/*
 * Stylesheet for the FB2 reader.
 *
 * Structure:
 *   1. Reset & base
 *   2. CSS variables & themes
 *   3. Book container & content layout
 *   4. Typography settings (fonts, line-height, alignment)
 *   5. Book content elements (paragraphs, headings, images, etc.)
 *   6. Notes
 *   7. Header, settings panel, TOC panel, overlay
 *   8. Modal
 *   9. Theme button colours
 *  10. Chrome visibility
 *  11. Page mode (pagination, columns, baseline grid, nav, footer)
 *  12. Desktop / mobile overrides
 */

/* ===================================================================
   1. Reset & base
   =================================================================== */

html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-size: 100%;
}

body {
    background-color: var(--bg-color);
}

/* ===================================================================
   2. CSS variables & themes
   =================================================================== */

:root {
    --bg-color: #ffffff;
    --text-color: #000000;
    --panel-bg-color: #f5f5f5;
    --panel-border-color: #cccccc;
    --header-button-bg: rgba(0, 0, 0, 0.05);
    --header-button-hover-bg: rgba(0, 0, 0, 0.1);
    --button-bg: #ffffff;
    --button-border: #cccccc;
    --link-color: #0066cc;
    --note-bg: #f5f5f5;
    --header-button-color: #000000;
    --button-color: #000000;
}

html.theme-light {
    --bg-color: #ffffff;
    --text-color: #111111;
    --panel-bg-color: #f7f7f7;
    --panel-border-color: #dddddd;
    --button-bg: #ffffff;
    --button-border: #cccccc;
    --link-color: #0066cc;
    --note-bg: #f5f5f5;
    --header-button-color: #111111;
    --button-color: #111111;
}

html.theme-parchment {
    --bg-color: #f9f3e5;
    --text-color: #4a3b2c;
    --panel-bg-color: #f2e7d1;
    --panel-border-color: #d6c7a6;
    --button-bg: #fff9e8;
    --button-border: #d6c7a6;
    --link-color: #8b4513;
    --note-bg: #f2e7d1;
    --header-button-color: #4a3b2c;
    --button-color: #4a3b2c;
}

html.theme-gray {
    --bg-color: #f0f0f0;
    --text-color: #2e2e2e;
    --panel-bg-color: #e9e9e9;
    --panel-border-color: #cccccc;
    --button-bg: #f7f7f7;
    --button-border: #cfcfcf;
    --link-color: #0055aa;
    --note-bg: #e0e0e0;
    --header-button-color: #2e2e2e;
    --button-color: #2e2e2e;
}

html.theme-dark {
    --bg-color: #141414;
    --text-color: #e0e0e0;
    --panel-bg-color: #2a2a2a;
    --panel-border-color: #3a3a3a;
    --header-button-bg: #444444;
    --header-button-color: #d6d6d6;
    --header-button-hover-bg: #666666;
    --button-bg: #4a4a4a;
    --button-border: #555555;
    --button-color: #d2d2d2;
    --link-color: #6db3f2;
    --note-bg: #2a2a2a;
    --seg-bg: rgba(255, 255, 255, 0.05);
}

/* ===================================================================
   3. Book container & content layout
   =================================================================== */

#book-container {
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    padding-left: 16px;
    padding-right: 16px;
    box-sizing: border-box;
    font-size: var(--font-size, 20px);
}

#book-container,
#progress-footer,
#header-icons {
    transition: opacity 0.15s ease;
}

.layout-pending #book-container,
.layout-pending #progress-footer,
.layout-pending #header-icons {
    opacity: 0;
    transition: none;
}

/* ===================================================================
   4. Typography settings (fonts, line-height, alignment)
   =================================================================== */

.font-cactus {
    font-family: "Cactus Classical Serif", serif;
}
.font-spectral {
    font-family: "Spectral", serif;
}
.font-inter {
    font-family: "Inter", sans-serif;
}
.font-roboto-mono {
    font-family: "Roboto Mono", monospace;
}

