/* ==== reader.css ==== */
/* 阅读器深色外框：仅装饰工具栏，不覆盖原课件背景或统一缩放图片。 */
.far-top, .far-bot, .far-help, .far-tts, .far-hot {
  box-sizing: border-box;
  position: fixed;
  z-index: 2147483000;
  color: #edf2fa;
  background: rgba(17, 25, 40, .98);
  font: 13px/1.4 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}
.far-top *, .far-bot *, .far-help *, .far-tts *, .far-hot * { box-sizing: border-box; }
.far-top, .far-bot {
  left: 0; right: 0;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  transition: transform .2s ease, opacity .2s ease;
}
.far-top {
  top: 0;
  display: grid;
  grid-template-columns: minmax(144px, 1fr) minmax(0, 3fr) minmax(144px, 1fr);
  align-items: center;
  gap: 12px;
  padding: calc(10px + env(safe-area-inset-top, 0px)) max(16px, env(safe-area-inset-right, 0px)) 10px max(16px, env(safe-area-inset-left, 0px));
  border-bottom: 1px solid #303b4e;
  box-shadow: 0 3px 18px rgba(0, 0, 0, .12);
}
.far-top.is-hidden, .far-bot.is-hidden { visibility: hidden; pointer-events: none; opacity: 0; }
.far-top.is-hidden { transform: translateY(-100%); }
.far-bot.is-hidden { transform: translateY(100%); }
.far-top .far-backbtn { justify-self: start; max-width: 100%; }
.far-backbtn span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.far-mtitle {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  text-align: center;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
}
.far-topright { display: flex; justify-content: flex-end; gap: 4px; }

/* 共用触屏按钮：保持至少 44px，原课件的 button 样式不应影响外框。 */
.far-top button, .far-bot button, .far-tts button, button.far-hot {
  appearance: none;
  position: static;
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-width: 44px;
  min-height: 44px;
  width: auto;
  height: auto;
  margin: 0;
  padding: 8px 10px;
  border: 1px solid transparent;
  border-radius: 10px;
  background: transparent;
  color: #c5cfde;
  font: inherit;
  line-height: 1.4;
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
  transition: background-color .16s, color .16s;
}
.far-top button:hover, .far-bot button:hover, .far-tts button:hover, button.far-hot:hover {
  background: #2c3950; color: #fff;
}
.far-top button:focus-visible, .far-bot button:focus-visible, .far-tts button:focus-visible, button.far-hot:focus-visible {
  outline: 2px solid #a7c7ff;
  outline-offset: 2px;
}
.far-top button:disabled, .far-bot button:disabled { opacity: .4; cursor: default; }
.far-top svg, .far-bot svg, .far-tts svg, .far-hot svg {
  width: 20px; height: 20px; flex: 0 0 auto;
  fill: none; stroke: currentColor; stroke-width: 1.8;
  stroke-linecap: round; stroke-linejoin: round;
}

/* 仅阅读控制和进度；字号不再藏进移动端不可见的附加区。 */
.far-bot {
  bottom: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 540px) minmax(164px, 1fr);
  align-items: center;
  gap: 24px;
  padding: 10px max(16px, env(safe-area-inset-right, 0px)) calc(10px + env(safe-area-inset-bottom, 0px)) max(16px, env(safe-area-inset-left, 0px));
  border-top: 1px solid #303b4e;
  box-shadow: 0 -3px 18px rgba(0, 0, 0, .12);
}
.far-ctrl { grid-column: 2; display: flex; flex-direction: column; align-items: center; gap: 10px; min-width: 0; }
.far-transport { display: flex; align-items: center; justify-content: center; gap: 8px; }
.far-bot .far-main {
  min-width: 116px;
  padding-inline: 14px;
  background: #e6efff;
  color: #15233b;
  font-weight: 600;
  white-space: nowrap;
}
.far-bot .far-main:hover { background: #fff; color: #15233b; }
.far-bot .far-main.is-on { background: #a9c9ff; color: #15233b; }
.far-progress { display: flex; align-items: center; gap: 8px; width: 100%; min-width: 0; font-size: 11px; color: #b1bed1; }
.far-progress > span:first-child, .far-progress em { flex: 0 0 auto; white-space: nowrap; }
.far-progress em { font-style: normal; font-variant-numeric: tabular-nums; }
.far-progress [data-pct] { min-width: 30px; text-align: right; }
.far-track { flex: 1; min-width: 16px; height: 5px; border-radius: 5px; background: #39465b; overflow: hidden; }
.far-track i { display: block; height: 100%; width: 0; background: #a0bfff; border-radius: inherit; transition: width .18s linear; }
.far-fs { grid-column: 3; justify-self: start; display: flex; align-items: center; gap: 0; color: #b1bed1; }
.far-fs > span { margin-right: 8px; font-size: 11px; white-space: nowrap; }
.far-fs b { min-width: 40px; text-align: center; font-size: 11px; font-weight: 500; font-variant-numeric: tabular-nums; }
.far-fs button { background: #202d42; }

