/* 道德經閱讀器：紙墨兩色，原文與白話等寬並列。 */
:root {
  --paper: #faf7f1;
  --paper-2: #f2ece1;
  --ink: #23201c;
  --ink-2: #6b6357;
  --rule: #ddd4c5;
  --accent: #8c3b2e;
  --accent-soft: #f0e2dd;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #1b1916;
    --paper-2: #24211d;
    --ink: #e8e2d7;
    --ink-2: #9c9385;
    --rule: #38332c;
    --accent: #d08a6e;
    --accent-soft: #3a2b25;
  }
}

* { box-sizing: border-box; }
/* 這是拿來讀的站，底字放大到 18px；版面全用 rem，動這一行就整體跟著長。 */
html { font-size: 112.5%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Noto Serif TC", "Songti TC", serif;
  line-height: 1.8;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.masthead {
  position: relative;
  padding: 2.4rem 1.5rem 1.6rem;
  text-align: center;
  border-bottom: 1px solid var(--rule);
}
.head-toggle {
  position: absolute;
  top: .7rem;
  right: .9rem;
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink-2);
  font-family: inherit;
  font-size: .72rem;
  letter-spacing: .05em;
  padding: .15rem .55rem;
  border-radius: 2px;
  cursor: pointer;
}
.head-toggle:hover { border-color: var(--accent); color: var(--accent); }

/* 收起標題：整個 masthead 縮成一條細列，小字書名與切換鈕同列 */
body.compact .masthead {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.4rem;
  padding: .55rem 3.5rem .55rem 1.5rem;
}
body.compact .masthead h1 { font-size: 1.2rem; letter-spacing: .25em; text-indent: .25em; }
body.compact .masthead .sub { display: none; }
body.compact .masthead .modebar { margin: 0; }
body.compact .head-toggle { top: 50%; transform: translateY(-50%); }
.masthead h1 { margin: 0; font-size: 2.6rem; letter-spacing: .35em; text-indent: .35em; }
.masthead h1 a { color: inherit; }
.masthead .sub { margin: .6rem 0 0; color: var(--ink-2); font-size: .9rem; letter-spacing: .1em; }

.modebar { margin: 1rem 0 0; }
.mode-toggle {
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink-2);
  font-family: inherit;
  font-size: .82rem;
  letter-spacing: .08em;
  padding: .3rem 1rem;
  border-radius: 2px;
  cursor: pointer;
}
.mode-toggle:hover { border-color: var(--accent); color: var(--accent); }
.quiz-link {
  margin-left: .8rem;
  font-size: .82rem;
  letter-spacing: .08em;
  border-bottom: 1px solid var(--rule);
}
.quiz-link:hover { text-decoration: none; border-bottom-color: var(--accent); }
.mode-toggle[aria-pressed="true"] {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}

/* 精簡模式：只留原文與全章通讀，白話與註解收起來 */
body.lean .seg,
body.lean .todo-box { display: none; }
body.lean .full-text { font-size: 1.45rem; line-height: 2; margin-bottom: 2.6rem; }

.layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 2.5rem;
  max-width: 1180px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

/* ── 左側索引 ───────────────────────────── */
.panel { margin-bottom: 2.5rem; }
.panel h2 {
  margin: 0 0 .4rem;
  font-size: .85rem;
  letter-spacing: .25em;
  color: var(--ink-2);
  font-weight: 500;
}
.hint { margin: 0 0 .8rem; font-size: .82rem; color: var(--ink-2); }

.chapter-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: .25rem;
}
.chapter-list li.part {
  grid-column: 1 / -1;
  padding: .9rem .1rem .25rem;
  font-size: .78rem;
  letter-spacing: .3em;
  color: var(--ink-2);
  border-bottom: 1px solid var(--rule);
  margin-bottom: .2rem;
}
.chapter-list li.part:first-child { padding-top: .1rem; }
.chapter-list a {
  display: block;
  text-align: center;
  padding: .3rem 0;
  border: 1px solid var(--rule);
  border-radius: 2px;
  color: var(--ink);
  font-size: .95rem;
  line-height: 1.3;
}
.chapter-list a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
/* 已讀：淡底色容易跟紙色混在一起，所以再加邊框、字色與右上角一點 */
.chapter-list a { position: relative; }
.chapter-list li.read a {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}
.chapter-list li.read a::after {
  content: "";
  position: absolute;
  top: 3px;
  right: 3px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent);
}
.chapter-list li.active.read a::after { background: var(--paper); }
.chapter-list li.active a { background: var(--accent); border-color: var(--accent); color: var(--paper); }

