/* ═══════════════════════════════════════════
   云端书库 v2.5 — 样式表
   优化：字体系统、滑块控制、行距/页宽可调、
   暗色模式、阅读进度条、响应式、打印样式
   ═══════════════════════════════════════════ */

/* ── CSS 变量 ── */
:root {
    --bg: #f5f1eb;
    --card-bg: #ffffff;
    --text: #2c2416;
    --text-secondary: #7a6e5d;
    --text-muted: #a89880;
    --accent: #8b5e3c;
    --accent-light: #c9a87c;
    --sidebar-bg: #faf7f2;
    --border: #e0d7cd;
    --hover: #f0e8de;
    --btn-bg: #fff;
    --btn-shadow: 0 2px 10px rgba(0,0,0,0.05);
    --overlay-bg: rgba(0,0,0,0.35);
    --content-width: 780px;
    --progress-color: #8b5e3c;
    --transition-speed: 0.25s;
    --radius: 10px;
    --radius-sm: 6px;
    --slider-track: #e0d7cd;
    --slider-fill: #8b5e3c;
    --slider-thumb: #6b3a20;
}

[data-theme="dark"] {
    --bg: #1a1814;
    --card-bg: #2a2620;
    --text: #d4cfc4;
    --text-secondary: #a09888;
    --text-muted: #6b6258;
    --accent: #d4a574;
    --accent-light: #8b6f50;
    --sidebar-bg: #1f1c17;
    --border: #3a352e;
    --hover: #333028;
    --btn-bg: #2a2620;
    --btn-shadow: 0 2px 10px rgba(0,0,0,0.2);
    --overlay-bg: rgba(0,0,0,0.6);
    --progress-color: #d4a574;
    --slider-track: #3a352e;
    --slider-fill: #d4a574;
    --slider-thumb: #e0b890;
}

/* ── 重置 ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
    font-family: "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
    background: var(--bg); color: var(--text);
    line-height: 1.8;
    transition: background var(--transition-speed), color var(--transition-speed);
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
mark { background: var(--highlight, #ffe08a); padding: 0 2px; border-radius: 2px; color: inherit; }

/* ═══════════════════════════════════════
   滑块通用样式
   ═══════════════════════════════════════ */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%; height: 6px;
    background: var(--slider-track);
    border-radius: 3px; outline: none;
    cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px; height: 20px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid var(--card-bg);
    box-shadow: 0 1px 4px rgba(0,0,0,0.15);
    cursor: pointer; transition: transform 0.15s;
}
input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); }
input[type="range"]::-moz-range-thumb {
    width: 20px; height: 20px; border-radius: 50%;
    background: var(--accent); border: 2px solid var(--card-bg);
    cursor: pointer;
}

/* ── 阅读进度条 ── */
.reading-progress {
    position: fixed; top: 0; left: 0; height: 3px;
    background: linear-gradient(90deg, var(--accent-light), var(--accent));
    z-index: 500; transition: width 0.1s linear;
    border-radius: 0 2px 2px 0;
}

/* ── 快捷键提示浮层 ── */
.shortcuts-overlay {
    position: fixed; top: 0; left: 0; right: 0; bottom: 0;
    z-index: 340; background: rgba(0,0,0,0.2);
    opacity: 0; visibility: hidden; transition: opacity 0.25s, visibility 0.25s;
}
.shortcuts-overlay.show { opacity: 1; visibility: visible; }
.shortcuts-hint {
    position: fixed; bottom: 20px; right: 24px; z-index: 350;
    background: var(--card-bg); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 15px 18px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    font-size: 0.82em; color: var(--text-secondary);
    opacity: 0; visibility: hidden;
    transform: translateY(8px);
    transition: opacity 0.25s, visibility 0.25s, transform 0.25s;
}
.shortcuts-hint.show { opacity: 1; visibility: visible; transform: translateY(0); }
.shortcuts-hint kbd {
    display: inline-block; padding: 2px 7px; background: var(--hover);
    border: 1px solid var(--border); border-radius: 4px;
    font-family: monospace; font-size: 0.9em; margin: 0 2px;
}
.shortcuts-hint .kb-row { display: flex; justify-content: space-between; gap: 12px; margin: 3px 0; }

