/* 精听库共享样式 —— library 与 video 两页共用 */
:root {
  --bg: #f5f4f0;
  --surface: #ffffff;
  --fg: #23282a;
  --muted: #68727a;
  --accent: #3d6b50;
  --accent-soft: #e2ede5;
  --line: #e1dfd6;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #14181a;
    --surface: #1b2123;
    --fg: #e7e5dd;
    --muted: #939ea2;
    --accent: #83ba97;
    --accent-soft: #233129;
    --line: #2b3336;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #14181a;
  --surface: #1b2123;
  --fg: #e7e5dd;
  --muted: #939ea2;
  --accent: #83ba97;
  --accent-soft: #233129;
  --line: #2b3336;
  color-scheme: dark;
}

/* Layout: single 700px reading column; shared tokens above, cards for repeated elements */
body {
  background: var(--bg);
  color: var(--fg);
  font-family: "Source Sans 3", -apple-system, "PingFang SC", "Segoe UI", sans-serif;
  font-size: 15.5px;
  line-height: 1.65;
  margin: 0;
  padding-block: 24px 64px;
  padding-inline: 20px;
}
.wrap { max-width: 700px; margin: 0 auto; }

h1, h2 { font-family: "Fraunces", Georgia, "Songti SC", serif; }
h1 {
  font-size: 30px;
  font-weight: 600;
  line-height: 1.2;
  margin: 0 0 6px;
  text-wrap: balance;
}
.eyebrow {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 10px;
}
.meta { color: var(--muted); font-size: 14px; margin: 0 0 18px; }
.meta a { color: var(--accent); }
.back {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 12.5px;
  color: var(--accent);
  text-decoration: none;
  display: inline-block;
  margin-bottom: 14px;
}
.back:hover { text-decoration: underline; }

.steps {
  background: var(--accent-soft);
  border-radius: 10px;
  padding: 14px 18px;
  margin: 0 0 28px;
  font-size: 14px;
}
.steps strong { font-weight: 600; }
.steps ol { margin: 6px 0 0; padding-left: 20px; }
.steps li { margin: 2px 0; }

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin: 0 0 16px;
}
.progress {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

button {
  font: inherit;
  font-size: 13.5px;
  color: var(--accent);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 6px 14px;
  cursor: pointer;
}
button:hover { border-color: var(--accent); }
button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* --- library: 全文搜索框 + 命中片段 --- */
.search {
  width: 100%;
  box-sizing: border-box;
  font: inherit;
  font-size: 14.5px;
  color: var(--fg);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 9px 14px;
  margin: 0 0 16px;
}
.search::placeholder { color: var(--muted); }
.search:focus { outline: none; border-color: var(--accent); }
mark {
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 3px;
  padding: 0 1px;
}
.sclip {
  display: block;
  margin-top: 8px;
  padding: 8px 12px;
  background: var(--bg);
  border-radius: 8px;
  text-decoration: none;
  color: inherit;
  font-size: 13.5px;
  line-height: 1.6;
}
.sclip:hover { background: var(--accent-soft); }
.sclip .tc { display: block; margin-bottom: 2px; }

/* --- library: category tabs + video cards --- */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 20px; }
.tab {
  font-size: 13.5px;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 14px;
  cursor: pointer;
}
.tab.active { color: var(--accent); border-color: var(--accent); background: var(--accent-soft); }
.tab:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* --- video page: single-clip navigation bar --- */
.clipnav {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin: 0 0 16px;
  padding: 10px 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
}
.clipdots { display: flex; flex-wrap: wrap; gap: 6px; }
.clipdots .tab {
  padding: 3px 10px;
  min-width: 30px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}
.tab.dot-done { border-color: var(--accent); color: var(--accent); }
.clipnav button:disabled { opacity: .45; cursor: not-allowed; }
.clipnav button:disabled:hover { border-color: var(--line); }

