/* ==========================================================================
   MARKDOWN READER PRO - DESIGN SYSTEM & THEMES
   ========================================================================== */

:root {
    /* Color Palette - Premium OLED Pitch Black Theme */
    --bg-primary: #000000;
    --bg-secondary: #121212;
    --bg-tertiary: #1e1e1e;
    --bg-glass: rgba(18, 18, 18, 0.88);
    
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --accent-light: rgba(99, 102, 241, 0.2);
    
    --border-color: rgba(255, 255, 255, 0.12);
    --border-hover: rgba(255, 255, 255, 0.25);
    
    --card-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.9);
    --header-height: 60px;
    --sidebar-width: 320px;
    
    /* Code block colors */
    --code-bg: #0d0d0d;
    --code-text: #e4e4e7;

    /* Highlight Search */
    --search-bg: #f59e0b;
    --search-text: #000;
    --search-current-bg: #ef4444;
    --search-current-text: #fff;
    
    /* Fonts */
    --font-family-sans: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-family-nanum: 'Nanum Gothic', 'Noto Sans KR', sans-serif;
    --font-family-serif: 'Lora', 'KoPub Batang', serif;
    --font-family-mono: 'Fira Code', 'JetBrains Mono', monospace;
    --font-family-heading: 'Plus Jakarta Sans', 'Noto Sans KR', sans-serif;

    /* User customizable defaults */
    --user-font-size: 16px;
    --user-line-height: 1.75;
    --user-indent-size: 1.2rem;
    --user-max-width: 900px;
}

/* OLED Black Theme */
[data-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #121212;
    --bg-tertiary: #1e1e1e;
    --bg-glass: rgba(18, 18, 18, 0.88);
    
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --accent-light: rgba(99, 102, 241, 0.2);
    
    --border-color: rgba(255, 255, 255, 0.12);
    --border-hover: rgba(255, 255, 255, 0.25);
    
    --card-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.9);
    --code-bg: #0d0d0d;
    --code-text: #e4e4e7;
}

/* --------------------------------------------------------------------------
   THEME VARIATIONS
   -------------------------------------------------------------------------- */

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --bg-glass: rgba(255, 255, 255, 0.9);
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: rgba(37, 99, 235, 0.1);
    
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    
    --card-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.07);
    --code-bg: #f8fafc;
    --code-text: #1e293b;
}

/* Warm Sepia Theme */
[data-theme="sepia"] {
    --bg-primary: #fbf7ee;
    --bg-secondary: #f4ecd8;
    --bg-tertiary: #e9dec4;
    --bg-glass: rgba(244, 236, 216, 0.92);
    
    --text-primary: #433422;
    --text-secondary: #6e5a44;
    --text-muted: #9a846c;
    
    --accent-color: #b45309;
    --accent-hover: #92400e;
    --accent-light: rgba(180, 83, 9, 0.12);
    
    --border-color: #e2d5ba;
    --border-hover: #d1c1a2;
    
    --card-shadow: 0 10px 25px -5px rgba(67, 52, 34, 0.08);
    --code-bg: #ede1c7;
    --code-text: #3d2f1f;
}

/* Cyber Neon Theme */
[data-theme="cyber"] {
    --bg-primary: #050814;
    --bg-secondary: #0d122b;
    --bg-tertiary: #182046;
    --bg-glass: rgba(13, 18, 43, 0.92);
    
    --text-primary: #00f0ff;
    --text-secondary: #70a5ff;
    --text-muted: #4362a6;
    
    --accent-color: #ff007f;
    --accent-hover: #d9006c;
    --accent-light: rgba(255, 0, 127, 0.2);
    
    --border-color: rgba(0, 240, 255, 0.2);
    --border-hover: rgba(0, 240, 255, 0.4);
    
    --card-shadow: 0 0 20px rgba(0, 240, 255, 0.15);
    --code-bg: #030611;
    --code-text: #00f0ff;
}

