/* ============================================================
   91SM · 阅读器 reader.html
   - 4 主题：暗紫 / 柔光 / 米白 / 纯黑（data-theme on body）
   - 4 字号 × 3 行距 × 3 字体 × 3 宽度（data-rs / data-rl / data-rf / data-rw）
   ============================================================ */

:root {
  --r-content-w: 720px;
  --r-font-size: 19px;
  --r-line-height: 2.0;
  --r-font-family: "Inter", "Noto Sans SC", system-ui, sans-serif;
  --r-page-pad-x: clamp(16px, 4vw, 80px);
}

/* ===== 主题色 ===== */

body[data-theme="dark"] {
  --r-bg:        #0F0820;
  --r-text:      #E8DFFF;
  --r-text-dim:  #A89BC4;
  --r-text-min:  #6B5B8F;
  --r-ui-bg:     rgba(15, 8, 32, 0.85);
  --r-ui-bg-solid: #1A1130;
  --r-ui-border: rgba(45, 31, 71, 0.85);
  --r-ui-border-hi: rgba(61, 42, 92, 0.95);
  --r-ui-hover:  rgba(255, 46, 126, 0.1);
  --r-accent:    #FF2E7E;
  --r-accent-2:  #C084FC;
  --r-divider:   rgba(192, 132, 252, 0.18);
}

body[data-theme="dim"] {
  --r-bg:        #1A1130;
  --r-text:      #F5F0FF;
  --r-text-dim:  #B0A4CE;
  --r-text-min:  #7C6CA0;
  --r-ui-bg:     rgba(26, 17, 48, 0.88);
  --r-ui-bg-solid: #221742;
  --r-ui-border: rgba(61, 42, 92, 0.85);
  --r-ui-border-hi: rgba(80, 55, 120, 0.95);
  --r-ui-hover:  rgba(255, 46, 126, 0.12);
  --r-accent:    #FF6BA8;
  --r-accent-2:  #DDB6FF;
  --r-divider:   rgba(192, 132, 252, 0.22);
}

body[data-theme="sepia"] {
  --r-bg:        #F5F0E8;
  --r-text:      #2A1F47;
  --r-text-dim:  #6E5F88;
  --r-text-min:  #A89BC4;
  --r-ui-bg:     rgba(245, 240, 232, 0.92);
  --r-ui-bg-solid: #EDE6D8;
  --r-ui-border: rgba(150, 130, 100, 0.32);
  --r-ui-border-hi: rgba(150, 130, 100, 0.55);
  --r-ui-hover:  rgba(192, 38, 211, 0.08);
  --r-accent:    #C2185B;
  --r-accent-2:  #8B3FCB;
  --r-divider:   rgba(107, 33, 168, 0.18);
}

body[data-theme="oled"] {
  --r-bg:        #000000;
  --r-text:      #FFFFFF;
  --r-text-dim:  #A89BC4;
  --r-text-min:  #6B5B8F;
  --r-ui-bg:     rgba(0, 0, 0, 0.9);
  --r-ui-bg-solid: #0A0408;
  --r-ui-border: rgba(45, 31, 71, 0.85);
  --r-ui-border-hi: rgba(61, 42, 92, 0.95);
  --r-ui-hover:  rgba(255, 46, 126, 0.12);
  --r-accent:    #FF2E7E;
  --r-accent-2:  #C084FC;
  --r-divider:   rgba(192, 132, 252, 0.22);
}

/* ===== 字号档 ===== */

body[data-rs="small"]  { --r-font-size: 16px; --r-info-pad: 22px; }

body[data-rs="medium"] { --r-font-size: 19px; --r-info-pad: 28px; }

body[data-rs="large"]  { --r-font-size: 22px; --r-info-pad: 32px; }

body[data-rs="xl"]     { --r-font-size: 25px; --r-info-pad: 36px; }

/* ===== 行距档 ===== */

body[data-rl="tight"]    { --r-line-height: 1.7; }

body[data-rl="standard"] { --r-line-height: 2.0; }

body[data-rl="loose"]    { --r-line-height: 2.4; }

/* ===== 字体档 ===== */

body[data-rf="sans"]  { --r-font-family: "Inter", "Noto Sans SC", system-ui, sans-serif; }

body[data-rf="serif"] { --r-font-family: "Noto Serif SC", "Source Han Serif", Georgia, serif; }

body[data-rf="hei"]   { --r-font-family: "Noto Sans SC", "Source Han Sans", system-ui, sans-serif; }

