/* ==========================================================================
   胖藍本 · 網頁好讀版
   典陸教育 Danlu Education
   Palette inspired by washi (和紙) + sumi (墨) + indigo accent
   ========================================================================== */

:root {
  --paper:      #f7f4ec;      /* warm off-white */
  --paper-2:    #efeadd;      /* slightly deeper paper */
  --paper-3:    #e8e2d1;      /* sidebar tint */
  --sumi:       #1f1f22;      /* near black text */
  --sumi-2:     #3c3c42;      /* secondary text */
  --muted:      #8a857a;      /* captions */
  --rule:       #cfc8b5;      /* hairline dividers */
  --rule-soft:  #e0dac8;
  --indigo:     #233a64;      /* accent */
  --indigo-2:   #324d7a;
  --indigo-ink: #1a2a4a;
  --gold:       #a07936;      /* subtle brand accent */
  --active:     #2c4674;
  --shadow:     0 1px 2px rgba(31,31,34,.04), 0 8px 28px rgba(31,31,34,.06);
  --serif:      "Noto Serif TC", "Songti TC", "PMingLiU", serif;
  --sans:       "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  --latin:      "Cormorant Garamond", "Noto Serif TC", serif;
  --sidebar-w:  296px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
[hidden] { display: none !important; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--sumi);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---------- layout -------------------------------------------------------- */
body {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  background: var(--paper-3);
  border-right: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
}

.main {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--paper);
}

/* ---------- brand --------------------------------------------------------- */
.brand {
  padding: 28px 24px 18px;
  border-bottom: 1px solid var(--rule-soft);
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.brand-mark {
  flex: 0 0 auto;
  width: 54px;
  height: 54px;
  background: var(--indigo-ink);
  color: var(--paper);
  display: grid;
  place-items: center;
  border-radius: 2px;
  font-family: var(--serif);
  letter-spacing: .02em;
}
.brand-kanji {
  font-size: 13px;
  line-height: 1.1;
  writing-mode: vertical-rl;
  font-weight: 500;
  padding: 6px 0;
}

.brand-meta { flex: 1 1 auto; min-width: 0; }
.brand-zh {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 14px;
  color: var(--sumi);
  letter-spacing: .04em;
}
.brand-en {
  margin-top: 4px;
  font-family: var(--latin);
  font-style: italic;
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .06em;
}

/* ---------- search -------------------------------------------------------- */
.search {
  padding: 16px 20px 8px;
  border-bottom: 1px solid var(--rule-soft);
}
.search input {
  width: 100%;
  padding: 9px 12px;
  font: inherit;
  font-size: 13.5px;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: 2px;
  color: var(--sumi);
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
.search input::placeholder { color: var(--muted); }
.search input:focus {
  border-color: var(--indigo);
  box-shadow: 0 0 0 2px rgba(35,58,100,.08);
}
.search .hint {
  margin-top: 6px;
  font-size: 11.5px;
  color: var(--muted);
  letter-spacing: .03em;
}
.search .hint b { color: var(--indigo); font-weight: 600; }

/* ---------- books nav ----------------------------------------------------- */
.books {
  flex: 1 1 auto;
  padding: 4px 0 16px;
  overflow-y: auto;
}

/* --- level 1: book (胖藍本 / 瘦藍本) --- */
.book {
  padding: 0;
  border-bottom: 1px solid var(--rule-soft);
}
.book:last-child { border-bottom: 0; }

.book-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 16px 20px 14px;
  cursor: pointer;
  user-select: none;
  background: linear-gradient(180deg, transparent, rgba(35,58,100,.025));
  transition: background .15s;
}
.book-head:hover { background: rgba(35,58,100,.06); }
.book-head:hover .book-label { color: var(--indigo); }
.book-label {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: .24em;
  color: var(--indigo-ink);
  transition: color .15s;
  flex: 0 0 auto;
}
.book-sub {
  flex: 1 1 auto;
  font-family: var(--latin);
  font-style: italic;
  font-size: 10.5px;
  color: var(--muted);
  letter-spacing: .05em;
  margin: 0 10px;
  text-align: right;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.book-caret {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 11px;
  transition: transform .2s;
}
.book.collapsed .book-caret { transform: rotate(-90deg); }
.book.collapsed .book-body { display: none; }

