------------------------------------------------------------
   DESKTOP - 1024px+
   -------------------------------------------------------------------------- */
@media (min-width: 1024px) {

    /* Hide bottom bar on desktop */
    .reader__bottombar {
        display: none;
    }

    .reader__main {
        padding-bottom: 0;
    }

    /* Sidebar always visible on desktop */
    .reader__sidebar {
        transform: translateX(0);
        top: var(--topbar-height);
        z-index: 50;
    }

    .reader__sidebar-close {
        display: none;
    }

    .reader__sidebar-overlay {
        display: none;
    }

    /* Hide menu toggle on desktop - sidebar is always visible */
    .reader__icon-btn--menu {
        display: none;
    }

    /* Show search in topbar on desktop - it lives in bottom bar on mobile */
    .reader__icon-btn--search {
        display: inline-flex;
    }

    /* Browse Contents not needed on desktop - TOC sidebar is visible */
    #browseBtn {
        display: none;
    }

    /* Offset main content */
    .reader__main {
        margin-left: var(--sidebar-width);
    }

    /* Home adjustments */
    .reader__home {
        padding: var(--space-2xl) var(--space-xl) var(--space-3xl);
    }

    .reader__home-title {
        font-size: 2.5rem;
    }

    .reader__home-desc {
        font-size: 1.0625rem;
    }

    /* Document adjustments */
    .reader__document {
        padding: var(--space-xl) var(--space-xl) var(--space-3xl);
    }

    .reader__document-body {
        font-size: 1.0625rem;
    }

    .reader__document-body h1 {
        font-size: 2rem;
    }

    .reader__document-body h2 {
        font-size: 1.5rem;
    }

    .reader__document-body h3 {
        font-size: 1.1875rem;
    }
}

/* --------------------------------------------------------------------------
   Reduced Motion
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}