/* ===== 宽度档 ===== */

body[data-rw="narrow"]   { --r-content-w: 560px; }

body[data-rw="standard"] { --r-content-w: 720px; }

body[data-rw="wide"]     { --r-content-w: 880px; }

/* ===== body 基础 ===== */

body.reader-body {
  background: var(--r-bg);
  color: var(--r-text);
  font-family: var(--r-font-family);
  font-size: var(--r-font-size);
  line-height: var(--r-line-height);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  transition: background-color 0.35s ease, color 0.35s ease;
  font-feature-settings: "ss01", "cv11";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  letter-spacing: 0.015em;
}

/* ===== Reading shell ===== */

.reader-shell {
  max-width: var(--r-content-w);
  margin: 0 auto;
  padding: 28px var(--r-page-pad-x) 48px;
  transition: max-width 0.3s ease, padding 0.3s ease;
}

body.reader-ui-visible .reader-shell {
  padding-top: 88px;
  padding-bottom: 200px;
}

/* 顶部信息条 */

.r-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-m);
  padding-bottom: var(--r-info-pad, 28px);
  margin-bottom: var(--space-l);
  border-bottom: 1px solid var(--r-divider);
  font-size: 12.5px;
  color: var(--r-text-dim);
  transition: opacity 0.35s ease;
}

.r-info.is-dim { opacity: 0.3; }

.r-info-left, .r-info-right {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 11.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--r-text-min);
}

/* h1 化（SEO 需求六：小说标题为 H1）后保持原 span 视觉：归零 UA 的 h1 margin/字号加成 */
.r-info-title {
  color: var(--r-text);
  font-weight: 500;
  font-size: 13.5px;
  letter-spacing: 0.04em;
  margin: 0;
}

/* 正文 */

.r-content p {
  margin: 0 0 1.4em;
  text-indent: 2em;
  color: var(--r-text);
  font-size: var(--r-font-size);
  line-height: var(--r-line-height);
}

.r-content p:first-child::first-letter {
  font-size: 1.4em;
  font-weight: 600;
  color: var(--r-accent-2);
  margin-right: 2px;
}

.r-content .poem {
  display: block;
  text-align: center;
  font-style: normal;
  color: var(--r-text-dim);
  margin: 2em auto;
  padding: 1.2em 0;
  border-top: 1px solid var(--r-divider);
  border-bottom: 1px solid var(--r-divider);
  letter-spacing: 0.1em;
  line-height: 1.9;
  font-size: 0.92em;
  max-width: 80%;
}

/* 章末 */

.r-end {
  margin-top: 64px;
  text-align: center;
}

.r-end-deco {
  display: flex;
  justify-content: center;
  margin-bottom: var(--space-l);
}

.r-end-deco-mark {
  width: 48px;
  height: 1px;
  background: var(--r-divider);
  position: relative;
}

.r-end-deco-mark::before {
  content: '';
  position: absolute;
  top: -3px;
  left: 50%;
  transform: translateX(-50%);
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--r-accent);
  box-shadow: 0 0 12px var(--r-accent);
}

.r-end-text {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 11.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--r-text-min);
  margin: 0 0 var(--space-xl);
}

.r-transitions {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 12px;
  align-items: stretch;
}

.r-trans-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-xs);
  padding: 18px 22px;
  border-radius: 10px;
  background: var(--r-ui-bg-solid);
  border: 1px solid var(--r-ui-border);
  text-decoration: none;
  color: var(--r-text);
  transition: all 0.2s;
}

.r-trans-btn.next { align-items: flex-end; text-align: right; }

.r-trans-btn:hover {
  border-color: var(--r-accent);
  background: var(--r-ui-hover);
}

.r-trans-btn .label {
  font-size: 11.5px;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  letter-spacing: 0.06em;
  color: var(--r-accent);
}

.r-trans-btn .title {
  font-size: 13.5px;
  color: var(--r-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}

.r-trans-toc {
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  background: transparent;
  border: 1px solid var(--r-ui-border);
  color: var(--r-text-dim);
  padding: 0 18px;
  border-radius: 10px;
  font-size: 12.5px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.2s;
  white-space: nowrap;
}

.r-trans-toc:hover {
  border-color: var(--r-accent);
  color: var(--r-text);
}

/* ===== Top toolbar ===== */

.r-toolbar-top {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--r-page-pad-x);
  background: var(--r-ui-bg);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--r-ui-border);
  z-index: 100;
  transform: translateY(-100%);
  transition: transform 0.3s ease;
  gap: 12px;
}