.line-height-compact #book-content {
    --lh-ratio: 1.3;
    --lh: calc(var(--lh-ratio) * 1em);
    line-height: var(--lh-ratio);
}
.line-height-normal #book-content {
    --lh-ratio: 1.5;
    --lh: calc(var(--lh-ratio) * 1em);
    line-height: var(--lh-ratio);
}
.line-height-loose #book-content {
    --lh-ratio: 1.7;
    --lh: calc(var(--lh-ratio) * 1em);
    line-height: var(--lh-ratio);
}

.align-left #book-content {
    text-align: left;
}
.align-justify #book-content {
    text-align: justify;
}

.hyphenation-no #book-content {
    -webkit-hyphens: none;
    -ms-hyphens: none;
    hyphens: none;
}

.hyphenation-yes #book-content {
    -webkit-hyphens: auto;
    -ms-hyphens: auto;
    hyphens: auto;
}

/* ===================================================================
   5. Book content elements
   =================================================================== */

/* --- Paragraphs --- */
#book-content p {
    margin: 0.4em 0;
    text-indent: 1.5em;
}

/* --- Links --- */
#book-content a {
    color: var(--link-color);
    text-decoration: none;
}
#book-content a:hover {
    text-decoration: underline;
}
#book-content a:visited {
    color: var(--link-color);
}

/* Flash source note reference when jumping back from notes. */
#book-content a.note__ref.note__ref--flash {
    position: relative;
    isolation: isolate;
}
#book-content a.note__ref.note__ref--flash::after {
    content: "";
    position: absolute;
    left: 50%;
    top: 50%;
    width: 2.8em;
    height: 2.8em;
    border-radius: 50%;
    background: #ff6fae;
    pointer-events: none;
    animation: note-ref-flash 2s ease-out forwards;
}

@keyframes note-ref-flash {
    0% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
    50% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
    100% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(1);
    }
}

/* --- Headings --- */
#book-content h1,
#book-content h2,
#book-content h3,
#book-content h4,
#book-content h5,
#book-content h6 {
    overflow-wrap: break-word;
    break-inside: avoid;
    page-break-inside: avoid;
    hyphens: none;
    font-weight: normal;
    margin: 0.8em 0;
    text-align: center;
}

#book-content h2 {
    font-size: 1.6em;
}
#book-content h3 {
    font-size: 1.2em;
}

#book-content h3,
#book-content h4,
#book-content h5,
#book-content h6 {
    margin: 0.6em 0;
}

/* FB2 renderer can nest block tags inside headings; normalize inner flow */
#book-content h1 *,
#book-content h2 *,
#book-content h3 *,
#book-content h4 *,
#book-content h5 *,
#book-content h6 * {
    margin: 0;
    padding: 0;
    text-indent: 0;
    line-height: inherit;
}

/* --- Inline styles --- */
#book-content em {
    font-style: italic;
}
#book-content strong {
    font-weight: bold;
}
#book-content cite {
    display: block;
    font-style: italic;
    opacity: 0.9;
    padding-right: 0.2em;
}
#book-content s {
    text-decoration: line-through;
}
#book-content sub,
#book-content sup {
    font-size: 0.6em;
}

/* --- Empty-line spacer --- */
#book-content .empty-line {
    display: block;
    width: 100%;
    height: var(--lh);
    break-inside: avoid;
    page-break-inside: avoid;
    -webkit-column-break-inside: avoid;
}

/* --- Images --- */
#book-content .img-wrap {
    display: block;
    width: 100%;
    break-inside: avoid;
    page-break-inside: avoid;
    -webkit-column-break-inside: avoid;
    overflow: hidden;
    margin: var(--lh) 0;
}
#book-content img {
    display: block;
    max-width: 100%;
    max-height: 100vh;
    object-fit: contain;
    margin: 0 auto;
    box-sizing: border-box;
}

/* --- Preamble: annotation --- */
#book-content #annotation {
    opacity: 0.75;
    margin: var(--lh) 0;
    font-style: italic;
    padding-right: 0.2em;
}