/* --------------------------------------------------------------------------
   GLOBAL RESET & BASE STYLES
   -------------------------------------------------------------------------- */

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

html, body {
    height: 100%;
    width: 100%;
    margin: 0;
    padding: 0;
    font-family: var(--font-family-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow: hidden;
    position: fixed;
    top: 0;
    left: 0;
}

/* Reading Progress Bar */
#reading-progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: transparent;
    z-index: 1000;
}

#reading-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent-color), #ec4899);
    box-shadow: 0 0 8px var(--accent-color);
    transition: width 0.1s ease-out;
}

/* App Wrapper */
#app {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

/* --------------------------------------------------------------------------
   HEADER NAVIGATION BAR (ALWAYS FIXED TOP UI)
   -------------------------------------------------------------------------- */

.navbar {
    height: var(--header-height);
    background-color: var(--bg-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.25rem;
    z-index: 100;
    gap: 1rem;
    flex-shrink: 0;
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-family: var(--font-family-heading);
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--text-primary);
    user-select: none;
}

.brand-icon {
    font-size: 1.4rem;
    color: var(--accent-color);
}

.badge {
    background: linear-gradient(135deg, var(--accent-color), #8b5cf6);
    color: #fff;
    font-size: 0.65rem;
    font-weight: 800;
    padding: 0.15rem 0.45rem;
    border-radius: 4px;
    letter-spacing: 0.5px;
}

.nav-center {
    flex: 1;
    max-width: 480px;
}



.nav-right {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

/* BUTTONS & CONTROLS */

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.45rem 0.9rem;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all 0.2s ease;
}

.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border-color: var(--border-color);
}

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

.icon-btn {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.95rem;
}

.icon-btn:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border-color: var(--border-hover);
}

/* View Mode Switcher */
.view-mode-toggle {
    display: flex;
    background-color: var(--bg-secondary);
    padding: 3px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.view-mode-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.35rem 0.65rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.88rem;
    transition: all 0.2s ease;
}

.view-mode-btn.active {
    background-color: var(--accent-color);
    color: #fff;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

/* DROPDOWNS */

.dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    padding: 0.6rem;
    min-width: 220px;
    display: none;
    flex-direction: column;
    gap: 0.3rem;
    z-index: 200;
    backdrop-filter: blur(16px);
}

.dropdown-menu.show {
    display: flex;
    animation: fadeInDown 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.menu-header {
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--text-muted);
    padding: 0.4rem 0.6rem 0.2rem;
    letter-spacing: 0.5px;
}

.setting-group {
    padding: 0.5rem 0.6rem;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.setting-group label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
}

.setting-group input[type="range"] {
    accent-color: var(--accent-color);
    width: 100%;
    cursor: pointer;
}

.font-selector, .width-selector {
    display: flex;
    gap: 0.25rem;
    background-color: var(--bg-primary);
    padding: 3px;
    border-radius: 6px;
}

.font-btn, .width-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 0.75rem;
    padding: 0.3rem;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.15s ease;
}

.font-btn.active, .width-btn.active {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    font-weight: 600;
}

.theme-option, .dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.85rem;
    cursor: pointer;
    text-align: left;
    transition: all 0.15s ease;
    width: 100%;
}

.theme-option:hover, .dropdown-item:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.theme-option.active {
    background-color: var(--accent-light);
    color: var(--accent-color);
    font-weight: 600;
}

/* --------------------------------------------------------------------------
   MAIN LAYOUT & SIDEBAR
   -------------------------------------------------------------------------- */

.main-container {
    display: flex;
    flex: 1;
    height: calc(100vh - var(--header-height));
    overflow: hidden;
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: margin-left 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    z-index: 50;
    flex-shrink: 0;
}

