/* pdf-book.css — full-textbook PDF reader.
 *
 * Sits alongside book-reader.css (the chunked text reader) and borrows the same
 * --accent contract, which style.css defines per .course-*. Do not hard-code a
 * colour here; an undefined --accent is what made every reader render green.
 */

#pdfbook {
  --pb-rail: 300px;
  --pb-top: 56px;   /* replaced at runtime with the real topnav height */
  display: grid;
  grid-template-columns: var(--pb-rail) minmax(0, 1fr);
  gap: 0;
  border-top: 1px solid var(--rule);
  min-height: 70vh;
}

/* ---------- contents rail ---------- */

.pb-side {
  border-right: 1px solid var(--rule);
  background: var(--bg-2);
  max-height: calc(100vh - var(--pb-top));
  position: sticky;
  top: var(--pb-top);
  overflow: auto;
  overscroll-behavior: contain;
}
.pb-side-head {
  position: sticky; top: 0; z-index: 2;
  background: var(--bg-2);
  border-bottom: 1px solid var(--rule);
  padding: 12px 14px 10px;
}
.pb-side-head .pb-book {
  font-family: 'Fraunces', Georgia, serif;
  font-size: .98rem; line-height: 1.25; color: var(--ink);
  display: block; margin-bottom: 2px;
}
.pb-side-head .pb-meta {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: .7rem; color: var(--ink-3); line-height: 1.4;
}
.pb-filter {
  width: 100%; margin-top: 10px;
  background: var(--bg); color: var(--ink);
  border: 1px solid var(--rule); border-radius: 6px;
  padding: 7px 9px; font-size: .8rem;
  font-family: 'Inter', system-ui, sans-serif;
}
.pb-filter:focus { outline: none; border-color: var(--accent); }

.pb-toc { list-style: none; margin: 0; padding: 8px 0 40px; }
.pb-toc li { margin: 0; }
.pb-toc button {
  display: flex; width: 100%; gap: 8px; align-items: baseline;
  background: none; border: 0; cursor: pointer; text-align: left;
  color: var(--ink-2);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: .78rem; line-height: 1.35;
  padding: 5px 14px 5px 14px;
  border-left: 2px solid transparent;
}
.pb-toc button:hover { background: var(--bg-3); color: var(--ink); }
.pb-toc button.on { color: var(--accent); border-left-color: var(--accent); background: var(--accent-soft); }
.pb-toc .lv2 button { padding-left: 28px; font-size: .74rem; }
.pb-toc .lv3 button { padding-left: 42px; font-size: .72rem; color: var(--ink-3); }
.pb-toc .lv4 button, .pb-toc .lv5 button { padding-left: 54px; font-size: .71rem; color: var(--ink-3); }
.pb-toc .pb-pg { margin-left: auto; color: var(--ink-3); font-size: .68rem; font-variant-numeric: tabular-nums; }
.pb-toc .pb-empty { padding: 14px; color: var(--ink-3); font-size: .78rem; }

/* ---------- toolbar ---------- */

.pb-main { min-width: 0; display: flex; flex-direction: column; }

.pb-bar {
  position: sticky; top: var(--pb-top); z-index: 3;
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
  padding: 8px 14px;
  background: rgba(22,22,26,.94);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
  font-family: 'Inter', system-ui, sans-serif;
}
.pb-bar button, .pb-bar a.pb-btn {
  background: var(--bg-3); color: var(--ink-2);
  border: 1px solid var(--rule); border-radius: 6px;
  font: inherit; font-size: .78rem; line-height: 1;
  padding: 7px 10px; cursor: pointer;
  transition: all .12s ease;
}
.pb-bar button:hover:not(:disabled), .pb-bar a.pb-btn:hover { color: var(--ink); border-color: var(--accent); }
.pb-bar button:disabled { opacity: .35; cursor: default; }
.pb-bar a.pb-btn { border-bottom: 1px solid var(--rule); }
.pb-bar .pb-gap { margin-left: auto; }
.pb-jump { display: flex; align-items: center; gap: 5px; color: var(--ink-3); font-size: .78rem; }
.pb-jump input {
  width: 4.6em; text-align: center;
  background: var(--bg); color: var(--ink);
  border: 1px solid var(--rule); border-radius: 6px;
  padding: 6px 4px; font: inherit; font-size: .78rem;
  font-variant-numeric: tabular-nums;
}
.pb-jump input:focus { outline: none; border-color: var(--accent); }
#pbToc { display: none; }

/* ---------- page stage ---------- */

.pb-stage {
  flex: 1; padding: 18px 14px 60px;
  display: flex; justify-content: center;
  background:
    repeating-linear-gradient(45deg, rgba(255,255,255,.012) 0 10px, transparent 10px 20px),
    var(--bg);
  overflow-x: auto;
}
.pb-page {
  position: relative;
  flex: 0 0 auto;
  box-shadow: 0 6px 30px rgba(0,0,0,.55);
  background: #fff;
  align-self: flex-start;
}
.pb-page canvas { display: block; }

/* Selectable text sits invisibly on top of the rendered page. */
.pb-text {
  position: absolute; inset: 0;
  overflow: hidden; opacity: .22; line-height: 1;
  forced-color-adjust: none;
}
.pb-text > span, .pb-text > br {
  position: absolute; white-space: pre;
  color: transparent; transform-origin: 0 0;
  cursor: text;
}
.pb-text ::selection { background: rgba(120,170,255,.75); }

.pb-status {
  color: var(--ink-3);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: .82rem;
  padding: 60px 20px; text-align: center;
}
.pb-status.err { color: var(--rose); }

.pb-foot {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: .72rem; color: var(--ink-3);
  padding: 0 14px 26px; text-align: center;
}

/* ---------- narrow screens ---------- */

@media (max-width: 900px) {
  #pdfbook { grid-template-columns: minmax(0, 1fr); }
  .pb-side {
    position: fixed; top: 0; left: 0; bottom: 0; z-index: 60;
    width: min(88vw, 340px); max-height: 100vh;
    border-right: 1px solid var(--rule);
    box-shadow: 0 0 60px rgba(0,0,0,.7);
    transform: translateX(-102%); transition: transform .2s ease;
  }
  .pb-side.open { transform: none; }
  .pb-scrim {
    position: fixed; inset: 0; z-index: 55;
    background: rgba(0,0,0,.55);
    opacity: 0; pointer-events: none; transition: opacity .2s ease;
  }
  .pb-scrim.on { opacity: 1; pointer-events: auto; }
  #pbToc { display: inline-block; }
  .pb-bar { top: 0; padding: 7px 10px; }
  .pb-stage { padding: 10px 6px 48px; }
  .pb-bar .pb-wide { display: none; }
}