/* --- Epigraphs, poems, stanzas --- */
#book-content div.epigraph {
    margin: var(--lh) 0;
    padding-left: 2em;
    font-style: italic;
    opacity: 0.8;
    padding-right: 0.2em;
}
#book-content div.poem {
    margin: var(--lh) 0;
    font-style: italic;
    padding-right: 0.2em;
}
#book-content div.stanza {
    margin-left: 2em;
    margin-bottom: var(--lh);
}
#book-content div.stanza p.verse {
    padding-left: 1em;
}
#book-content p.text-author {
    text-align: right;
    font-style: italic;
    margin-top: 0;
    text-indent: 0;
    padding-right: 0.2em;
}

/* ===================================================================
   6. Notes
   =================================================================== */

#book-content section.notes {
    margin-top: 2em;
}
#book-content section.notes .note {
    margin: 1em 0;
    padding: 0.2em 1em;
    background-color: var(--note-bg);
    border: 1px solid var(--panel-border-color);
    border-radius: 4px;
    break-inside: avoid;
    page-break-inside: avoid;
    -webkit-column-break-inside: avoid;
}
#book-content section.notes .note__backrefs {
    display: inline;
    margin-right: 0.3em;
    margin-left: -0.3em;
}
#book-content section.notes .note__backref {
    display: inline;
    color: var(--button-color);
    text-decoration: none;
}
#book-content section.notes .note__backref svg {
    width: 1.1em;
    height: 1.1em;
    vertical-align: -0.15em;
    fill: currentColor;
}
#book-content section.notes .note__backref:hover {
    opacity: 0.7;
}
#book-content section.notes .note__title {
    display: inline;
    font-weight: bold;
    margin-right: 1em;
}
#book-content section.notes .note__body {
    display: contents;
}
#book-content section.notes .note__body p:first-child {
    display: inline;
}

/* ===================================================================
   7. Header, settings panel, TOC panel, overlay
   =================================================================== */

/* --- Header --- */
#reader-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 3rem;
    display: flex;
    align-items: center;
    padding: 0.5rem 1rem;
    z-index: 1000;
    pointer-events: none;
}

#header-icons {
    margin-left: auto;
    display: flex;
    gap: 0.5rem;
    background-color: var(--bg-color);
    padding: 4px 8px;
    border-radius: 26px;
}

#reader-header button {
    pointer-events: all;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background-color: var(--header-button-bg);
    color: var(--header-button-color);
    border: 1px solid var(--button-border);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: none;
    line-height: 1;
    -webkit-tap-highlight-color: transparent;
}
#reader-header button[hidden] {
    display: none;
}
#reader-header button:focus {
    outline: none;
}
@media (hover: hover) and (pointer: fine) {
    #reader-header button:hover {
        background-color: var(--header-button-hover-bg);
    }
}

/* --- Settings panel --- */
#settings-panel {
    position: fixed;
    top: 0;
    right: 0;
    width: 320px;
    height: 100%;
    background-color: var(--panel-bg-color);
    color: var(--text-color);
    border-left: 1px solid var(--panel-border-color);
    transform: translateX(100%);
    transition: none;
    z-index: 1001;
    display: flex;
    flex-direction: column;
}
#settings-panel.open {
    transform: translateX(0);
}

#settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--panel-border-color);
}
#settings-header h2 {
    margin: 0;
    font-size: 1.2rem;
}
#settings-header button {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-color);
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
}

#settings-body {
    padding: 0 1rem 1rem;
    overflow-y: auto;
    overscroll-behavior-y: contain;
    flex: 1;
}

.option-group {
    margin-top: 1rem;
}
.option-title {
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-color);
    opacity: 0.7;
}
.option-buttons {
    display: flex;
    flex-wrap: nowrap;
    gap: 0.5rem;
}
.option-buttons .option-button {
    flex: 1 1 0;
    min-width: 0;
}