/* ═══════════════════════════════════════
   首页 / 书架
   ═══════════════════════════════════════ */
.home-wrap {
    display: flex; justify-content: center;
    height: 100vh; height: 100dvh;
    padding: 24px 16px; box-sizing: border-box;
    overflow: hidden;
}
.home-inner { max-width: 900px; width: 100%; display:flex; flex-direction:column; height:100%; }
.site-header { text-align: center; margin-bottom: 28px; flex-shrink:0; }
.site-header .site-name {
    font-size: 2.6em; font-weight: 900; color: var(--accent);
    letter-spacing: 4px;
    background: linear-gradient(135deg, var(--accent) 0%, #c4956a 100%);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.site-header .site-desc {
    font-size: 0.95em; color: var(--text-secondary); margin-top: 10px;
    font-style: italic; letter-spacing: 1px;
}
.site-header .site-ornament {
    margin-top: 12px; font-size: 0.85em; color: var(--text-muted);
    letter-spacing: 8px; opacity: 0.6;
}

/* 继续阅读 */
.continue-section {
    max-width: 720px; margin: 0 auto 28px; flex-shrink:0;
}
.continue-title {
    font-size: 0.82em; color: var(--text-muted);
    margin-bottom: 12px; padding-left: 4px;
}
.continue-list {
    display: flex; flex-direction: column; gap: 10px;
}
.continue-card {
    display: flex; flex-direction: column; gap: 6px;
    padding: 14px 18px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer; transition: border-color 0.2s, box-shadow 0.2s;
    opacity: 1;
}
.continue-card:hover {
    border-color: var(--accent);
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
}
.continue-book-info {
    display: flex; align-items: center; gap: 8px;
}
.continue-book-title {
    font-size: 0.95em; font-weight: 600; color: var(--text);
    overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 360px;
}
.continue-book-meta {
    font-size: 0.78em; color: var(--text-muted);
    margin-left: auto; flex-shrink: 0;
}
.continue-progress-wrap {
    display: flex; align-items: center; gap: 10px;
}
.continue-progress-bar {
    flex: 1; height: 4px; background: var(--slider-track);
    border-radius: 2px; overflow: hidden;
}
.continue-progress-fill {
    height: 100%; background: var(--accent); border-radius: 2px;
    transition: width 0.5s ease;
}
.continue-time {
    font-size: 0.72em; color: var(--text-muted); flex-shrink: 0;
}
.continue-fold {
    display: flex; flex-direction: column; gap: 10px;
}
.continue-toggle {
    display: block; width: 100%; margin-top: 6px; padding: 8px 0;
    background: transparent; border: 1px dashed var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-muted); font-size: 0.8em; cursor: pointer;
    transition: border-color 0.2s, color 0.2s;
}
.continue-toggle:hover {
    border-color: var(--accent); color: var(--accent);
}
/* 书架搜索栏 */
.bookshelf-search {
    display: flex; align-items: center;
    max-width: 460px; margin: 0 auto 24px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 9px 14px;
    transition: border-color 0.2s, box-shadow 0.2s;
    flex-shrink:0;
}
.bookshelf-search:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(139,94,60,0.08);
}
.bookshelf-search input {
    flex: 1; border: none; outline: none; background: transparent;
    font-size: 0.9em; color: var(--text); font-family: inherit;
    min-width: 0;
}
.bookshelf-search input::placeholder { color: var(--text-muted); }
.bookshelf-search .book-count-badge {
    font-size: 0.72em; color: var(--text-muted); flex-shrink: 0;
    padding-left: 10px; border-left: 1px solid var(--border);
    margin-left: 8px;
}
.bookshelf-sort { display:flex; gap:2px; flex-shrink:0; margin-right:8px; }
.bookshelf-sort .sort-btn {
    font-size:.72em; padding:3px 8px; border:1px solid var(--border);
    background:transparent; color:var(--text-muted); border-radius:4px;
    cursor:pointer; font-family:inherit; transition:all .2s;
}
.bookshelf-sort .sort-btn:hover { border-color:var(--accent); color:var(--accent); }
.bookshelf-sort .sort-btn.active { background:var(--accent); color:#fff; border-color:var(--accent); }
.bookshelf-no-result { text-align: center; padding: 40px 0 20px; flex-shrink:0; }
.bookshelf-fold-btn:hover { border-color:var(--accent); color:var(--accent); }

