/**
 * 全课程统一底栏导航（紧凑版）：仅作用于 nav.lesson-pager / nav.lesson-footer-nav
 */
:root {
  --grammar-pager-accent: #0d9488;
  --grammar-pager-accent-ink: #0f766e;
  --grammar-pager-gap: 2.35rem;
  --grammar-pager-logo-slot: clamp(4.25rem, 17vw, 6.5rem);
}

/* 缩小底栏占位，不影响页内其他按钮 */
body.has-lesson-pager {
  --lesson-pager-gap: var(--grammar-pager-gap) !important;
  --lesson-l03-pager-gap: var(--grammar-pager-gap) !important;
  padding-bottom: max(var(--grammar-pager-gap), env(safe-area-inset-bottom, 0px)) !important;
}

body.has-lesson-pager nav.lesson-pager,
body.has-lesson-pager nav.lesson-footer-nav,
body.has-lesson-pager #app nav.lesson-pager {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 200;
  display: grid;
  align-items: center;
  gap: 0.28rem;
  margin: 0;
  padding: 0.18rem 0.35rem;
  padding-bottom: max(0.18rem, env(safe-area-inset-bottom, 0px));
  background: rgba(255, 255, 255, 0.97);
  border-top: 1.5px solid var(--grammar-pager-accent);
  box-shadow: 0 -4px 16px rgba(15, 23, 42, 0.08);
  backdrop-filter: blur(8px);
  font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

/* 三列底栏：左按钮区 | 居中 Logo 槽 | 右按钮区 */
body.has-lesson-pager nav.lesson-pager.is-file-nav,
body.has-lesson-pager #app nav.lesson-pager.is-file-nav {
  grid-template-columns: minmax(0, 1fr) var(--grammar-pager-logo-slot) minmax(0, 1fr);
}

body.has-lesson-pager nav.lesson-pager.is-file-nav > .pager-prev,
body.has-lesson-pager nav.lesson-pager.is-file-nav > span.pager-prev {
  grid-column: 1;
  justify-self: stretch;
}

body.has-lesson-pager nav.lesson-pager.is-file-nav > .pager-logo {
  grid-column: 2;
  justify-self: center;
}

body.has-lesson-pager nav.lesson-pager.is-file-nav > .pager-next,
body.has-lesson-pager nav.lesson-pager.is-file-nav > span.pager-next {
  justify-self: stretch;
}

/* 讲义页顶栏已有「本讲目录」，勿在底栏再注入第四枚按钮 */
body.grammar-handout-page nav.lesson-pager.is-file-nav > .l11-index-link,
body.grammar-handout-page nav.lesson-pager.is-file-nav > .l13-index-link,
body.grammar-handout-page nav.lesson-pager.is-file-nav > .lesson-index-link:not(.pager-logo) {
  display: none !important;
}

body.has-lesson-pager nav.lesson-pager.is-file-nav > .pager-next,
body.has-lesson-pager nav.lesson-pager.is-file-nav > span.pager-next {
  grid-column: 3;
}

/* 课内多屏翻页：左（上一页）| Logo | 右（页码 + 下一页）*/
body.has-lesson-pager nav.lesson-pager.is-intra-nav,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav {
  grid-template-columns: minmax(0, 1fr) var(--grammar-pager-logo-slot) minmax(0, 1fr) !important;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-zone--left,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-zone--left {
  grid-column: 1;
  justify-self: stretch;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-logo,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-logo {
  grid-column: 2;
  justify-self: center;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-zone--right,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-zone--right {
  grid-column: 3;
  justify-self: stretch;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-zone,
body.has-lesson-pager nav.lesson-pager.is-l00-unified > .pager-zone,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-zone {
  display: flex;
  align-items: center;
  gap: 0.28rem;
  min-width: 0;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-zone--left,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-zone--left {
  justify-content: flex-start;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav > .pager-zone--right,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav > .pager-zone--right {
  justify-content: flex-end;
}

/* L00 三区见 assets/l00-unified-pager.css */
body.has-lesson-pager nav.lesson-pager.is-l00-unified > .pager-zone {
  min-width: 0;
}