.videos { display: flex; flex-direction: column; gap: 14px; }
.vcard {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  display: block;
  text-decoration: none;
  color: inherit;
}
.vcard:hover { border-color: var(--accent); }
.vcard-top { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.vcard-title { font-family: "Fraunces", Georgia, serif; font-size: 19px; font-weight: 600; }
.vcard-title:hover { color: var(--accent); }
.chip {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 2px 10px;
  margin-left: auto;
}
.vcard-sub { color: var(--muted); font-size: 13.5px; margin-top: 4px; font-variant-numeric: tabular-nums; }
.empty { color: var(--muted); padding: 24px 0; }

/* --- CEFR 难度徽章(A/A2/B/B2/C = 雅思 5/6/7/8/9) --- */
.lvl {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11px;
  letter-spacing: 0.08em;
  border-radius: 999px;
  padding: 2px 10px;
  white-space: nowrap;
}
.lvl-A  { color: #2e7d4f; background: #e2f0e6; border: 1px solid #bcdcc6; }
.lvl-A2 { color: #1f6f6f; background: #dff0ef; border: 1px solid #b8dcd9; }
.lvl-B  { color: #8a6d1f; background: #f4ecd7; border: 1px solid #e0d0a2; }
.lvl-B2 { color: #a05621; background: #f7e8dc; border: 1px solid #e5c8ac; }
.lvl-C  { color: #b04a42; background: #f8e3e1; border: 1px solid #e6bfba; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .lvl-A  { color: #93d1a8; background: #1d2f24; border-color: #2c4636; }
  :root:not([data-theme="light"]) .lvl-A2 { color: #8cccc9; background: #17302e; border-color: #274a47; }
  :root:not([data-theme="light"]) .lvl-B  { color: #d4bc7e; background: #332c18; border-color: #4d4224; }
  :root:not([data-theme="light"]) .lvl-B2 { color: #e0a475; background: #38271a; border-color: #553b26; }
  :root:not([data-theme="light"]) .lvl-C  { color: #e3938b; background: #3a211e; border-color: #5a322e; }
}
:root[data-theme="dark"] .lvl-A  { color: #93d1a8; background: #1d2f24; border-color: #2c4636; }
:root[data-theme="dark"] .lvl-A2 { color: #8cccc9; background: #17302e; border-color: #274a47; }
:root[data-theme="dark"] .lvl-B  { color: #d4bc7e; background: #332c18; border-color: #4d4224; }
:root[data-theme="dark"] .lvl-B2 { color: #e0a475; background: #38271a; border-color: #553b26; }
:root[data-theme="dark"] .lvl-C  { color: #e3938b; background: #3a211e; border-color: #5a322e; }
/* 练习页 meta 行里的徽章与链接对齐 */
.lvl-badge { margin-right: 10px; }

/* --- video page: clip cards --- */
.clips { display: flex; flex-direction: column; gap: 14px; }
.clip {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px 18px;
}
.clip-head { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.clip-no { font-family: "Fraunces", Georgia, serif; font-size: 19px; font-weight: 600; }
.tc {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.play {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.play:hover { border-bottom-color: var(--accent); }
.done-label {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
  cursor: pointer;
}
.done-label input { accent-color: var(--accent); width: 15px; height: 15px; }