.bookshelf {
    display: flex; flex-direction: column;
    gap: 10px; padding: 0;
    max-width: 600px; margin: 0 auto;
    flex:1; min-height:0;
}
.bookshelf-wrap { position:relative; flex:1; min-height:0; display:flex; flex-direction:column; }
.bookshelf-wrap.collapsed .bookshelf { overflow:hidden; max-height:340px; }
.bookshelf-wrap.expanded .bookshelf { overflow-y:auto; max-height:none; }
.bookshelf-fold-btn {
    display:block; margin:12px auto 0; padding:8px 20px;
    background:var(--card-bg); border:1px solid var(--border);
    border-radius:20px; color:var(--text-muted); font-size:.8em;
    cursor:pointer; font-family:inherit; transition:all .2s;
    flex-shrink:0;
}
.bookshelf-fold-btn:hover { border-color:var(--accent); color:var(--accent); }

/* 书籍卡片 */
.book-card {
    background: var(--card-bg);
    border-radius: 10px;
    border: 1px solid var(--border);
    padding: 16px 18px;
    cursor: pointer;
    display: flex; align-items: center; gap: 14px;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    text-decoration: none;
}
.book-card:hover {
    transform: translateX(4px) scale(1);
    border-color: var(--accent);
    box-shadow: 2px 4px 16px rgba(0,0,0,0.06);
}
.book-card .book-info { flex: 1; min-width: 0; }
.book-card .book-title {
    font-size: 1em; font-weight: 700; color: var(--text);
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.book-card .book-meta { font-size: 0.76em; color: var(--text-muted); margin-top: 2px; }
.book-card .book-arrow { color: var(--text-muted); font-size: 1.1em; flex-shrink: 0; }

/* 桌面端：网格卡片 */
@media (min-width: 640px) {
    .bookshelf {
        flex-direction: row; flex-wrap: wrap; justify-content: center;
        gap: 20px; max-width: 780px;
    }
    .book-card {
        flex-direction: column; text-align: center;
        width: 170px; padding: 30px 16px 22px; gap: 12px;
    }
    .book-card:hover { transform: translateY(-4px); }
    .book-card .book-arrow { display: none; }
}
@media (min-width: 900px) {
    .book-card { width: 190px; }
}
.empty-state { text-align: center; color: var(--text-secondary); padding: 80px 20px; }
.empty-state .empty-text { font-size: 1.1em; }

@media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); }
    .sidebar.open { transform: translateX(0); }
    .sidebar-overlay.show { display: block; }
    .main-content { margin-left: 0; padding: 25px 16px; padding-top: 65px; }
    .mobile-menu-btn { display: flex; }
    .chapter-title { font-size: 1.5em; }
    .auto-next-bar { font-size: 0.82em; padding: 10px 12px; }
    .back-to-top { bottom: 70px; right: 14px; }
    .shortcut-btn { bottom: 122px; right: 14px; }
    .shortcuts-hint { right: 14px; bottom: 120px; }
    /* 手机没键盘，隐藏快捷键 */
    .shortcut-btn, .shortcuts-hint, .shortcuts-overlay { display: none !important; }
    .home-wrap { padding: 24px 14px; }
    .site-header .site-name { font-size: 1.8em; letter-spacing: 2px; }
    .site-header { margin-bottom: 32px; }
    .bookshelf-search { max-width: 100%; margin-bottom: 24px; }
}