/* 仅底栏内直接子元素，不波及课件里的 button / a */
body.has-lesson-pager nav.lesson-pager > .pager-prev,
body.has-lesson-pager nav.lesson-pager > .pager-next,
body.has-lesson-pager nav.lesson-pager > .pager-home,
body.has-lesson-pager nav.lesson-pager > .pager-logo,
body.has-lesson-pager nav.lesson-pager > .lesson-index-link,
body.has-lesson-pager nav.lesson-pager > .l13-index-link,
body.has-lesson-pager nav.lesson-pager > button.pager-prev,
body.has-lesson-pager nav.lesson-pager > button.pager-next,
body.has-lesson-pager nav.lesson-pager > .pager-mid,
body.has-lesson-pager nav.lesson-pager > span.pager-prev,
body.has-lesson-pager nav.lesson-pager > span.pager-next,
body.has-lesson-pager nav.lesson-footer-nav > a,
body.has-lesson-pager nav.lesson-footer-nav > span.pager-muted,
body.has-lesson-pager #app nav.lesson-pager > .pager-prev,
body.has-lesson-pager #app nav.lesson-pager > .pager-next,
body.has-lesson-pager #app nav.lesson-pager > .pager-home,
body.has-lesson-pager #app nav.lesson-pager > .pager-logo,
body.has-lesson-pager #app nav.lesson-pager > .lesson-index-link,
body.has-lesson-pager #app nav.lesson-pager > .l13-index-link,
body.has-lesson-pager #app nav.lesson-pager > button.pager-prev,
body.has-lesson-pager #app nav.lesson-pager > button.pager-next,
body.has-lesson-pager #app nav.lesson-pager > .pager-mid,
body.has-lesson-pager #app nav.lesson-pager > span.pager-prev,
body.has-lesson-pager #app nav.lesson-pager > span.pager-next {
  flex: 1 1 0;
  min-width: 0;
  min-height: 28px;
  max-height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  padding: 0.16rem 0.32rem;
  border-radius: 8px;
  border: 1.5px solid #5d4037;
  font-size: clamp(0.7rem, 2vw, 0.78rem);
  font-weight: 800;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
  box-shadow: 0 1px 0 rgba(93, 64, 55, 0.1);
  transition: filter 0.15s ease, transform 0.1s ease;
  font-family: inherit;
  box-sizing: border-box;
}

body.has-lesson-pager nav.lesson-pager > .pager-prev,
body.has-lesson-pager nav.lesson-footer-nav > .pager-prev,
body.has-lesson-pager nav.lesson-pager > span.pager-prev.pager-muted,
body.has-lesson-pager #app nav.lesson-pager > .pager-prev,
body.has-lesson-pager #app nav.lesson-pager > button.pager-prev,
body.has-lesson-pager #app nav.lesson-pager > span.pager-prev.pager-muted {
  color: #334155;
  background: linear-gradient(180deg, #fff, #f8fafc);
}

body.has-lesson-pager nav.lesson-pager > .pager-home,
body.has-lesson-pager nav.lesson-pager > .lesson-index-link,
body.has-lesson-pager nav.lesson-pager > .l13-index-link,
body.has-lesson-pager #app nav.lesson-pager > .pager-home,
body.has-lesson-pager #app nav.lesson-pager > .lesson-index-link,
body.has-lesson-pager #app nav.lesson-pager > .l13-index-link {
  flex: 0.8 1 0;
  color: var(--grammar-pager-accent-ink) !important;
  background: linear-gradient(180deg, #f0fdfa, #ccfbf1) !important;
  border-color: var(--grammar-pager-accent) !important;
  box-shadow: 0 1px 0 rgba(13, 148, 136, 0.18) !important;
}

body.has-lesson-pager nav.lesson-pager > .pager-next,
body.has-lesson-pager nav.lesson-footer-nav > .pager-next,
body.has-lesson-pager nav.lesson-pager > span.pager-next.pager-muted,
body.has-lesson-pager #app nav.lesson-pager > .pager-next,
body.has-lesson-pager #app nav.lesson-pager > button.pager-next,
body.has-lesson-pager #app nav.lesson-pager > span.pager-next.pager-muted {
  color: #fff !important;
  background: linear-gradient(135deg, #14b8a6, var(--grammar-pager-accent-ink)) !important;
  border-color: var(--grammar-pager-accent-ink) !important;
  box-shadow: 0 2px 0 rgba(15, 118, 110, 0.28) !important;
}

body.has-lesson-pager nav.lesson-pager > .pager-mid,
body.has-lesson-pager #app nav.lesson-pager > .pager-mid {
  flex: none;
  width: auto;
  min-width: 2.8rem;
  min-height: 28px;
  max-height: 32px;
  padding: 0.16rem 0.3rem;
  border-radius: 8px;
  border: 1.5px solid var(--grammar-pager-accent);
  background: linear-gradient(180deg, #fff, #f0fdfa);
  color: var(--grammar-pager-accent-ink);
  font-weight: 900;
  font-size: clamp(0.68rem, 1.9vw, 0.76rem);
  font-variant-numeric: tabular-nums;
  cursor: default;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.9);
}