/* --- Inline layout: title and buttons on one row --- */
.option-group-inline {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}
.option-group-inline .option-title {
    margin-bottom: 0;
    flex: 0 0 5.5em;
    white-space: nowrap;
}
.option-group-inline .option-buttons {
    flex: 1 1 0;
    min-width: 0;
}

/* --- Centered layout: buttons centered --- */
.option-group-centered .option-buttons {
    justify-content: center;
}
.option-button {
    background-color: transparent;
    border: 1px solid var(--button-border);
    border-radius: 6px;
    color: var(--text-color);
    padding: 8px 10px;
    font-size: 0.9rem;
    transition:
        background-color 0.12s,
        border-color 0.12s;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 32px;
    box-sizing: border-box;
}
#reset-settings-button {
    width: 100%;
    opacity: 0.6;
    font-size: 0.8rem;
    padding: 10px;
    height: auto;
}
#reset-settings-button:hover {
    opacity: 0.9;
}
.option-button {
    cursor: pointer;
}
.option-button:disabled {
    cursor: default;
    opacity: 0.35;
}

/* --- Segmented control --- */
.seg-group {
    gap: 0;
    background-color: var(--seg-bg, rgba(0, 0, 0, 0.06));
    border-radius: 8px;
    padding: 3px;
}
.seg-group .option-button {
    border: none;
    border-radius: 6px;
    background: transparent;
    font-size: 0.85rem;
    padding: 7px 10px;
    color: var(--text-color);
    opacity: 0.7;
}
.seg-group .option-button.selected {
    background-color: var(--button-bg);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.25);
    opacity: 1;
    font-weight: 500;
}

/* --- Theme swatches --- */
.theme-swatches {
    gap: 0.5rem;
    justify-content: center;
}
.theme-swatch {
    flex: 0 0 auto !important;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    border: none !important;
    background: transparent !important;
    padding: 4px !important;
    border-radius: 0 !important;
    height: auto !important;
    transition: none;
}
.theme-swatch .swatch {
    display: block;
    width: 44px;
    height: 24px;
    border-radius: 6px;
    border: none;
    box-sizing: border-box;
    box-shadow: 0 0.5px 2px rgba(0, 0, 0, 0.15);
}
.theme-swatch .swatch-label {
    font-size: 0.7rem;
    opacity: 0.5;
    color: var(--text-color);
    border-bottom: 2px solid transparent;
    padding-bottom: 1px;
}
.theme-swatch.selected .swatch-label {
    opacity: 1;
    border-bottom-color: var(--text-color);
}

/* Auto theme swatch: half light / half dark */
.theme-swatch .swatch-auto {
    background: transparent;
    overflow: visible;
    box-shadow: none;
    clip-path: inset(0 round 6px);
    filter: drop-shadow(0 0.5px 2px rgba(0, 0, 0, 0.15));
    position: relative;
}
.theme-swatch .swatch-auto::before {
    content: "";
    position: absolute;
    inset: 0;
    background: #fff;
    clip-path: polygon(0 0, 100% 0, 0% 100%);
}
.theme-swatch .swatch-auto::after {
    content: "";
    position: absolute;
    inset: 0;
    background: #1a1a1a;
    clip-path: polygon(100% 0, 100% 100%, 0% 100%);
}

/* --- Font group --- */
#font-group-buttons {
    gap: 0.5rem;
    align-items: center;
}
#font-group-buttons .option-button {
    padding: 0 8px;
    height: 34px;
    line-height: 1;
    position: relative;
    border: none;
    border-radius: 0;
    background-color: transparent;
    border-bottom: 2px solid transparent;
    opacity: 0.55;
    color: var(--text-color);
    transition: none;
}
#font-group-buttons .option-button.selected {
    border-bottom-color: var(--text-color);
    opacity: 1;
}

/* --- Font size buttons --- */
#font-size-buttons {
    display: flex;
    align-items: center;
    gap: 0;
    justify-content: center;
}
#font-size-buttons .fs-btn {
    flex: 0 0 auto;
    width: 40px;
    border-radius: 6px;
    border: 1px solid var(--button-border);
    background: transparent;
    font-weight: 500;
}
#font-size-buttons .fs-btn:active {
    background-color: var(--header-button-bg);
}
#font-size-buttons #font-size-display {
    flex: 0 0 90px;
    width: 90px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 500;
    opacity: 0.8;
    overflow: hidden;
}