.sidebar.collapsed {
    margin-left: calc(-1 * var(--sidebar-width));
}

.sidebar-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-primary);
}

.sidebar-tab {
    flex: 1;
    padding: 0.75rem 0.5rem;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-muted);
    font-size: 0.82rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    transition: all 0.2s ease;
}

.sidebar-tab:hover {
    color: var(--text-secondary);
}

.sidebar-tab.active {
    color: var(--accent-color);
    border-bottom-color: var(--accent-color);
    background-color: var(--bg-secondary);
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    display: none;
    flex-direction: column;
    padding: 0.75rem;
}

.sidebar-content.active {
    display: flex;
}

/* File Filter & List */
.sidebar-search {
    position: relative;
    display: flex;
    align-items: center;
    margin-bottom: 0.75rem;
}

.sidebar-search i {
    position: absolute;
    left: 0.75rem;
    color: var(--text-muted);
    font-size: 0.8rem;
}

.sidebar-search input {
    width: 100%;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.4rem 0.6rem 0.4rem 2rem;
    color: var(--text-primary);
    font-size: 0.8rem;
    outline: none;
}

.sidebar-search input:focus {
    border-color: var(--accent-color);
}

.file-list-group {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 0.75rem;
    border-radius: 8px;
    background-color: transparent;
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.15s ease;
}

.file-item:hover {
    background-color: var(--bg-tertiary);
}

.file-item.active {
    background-color: var(--accent-light);
    border-color: var(--accent-color);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    overflow: hidden;
}

.file-icon {
    color: var(--accent-color);
    font-size: 0.9rem;
    flex-shrink: 0;
}

.file-name {
    font-size: 0.84rem;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-size {
    font-size: 0.7rem;
    color: var(--text-muted);
    flex-shrink: 0;
    margin-left: 0.4rem;
}

/* TOC Tree Container */
.toc-container {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.empty-toc {
    font-size: 0.82rem;
    color: var(--text-muted);
    text-align: center;
    padding: 2rem 1rem;
}

.toc-item {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.82rem;
    padding: 0.35rem 0.6rem;
    border-radius: 6px;
    border-left: 2px solid transparent;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: all 0.15s ease;
}

.toc-item:hover {
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
}

.toc-item.active {
    color: var(--accent-color);
    border-left-color: var(--accent-color);
    background-color: var(--accent-light);
    font-weight: 600;
}

.toc-h1 { padding-left: 0.5rem; font-weight: 600; }
.toc-h2 { padding-left: 1.0rem; }
.toc-h3 { padding-left: 1.5rem; font-size: 0.78rem; opacity: 0.9; }
.toc-h4 { padding-left: 2.0rem; font-size: 0.75rem; opacity: 0.8; }

/* --------------------------------------------------------------------------
   WORKSPACE CONTENT & VIEWER
   -------------------------------------------------------------------------- */

.content-workspace {
    flex: 1;
    display: flex;
    overflow: hidden;
    position: relative;
}

/* Reader Mode Default */
.content-workspace.reader-mode .editor-container { display: none; }
.content-workspace.reader-mode .viewer-container { width: 100%; }

/* Editor Mode Only */
.content-workspace.editor-mode .editor-container { width: 100%; }
.content-workspace.editor-mode .viewer-container { display: none; }

/* Split Mode (Top: Viewer, Bottom: Editor) */
.content-workspace.split-mode {
    flex-direction: column;
}

.content-workspace.split-mode .viewer-container {
    order: 1;
    width: 100%;
    height: 50%;
    border-bottom: 1px solid var(--border-color);
}

.content-workspace.split-mode .editor-container {
    order: 2;
    width: 100%;
    height: 50%;
    border-right: none;
}

.editor-container {
    display: flex;
    flex-direction: column;
    background-color: var(--bg-primary);
    height: 100%;
}

.pane-header {
    height: 38px;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.78rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.pane-status {
    font-size: 0.7rem;
    color: #10b981;
}