/* 隐藏后保留可点击、可聚焦的恢复按钮，不留不可见的全宽遮挡区。 */
button.far-hot {
  position: fixed;
  top: calc(8px + env(safe-area-inset-top, 0px));
  right: max(12px, env(safe-area-inset-right, 0px));
  background: #111928;
  border-color: #465775;
  box-shadow: 0 4px 16px rgba(0, 0, 0, .2);
}
.far-hot[hidden], .far-help[hidden], .far-tts[hidden] { display: none; }

/* 桌面翻页热区，dr3 启动页和 iframe 外壳不挂载。 */
.far-tap { position: fixed; top: var(--far-top-height, 0px); bottom: var(--far-bottom-height, 0px); width: 12%; z-index: 2147482900; cursor: pointer; background: transparent; }
.far-tap--l { left: 0; }
.far-tap--r { right: 0; }
.far-tap::after {
  content: ""; position: absolute; top: 50%; transform: translateY(-50%);
  width: 44px; height: 44px; border-radius: 50%;
  background-color: rgba(17, 26, 43, .55); opacity: 0; transition: opacity .2s;
  background-repeat: no-repeat; background-position: center;
}
.far-tap--l::after { left: 12px; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='18' height='18' viewBox='0 0 24 24' fill='none' stroke='%23fff' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M15 18l-6-6 6-6'/%3E%3C/svg%3E"); }
.far-tap--r::after { right: 12px; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='18' height='18' viewBox='0 0 24 24' fill='none' stroke='%23fff' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M9 18l6-6-6-6'/%3E%3C/svg%3E"); }
.far-tap:hover::after { opacity: 1; }
@media (hover: none), (pointer: coarse) { .far-tap { display: none; } }

.far-help {
  right: max(12px, env(safe-area-inset-right, 0px));
  top: calc(var(--far-top-height, 0px) + 10px + env(safe-area-inset-top, 0px));
  z-index: 2147483002;
  width: min(300px, calc(100vw - 24px - env(safe-area-inset-left, 0px) - env(safe-area-inset-right, 0px)));
  max-height: calc(var(--far-viewport-height, 100vh) - var(--far-top-height, 0px) - var(--far-bottom-height, 0px) - 24px - env(safe-area-inset-top, 0px));
  overflow: auto;
  padding: 14px 16px;
  border: 1px solid #465775;
  border-radius: 14px;
  box-shadow: 0 12px 36px rgba(0, 0, 0, .25);
}
.far-help h5 { margin: 0 0 10px; font: inherit; font-weight: 600; color: #fff; }
.far-help div { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 5px 0; font-size: 12px; }
.far-help div > span:last-child { white-space: nowrap; }
.far-help kbd { display: inline-block; min-width: 22px; padding: 2px 6px; text-align: center; background: #2c3950; border: 1px solid #465775; border-radius: 5px; font: 11px/1.4 ui-monospace, Menlo, Consolas, monospace; }