/* --- Icon buttons (alignment & spacing) --- */
.seg-group .align-icon,
.seg-group .lh-icon {
    padding: 0 8px;
}
.seg-group .align-icon svg,
.seg-group .lh-icon svg {
    display: block;
}

/* --- TOC panel --- */
#toc-panel {
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    height: 100%;
    background-color: var(--panel-bg-color);
    color: var(--text-color);
    border-left: 1px solid var(--panel-border-color);
    transform: translateX(100%);
    transition: none;
    z-index: 1001;
    display: flex;
    flex-direction: column;
}
#toc-panel.open {
    transform: translateX(0);
}
#toc-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--panel-border-color);
}
#toc-header h2 {
    margin: 0;
    font-size: 1.2rem;
}
#toc-header button {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-color);
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
}
#toc-body {
    padding: 0.5rem 1rem 1rem;
    overflow-y: auto;
    overscroll-behavior-y: contain;
    flex: 1;
}

#toc-list {
    list-style: none;
    margin: 0;
    padding: 0;
}
#toc-list li {
    margin-bottom: 0.5rem;
}
#toc-list ul {
    list-style: none;
    padding-left: 1rem;
    margin: 0;
}
#toc-list a {
    display: block;
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.9rem;
    padding: 0.25rem 0;
}
#toc-list a:hover {
    text-decoration: none;
    background-color: var(--header-button-bg);
}
#toc-list a.toc-current {
    font-weight: bold;
    background-color: var(--header-button-bg);
}

/* --- Overlay --- */
#overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.3);
    opacity: 0;
    pointer-events: none;
    transition: none;
    z-index: 1000;
}
#overlay.visible {
    opacity: 1;
    pointer-events: auto;
}

/* ===================================================================
   8. Modal (note popups)
   =================================================================== */

#note-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    align-items: center;
    justify-content: center;
    z-index: 2000;
}
#note-modal.open {
    display: flex;
}
#modal-content {
    background-color: var(--panel-bg-color);
    color: var(--text-color);
    padding: 1rem;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
    border-radius: 4px;
    position: relative;
}
#modal-close {
    position: absolute;
    top: 0.25rem;
    right: 0.25rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-color);
    cursor: pointer;
}
#modal-content p {
    margin: 0.5em 0;
}

/* ===================================================================
   9. Theme swatch colours (handled via inline styles on .swatch spans)
   =================================================================== */

/* ===================================================================
   10. Chrome visibility (hide header icons & progress footer)
   =================================================================== */

.chrome-hidden #header-icons,
.chrome-hidden #progress-footer {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: none;
}

/* Reveal chrome when hovering over the header area (desktop only).
   On touch devices the invisible header must not steal taps from backrefs. */
@media (hover: hover) and (pointer: fine) {
    .chrome-hidden #reader-header {
        pointer-events: auto;
    }
}

/* ===================================================================
   11. Page mode (pagination, columns, baseline grid, nav, footer)
   =================================================================== */

body.mode-page {
    overflow: hidden;
    overscroll-behavior: none;
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    touch-action: pan-x;
    --page-nav-hit-zone: clamp(40px, 4vw, 56px);
    --page-nav-hit-zone-desktop: 80px;
    --page-nav-safe: calc(clamp(40px, 4vw, 56px) + 6px);
}

#book-container.mode-page {
    width: 100vw;
    height: 100vh;
    height: 100dvh;
    overflow: hidden;
    padding: 0;
    box-sizing: border-box;
}

#book-container.mode-page #book-content {
    width: 100vw !important;
    max-width: 100vw !important;
    margin: 0 !important;
    height: 100%;
    overflow: hidden;
    column-fill: auto;
    column-gap: 5rem;
    box-sizing: border-box;
}