.keyword-cloud { display: flex; flex-wrap: wrap; gap: .4rem; }
.kw {
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink);
  font-family: inherit;
  font-size: 1.12rem;
  padding: .15rem .6rem;
  cursor: pointer;
  border-radius: 2px;
}
.kw:hover, .kw.on { border-color: var(--accent); color: var(--accent); }
.kw .n { font-size: .7rem; color: var(--ink-2); margin-left: .3rem; }

/* ── 右側正文 ───────────────────────────── */
.chapnav {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  font-size: .9rem;
  color: var(--ink-2);
  margin: 0 0 1rem;
}
.chapnav .cur { letter-spacing: .15em; }
.chapnav .done { color: var(--accent); font-size: .8rem; margin: 0 .15rem; }
.chapnav + .chapter-head { margin-top: 0; }
.readthrough + .chapnav, .todo-box + .chapnav { margin-top: 2.4rem; padding-top: 1rem; border-top: 1px solid var(--rule); }

.head-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}
.read-toggle {
  flex: none;
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink-2);
  font-family: inherit;
  font-size: .8rem;
  letter-spacing: .08em;
  padding: .25rem .8rem;
  border-radius: 2px;
  cursor: pointer;
}
.read-toggle:hover { border-color: var(--accent); color: var(--accent); }
.read-toggle.on { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }

.chapter-head { border-bottom: 2px solid var(--ink); padding-bottom: .8rem; margin-bottom: 1.6rem; }
.chapter-head h2 { margin: 0; font-size: 1.9rem; letter-spacing: .1em; }
.chapter-head .meta { margin: .4rem 0 0; font-size: .82rem; color: var(--ink-2); }
.badge {
  display: inline-block;
  font-size: .7rem;
  letter-spacing: .1em;
  padding: .1rem .5rem;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 2px;
  margin-left: .6rem;
  vertical-align: .15em;
}

.full-text {
  background: var(--paper-2);
  padding: 1.3rem 1.5rem;
  font-size: 1.3rem;
  letter-spacing: .04em;
  margin-bottom: 2.2rem;
}

.seg {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.6rem;
  padding: 1rem 0;
  border-bottom: 1px dotted var(--rule);
  scroll-margin-top: 1rem;
}
.seg .orig { font-size: 1.45rem; letter-spacing: .05em; }
.seg .orig .sid { font-size: .68rem; color: var(--ink-2); letter-spacing: .05em; margin-right: .5rem; vertical-align: .35em; }
.seg .plain { color: var(--ink-2); font-size: 1.05rem; }
.seg .alt { margin-top: .5rem; font-size: .92rem; color: var(--ink-2); border-left: 2px solid var(--rule); padding-left: .7rem; }
.seg.hit { background: var(--accent-soft); }
.seg mark { background: none; color: var(--accent); font-weight: 700; }

.notes { grid-column: 1 / -1; margin: .2rem 0 0; padding: 0; list-style: none; }
.notes li { font-size: .94rem; color: var(--ink-2); padding: .35rem 0 .35rem .9rem; border-left: 2px solid var(--rule); margin-top: .4rem; }
.notes .type {
  font-size: .68rem;
  letter-spacing: .1em;
  border: 1px solid var(--rule);
  padding: 0 .35rem;
  margin-right: .5rem;
  color: var(--ink-2);
}
.notes .term { color: var(--ink); font-weight: 700; margin-right: .4rem; }
.notes .source { color: var(--ink-2); font-size: .78rem; }
.notes .see { margin-left: .3rem; }

.readthrough { margin-top: 2.4rem; }
.readthrough h3 { font-size: .85rem; letter-spacing: .25em; color: var(--ink-2); font-weight: 500; margin-bottom: .6rem; }
.readthrough p { margin: 0; font-size: 1.05rem; }

.todo-box { margin-top: 2.4rem; font-size: .88rem; color: var(--ink-2); border: 1px dashed var(--rule); padding: .8rem 1rem; }
.todo-box ul { margin: .4rem 0 0; padding-left: 1.2rem; }

.kw-result { margin-bottom: 2rem; background: var(--paper-2); padding: 1rem 1.2rem; }
.kw-result h3 { margin: 0 0 .5rem; font-size: 1rem; }
.kw-result ul { margin: 0; padding-left: 1.2rem; }
.kw-result li { font-size: .98rem; }
.kw-result .close { float: right; }