body.has-lesson-pager nav.lesson-pager > .pager-muted,
body.has-lesson-pager nav.lesson-footer-nav > .pager-muted,
body.has-lesson-pager nav.lesson-pager > span.pager-muted,
body.has-lesson-pager #app nav.lesson-pager > span.pager-muted {
  opacity: 0.42;
  cursor: not-allowed;
  box-shadow: none;
  pointer-events: none;
}

body.has-lesson-pager nav.lesson-pager > button:disabled,
body.has-lesson-pager #app nav.lesson-pager > button:disabled {
  opacity: 0.42;
  cursor: not-allowed;
  box-shadow: none;
}

body.has-lesson-pager nav.lesson-pager > a:hover,
body.has-lesson-pager nav.lesson-pager > button:hover:not(:disabled),
body.has-lesson-pager #app nav.lesson-pager > a:hover,
body.has-lesson-pager #app nav.lesson-pager > button:hover:not(:disabled) {
  filter: brightness(1.04);
}

body.has-lesson-pager nav.lesson-pager > a:active,
body.has-lesson-pager nav.lesson-pager > button:active:not(:disabled),
body.has-lesson-pager #app nav.lesson-pager > a:active,
body.has-lesson-pager #app nav.lesson-pager > button:active:not(:disabled) {
  transform: translateY(1px);
}

body.has-lesson-pager nav.lesson-pager .nav-sep {
  display: none !important;
}

body.has-lesson-pager nav.lesson-pager.is-file-nav > .pager-mid {
  display: none !important;
}

/* 分区内按钮：继承与直接子元素相同的基础样式 */
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-prev,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-next,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > button.pager-prev,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > button.pager-next,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-mid,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-prev,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-next,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > button.pager-prev,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > button.pager-next,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-mid {
  flex: 1 1 0;
  min-width: 0;
  min-height: 28px;
  max-height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  padding: 0.16rem 0.32rem;
  border-radius: 8px;
  border: 1.5px solid #5d4037;
  font-size: clamp(0.7rem, 2vw, 0.78rem);
  font-weight: 800;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
  box-sizing: border-box;
  font-family: inherit;
  box-shadow: 0 1px 0 rgba(93, 64, 55, 0.1);
  transition: filter 0.15s ease, transform 0.1s ease;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-prev,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > button.pager-prev,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-prev,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > button.pager-prev {
  color: #334155;
  background: linear-gradient(180deg, #fff, #f8fafc);
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-next,
body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > button.pager-next,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-next,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > button.pager-next {
  color: #fff !important;
  background: linear-gradient(135deg, #14b8a6, var(--grammar-pager-accent-ink)) !important;
  border-color: var(--grammar-pager-accent-ink) !important;
  box-shadow: 0 2px 0 rgba(15, 118, 110, 0.28) !important;
}

body.has-lesson-pager nav.lesson-pager.is-intra-nav .pager-zone > .pager-mid,
body.has-lesson-pager #app nav.lesson-pager.is-intra-nav .pager-zone > .pager-mid {
  flex: 0 0 auto;
  min-width: 2.8rem;
  max-width: 42%;
  padding: 0.16rem 0.3rem;
  border-color: var(--grammar-pager-accent);
  background: linear-gradient(180deg, #fff, #f0fdfa);
  color: var(--grammar-pager-accent-ink);
  font-weight: 900;
  font-size: clamp(0.68rem, 1.9vw, 0.76rem);
  font-variant-numeric: tabular-nums;
  cursor: default;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.9);
}

@media (min-width: 640px) {
  body.has-lesson-pager nav.lesson-pager,
  body.has-lesson-pager nav.lesson-footer-nav,
  body.has-lesson-pager #app nav.lesson-pager {
    gap: 0.26rem;
    padding: 0.22rem 0.42rem;
    padding-bottom: max(0.22rem, env(safe-area-inset-bottom, 0px));
  }

  body.has-lesson-pager nav.lesson-pager > .pager-prev,
  body.has-lesson-pager nav.lesson-pager > .pager-next,
  body.has-lesson-pager nav.lesson-pager > .pager-home,
  body.has-lesson-pager nav.lesson-pager > button.pager-prev,
  body.has-lesson-pager nav.lesson-pager > button.pager-next,
  body.has-lesson-pager nav.lesson-pager > .pager-mid,
  body.has-lesson-pager #app nav.lesson-pager > .pager-prev,
  body.has-lesson-pager #app nav.lesson-pager > .pager-next,
  body.has-lesson-pager #app nav.lesson-pager > .pager-home,
  body.has-lesson-pager #app nav.lesson-pager > button.pager-prev,
  body.has-lesson-pager #app nav.lesson-pager > button.pager-next,
  body.has-lesson-pager #app nav.lesson-pager > .pager-mid {
    min-height: 30px;
    max-height: 34px;
  }
}