/* 片段进度条 —— 可拖动,但只在片段内 seek(不能跨片段) */
.pbar {
  position: relative;
  height: 16px; /* 含上下留白的点击/拖动热区 */
  margin: 8px 0 0;
  cursor: pointer;
  touch-action: none; /* 拖动进度条时不触发页面滚动 */
}
.pbar::before { /* 轨道 */
  content: "";
  position: absolute;
  left: 0; right: 0; top: 6px;
  height: 4px;
  border-radius: 2px;
  background: var(--line);
}
.pbar-fill {
  position: absolute;
  left: 0; top: 6px;
  height: 4px;
  width: 0%;
  border-radius: 2px;
  background: var(--accent);
  pointer-events: none;
}
.pbar-fill::after { /* 拖点手柄(YouTube 式) */
  content: "";
  position: absolute;
  right: -4px; top: 50%;
  transform: translateY(-50%);
  width: 9px; height: 9px;
  border-radius: 50%;
  background: var(--accent);
}
.pbar-buffer { /* 已缓冲部分,画在已播放色之下 */
  position: absolute;
  left: 0; top: 6px;
  height: 4px;
  width: 0%;
  border-radius: 2px;
  background: var(--accent);
  opacity: 0.22;
  pointer-events: none;
}
.pbar-tip { /* 拖动时的 MM:SS 气泡 */
  position: absolute;
  bottom: 16px;
  transform: translateX(-50%);
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11px;
  background: var(--fg);
  color: var(--bg);
  padding: 2px 7px;
  border-radius: 6px;
  white-space: nowrap;
  pointer-events: none;
  z-index: 2;
}
.pbar:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }
.gist { font-size: 14.5px; margin: 8px 0 10px; }
.gist .tag {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--accent);
  text-transform: uppercase;
  margin-right: 8px;
}
.actions { display: flex; gap: 8px; margin: 0 0 12px; flex-wrap: wrap; }
.transcript { font-size: 15.5px; line-height: 1.75; margin: 0 0 14px; }
.vocab { border-top: 1px dashed var(--line); padding-top: 12px; font-size: 13.5px; margin: 0; }
.vocab dt { font-weight: 600; display: inline; }
.vocab dd { display: inline; margin: 0 18px 4px 0; color: var(--muted); }
.vocab dd::before { content: "— "; }

.foot { color: var(--muted); font-size: 13px; margin-top: 28px; }
[hidden] { display: none !important; }

/* 理解题 */
.quiz { margin: 12px 0 0; }
.quiz[hidden] { display: none; }
.quiz-head {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 8px;
}
.quiz-q { margin: 0 0 14px; }
.quiz-question { margin: 0 0 6px; font-weight: 600; }
.quiz-opts { display: flex; flex-direction: column; gap: 6px; }
.quiz-opt {
  text-align: left;
  font: inherit;
  font-size: 14.5px;
  line-height: 1.5;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--fg);
  cursor: pointer;
}
.quiz-opt:hover { border-color: var(--accent); }
.quiz-q.answered .quiz-opt { cursor: default; opacity: .75; }
.quiz-opt.correct {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--fg);
  font-weight: 600;
}
.quiz-opt.wrong {
  border-color: #c2554e;
  color: #c2554e;
  text-decoration: line-through;
}
.quiz-why {
  margin: 8px 0 0;
  font-size: 13.5px;
  color: var(--muted);
  background: var(--surface);
  border-left: 3px solid var(--accent);
  padding: 6px 10px;
  border-radius: 0 6px 6px 0;
}
.quiz-redo {
  margin-top: 6px;
  font: inherit;
  font-size: 12.5px;
  color: var(--muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  text-decoration: underline;
}

/* 页内音频播放条 */
#playerBar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 50;
  background: var(--surface);
  border-top: 1px solid var(--line);
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
}
.pb-inner {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 20px;
}
.pb-player iframe { display: block; border: 0; border-radius: 8px; }
.pb-meta { flex: 1; min-width: 0; font-size: 13px; color: var(--muted); }
#pbClose {
  font-size: 18px;
  line-height: 1;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: none;
  color: var(--muted);
  cursor: pointer;
}
#pbClose:hover { color: var(--fg); border-color: var(--accent); }
body.has-bar { padding-bottom: 150px; }
.play {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
  color: var(--accent);
  background: none;
  border: none;
  border-bottom: 1px solid transparent;
  cursor: pointer;
  padding: 0;
}
.play:hover { border-bottom-color: var(--accent); }
.play.playing { font-weight: 600; }
.yt-link {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 11.5px;
  color: var(--muted);
  text-decoration: none;
}
.yt-link:hover { color: var(--fg); }