/* Kombyno landing — Act 4, "none of our business" (prefix a4-). */

.a4-section {
  padding: clamp(5rem, 12vw, 8rem) clamp(1.25rem, 6vw, 5rem);
}

.a4-inner {
  max-width: 72rem;
  margin: 0 auto;
}

.a4-sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* ---- Head ---- */
.a4-head { max-width: 42rem; margin: 0 0 clamp(3rem, 6vw, 4.5rem); }

.a4-h2 {
  margin: 0 0 var(--kb-space-4);
  font-weight: var(--kb-fw-semibold);
  font-size: clamp(2rem, 5vw, var(--kb-text-h1));
  line-height: var(--kb-lh-tight);
  letter-spacing: var(--kb-tracking-tight);
  color: var(--kb-text);
}

.a4-lead {
  margin: 0;
  font-size: var(--kb-text-lg);
  line-height: var(--kb-lh-body);
  color: var(--kb-text-secondary);
}

/* ---- Boundary stage ---- */
.a4-boundary {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: stretch;
  gap: clamp(1.5rem, 4vw, 2.5rem);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  border-radius: var(--kb-radius-lg);
  background: var(--kb-surface);
  border: 1px solid var(--kb-border);
}

.a4-col { min-width: 0; }

.a4-col-label {
  margin: 0 0 var(--kb-space-4);
  font-size: var(--kb-text-xs);
  text-transform: uppercase;
  letter-spacing: .18em;
  color: var(--kb-text-muted);
}

.a4-rows {
  list-style: none;
  margin: 0; padding: 0;
  display: flex; flex-direction: column;
  gap: var(--kb-space-2);
}

.a4-row {
  padding: var(--kb-space-3) var(--kb-space-4);
  border-radius: var(--kb-radius-sm);
  border: 1px solid var(--kb-border);
  background: rgba(251, 244, 234, .03);
  font-size: var(--kb-text-sm);
  color: var(--kb-text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.a4-col--server .a4-row--cipher {
  color: var(--kb-teal-300);
  letter-spacing: .02em;
  font-variant-numeric: tabular-nums;
}

.a4-cipher-text { display: inline-block; }

/* ---- Split / padlock ---- */
.a4-split {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--kb-space-3);
}

.a4-hairline {
  width: 1px;
  flex: 1 1 auto;
  min-height: 2rem;
  background: var(--kb-border-strong);
}

.a4-lock {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem; height: 2.5rem;
  border-radius: 50%;
  border: 1px solid rgba(87, 201, 184, .3);
  background: rgba(87, 201, 184, .08);
  color: var(--kb-teal-300);
  animation: a4-lock-pulse 2.8s var(--kb-ease) infinite;
}

@keyframes a4-lock-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(87, 201, 184, .28); }
  50%      { box-shadow: 0 0 0 9px rgba(87, 201, 184, 0); }
}

/* ---- Proof points ---- */
.a4-proofs {
  margin-top: clamp(2.5rem, 6vw, 4rem);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.a4-proof-h {
  margin: 0 0 var(--kb-space-2);
  font-size: var(--kb-text-h4);
  font-weight: var(--kb-fw-semibold);
  letter-spacing: var(--kb-tracking-tight);
  color: var(--kb-text);
}

.a4-proof-p {
  margin: 0;
  font-size: var(--kb-text-sm);
  line-height: var(--kb-lh-body);
  color: var(--kb-text-secondary);
}

/* ---- Wink ---- */
.a4-wink {
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  text-align: right;
  font-size: var(--kb-text-xs);
  font-style: italic;
  letter-spacing: .04em;
  color: var(--kb-text-muted);
}

/* ---- Responsive ---- */
@media (max-width: 1024px) {
  .a4-proofs { grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
}

@media (max-width: 768px) {
  .a4-boundary {
    grid-template-columns: 1fr;
  }
  .a4-split {
    flex-direction: row;
    width: 100%;
    padding: var(--kb-space-2) 0;
  }
  .a4-hairline { width: 100%; height: 1px; min-height: 0; }
  .a4-proofs { grid-template-columns: 1fr; gap: 1.75rem; }
  .a4-wink { text-align: left; }
}

@media (max-width: 640px) {
  .a4-row { font-size: var(--kb-text-xs); }
}

/* ---- Reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
  .a4-lock { animation: none; }
}