/* ═══════════════════════════════════════
   阅读器布局
   ═══════════════════════════════════════ */
.reader-layout { display: flex; min-height: 100vh; }
.sidebar {
    width: 300px; background: var(--sidebar-bg);
    border-right: 1px solid var(--border);
    display: flex; flex-direction: column;
    position: fixed; top: 0; left: 0; bottom: 0;
    z-index: 201;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background var(--transition-speed);
    overflow: hidden;
}
.sidebar-header {
    padding: 20px 20px 14px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}
.sidebar-header h2 {
    font-size: 1.1em; color: var(--accent); font-weight: 700; margin-bottom: 2px;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.sidebar-header .back-home { font-size: 0.82em; color: var(--text-muted); }
.sidebar-header .back-home:hover { color: var(--accent); }

/* ── 阅读设置面板 ── */
.settings-panel {
    padding: 14px 20px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}
.settings-panel .setting-header {
    font-size: 0.78em; color: var(--text-muted); font-weight: 600;
    text-transform: uppercase; letter-spacing: 1px; margin-bottom: 10px;
    display: flex; align-items: center; justify-content: space-between;
}
.settings-panel .setting-header .theme-toggle-btn {
    background: none; border: 1px solid var(--border); color: var(--text);
    width: 32px; height: 32px; border-radius: 50%; cursor: pointer;
    font-size: 0.95em; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s;
}
.settings-panel .setting-header .theme-toggle-btn:hover {
    background: var(--hover); border-color: var(--accent);
}

.setting-row {
    display: flex; align-items: center; gap: 10px; margin-bottom: 10px;
}
.setting-row:last-child { margin-bottom: 0; }
.setting-row .setting-label {
    font-size: 0.78em; color: var(--text-secondary);
    min-width: 38px; flex-shrink: 0; font-weight: 500;
}
.setting-row .setting-value {
    font-size: 0.76em; color: var(--accent); font-weight: 700;
    min-width: 36px; text-align: right; flex-shrink: 0;
}
.setting-row .slider-wrap {
    flex: 1; display: flex; align-items: center; gap: 4px;
}
.setting-row .slider-end {
    font-size: 0.68em; color: var(--text-muted); flex-shrink: 0;
}

/* 字体选择器 */
.font-selector {
    width: 100%; padding: 6px 10px;
    border: 1px solid var(--border); border-radius: var(--radius-sm);
    background: var(--card-bg); color: var(--text); font-size: 0.84em;
    outline: none; cursor: pointer; transition: border 0.2s;
    margin-bottom: 10px;
    font-family: inherit;
}
.font-selector:focus { border-color: var(--accent); }

/* 页宽按钮组 */
.width-group {
    display: flex; gap: 2px; margin-bottom: 10px;
}
.width-group button {
    flex: 1; padding: 6px 4px; font-size: 0.74em;
    background: var(--btn-bg); border: 1px solid var(--border);
    color: var(--text); cursor: pointer; transition: all 0.2s;
    border-radius: 0; white-space: nowrap;
}
.width-group button:first-child { border-radius: var(--radius-sm) 0 0 var(--radius-sm); }
.width-group button:last-child { border-radius: 0 var(--radius-sm) var(--radius-sm) 0; }
.width-group button.active-width {
    background: var(--accent); color: #fff; border-color: var(--accent);
}
.width-group button:hover:not(.active-width) { background: var(--hover); }

