.md-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1rem;
  align-items: end;
  margin-bottom: 0.85rem;
}

.md-field {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.md-field label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.md-field select {
  font-family: var(--mono);
  font-size: 0.9rem;
  padding: 0.4rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--ink);
}

.bit-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0.5rem 0 0.85rem;
}

.bit-btn {
  font-family: var(--mono);
  font-size: 0.85rem;
  min-width: 3.6rem;
  padding: 0.45rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}
.bit-btn.on {
  background: color-mix(in srgb, var(--accent) 22%, var(--surface));
  border-color: var(--accent);
  font-weight: 700;
}
.bit-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.block-stage {
  display: grid;
  gap: 1rem;
  align-items: start;
}
@media (min-width: 720px) {
  .block-stage {
    grid-template-columns: 1.2fr 0.9fr;
  }
}

.block-card {
  border: 1px solid var(--line);
  border-radius: 12px;
  background:
    linear-gradient(160deg, color-mix(in srgb, var(--accent) 6%, var(--surface)), var(--surface) 55%),
    var(--surface);
  padding: 1rem;
  min-height: 220px;
}

.block-title {
  margin: 0 0 0.75rem;
  font-size: 0.95rem;
  font-weight: 650;
}

.io-col {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.io-line {
  display: grid;
  grid-template-columns: 4.5rem 1fr auto;
  gap: 0.45rem;
  align-items: center;
  font-family: var(--mono);
  font-size: 0.88rem;
  padding: 0.3rem 0.4rem;
  border-radius: 8px;
  border: 1px solid transparent;
}
.io-line.active {
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--line));
}
.io-line .wire {
  height: 3px;
  border-radius: 2px;
  background: var(--line);
}
.io-line.active .wire {
  background: var(--accent);
}
.io-line .val {
  font-weight: 700;
  min-width: 1.2rem;
  text-align: center;
}

.mux-layout {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 0.75rem;
  align-items: center;
}
.mux-layout.mux-wide {
  grid-template-columns: 1fr;
  gap: 0.85rem;
}
.mux-layout.mux-wide .mux-body {
  justify-self: center;
}

.chip-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(3.4rem, 1fr));
  gap: 0.35rem;
}
.chip {
  font-family: var(--mono);
  font-size: 0.75rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.35rem 0.3rem;
  text-align: center;
  background: var(--surface);
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  color: var(--muted);
}
.chip strong {
  font-size: 1rem;
  color: var(--ink);
}
.chip.active {
  background: color-mix(in srgb, var(--accent) 16%, var(--surface));
  border-color: var(--accent);
  color: var(--ink);
}

.mux-body {
  width: 7.5rem;
  min-height: 9rem;
  clip-path: polygon(0 0, 100% 18%, 100% 82%, 0 100%);
  background: color-mix(in srgb, var(--ink) 8%, var(--surface));
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.75rem 0.5rem;
  font-family: var(--mono);
  font-size: 0.8rem;
  text-align: center;
}
.mux-body .y {
  font-size: 1.25rem;
  font-weight: 700;
}

.dec-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.75rem 1rem;
  align-items: start;
}

.out-bus {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.formula {
  font-family: var(--mono);
  font-size: 0.95rem;
  margin: 0;
  padding: 0.65rem 0.75rem;
  background: var(--surface2);
  border-radius: 8px;
  border: 1px solid var(--line);
  word-break: break-word;
}

.md-meta {
  margin: 0.5rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
}

.quiz-choices {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin: 0.5rem 0;
}
.quiz-choices label {
  display: flex;
  gap: 0.5rem;
  align-items: flex-start;
  font-family: var(--mono);
  font-size: 0.88rem;
  padding: 0.45rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  cursor: pointer;
}
.quiz-choices label:has(input:checked) {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}