/*
 * Page-mode baseline grid overrides.
 * Collapse paragraph margins, zero-out section spacing, and compensate
 * heading line-height/margins so every element sits on the baseline grid.
 */
#book-container.mode-page #book-content p {
    margin: 0;
}
#book-container.mode-page #book-content section {
    margin: 0;
    padding: 0;
}
#book-container.mode-page #book-content div.epigraph,
#book-container.mode-page #book-content div.poem,
#book-container.mode-page #book-content div.stanza {
    margin: 0;
}

/* Start every new section on a new column in page mode (not in Firefox unfortunately).
   Only adjacent sibling sections get the break — not the first child section inside
   a parent, which naturally flows after headings/images/epigraphs. */
#book-container.mode-page #book-content section.section {
    break-before: column;
    -webkit-column-break-before: always;
}
#book-container.mode-page #book-content h2 {
    --lh: calc(var(--lh-ratio) * 1em / 1.6);
    line-height: calc(var(--lh-ratio) / 1.6);
    margin: var(--lh) 0;
}
#book-container.mode-page #book-content h3 {
    --lh: calc(var(--lh-ratio) * 1em / 1.2);
    line-height: calc(var(--lh-ratio) / 1.2);
    margin: var(--lh) 0;
}

#book-container.mode-page #book-content .img-wrap {
    margin: 0;
    max-height: 100%;
}
#book-container.mode-page #book-content img {
    max-height: 100%;
}

/* Safari multi-column fallback */
@supports (-webkit-touch-callout: none) {
    #book-container.mode-page #book-content {
        column-count: auto;
        -webkit-column-count: auto;
    }
}

/* --- Page navigation arrows --- */
.page-nav {
    display: none;
    position: fixed;
    top: 0;
    bottom: 0;
    width: var(--page-nav-hit-zone);
    box-sizing: border-box;
    z-index: 100;
    align-items: center;
    justify-content: center;
    -webkit-tap-highlight-color: transparent;
    /* Navigation is handled by a JS document click handler that
       yields to interactive elements.  page-nav is purely visual. */
    pointer-events: none;
}

#page-nav-prev {
    left: 0;
    padding-right: calc(var(--page-nav-hit-zone) - var(--page-nav-safe));
}
#page-nav-next {
    right: 0;
    padding-left: calc(var(--page-nav-hit-zone) - var(--page-nav-safe));
}
.page-nav__arrow {
    width: 16px;
    height: 56px;
    fill: var(--text-color);
    opacity: 0;
}
body.mode-page .page-nav {
    display: flex;
}
.page-nav.disabled {
    display: none !important;
}

/* --- Progress footer --- */
#progress-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 16px;
    background-color: var(--panel-bg-color);
    border-top: 1px solid var(--panel-border-color);
    font-size: 0.8rem;
    color: var(--text-color);
    z-index: 100;
    box-sizing: border-box;
}
#progress-chapter {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    margin-right: 12px;
    opacity: 0.85;
}
#progress-value {
    flex-shrink: 0;
    font-weight: 500;
    opacity: 0.85;
}

/* ===================================================================
   12. Desktop / mobile overrides
   =================================================================== */

/* --- Desktop (>= 901px) --- */
@media (min-width: 901px) {
    body.mode-page {
        --page-nav-hit-zone: var(--page-nav-hit-zone-desktop);
    }

    #book-container.mode-page #book-content {
        column-count: 2;
        padding-left: var(--page-nav-safe);
        padding-right: var(--page-nav-safe);
        padding-top: 12px;
        padding-bottom: 32px;
    }

    /* User preference: force single column on wide screens */
    #book-container.mode-page.columns-1 #book-content {
        column-count: 1;
    }

    .page-nav.hovered .page-nav__arrow {
        opacity: 0.6;
    }

    #book-container.mode-scroll {
        padding-left: calc(48px + 3%);
        padding-right: calc(48px + 3%);
    }
}