.r-toolbar-top.is-visible { transform: translateY(0); }

.r-tb-left, .r-tb-right {
  display: flex;
  align-items: center;
  gap: var(--space-s);
}

.r-tb-center {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-size: 13px;
  color: var(--r-text-dim);
  overflow: hidden;
  white-space: nowrap;
}

.r-tb-center .book-name {
  color: var(--r-text);
  font-weight: 600;
  max-width: 30vw;
  overflow: hidden;
  text-overflow: ellipsis;
}

.r-tb-center .div { color: var(--r-text-min); }

.r-tb-center .chapter-name {
  color: var(--r-text-dim);
  max-width: 36vw;
  overflow: hidden;
  text-overflow: ellipsis;
}

.r-icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  height: 32px;
  min-width: 32px;
  padding: 0 var(--space-s);
  border-radius: 6px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--r-text-dim);
  cursor: pointer;
  text-decoration: none;
  font-family: inherit;
  font-size: 12px;
  transition: all 0.15s;
}

.r-icon-btn:hover {
  background: var(--r-ui-hover);
  color: var(--r-text);
}

.r-icon-btn.with-label {
  padding: 0 10px 0 var(--space-s);
  border-color: var(--r-ui-border);
}

.r-icon-btn.with-label:hover {
  border-color: var(--r-accent);
}

/* 主题色块切换 */

.r-theme-pick {
  display: flex;
  gap: var(--space-xs);
  padding-left: var(--space-s);
  margin-left: var(--space-xs);
  border-left: 1px solid var(--r-ui-border);
}

.r-theme-swatch {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.15s;
  padding: 0;
}

.r-theme-swatch[data-theme="dark"]  { background: linear-gradient(135deg, #0F0820, #2E1065); }

.r-theme-swatch[data-theme="dim"]   { background: linear-gradient(135deg, #1A1130, #4C1D95); }

.r-theme-swatch[data-theme="sepia"] { background: linear-gradient(135deg, #F5F0E8, #D8C9B0); }

.r-theme-swatch[data-theme="oled"]  { background: #000; border-color: #333; }

.r-theme-swatch:hover { transform: scale(1.1); }

.r-theme-swatch.is-on { border-color: var(--r-accent); box-shadow: 0 0 0 2px var(--r-bg); }

/* Hover zones */

.r-hover-zone {
  position: fixed;
  left: 0;
  right: 0;
  height: 60px;
  z-index: 50;
  pointer-events: auto;
}

.r-hover-zone.top { top: 0; }

.r-hover-zone.bot { bottom: 0; }

/* ===== Bottom toolbar ===== */

.r-toolbar-bot {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  gap: var(--space-m);
  padding: var(--space-m) var(--r-page-pad-x) 22px;
  background: var(--r-ui-bg);
  backdrop-filter: blur(20px);
  border-top: 1px solid var(--r-ui-border);
  z-index: 100;
  transform: translateY(100%);
  transition: transform 0.3s ease;
}

.r-toolbar-bot.is-visible { transform: translateY(0); }

.r-progress-wrap { flex: 1; min-width: 0; }

.r-progress-bar {
  height: 4px;
  background: var(--r-ui-border);
  border-radius: 2px;
  position: relative;
  cursor: pointer;
  overflow: hidden;
}

.r-progress-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--r-accent), var(--r-accent-2));
  border-radius: 2px;
  transition: width 0.15s ease;
}

.r-progress-meta {
  display: flex;
  justify-content: space-between;
  margin-top: 6px;
  font-size: 11.5px;
  color: var(--r-text-dim);
  font-family: "JetBrains Mono", ui-monospace, monospace;
  letter-spacing: 0.04em;
}

.r-progress-meta em {
  font-style: normal;
  color: var(--r-text);
  font-weight: 500;
}

.r-bot-actions {
  display: flex;
  align-items: center;
  gap: var(--space-s);
}

.r-nav-btn {
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  background: transparent;
  border: 1px solid var(--r-ui-border);
  color: var(--r-text-dim);
  padding: 0 12px;
  height: 32px;
  border-radius: 6px;
  font-size: 12.5px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s;
}

.r-nav-btn:hover {
  border-color: var(--r-accent);
  color: var(--r-text);
}

.r-shelf-btn { width: 36px; padding: 0; }

.r-shelf-btn.is-on { color: var(--r-accent); }

.r-shelf-btn.is-on svg { fill: var(--r-accent); }

/* ===== Resume toast ===== */

.r-resume-toast {
  position: fixed;
  top: 76px;
  left: 50%;
  transform: translateX(-50%) translateY(-12px);
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--r-ui-bg-solid);
  border: 1px solid var(--r-accent);
  color: var(--r-text);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  backdrop-filter: blur(12px);
  box-shadow: 0 12px 30px -8px var(--r-accent);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.22s, transform 0.22s;
  z-index: 90;
}