/* ── 搜索 ── */
.search-box {
    padding: 10px 20px; border-bottom: 1px solid var(--border);
    display: flex; gap: 4px; flex-shrink: 0;
}
.search-box input {
    flex: 1; min-width: 0; padding: 8px 12px; border: 1px solid var(--border);
    border-radius: var(--radius-sm); font-size: 0.85em; background: var(--card-bg); color: var(--text);
    outline: none; transition: border 0.2s, box-shadow 0.2s;
}
.search-box input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(139,94,60,0.1); }
.search-box button {
    padding: 8px 14px; background: var(--accent); color: #fff;
    border: none; border-radius: var(--radius-sm); cursor: pointer; font-size: 0.85em;
    white-space: nowrap; transition: opacity 0.2s;
}
.search-box button:hover { opacity: 0.9; }

/* ── 章节列表 ── */
.sidebar-scroll { flex: 1; overflow-y: auto; display: flex; flex-direction: column; }
.chapter-list-wrap { flex: 1; padding: 6px 8px; overflow-y: auto; }

.vol-group { margin-bottom: 2px; }
.vol-header {
    padding: 10px 12px; cursor: pointer; font-weight: 700;
    font-size: 0.88em; color: var(--accent);
    display: flex; align-items: center; gap: 6px;
    border-radius: var(--radius-sm); transition: background 0.15s;
    user-select: none; position: sticky; top: 0;
    background: var(--sidebar-bg); z-index: 1;
}
.vol-header:hover { background: var(--hover); }
.vol-arrow {
    display: inline-block; transition: transform 0.25s;
    font-size: 0.6em; flex-shrink: 0; opacity: 0.7;
}
.vol-group.open .vol-arrow { transform: rotate(90deg); opacity: 1; }
.vol-chapters { display: none; padding-left: 4px; }
.vol-group.open .vol-chapters { display: block; animation: fadeSlideIn 0.25s ease; }
@keyframes fadeSlideIn { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: translateY(0); } }
.vol-chapters a, .no-vol-link {
    display: block; padding: 8px 12px 8px 18px; border-radius: 4px;
    font-size: 0.84em; color: var(--text); transition: background 0.15s, color 0.15s;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
    border-left: 2px solid transparent;
}
.vol-chapters a:hover, .no-vol-link:hover { background: var(--hover); color: var(--accent); }
.vol-chapters a.active, .no-vol-link.active {
    color: var(--accent); font-weight: 700;
    border-left-color: var(--accent); background: var(--hover);
}

.search-results { flex: 1; padding: 10px; overflow-y: auto; display: none; }
.search-results.show { display: block; }
.search-results .result-item { margin-bottom: 10px; }
.search-results .result-title { font-weight: 700; margin-bottom: 4px; color: var(--accent); font-size: 0.9em; }
.search-results .result-line {
    display: block; padding: 4px 8px; border-radius: 4px;
    font-size: 0.8em; color: var(--text); transition: background 0.15s; margin-left: 6px;
}
.search-results .result-line:hover { background: var(--hover); }
.search-results .back-to-toc {
    display: block; padding: 6px; margin-bottom: 10px; font-size: 0.85em;
    color: var(--accent); cursor: pointer;
}

.sidebar-footer {
    padding: 12px 20px; border-top: 1px solid var(--border); flex-shrink: 0;
    font-size: 0.72em; color: var(--text-muted); text-align: center;
}

/* ═══════════════════════════════════════
   正文区
   ═══════════════════════════════════════ */
.main-content {
    margin-left: 300px; flex: 1;
    padding: 40px 60px;
    transition: margin 0.3s, padding 0.25s;
    display: flex; justify-content: center;
    min-height: 100vh;
}
.content-wrapper {
    width: 100%;
    max-width: var(--content-width);
}
.chapter-title {
    font-size: 2em; font-weight: 800; margin-bottom: 8px;
    color: var(--accent); border-left: 5px solid var(--accent); padding-left: 18px;
    letter-spacing: 0.5px;
}
.reading-estimate {
    font-size: 0.78em; color: var(--text-muted); margin-bottom: 22px;
    display: inline-flex; align-items: center; gap: 6px;
    padding: 4px 12px; background: var(--hover);
    border-radius: var(--radius-sm);
}
.reading-estimate kbd {
    font-family: monospace; font-size: 0.85em; padding: 1px 5px;
    background: var(--hover); border-radius: 3px;
}