.far-tts {
  left: 50%; bottom: calc(var(--far-bottom-height, 0px) + 10px + env(safe-area-inset-bottom, 0px));
  transform: translateX(-50%); z-index: 2147483002;
  display: flex; align-items: center; gap: 10px;
  max-width: calc(100vw - 24px - env(safe-area-inset-left, 0px) - env(safe-area-inset-right, 0px));
  width: max-content;
  padding: 4px 6px 4px 16px;
  border: 1px solid #465775; border-radius: 16px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, .25);
}
.far-tts [data-tts-msg] { min-width: 0; }
.far-tts button { background: #2c3950; }
.far-wave { display: inline-flex; flex: 0 0 auto; gap: 2px; align-items: flex-end; height: 14px; }
.far-wave i { width: 2px; background: #a0bfff; border-radius: 2px; animation: far-wave 1s ease-in-out infinite; }
.far-wave i:nth-child(1) { height: 6px; }
.far-wave i:nth-child(2) { height: 12px; animation-delay: .15s; }
.far-wave i:nth-child(3) { height: 8px; animation-delay: .3s; }
.far-wave i:nth-child(4) { height: 14px; animation-delay: .45s; }
@keyframes far-wave { 0%, 100% { transform: scaleY(.5); } 50% { transform: scaleY(1); } }

/* 字号只作用于外层文档字体，不再用根节点 zoom 连图片和交互坐标一起缩放。 */
html.far-zoomed { font-size: calc(var(--far-root-font, 16px) * var(--far-zoom, 1)); }
html.far-zoomed > body { font-size: calc(var(--far-body-font, 16px) * var(--far-zoom, 1)); }
/* CSS 变量由 ResizeObserver 实测更新；取消 far-pad 即恢复原文档内边距。 */
html.far-pad { scroll-padding-top: var(--far-top-height, 0px); scroll-padding-bottom: var(--far-bottom-height, 0px); }
html.far-pad > body {
  padding-top: calc(var(--far-body-top, 0px) + var(--far-top-height, 0px)) !important;
  padding-bottom: calc(var(--far-body-bottom, 0px) + var(--far-bottom-height, 0px)) !important;
}

@media (max-width: 900px) {
  .far-bot { grid-template-columns: minmax(0, 1fr) auto; gap: 16px; }
  .far-ctrl { grid-column: 1; }
  .far-fs { grid-column: 2; }
}
@media (max-width: 640px) {
  .far-top { grid-template-columns: auto minmax(0, 1fr) auto; gap: 6px; padding: calc(6px + env(safe-area-inset-top, 0px)) max(8px, env(safe-area-inset-right, 0px)) 6px max(8px, env(safe-area-inset-left, 0px)); }
  .far-backbtn span { display: none; }
  .far-topright { gap: 0; }
  .far-mtitle { font-size: 14px; }
  .far-bot { gap: 8px 12px; padding-inline: max(12px, env(safe-area-inset-left, 0px)) max(12px, env(safe-area-inset-right, 0px)); }
  .far-ctrl { display: contents; }
  .far-transport { grid-column: 1; grid-row: 1; gap: 4px; }
  .far-fs { grid-column: 2; grid-row: 1; justify-self: end; }
  .far-fs > span { display: none; }
  .far-progress { grid-column: 1 / -1; grid-row: 2; }
}
@media (max-width: 400px) {
  .far-bot { grid-template-columns: minmax(0, 1fr); }
  .far-transport { grid-column: 1; }
  .far-fs { grid-column: 1; grid-row: 3; justify-self: center; }
  .far-fs > span { display: inline; }
  .far-progress { gap: 6px; }
}
@media (prefers-reduced-motion: reduce) {
  .far-top, .far-bot, .far-top button, .far-bot button, .far-tts button, button.far-hot, .far-track i, .far-tap::after { transition: none; }
  .far-wave i { animation: none; }
}
@media print {
  .far-top, .far-bot, .far-hot, .far-tap, .far-help, .far-tts { display: none !important; }
  html.far-pad > body { padding-top: var(--far-body-top, 0px) !important; padding-bottom: var(--far-body-bottom, 0px) !important; }
}