.r-resume-toast.is-shown {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== Toast (通用) ===== */

.r-toast {
  position: fixed;
  bottom: 100px;
  left: 50%;
  transform: translateX(-50%);
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--r-ui-bg-solid);
  border: 1px solid var(--r-accent);
  color: var(--r-text);
  font-size: 13px;
  letter-spacing: 0.02em;
  backdrop-filter: blur(12px);
  box-shadow: 0 12px 30px -8px var(--r-accent);
  z-index: 200;
  opacity: 0;
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: none;
}

.r-toast.is-shown {
  opacity: 1;
  transform: translateX(-50%) translateY(-6px);
}

/* ===== Drawer (TOC + Settings) ===== */

.r-drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(4px);
  z-index: 150;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s;
}

.r-drawer-overlay.is-open {
  opacity: 1;
  pointer-events: auto;
}

.r-drawer, .r-settings {
  position: fixed;
  top: 0;
  bottom: 0;
  width: 380px;
  max-width: 90vw;
  background: var(--r-ui-bg-solid);
  border-left: 1px solid var(--r-ui-border);
  z-index: 200;
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  box-shadow: -20px 0 40px rgba(0, 0, 0, 0.3);
}

.r-drawer {
  right: 0;
}

.r-settings {
  right: 0;
}

.r-drawer.is-open, .r-settings.is-open {
  transform: translateX(0);
}

.r-drawer-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  padding: 22px var(--space-l) 18px;
  border-bottom: 1px solid var(--r-ui-border);
}

.r-drawer-head h3 {
  margin: 0 0 var(--space-xs);
  font-size: 16px;
  font-weight: 600;
  color: var(--r-text);
}

.r-drawer-head .subtitle {
  font-size: 11.5px;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--r-text-min);
}

/* TOC list */

.r-drawer-list {
  flex: 1;
  overflow-y: auto;
  padding: 12px 12px var(--space-l);
}

.r-drawer-item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 12px;
  border-radius: 6px;
  text-decoration: none;
  color: var(--r-text-dim);
  font-size: 13.5px;
  transition: all 0.15s;
  cursor: pointer;
}

.r-drawer-item:hover {
  background: var(--r-ui-hover);
  color: var(--r-text);
}

.r-drawer-item .no {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 10.5px;
  color: var(--r-text-min);
  letter-spacing: 0.06em;
  white-space: nowrap;
  flex: none;
}

.r-drawer-item.is-current {
  background: var(--r-ui-hover);
  color: var(--r-accent);
  font-weight: 500;
}

.r-drawer-item.is-current .no { color: var(--r-accent); }

.r-drawer-item.is-current::before {
  content: '►';
  margin-right: calc(-1 * var(--space-s));
  font-size: 9px;
  color: var(--r-accent);
}

.r-drawer-item.is-read { opacity: 0.6; }

.r-drawer-item.is-read .no { color: var(--r-text-min); }

/* Settings body */

.r-settings-body {
  flex: 1;
  overflow-y: auto;
  padding: 22px var(--space-l) 36px;
  display: flex;
  flex-direction: column;
  gap: var(--space-l);
}

.r-setting-label {
  font-size: 12.5px;
  color: var(--r-text-dim);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: var(--space-s);
}

.r-setting-label .value {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 11px;
  color: var(--r-accent);
  letter-spacing: 0.04em;
}

.r-theme-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-s);
}

.r-theme-row .opt {
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  display: flex;
  align-items: center;
  gap: var(--space-s);
  padding: 10px 12px;
  background: transparent;
  border: 1px solid var(--r-ui-border);
  border-radius: 6px;
  color: var(--r-text-dim);
  font-size: 12.5px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s;
}

.r-theme-row .opt .sw {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 1px solid var(--r-ui-border);
}

.r-theme-row .opt[data-theme="dark"]  .sw { background: linear-gradient(135deg, #0F0820, #2E1065); }

.r-theme-row .opt[data-theme="dim"]   .sw { background: linear-gradient(135deg, #1A1130, #4C1D95); }

.r-theme-row .opt[data-theme="sepia"] .sw { background: linear-gradient(135deg, #F5F0E8, #D8C9B0); }