/* 听书按钮 */
.tts-btn {
    background: var(--hover); border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 3px 10px; border-radius: var(--radius-sm);
    font-size: 0.88em; cursor: pointer;
    transition: background 0.2s, color 0.2s, border-color 0.2s;
    font-family: inherit;
}
.tts-btn:hover { border-color: var(--accent); color: var(--accent); }
.tts-btn.playing { background: var(--accent); color: #fff; border-color: var(--accent); }

/* 听书声音选择 */
.tts-voice-select {
    background: var(--btn-bg); border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 3px 6px; border-radius: var(--radius-sm);
    font-size: 0.8em; cursor: pointer; max-width: 120px;
    font-family: inherit;
}
.tts-voice-select:focus { outline: none; border-color: var(--accent); }

/* 听书高亮句 */
.tts-highlight {
    background: rgba(139,94,60,0.15) !important;
    border-radius: 2px;
    transition: background 0.15s;
}

/* 阅读进度信息 */
.reading-progress-info {
    margin-bottom: 22px; padding: 10px 14px;
    background: var(--hover); border-radius: var(--radius-sm);
    display: flex; align-items: center; gap: 12px;
    flex-wrap: wrap;
}
.progress-info-text {
    font-size: 0.82em; color: var(--text-secondary);
    white-space: nowrap;
}
.progress-info-text strong { color: var(--accent); }
.progress-info-bar {
    flex: 1; min-width: 60px; height: 4px;
    background: var(--slider-track);
    border-radius: 2px; overflow: hidden;
}
.progress-info-fill {
    height: 100%; background: var(--accent);
    border-radius: 2px;
    transition: width 0.6s ease;
}

.chapter-nav {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 18px; gap: 10px;
}
.chapter-nav a, .chapter-nav span.nav-label {
    font-size: 0.9em; padding: 6px 14px; border-radius: var(--radius-sm);
    background: var(--btn-bg); border: 1px solid var(--border); color: var(--text);
    transition: all 0.2s; cursor: pointer;
    display: inline-flex; align-items: center; gap: 4px;
}
.chapter-nav a:hover { background: var(--hover); border-color: var(--accent); color: var(--accent); }
.chapter-nav a.disabled, .chapter-nav span.disabled {
    opacity: 0.25; cursor: default; pointer-events: none;
}

/* 正文：字体大小和行高由 JS 动态设置 */
.chapter-text {
    font-size: 18px;
    line-height: 2.0;
    word-break: break-word;
    text-align: justify;
}
.chapter-text p { text-indent: 2em; margin: 0; }

.chapter-bottom-nav { margin-top: 35px; }

/* 自动下一章 */
.auto-next-bar {
    position: fixed; bottom: 0; left: 0; width: 100%;
    background: var(--accent); color: #fff;
    display: flex; align-items: center; justify-content: center;
    padding: 14px 20px; z-index: 400;
    transform: translateY(100%); transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 0.92em; gap: 12px;
    box-shadow: 0 -3px 15px rgba(0,0,0,0.12);
}
.auto-next-bar.show { transform: translateY(0); }
.auto-next-bar .cancel-btn {
    background: rgba(255,255,255,0.2); border: none; color: #fff;
    padding: 6px 14px; border-radius: 4px; cursor: pointer; font-size: 0.85em; margin-left: 8px;
    transition: background 0.2s;
}
.auto-next-bar .cancel-btn:hover { background: rgba(255,255,255,0.35); }