/* ── 本章小考 ──────────────────────────── */
.chapquiz {
  margin-top: 2.6rem;
  padding-top: 1.4rem;
  border-top: 1px solid var(--rule);
}
.chapquiz h3 {
  margin: 0 0 .3rem;
  font-size: .85rem;
  letter-spacing: .25em;
  color: var(--ink-2);
  font-weight: 500;
}
.cq-intro { margin: 0 0 1rem; font-size: .8rem; color: var(--ink-2); }
.cq-foot {
  margin: 1.4rem 0 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: .9rem;
  color: var(--ink-2);
}
.cq-foot .pass { color: var(--accent); font-weight: 700; letter-spacing: .05em; }
.cq-reset {
  flex: none;
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink-2);
  font-family: inherit;
  font-size: .8rem;
  padding: .25rem .9rem;
  border-radius: 2px;
  cursor: pointer;
}
.cq-reset:hover { border-color: var(--accent); color: var(--accent); }
.pass-badge { border-style: solid; }

/* 側欄：讀過是圓點，考核通過改標 ✓（通過幾乎一定也讀過，所以讓 ✓ 蓋過圓點） */
.chapter-list li.pass a {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 700;
}
.chapter-list li.pass a::after {
  content: "✓";
  background: none;
  width: auto;
  height: auto;
  top: -1px;
  right: 2px;
  font-size: .6rem;
  line-height: 1;
  color: var(--accent);
}
.chapter-list li.active.pass a::after { color: var(--paper); }

/* 精簡模式是為了讀原文，小考跟著收起來 */
body.lean .chapquiz { display: none; }

/* ── 綜合小測驗 ────────────────────────── */
.quiz-score {
  font-size: .85rem;
  color: var(--ink-2);
  letter-spacing: .05em;
  margin: 0 0 1.6rem;
}
.quiz-list { list-style: none; margin: 0; padding: 0; counter-reset: none; }
.qitem {
  border-bottom: 1px dotted var(--rule);
  padding: 1.1rem 0 1.3rem;
}
.q-stmt { margin: 0 0 .7rem; font-size: 1.08rem; line-height: 1.9; }
.q-no {
  display: inline-block;
  min-width: 1.6rem;
  color: var(--ink-2);
  font-size: .85rem;
}
.q-btns { margin: 0; display: flex; gap: .5rem; }
.q-btns button {
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink);
  font-family: inherit;
  font-size: .95rem;
  padding: .2rem 1.4rem;
  border-radius: 2px;
  cursor: pointer;
}
.q-btns button:hover { border-color: var(--accent); color: var(--accent); }
.q-btns button.picked { background: var(--accent); border-color: var(--accent); color: var(--paper); }
.q-verdict { margin: .8rem 0 .4rem; font-size: .9rem; letter-spacing: .08em; }
.q-verdict.ok { color: var(--accent); }
.q-verdict.ng { color: var(--ink-2); }
.q-explain {
  margin: 0;
  font-size: .92rem;
  color: var(--ink-2);
  border-left: 2px solid var(--rule);
  padding-left: .9rem;
}
.q-ref { margin: .5rem 0 0; font-size: .82rem; color: var(--ink-2); padding-left: .9rem; }
.quiz-foot {
  margin-top: 2rem;
  display: flex;
  align-items: center;
  gap: 1.2rem;
  font-size: .85rem;
}
.quiz-reset {
  border: 1px solid var(--rule);
  background: none;
  color: var(--ink-2);
  font-family: inherit;
  font-size: .82rem;
  padding: .25rem .9rem;
  border-radius: 2px;
  cursor: pointer;
}
.quiz-reset:hover { border-color: var(--accent); color: var(--accent); }

/* 精簡模式是為了讀原文，測驗頁不受影響 */
body.lean .quiz .seg { display: block; }

.loading { color: var(--ink-2); }

footer {
  border-top: 1px solid var(--rule);
  padding: 1.6rem 1.5rem 3rem;
  text-align: center;
  font-size: .78rem;
  color: var(--ink-2);
}
footer p { margin: .3rem 0; }

@media (max-width: 860px) {
  html { font-size: 106%; }
  .layout { grid-template-columns: 1fr; gap: 1.5rem; }
  .sidebar { order: 2; border-top: 1px solid var(--rule); padding-top: 1.5rem; }
  .chapter-list { grid-template-columns: repeat(7, 1fr); }
  .seg { grid-template-columns: 1fr; gap: .5rem; }
  .masthead h1 { font-size: 2rem; }
  body.compact .masthead { flex-wrap: wrap; gap: .5rem .9rem; padding-right: 4rem; }
  .seg .orig { font-size: 1.32rem; }
  .full-text { font-size: 1.18rem; }
}