#raw-markdown-input {
    flex: 1;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-family-mono);
    font-size: 0.9rem;
    line-height: 1.6;
    padding: 1.5rem;
    border: none;
    outline: none;
    resize: none;
}

.viewer-container {
    flex: 1;
    height: 100%;
    overflow-y: auto;
    padding: 2.5rem 2rem;
    scroll-behavior: smooth;
}

/* Document Meta Bar */
.doc-meta-bar {
    max-width: var(--user-max-width);
    margin: 0 auto 2.5rem auto;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.doc-title-display {
    font-family: var(--font-family-heading);
    font-size: 2.2rem;
    font-weight: 800;
    line-height: 1.3;
    color: var(--text-primary);
    margin-bottom: 1rem;
    letter-spacing: -0.5px;
}

.meta-right {
    display: flex;
    gap: 1.25rem;
    align-items: center;
}

.meta-item {
    font-size: 0.82rem;
    color: var(--text-muted);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

/* --------------------------------------------------------------------------
   RICH MARKDOWN TYPOGRAPHY & RENDERING BODY
   -------------------------------------------------------------------------- */

.markdown-body {
    max-width: var(--user-max-width);
    margin: 0 auto;
    font-size: var(--user-font-size);
    line-height: var(--user-line-height);
    color: var(--text-primary);
    word-wrap: break-word;
}

/* Font family modifier classes */
.markdown-body.font-sans { font-family: var(--font-family-sans); }
.markdown-body.font-nanum { font-family: var(--font-family-nanum); }
.markdown-body.font-serif { font-family: var(--font-family-serif); }
.markdown-body.font-mono { font-family: var(--font-family-mono); }

/* Width modifier classes */
.markdown-body.width-narrow { max-width: 760px; }
.markdown-body.width-normal { max-width: 900px; }
.markdown-body.width-wide { max-width: 1100px; }

/* Headings */
.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
    font-family: var(--font-family-heading);
    color: var(--text-primary);
    font-weight: 700;
    line-height: 1.35;
    margin-top: 2rem;
    margin-bottom: 1rem;
    position: relative;
    scroll-margin-top: 80px;
}

.markdown-body h1 {
    font-size: 2rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.markdown-body h2 {
    font-size: 1.55rem;
    padding-bottom: 0.4rem;
    border-bottom: 1px solid var(--border-color);
}

.markdown-body h3 { font-size: 1.25rem; }
.markdown-body h4 { font-size: 1.1rem; }
.markdown-body h5 { font-size: 0.95rem; text-transform: uppercase; letter-spacing: 0.5px; }

/* Heading Anchor Link Hover */
.heading-anchor {
    position: absolute;
    left: -1.4rem;
    color: var(--accent-color);
    opacity: 0;
    text-decoration: none;
    font-size: 0.9em;
    transition: opacity 0.2s ease;
}

.markdown-body h1:hover .heading-anchor,
.markdown-body h2:hover .heading-anchor,
.markdown-body h3:hover .heading-anchor {
    opacity: 1;
}

/* Paragraphs & Text Formatting */
.markdown-body p {
    margin-bottom: 1.25rem;
}

.markdown-body strong {
    font-weight: 700;
    color: var(--text-primary);
}

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

.markdown-body hr {
    height: 2px;
    padding: 0;
    margin: 2.5rem 0;
    background-color: var(--border-color);
    border: none;
}

/* Links */
.markdown-body a {
    color: var(--accent-color);
    text-decoration: none;
    border-bottom: 1px dashed var(--accent-color);
    transition: all 0.15s ease;
}

.markdown-body a:hover {
    color: var(--accent-hover);
    border-bottom-style: solid;
    background-color: var(--accent-light);
}

/* Lists (Customizable Indentation) */
.markdown-body ul,
.markdown-body ol {
    padding-left: var(--user-indent-size, 1.2rem);
    margin-bottom: 1.1rem;
}

