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

.rca-field {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.rca-field label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.rca-field select,
.rca-field input {
  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);
  min-width: 4.5rem;
}

.bit-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin: 0.25rem 0 0.55rem;
}
.bit-btn {
  font-family: var(--mono);
  font-size: 0.82rem;
  min-width: 3rem;
  padding: 0.35rem 0.45rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  cursor: pointer;
  color: var(--ink);
}
.bit-btn.on {
  background: color-mix(in srgb, var(--accent) 22%, var(--surface));
  border-color: var(--accent);
  font-weight: 700;
}

.step-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: center;
  margin: 0.75rem 0 1rem;
}
.step-bar .step-label {
  font-family: var(--mono);
  font-size: 0.88rem;
  margin-left: 0.35rem;
  color: var(--muted);
}

.fa-chain {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  justify-content: center;
  margin: 0.5rem 0 1rem;
}

.fa-stage {
  flex: 0 0 auto;
  width: 7.2rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.55rem 0.5rem;
  background: var(--surface);
  font-family: var(--mono);
  font-size: 0.75rem;
  opacity: 0.4;
  transition: opacity 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}
.fa-stage.revealed {
  opacity: 1;
}
.fa-stage.active {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 35%, transparent);
  opacity: 1;
}
.fa-stage h3 {
  margin: 0 0 0.4rem;
  font-size: 0.8rem;
  text-align: center;
}
.fa-stage .row {
  display: flex;
  justify-content: space-between;
  gap: 0.25rem;
  margin: 0.15rem 0;
}
.fa-stage .carry-in {
  color: var(--muted);
  font-size: 0.7rem;
  text-align: center;
  margin-bottom: 0.25rem;
}
.fa-stage .sum {
  margin-top: 0.35rem;
  text-align: center;
  font-weight: 700;
  font-size: 0.95rem;
}
.fa-stage .cout {
  margin-top: 0.25rem;
  text-align: center;
  font-size: 0.78rem;
}
.fa-stage .cout.on {
  color: var(--ok, #1b7a3d);
  font-weight: 700;
}

.ripple-arrow {
  align-self: center;
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--muted);
  writing-mode: horizontal-tb;
  flex: 0 0 auto;
  width: 1.2rem;
  text-align: center;
  opacity: 0.35;
}
.ripple-arrow.revealed {
  opacity: 1;
  color: var(--accent);
  font-weight: 700;
}

.result-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 0.95rem;
  margin: 0.5rem 0 0.75rem;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface2);
}
.result-strip .big {
  font-size: 1.15rem;
  font-weight: 700;
}

.eq-note {
  margin: 0.35rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
}

.delay-note {
  margin: 0.75rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
}
.delay-note strong {
  color: var(--ink);
  font-weight: 600;
}