/* ── 回到顶部 / 快捷键按钮 ── */
.back-to-top, .shortcut-btn {
    position: fixed; width: 44px; height: 44px; border-radius: 50%;
    background: var(--accent); color: #fff; border: none;
    font-size: 1.2em; cursor: pointer; z-index: 300;
    opacity: 0; visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s, transform 0.2s;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 3px 12px rgba(0,0,0,0.15);
}
.back-to-top { bottom: 80px; right: 24px; }
.shortcut-btn { bottom: 132px; right: 24px; }
.back-to-top.show, .shortcut-btn.show { opacity: 1; visibility: visible; }
.back-to-top:hover, .shortcut-btn:hover { transform: scale(1.1); }

/* 浮动阅读进度 */
.float-progress {
    position: fixed; bottom: 20px; right: 24px; z-index: 300;
    background: var(--card-bg); color: var(--text-muted);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 4px 10px;
    font-size: 0.72em;
    opacity: 0; visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    box-shadow: 0 1px 6px rgba(0,0,0,0.06);
    white-space: nowrap;
    cursor: default;
    pointer-events: none;
}
.float-progress.show { opacity: 0.7; visibility: visible; }
.float-progress:hover { opacity: 1; }

/* ── 移动端 ── */
.mobile-menu-btn {
    display: none; position: fixed; top: 15px; left: 15px; z-index: 200;
    background: var(--btn-bg); border: 1px solid var(--border); border-radius: 8px;
    width: 42px; height: 42px; cursor: pointer; box-shadow: var(--btn-shadow); font-size: 1.3em; color: var(--text);
    align-items: center; justify-content: center;
}
.sidebar-overlay {
    display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0;
    background: var(--overlay-bg); z-index: 99;
}

/* ═══════════════════════════════════════
   响应式
   ═══════════════════════════════════════ */
@media (min-width: 1200px) { :root { --content-width: 820px; } }
@media (min-width: 1600px) { :root { --content-width: 900px; } }

@media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); }
    .sidebar.open { transform: translateX(0); }
    .sidebar-overlay.show { display: block; }
    .main-content { margin-left: 0; padding: 25px 16px; padding-top: 65px; }
    .mobile-menu-btn { display: flex; }
    .chapter-title { font-size: 1.5em; }
    .auto-next-bar { font-size: 0.82em; padding: 10px 12px; }
    .back-to-top { bottom: 70px; right: 14px; }
    .shortcut-btn { bottom: 122px; right: 14px; }
    .shortcuts-hint { right: 14px; bottom: 120px; }
    .home-wrap { padding: 24px 14px; }
}

/* ═══════════════════════════════════════
   滚动条美化
   ═══════════════════════════════════════ */
.sidebar-scroll::-webkit-scrollbar,
.chapter-list-wrap::-webkit-scrollbar { width: 5px; }
.sidebar-scroll::-webkit-scrollbar-track,
.chapter-list-wrap::-webkit-scrollbar-track { background: transparent; }
.sidebar-scroll::-webkit-scrollbar-thumb,
.chapter-list-wrap::-webkit-scrollbar-thumb { background: var(--border); border-radius: 10px; }
.sidebar-scroll::-webkit-scrollbar-thumb:hover,
.chapter-list-wrap::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

body::-webkit-scrollbar { width: 8px; }
body::-webkit-scrollbar-track { background: var(--bg); }
body::-webkit-scrollbar-thumb { background: var(--border); border-radius: 10px; }
body::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── 打印样式 ── */
@media print {
    .sidebar, .mobile-menu-btn, .auto-next-bar, .back-to-top,
    .shortcut-btn, .shortcuts-hint, .reading-progress,
    .chapter-nav, .chapter-bottom-nav, .sidebar-overlay { display: none !important; }
    .main-content { margin-left: 0 !important; padding: 0 !important; }
    body { background: #fff; color: #000; }
    .chapter-title { border-left-color: #000; color: #000; }
    .chapter-text { line-height: 1.6; }
}