.markdown-body li {
    margin-bottom: 0.35rem;
}

.markdown-body li > ul,
.markdown-body li > ol {
    padding-left: var(--user-indent-size, 1.2rem);
    margin-top: 0.3rem;
    margin-bottom: 0;
}

/* Task lists (checklists) */
.markdown-body ul.contains-task-list {
    list-style: none;
    padding-left: 0.5rem;
}

.markdown-body li.task-list-item {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
}

.markdown-body input[type="checkbox"] {
    accent-color: var(--accent-color);
    margin-top: 0.25rem;
    cursor: pointer;
}

/* Blockquotes & Callouts */
.markdown-body blockquote {
    margin: 1.5rem 0;
    padding: 1rem 1.25rem;
    color: var(--text-secondary);
    background-color: var(--bg-secondary);
    border-left: 4px solid var(--accent-color);
    border-radius: 0 8px 8px 0;
    font-size: 0.95em;
}

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

/* Tables */
.markdown-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.9em;
    overflow-x: auto;
    display: block;
}

.markdown-body th,
.markdown-body td {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    text-align: left;
}

.markdown-body th {
    background-color: var(--bg-secondary);
    font-weight: 700;
    color: var(--text-primary);
}

.markdown-body tr:nth-child(even) {
    background-color: rgba(255, 255, 255, 0.02);
}

.markdown-body tr:hover {
    background-color: var(--accent-light);
}

/* Code Blocks & Inline Code */
.markdown-body code:not(pre code) {
    background-color: var(--bg-tertiary);
    color: var(--accent-color);
    font-family: var(--font-family-mono);
    font-size: 0.85em;
    padding: 0.2em 0.4em;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

.code-block-wrapper {
    position: relative;
    margin: 1.5rem 0;
    border-radius: 10px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: var(--bg-secondary);
    padding: 0.4rem 1rem;
    border-bottom: 1px solid var(--border-color);
    font-family: var(--font-family-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
}

.copy-code-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    transition: all 0.2s ease;
}

.copy-code-btn:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.markdown-body pre {
    background-color: var(--code-bg);
    color: var(--code-text);
    padding: 1.2rem;
    overflow-x: auto;
    font-family: var(--font-family-mono);
    font-size: 0.88em;
    line-height: 1.55;
    margin: 0;
}



/* Images & Media */
.markdown-body img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 1rem 0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* --------------------------------------------------------------------------
   FLOATING CONTROLS & DRAG-DROP OVERLAY
   -------------------------------------------------------------------------- */

.floating-controls {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    z-index: 90;
}

.floating-btn {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: all 0.2s ease;
}

.floating-btn:hover {
    background-color: var(--accent-color);
    color: #fff;
    transform: translateY(-2px);
}

.drag-drop-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(12px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    pointer-events: none;
}

.drag-drop-overlay.active {
    display: flex;
}

.drop-zone-card {
    border: 3px dashed var(--accent-color);
    border-radius: 20px;
    padding: 4rem;
    text-align: center;
    background-color: var(--bg-secondary);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
    max-width: 500px;
}

.drop-icon {
    font-size: 4rem;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
    animation: bounce 1.5s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.drop-zone-card h2 {
    font-size: 1.5rem;
    margin-bottom: 0.75rem;
}

.drop-zone-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Live Reload Toast Notification */
.live-reload-toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background-color: var(--accent-color);
    color: #fff;
    padding: 0.65rem 1.3rem;
    border-radius: 30px;
    font-size: 0.84rem;
    font-weight: 600;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
    display: flex;
    align-items: center;
    gap: 0.6rem;
    z-index: 999;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.live-reload-toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.toggle-group {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
}

.toggle-group label {
    cursor: pointer;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.toggle-group input[type="checkbox"] {
    accent-color: var(--accent-color);
    width: 18px;
    height: 18px;
    cursor: pointer;
}