/* Safari desktop fallback */
@supports (-webkit-touch-callout: none) {
    @media (min-width: 901px) {
        #book-container.mode-page #book-content {
            -webkit-column-width: calc(
                (100vw - (var(--page-nav-safe) * 2) - 5rem) / 2
            );
            column-width: calc((100vw - (var(--page-nav-safe) * 2) - 5rem) / 2);
        }
        #book-container.mode-page.columns-1 #book-content {
            -webkit-column-width: auto;
            column-width: auto;
        }
    }
}

/* --- Mobile / tablet (<= 900px) --- */
@media (max-width: 900px) {
    /* Scroll mode */
    body.mode-scroll {
        overflow-x: hidden;
    }

    #book-container.mode-scroll {
        padding-left: 20px;
        padding-right: 20px;
    }
    #book-container.mode-scroll #book-content {
        width: 100%;
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
        overflow-x: hidden;
    }

    /* Page mode */
    body.mode-page {
        --page-nav-hit-zone: calc(100vw / 4);
    }
    #book-container.mode-page #book-content {
        column-count: 1;
        /* Use margin instead of padding-left/right so Safari includes the
           full column width in scrollWidth (it omits trailing padding). */
        width: calc(100vw - 40px) !important;
        max-width: calc(100vw - 40px) !important;
        margin: 0 20px !important;
        padding-top: calc(var(--lh, 1em) / 2);
        padding-bottom: calc(
            max(
                var(--lh, 1em) / 2,
                env(safe-area-inset-bottom),
                var(--viewport-offset, 0px)
            )
        );
    }
    .page-nav__arrow {
        display: none;
    }

    /* Safari mobile fallback */
    @supports (-webkit-touch-callout: none) {
        #book-container.mode-page #book-content {
            -webkit-column-width: calc(100vw - 40px);
            column-width: calc(100vw - 40px);
        }
    }

    /* Panels: max-width so they don't fill the whole screen on laptops */
    #settings-panel,
    #toc-panel {
        width: min(100vw, 360px);
        height: 100vh;
        height: 100dvh;
    }

    #columns-group {
        display: none;
    }
}

/* Full-screen panels & enlarged touch targets on real touch devices */
@media (max-width: 900px) and (pointer: coarse) {
    #settings-panel,
    #toc-panel {
        width: 100vw;
        left: 0;
        right: 0;
        border-left: none;
    }

    #settings-header,
    #toc-header {
        padding-top: calc(12px + env(safe-area-inset-top));
        padding-left: 16px;
        padding-right: 16px;
        padding-bottom: 12px;
    }
    #settings-header h2,
    #toc-header h2 {
        font-size: 1.35rem;
    }

    #settings-header button,
    #toc-header button {
        font-size: 2rem;
        width: 44px;
        height: 44px;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    #settings-body {
        padding-bottom: calc(16px + env(safe-area-inset-bottom));
        -webkit-overflow-scrolling: touch;
    }
    #toc-body {
        padding-bottom: calc(16px + env(safe-area-inset-bottom));
        -webkit-overflow-scrolling: touch;
    }

    .option-title {
        font-size: 0.95rem;
    }
    .option-buttons {
        gap: 0.6rem;
    }
    .option-button {
        font-size: 1rem;
        padding: 10px 10px;
        min-height: 44px;
    }
    .seg-group {
        gap: 0;
        padding: 3px;
    }
    .seg-group .option-button {
        font-size: 0.9rem;
        padding: 10px;
        min-height: 44px;
    }
    #font-size-buttons .fs-btn {
        width: 3rem;
        min-height: 44px;
    }
    #font-size-buttons span {
        font-size: 1.05rem;
    }
    .theme-swatch .swatch {
        width: 42px;
        height: 42px;
    }
    .theme-swatch .swatch-label {
        font-size: 0.75rem;
    }
    #font-group-buttons .option-button {
        font-size: 1.05rem;
        padding: 12px 8px;
        min-height: 44px;
    }
    #toc-list a {
        font-size: 1rem;
        padding: 0.55rem 0.25rem;
    }
    #toc-list li {
        margin-bottom: 0.25rem;
    }
}