.book-body {
  padding: 4px 0 12px;
}

/* --- level 2: volume (胖 · 冊) / topic (瘦 · 主題) --- */
.volumes {
  flex: 1 1 auto;
  padding: 8px 0 16px;
  overflow-y: auto;
}
.volume, .topic {
  padding: 2px 20px 2px 24px;
}
.volume-head, .topic-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 7px 4px 6px;
  cursor: pointer;
  user-select: none;
  border-bottom: 1px dashed var(--rule-soft);
}
.volume-head:hover .volume-label,
.topic-head:hover .topic-label { color: var(--indigo); }
.volume-label, .topic-label {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--sumi);
  transition: color .15s;
}
.volume-range, .topic-range {
  font-family: var(--latin);
  font-style: italic;
  font-size: 10.5px;
  color: var(--muted);
  letter-spacing: .05em;
}
.volume-caret, .topic-caret {
  margin-left: 8px;
  color: var(--muted);
  font-size: 10px;
  transition: transform .2s;
}
.volume.collapsed .volume-caret,
.topic.collapsed .topic-caret { transform: rotate(-90deg); }
.volume.collapsed .rounds,
.topic.collapsed .rounds { display: none; }

.rounds {
  list-style: none;
  padding: 6px 0 4px;
  margin: 0;
}
.round-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 8px;
  margin: 1px 0;
  font-size: 13px;
  color: var(--sumi-2);
  cursor: pointer;
  border-radius: 2px;
  transition: background .15s, color .15s;
  gap: 8px;
}
.round-item:hover { background: rgba(35,58,100,.06); color: var(--sumi); }
.round-item.active {
  background: var(--indigo);
  color: var(--paper);
}
.round-item.active .round-meta { color: rgba(247,244,236,.7); }
.round-item.hit { background: rgba(160,121,54,.12); }
.round-num {
  font-family: var(--latin);
  font-size: 12px;
  font-style: italic;
  opacity: .8;
  width: 22px;
  flex: 0 0 auto;
}
.round-label {
  flex: 1 1 auto;
  font-family: var(--serif);
  letter-spacing: .04em;
}
.round-meta {
  flex: 0 0 auto;
  font-size: 11px;
  color: var(--muted);
  font-family: var(--latin);
  font-style: italic;
}

/* ---------- credit -------------------------------------------------------- */
.credit {
  padding: 14px 20px 18px;
  border-top: 1px solid var(--rule-soft);
  font-family: var(--serif);
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .2em;
  text-align: center;
}
.credit-en {
  margin-top: 2px;
  font-family: var(--latin);
  font-style: italic;
  letter-spacing: .15em;
  font-size: 11px;
}

/* ---------- topbar -------------------------------------------------------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  padding: 14px 28px;
  background: rgba(247,244,236,.94);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--rule-soft);
  display: flex;
  align-items: center;
  gap: 20px;
}

.menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--rule);
  color: var(--sumi);
  padding: 4px 10px;
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  border-radius: 2px;
}

.breadcrumb {
  flex: 1 1 auto;
  font-family: var(--serif);
  font-size: 14px;
  letter-spacing: .06em;
  color: var(--sumi);
  min-width: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.breadcrumb .sep { color: var(--muted); margin: 0 10px; }
.breadcrumb .crumb-vol { color: var(--muted); }
.breadcrumb .crumb-round { color: var(--sumi); font-weight: 500; }
.crumb-muted { color: var(--muted); font-style: italic; font-family: var(--latin); font-size: 13px; }

.tabs {
  flex: 0 0 auto;
  display: flex;
  gap: 2px;
  background: var(--paper-2);
  padding: 3px;
  border-radius: 3px;
  border: 1px solid var(--rule-soft);
}
.tab {
  font: inherit;
  font-family: var(--serif);
  font-size: 13px;
  letter-spacing: .1em;
  padding: 5px 16px;
  background: transparent;
  color: var(--sumi-2);
  border: 0;
  border-radius: 2px;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.tab:hover:not(:disabled) { color: var(--indigo); }
.tab.active {
  background: var(--indigo);
  color: var(--paper);
}
.tab:disabled {
  color: var(--muted);
  cursor: not-allowed;
  text-decoration: line-through;
  opacity: .6;
}