/* --------------------------------------------------------------------------
   MOBILE & TABLET RESPONSIVE STYLES
   -------------------------------------------------------------------------- */

.sidebar-overlay {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100vw;
    height: calc(100vh - var(--header-height));
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: none;
    z-index: 45;
}

.sidebar-overlay.active {
    display: block;
}

@media (max-width: 768px) {
    :root {
        --header-height: 54px;
    }

    .navbar {
        padding: 0 0.75rem;
        gap: 0.5rem;
    }

    .brand-name {
        font-size: 0.95rem;
    }

    .brand .badge {
        display: none;
    }

    .nav-center {
        max-width: 160px;
    }

    .search-box {
        padding: 0.3rem 0.5rem;
    }

    /* Prevent mobile auto-zoom on input focus */
    input, textarea, select {
        font-size: 16px !important;
    }

    .search-box input {
        font-size: 16px !important;
    }

    .btn span, .btn-text-hide {
        display: none;
    }

    .btn {
        padding: 0.4rem 0.6rem;
    }

    /* Mobile Sidebar as Drawer Overlay */
    .sidebar {
        position: fixed;
        top: var(--header-height);
        bottom: 0;
        left: 0;
        width: 82vw;
        max-width: 300px;
        z-index: 50;
        box-shadow: 10px 0 25px rgba(0, 0, 0, 0.4);
        transform: translateX(0);
        transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }

    .sidebar.collapsed {
        transform: translateX(-100%);
        margin-left: 0;
    }

    .content-workspace.split-mode {
        flex-direction: column;
    }

    .content-workspace.split-mode .viewer-container {
        order: 1;
        width: 100%;
        height: 55%;
        border-bottom: 1px solid var(--border-color);
    }

    .content-workspace.split-mode .editor-container {
        order: 2;
        width: 100%;
        height: 45%;
        border-right: none;
    }

    .viewer-container {
        padding: 1.25rem 0.85rem;
    }

    .doc-title-display {
        font-size: 1.65rem;
        margin-bottom: 0.75rem;
    }

    .doc-meta-bar {
        margin-bottom: 1.5rem;
        padding-bottom: 1rem;
    }

    .meta-right {
        flex-wrap: wrap;
        gap: 0.6rem 1rem;
    }

    .meta-item {
        font-size: 0.75rem;
    }

    .markdown-body h1 { font-size: 1.6rem; }
    .markdown-body h2 { font-size: 1.35rem; }
    .markdown-body h3 { font-size: 1.15rem; }

    .markdown-body table {
        font-size: 0.8rem;
    }

    .markdown-body th, .markdown-body td {
        padding: 0.5rem 0.65rem;
    }

    .floating-controls {
        bottom: 1.25rem;
        right: 1rem;
    }

    .floating-btn {
        width: 38px;
        height: 38px;
        font-size: 0.9rem;
    }

    .dropdown-menu {
        right: -0.5rem;
        min-width: 200px;
    }
}

@media (max-width: 480px) {
    .nav-center {
        display: none; /* Hide search input on extra small screens to save space */
    }

    .doc-title-display {
        font-size: 1.4rem;
    }
}

/* --------------------------------------------------------------------------
   PRINT STYLESHEET
   -------------------------------------------------------------------------- */

@media print {
    #reading-progress-container,
    .navbar,
    .sidebar,
    .sidebar-overlay,
    .pane-header,
    #editor-container,
    .floating-controls,
    .search-box {
        display: none !important;
    }

    body, html, #app, .main-container, .viewer-container {
        height: auto !important;
        overflow: visible !important;
        background: #fff !important;
        color: #000 !important;
    }

    .viewer-container {
        padding: 0 !important;
    }

    .markdown-body {
        max-width: 100% !important;
        color: #000 !important;
    }

    .markdown-body pre {
        background-color: #f5f5f5 !important;
        color: #000 !important;
        border: 1px solid #ccc !important;
    }
}