/* Shared building blocks for interactive demos */
.demo {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  padding: clamp(14px, 2vw, 22px);
  display: flex;
  flex-direction: column;
  gap: 14px;
  min-width: 0;
}
.controls { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.label { font-size: 0.8em; color: var(--muted); font-weight: 600; }
.empty { font-size: 0.8em; color: var(--muted); }
.log {
  font-size: 0.88em;
  min-height: 2.9em;
  border-left: 3px solid var(--accent);
  padding: 2px 0 2px 12px;
  margin: 0;
}
.log.ok { border-color: var(--ok); }
.log.warn { border-color: var(--block); }
.log.bad { border-color: var(--block); background: var(--block-soft); border-radius: 0 6px 6px 0; }
.log .old { color: var(--muted); font-size: 0.92em; margin-top: 4px; }
.note { font-size: 0.85em; color: var(--muted); margin: 0; }

.val {
  display: inline-grid; place-items: center; flex: none;
  min-width: 1.85em; height: 1.85em; padding: 0 0.2em;
  border-radius: 5px; background: var(--value); color: var(--ink);
  border: 1.5px solid var(--ink); font-family: var(--mono); font-weight: 700; font-size: 0.8em;
}
.val.done { background: var(--ok-soft); border-color: var(--ok); }
.queue { display: flex; flex-wrap: wrap; gap: 5px; align-items: center; min-height: 1.9em; }
.queue .more { font-size: 0.75em; color: var(--muted); font-family: var(--mono); }
.pair { display: inline-flex; gap: 2px; align-items: center; }
.track { flex: 1; height: 8px; border-radius: 4px; background: var(--line); overflow: hidden; min-width: 40px; }
.track .fill { height: 100%; width: 0; background: var(--accent); }
.slider { display: flex; flex-direction: column; gap: 6px; }
.slider.inline { flex-direction: row; align-items: center; gap: 10px; }
.slider input { accent-color: var(--accent-deep); min-width: 100px; flex: 1; height: 28px; }
.slider output { font-family: var(--mono); font-weight: 700; min-width: 1ch; }
.toggle { display: flex; align-items: center; gap: 10px; font-size: 0.9em; cursor: pointer; }
.toggle input, .sel-toggle input { width: 20px; height: 20px; accent-color: var(--accent-deep); margin: 0; }

/* Quiz */
.quiz { display: flex; flex-direction: column; gap: 10px; }
.opt {
  font: inherit; font-size: 0.95em; text-align: left;
  padding: 14px 16px; border-radius: 10px; border: 1.5px solid var(--ink);
  background: var(--panel); color: var(--ink); cursor: pointer;
  font-family: var(--mono); font-size: 0.85em;
}
.opt:hover:not(:disabled) { background: var(--accent-soft); }
.opt.text { font-family: var(--font); font-size: 0.95em; }
.opt:disabled { cursor: default; opacity: 0.55; }
.opt.right { background: var(--ok-soft); border-color: var(--ok); opacity: 1; }
.opt.wrong { background: var(--block-soft); border-color: var(--block); opacity: 1; }
.explain { border-left: 4px solid var(--ok); padding: 6px 0 6px 14px; font-size: 0.95em; }
.explain.missed { border-color: var(--block); }


/* Small and selected buttons */
.btn.small { min-height: 34px; font-size: 0.78em; padding: 0.3em 0.8em; }
.btn.sel { background: var(--ink); color: #fff; }
.btn.sel:hover:not(:disabled) { background: var(--accent-deep); border-color: var(--accent-deep); color: #fff; }

/* Label chip (technology, topic) */
.tech {
  align-self: flex-start;
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.8em;
  font-weight: 700;
  padding: 0.25em 0.7em;
  border-radius: 6px;
  background: var(--accent);
  color: var(--accent-ink, #fff);
}

/* Stat tiles */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.stat { border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; display: flex; flex-direction: column; }
.stat b { font-size: 1.25em; font-variant-numeric: tabular-nums; }
.stat span { font-size: 0.75em; color: var(--muted); }
.stat.warn b { color: var(--block); }

/* When to use / when not */
.fit { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(16px, 3vw, 40px); margin-top: 8px; }
.fit.single { grid-template-columns: 1fr; }
.fit-col h3 { font-size: 1.1em; display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.fit-col h3::before {
  content: "";
  width: 1.4em; height: 1.4em; border-radius: 50%;
  background: var(--ok) no-repeat center / 62% url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2 6.5 5 9l5-6' fill='none' stroke='white' stroke-width='2'/%3E%3C/svg%3E");
}
.fit-col.no h3::before {
  background-color: var(--block);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M3 3l6 6M9 3l-6 6' fill='none' stroke='white' stroke-width='2'/%3E%3C/svg%3E");
}
.fit-col ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.fit-col li { padding: 10px 14px; border-radius: 8px; background: var(--panel); border-left: 4px solid var(--ok); }
.fit-col.no li { border-left-color: var(--block); }
.alt { display: block; margin-top: 4px; font-size: 0.85em; font-weight: 600; color: var(--muted); }
@media (max-width: 760px) { .fit { grid-template-columns: 1fr; } }

/* Summary */
.summary { gap: 0.8em; font-size: 1.05em; max-width: 66ch; }
.proverb { margin: 8px 0 0; font-size: clamp(1.3rem, 1.4vw + 0.8rem, 1.9rem); font-weight: 600; max-width: 30ch; line-height: 1.25; }
.proverb cite { display: block; margin-top: 8px; font-size: 0.5em; font-style: normal; color: var(--muted); font-weight: 400; }
.back-link { display: inline-flex; align-items: center; text-decoration: none; }

/* Series navigation on the last slide: back to the list, previous and next deck in one row */
.series-nav { display: flex; flex-wrap: wrap; align-items: stretch; gap: 8px; margin-top: 4px; }
.series-nav .back-link { align-self: center; }
.series-nav a:not(.btn) {
  flex: 1 1 200px; max-width: 320px; display: flex; flex-direction: column; justify-content: center; gap: 1px;
  padding: 5px 12px; border-radius: 10px; border: 1.5px solid var(--line);
  background: var(--panel); color: var(--ink); text-decoration: none; font-size: 0.88em;
}
.series-nav a:not(.btn):hover { border-color: var(--accent); background: var(--accent-soft); }
.series-nav span { font-size: 0.8em; color: var(--muted); font-weight: 600; }
.series-nav b { line-height: 1.25; }
.series-nav .series-next { text-align: right; }
.slide-inner:has(.series-nav) { gap: 0.7em; }
.slide-inner:has(.series-nav) .points { gap: 0.4em; }
.slide-inner:has(.series-nav) .proverb { margin-top: 0; }
@media (max-width: 560px) {
  .series-nav a:not(.btn) { flex-basis: 100%; max-width: none; }
  .series-nav .back-link { order: 3; }
}