/* CODE tab (paper-code/paper-code.js): a Study course's paper-replication
   notebooks and drills. Cells are the app's own .nbv-* cells
   (styles/practice/notebook-view.css); this is the page around them. Fixed
   under the topbar like the Article page, so the course page's own layout
   rules never reach it. */
#page-paper-code.page { padding: 0; }
#page-paper-code:not(.hidden) {
  background: var(--bg);
  inset: var(--dd-topbar-h, 44px) 0 0 0;
  overflow-y: auto;
  position: fixed;
  z-index: 40;
}
.pc-empty { color: var(--muted); padding: 40px 24px; text-align: center; }

.pc-head {
  align-items: center;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  padding: 12px 24px;
  position: sticky;
  top: 0;
  z-index: 2;
}
#page-paper-code .pc-title { font-size: 18px; font-weight: 700; margin: 0; }
.pc-views, .pc-tools { align-items: center; display: flex; flex-wrap: wrap; gap: 8px; }
.pc-tools { margin-left: auto; }
.pc-view, .pc-btn {
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  color: var(--text);
  cursor: pointer;
  font: inherit;
  font-size: 13px;
  padding: 5px 10px;
}
.pc-view[aria-pressed="true"] { border-color: var(--accent); color: var(--accent-text); }
.pc-btn-quiet { background: none; color: var(--muted); }
.pc-view:hover, .pc-btn:hover { border-color: var(--text); }
.pc-kernel { color: var(--muted); font-size: 12px; }
.pc-kernel[data-state="ready"] { color: var(--ok); }
.pc-kernel[data-state="busy"], .pc-kernel[data-state="loading"] { color: var(--warn); }
.pc-kernel[data-state="error"] { color: var(--danger); }

.pc-host { padding: 18px 24px 80px; }
.pc-notebook { margin: 0 auto; max-width: 860px; }
.pc-tag {
  color: var(--muted);
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.04em;
  margin: 2px 0 4px;
  text-transform: uppercase;
}
.pc-tag-exercise { color: var(--accent-text); }
.pc-tag-test { color: var(--info); }
.pc-figs { display: grid; gap: 8px; margin-top: 8px; }
.pc-figs img { background: var(--img-mat); border-radius: 4px; max-width: 100%; }
#page-paper-code .nbv-out { max-height: 420px; overflow: auto; }
/* A long inline call in the prose would widen the page on a phone. */
#page-paper-code .nbv-md code { overflow-wrap: anywhere; }

/* Drills: the list left, one drill right; stacked on a phone. */
.pc-drills { display: grid; gap: 20px; grid-template-columns: 220px minmax(0, 1fr); margin: 0 auto; max-width: 1100px; }
.pc-drill-list { list-style: none; margin: 0; padding: 0; }
.pc-drill-list li { margin-bottom: 4px; }
.pc-drill-list button {
  background: none;
  border: 1px solid transparent;
  border-radius: 6px;
  color: var(--text);
  cursor: pointer;
  font: inherit;
  font-size: 14px;
  padding: 6px 8px;
  text-align: left;
  width: 100%;
}
.pc-drill-list li.is-current button { background: var(--surface); border-color: var(--border-strong); }
.pc-drill-list li.is-passed button::after { color: var(--ok); content: " ✓"; }
.pc-drill h3 { font-size: 18px; margin: 0 0 8px; }
.pc-drill-prompt { color: var(--text); line-height: 1.6; margin-bottom: 12px; }
.pc-drill-prompt code { background: var(--input-bg); border-radius: 3px; padding: 0 3px; }
.pc-cases { border-collapse: collapse; font-size: 13px; margin: 10px 0; width: 100%; }
.pc-cases th, .pc-cases td { border-bottom: 1px solid var(--border); padding: 4px 8px; text-align: left; vertical-align: top; }
.pc-cases th { color: var(--muted); font-weight: 600; }
.pc-cases td code { overflow-wrap: anywhere; white-space: pre-wrap; }
.pc-cases tr.is-pass td:first-child { color: var(--ok); }
.pc-cases tr.is-fail td:first-child { color: var(--danger); }
@media (max-width: 760px) {
  .pc-head, .pc-host { padding-left: 14px; padding-right: 14px; }
  .pc-tools { margin-left: 0; }
  .pc-drills { grid-template-columns: minmax(0, 1fr); }
  /* The list as wrapping chips, so the drill is not a screen away. */
  .pc-drill-list { display: flex; flex-wrap: wrap; gap: 4px; }
  .pc-drill-list li { margin: 0; }
  .pc-drill-list button { font-size: 13px; padding: 4px 8px; width: auto; }
}