.r-theme-row .opt[data-theme="oled"]  .sw { background: #000; }

.r-theme-row .opt:hover { border-color: var(--r-accent); color: var(--r-text); }

.r-theme-row .opt.is-on {
  border-color: var(--r-accent);
  background: var(--r-ui-hover);
  color: var(--r-text);
}

.r-seg {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  background: var(--r-ui-bg);
  border: 1px solid var(--r-ui-border);
  border-radius: 6px;
  padding: 3px;
  gap: 2px;
}

.r-seg button {
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  background: transparent;
  border: none;
  color: var(--r-text-dim);
  padding: var(--space-s) 6px;
  border-radius: 4px;
  font-size: 12.5px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s;
}

.r-seg button:hover { color: var(--r-text); }

.r-seg button.is-on {
  background: var(--r-accent);
  color: #fff;
}

.r-select {
  width: 100%;
  -webkit-appearance: none;
     -moz-appearance: none;
          appearance: none;
  background: var(--r-ui-bg);
  border: 1px solid var(--r-ui-border);
  border-radius: 6px;
  color: var(--r-text);
  font-family: inherit;
  font-size: 13px;
  padding: 10px 12px;
  cursor: pointer;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23A89BC4' stroke-width='2'><path d='m6 9 6 6 6-6'/></svg>");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 32px;
}

.r-select:focus { outline: 1px solid var(--r-accent); outline-offset: -1px; }

/* ===== 404 ===== */

/* 全局兜底：hidden 属性必须隐藏元素（reader.html 不加载 themes.css，需在此独立兜底）。
   覆盖 404 视图、工具栏 tb-top/tb-bot、hover 区、reader-shell 等所有 display:flex 元素，
   防止被组件的 display 压过。元素无 hidden 时不受影响，零副作用。 */

[hidden] { display: none !important; }

.r-404 {
  max-width: 720px;
  margin: 0 auto;
  padding: 120px var(--r-page-pad-x) var(--space-xxl);
  text-align: center;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.r-404__icon {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 92px;
  font-weight: 800;
  background: linear-gradient(135deg, var(--r-accent), var(--r-accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  letter-spacing: 0.05em;
  margin-bottom: 14px;
}

.r-404__title {
  font-size: 26px;
  font-weight: 700;
  color: var(--r-text);
  margin: 0 0 var(--space-s);
}

.r-404__sub {
  font-size: 14px;
  color: var(--r-text-dim);
  margin: 0 0 30px;
}

.r-404__action {
  display: inline-flex;
  align-items: center;
  padding: 12px 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--r-accent), var(--r-accent-2));
  color: #fff;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  transition: all 0.2s;
  box-shadow: 0 6px 18px var(--r-accent);
}

.r-404__action:hover { transform: translateY(-1px); }

/* ===== Responsive ===== */

@media (max-width: 768px) {
  .r-toolbar-top {
    height: 50px;
    padding: 0 var(--space-m);
  }
  .r-tb-center { display: none; }
  .r-tb-right .r-theme-pick { display: none; } /* 移动端只在设置抽屉里切换 */
  .reader-shell { padding: 24px var(--r-page-pad-x) 44px; }
  body.reader-ui-visible .reader-shell { padding-top: 70px; padding-bottom: 160px; }

  .r-transitions { grid-template-columns: 1fr; gap: 10px; }
  .r-trans-btn { padding: 14px var(--space-m); }
  .r-trans-btn.next { align-items: flex-start; text-align: left; }

  .r-toolbar-bot { padding: 12px var(--space-m) 18px; flex-direction: column; align-items: stretch; gap: 10px; }
  .r-bot-actions { justify-content: space-between; }
  .r-hover-zone.bot { display: none; pointer-events: none; }

  .r-drawer, .r-settings { width: 100vw; }

  .r-resume-toast { top: 64px; font-size: 11.5px; padding: var(--space-s) 14px; }
}

/* ── 回到顶部（阅读器悬浮按钮）── */
.r-back-to-top {
  position: fixed;
  right: 18px;
  bottom: 76px;
  z-index: 60;
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  border: 1px solid var(--r-ui-border, rgba(255,255,255,.14));
  background: var(--r-ui-bg-solid, rgba(20,16,28,.92));
  color: var(--r-accent, #FF2E7E);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity .25s, transform .25s, visibility .25s;
  -webkit-tap-highlight-color: transparent;
}
.r-back-to-top.is-show { opacity: 1; visibility: visible; transform: translateY(0); }
.r-back-to-top:hover { border-color: var(--r-accent, #FF2E7E); }
@media (max-width: 768px) { .r-back-to-top { right: 12px; bottom: 64px; width: 38px; height: 38px; } }