/* ---------- viewer -------------------------------------------------------- */
.viewer {
  flex: 1 1 auto;
  padding: 32px 28px 64px;
  max-width: 980px;
  width: 100%;
  margin: 0 auto;
}

.page-card {
  margin: 0 auto 20px;
  background: #fff;
  box-shadow: var(--shadow);
  border-radius: 2px;
  overflow: hidden;
  position: relative;
}
.page-card img {
  display: block;
  width: 100%;
  height: auto;
}
.page-num {
  position: absolute;
  bottom: 8px;
  right: 14px;
  font-family: var(--latin);
  font-style: italic;
  font-size: 11px;
  color: var(--muted);
  background: rgba(255,255,255,.85);
  padding: 2px 8px;
  border-radius: 2px;
}

.viewer-meta {
  text-align: center;
  margin: 8px 0 32px;
  color: var(--muted);
  font-family: var(--serif);
  letter-spacing: .15em;
  font-size: 12px;
}
.viewer-meta .divider {
  display: inline-block;
  width: 24px;
  border-top: 1px solid var(--rule);
  vertical-align: middle;
  margin: 0 14px;
}

.empty-note {
  max-width: 560px;
  margin: 80px auto;
  text-align: center;
  padding: 40px 32px;
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: var(--paper-2);
}
.empty-note h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-weight: 500;
  letter-spacing: .1em;
}
.empty-note p {
  margin: 4px 0;
  color: var(--sumi-2);
  font-size: 13.5px;
}
.empty-note .muted { color: var(--muted); font-size: 12px; margin-top: 16px; }

/* ---------- welcome ------------------------------------------------------- */
.welcome {
  display: grid;
  place-items: center;
  min-height: 60vh;
}
.welcome-card {
  max-width: 560px;
  text-align: center;
  padding: 48px 48px 40px;
}
.logo-zh {
  font-family: var(--serif);
  font-size: 56px;
  letter-spacing: .5em;
  color: var(--indigo-ink);
  padding-left: .5em;   /* visually center with wide letter-spacing */
  font-weight: 500;
}
.logo-sub {
  margin-top: 10px;
  font-family: var(--latin);
  font-style: italic;
  letter-spacing: .3em;
  color: var(--gold);
  font-size: 14px;
}
.welcome-card hr {
  border: 0;
  border-top: 1px solid var(--rule);
  max-width: 40px;
  margin: 24px auto;
}
.welcome-line {
  margin: 4px 0;
  font-family: var(--serif);
  font-size: 14px;
  color: var(--sumi);
  letter-spacing: .08em;
}
.welcome-line.muted { color: var(--muted); font-size: 13px; }
.welcome-tips {
  margin: 28px auto 0;
  list-style: none;
  padding: 0;
  text-align: left;
  max-width: 320px;
  color: var(--sumi-2);
  font-size: 13.5px;
  line-height: 2;
}
.welcome-tips li {
  padding-left: 18px;
  position: relative;
}
.welcome-tips li::before {
  content: "·";
  position: absolute;
  left: 4px;
  color: var(--indigo);
  font-weight: 700;
}
.welcome-tips .k {
  font-family: var(--serif);
  color: var(--indigo);
  padding: 0 3px;
  font-weight: 500;
}
.welcome-brand {
  margin-top: 36px;
  font-family: var(--serif);
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .3em;
}
.welcome-brand .sep { opacity: .4; margin: 0 6px; }

/* ---------- responsive ---------------------------------------------------- */
@media (max-width: 900px) {
  body { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: min(86vw, 320px);
    z-index: 20;
    transform: translateX(-100%);
    transition: transform .2s ease;
    box-shadow: 0 0 30px rgba(0,0,0,.15);
  }
  body.nav-open .sidebar { transform: translateX(0); }
  body.nav-open::after {
    content: "";
    position: fixed; inset: 0;
    background: rgba(0,0,0,.35);
    z-index: 15;
  }
  .menu-toggle { display: inline-block; }
  .viewer { padding: 20px 16px 48px; }
  .topbar { padding: 10px 14px; gap: 10px; }
  .tabs { padding: 2px; }
  .tab { padding: 5px 10px; font-size: 12px; letter-spacing: .06em; }
  .logo-zh { font-size: 42px; }
}

/* ---------- scrollbar polish -------------------------------------------- */
.sidebar::-webkit-scrollbar { width: 6px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 3px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }