/* ============================================================
   Section: «ГОСТ требует — Документатор делает»  (#gost-chains)
   ============================================================ */

.gost-chains {
  background: var(--paper);
}

.gost-chains__header {
  max-width: var(--max-w-narrow);
  margin: 0 0 var(--s-12);
}
.gost-chains__header .lead {
  margin-top: var(--s-3);
  max-width: 760px;
}

/* ----- List of chains ----- */
.chains {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-12);
}

.chain {
  padding-top: var(--s-8);
  border-top: 1px solid var(--graphite-200);
}

.chain__index {
  display: flex;
  align-items: baseline;
  gap: var(--s-4);
  margin-bottom: var(--s-6);
}
.chain__num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--indigo-700);
  letter-spacing: 0.06em;
}
.chain__title {
  font-size: 24px;
  line-height: 1.25;
  font-weight: 700;
  color: var(--ink-900);
  margin: 0;
}

/* ----- 3-column grid: A → B → C ----- */
.chain__grid {
  display: grid;
  grid-template-columns:
    minmax(0, 1fr)
    32px
    minmax(0, 1fr)
    32px
    minmax(0, 1.15fr);
  gap: var(--s-4);
  /* don't force every card to match the tallest column — cards should
     have their natural min-height (otherwise the visual is "blank stretched cards") */
  align-items: start;
}

.chain__col {
  display: flex;
  flex-direction: column;
  padding: var(--s-6);
  background: var(--paper-pure);
  border: var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  min-width: 0;
  /* card sizes to its own content height, not the row height */
  align-self: start;
}

.chain__col--req  { border-top: 3px solid var(--graphite-300); }
.chain__col--do   { border-top: 3px solid var(--indigo-500); }
.chain__col--out  { border-top: 3px solid var(--ink-900); }

.chain__eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--graphite-500);
  margin-bottom: var(--s-3);
}
.chain__col--do   .chain__eyebrow { color: var(--indigo-700); }
.chain__col--out  .chain__eyebrow { color: var(--ink-900); }

.chain__ref {
  font-size: 13px;
  color: var(--ink-900);
  margin: 0 0 var(--s-3);
  font-weight: 600;
}

.chain__quote {
  margin: 0;
  padding: var(--s-3) var(--s-4);
  border-left: 3px solid var(--indigo-100);
  background: var(--indigo-50);
  color: var(--graphite-900);
  font-size: 15px;
  line-height: 1.55;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.chain__do-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--graphite-900);
}
.chain__do-text em {
  font-style: normal;
  font-weight: 600;
  color: var(--indigo-700);
}

/* ----- Arrows between columns ----- */
.chain__arrow--inline {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--indigo-500);
  align-self: center;
}

/* ----- Mockup (column C) ----- */
.mockup {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
  flex: 1;
}
.mockup__cap {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--graphite-500);
}
.mockup__body {
  background: var(--graphite-100);
  border: 1px solid var(--graphite-200);
  border-radius: var(--radius);
  padding: var(--s-3) var(--s-4);
  overflow-x: auto;
  flex: 1;
}
.mockup__pre {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  color: var(--ink-900);
  white-space: pre;
  tab-size: 2;
}
.mockup__body--svg {
  padding: var(--s-4);
  background: var(--paper-pure);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ----- Footnote ----- */
.chains__footnote {
  margin-top: var(--s-12);
  padding-top: var(--s-6);
  border-top: 1px solid var(--graphite-200);
  font-size: 14px;
  color: var(--graphite-700);
  max-width: 720px;
}

/* ============================================================
   Tablet: arrows still horizontal, narrower columns
   ============================================================ */
@media (max-width: 1100px) {
  .chain__grid {
    grid-template-columns:
      minmax(0, 1fr)
      24px
      minmax(0, 1fr)
      24px
      minmax(0, 1.1fr);
    gap: var(--s-3);
  }
  .chain__col { padding: var(--s-4); }
  .mockup__pre { font-size: 11px; }
}

/* ============================================================
   Mobile: stack vertically, arrows rotate 90°
   ============================================================ */
@media (max-width: 820px) {
  .chain__grid {
    grid-template-columns: 1fr;
    gap: var(--s-3);
  }
  .chain__arrow--inline {
    transform: rotate(90deg);
    height: 24px;
    margin: var(--s-1) 0;
  }
  .chains { gap: var(--s-8); }
}

/* === Accordion v3.2 (session 26) === */
/* Each chain is a <details> wrapped in a <li class="chain-item">. */
.chains {
  gap: 12px;
}
.chain-item {
  list-style: none;
}
.chain {
  padding-top: 0;
  border-top: 0;
  border: 1px solid rgba(14, 27, 46, 0.08);
  border-radius: 14px;
  background: #fff;
  margin-bottom: 0;
  overflow: hidden;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.chain[open] {
  border-color: rgba(14, 27, 46, 0.16);
  box-shadow: 0 8px 32px rgba(14, 27, 46, 0.06);
}
.chain__summary {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px 24px;
  cursor: pointer;
  list-style: none;
  min-height: 64px;
  font: 700 17px/1.3 var(--font-display, Manrope, sans-serif);
  color: var(--ink-900, #0E1B2E);
  user-select: none;
  transition: background 0.15s ease;
}
.chain__summary::-webkit-details-marker { display: none; }
.chain__summary::marker { content: ""; }
.chain__summary:hover { background: rgba(14, 27, 46, 0.03); }
.chain__summary:focus-visible {
  outline: 2px solid var(--accent, var(--indigo-500, #E25822));
  outline-offset: -2px;
}
/* Override base .chain__num + .chain__title inside the summary */
.chain__summary .chain__num {
  font: 700 13px/1 var(--font-mono, "JetBrains Mono", monospace);
  color: rgba(14, 27, 46, 0.45);
  letter-spacing: 0.06em;
  flex-shrink: 0;
  min-width: 24px;
}
.chain__summary .chain__title {
  flex: 1;
  min-width: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--ink-900, #0E1B2E);
  margin: 0;
}
.chain__summary .chain__arrow {
  font-size: 14px;
  color: rgba(14, 27, 46, 0.5);
  transition: transform 0.25s cubic-bezier(0.2, 0.7, 0.3, 1);
  flex-shrink: 0;
  line-height: 1;
  display: inline-block;
  align-self: center;
}
.chain[open] > .chain__summary .chain__arrow { transform: rotate(90deg); }
.chain__body {
  padding: 0 24px 24px;
  animation: chainSlide 0.35s cubic-bezier(0.2, 0.7, 0.3, 1) both;
}
@keyframes chainSlide {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}
@media (max-width: 640px) {
  .chain__summary {
    padding: 16px 18px;
    font-size: 15px;
    gap: 12px;
    min-height: 56px;
  }
  .chain__summary .chain__title { font-size: 15px; }
  .chain__body { padding: 0 18px 18px; }
}
@media (prefers-reduced-motion: reduce) {
  .chain__summary .chain__arrow { transition: none; }
  .chain__body { animation: none; }
}

/* ============================================================
   Session-30: упрощённая цепочка — 2 чек-листа + таблица
   ============================================================ */

.chain-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--s-6);
  margin: 0 0 var(--s-10);
}
@media (max-width: 820px) {
  .chain-pair { grid-template-columns: 1fr; gap: var(--s-5); }
}

.chain-col {
  background: var(--paper-pure, #fff);
  border: 1px solid var(--graphite-200, #E5E7EB);
  border-radius: 14px;
  padding: var(--s-7) var(--s-7);
  box-shadow: 0 1px 0 rgba(14,27,46,.04), 0 12px 32px -22px rgba(14,27,46,.18);
}
.chain-col--req { border-left: 3px solid #C1440E; }
.chain-col--do  { border-left: 3px solid #16823F; }

.chain-col__eyebrow {
  display: inline-block;
  font: 700 11px/1 var(--font-mono);
  letter-spacing: .12em;
  text-transform: uppercase;
  color: rgba(14,27,46,.55);
  margin-bottom: var(--s-2);
}
.chain-col__ref {
  font: 600 13px/1.3 var(--font-mono);
  color: var(--ink-900, #0E1B2E);
  margin: 0 0 var(--s-5);
  letter-spacing: .01em;
}

.chain-checks {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-3);
}
.chain-checks li {
  display: grid;
  grid-template-columns: 22px 1fr;
  gap: 10px;
  align-items: start;
  font: 500 15px/1.5 var(--font-body);
  color: var(--ink-800, #1F2937);
}
.chain-checks__mark {
  display: inline-flex;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  align-items: center;
  justify-content: center;
  font: 700 12px/1 var(--font-mono);
  flex-shrink: 0;
  margin-top: 1px;
}
.chain-checks__mark--req {
  background: rgba(193, 68, 14, .10);
  color: #C1440E;
}
.chain-checks__mark--do {
  background: rgba(22, 130, 63, .12);
  color: #16823F;
}

/* ----- Output mockup (фрагмент таблицы) ----- */
.chain-output {
  margin: 0;
  background: var(--paper-pure, #fff);
  border: 1px solid var(--graphite-200, #E5E7EB);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: 0 1px 0 rgba(14,27,46,.04), 0 12px 32px -22px rgba(14,27,46,.18);
}
.chain-output__cap {
  padding: var(--s-4) var(--s-6);
  background: rgba(14,27,46,.03);
  border-bottom: 1px solid var(--graphite-200, #E5E7EB);
  font: 600 13px/1.3 var(--font-body);
  color: var(--ink-800, #1F2937);
}
.chain-output__body {
  overflow-x: auto;
}
.chain-output__pre {
  margin: 0;
  padding: var(--s-5) var(--s-6);
  font: 500 12.5px/1.55 var(--font-mono);
  color: var(--ink-900, #0E1B2E);
  white-space: pre;
  min-width: 720px;
}
@media (max-width: 640px) {
  .chain-output__pre { font-size: 11px; min-width: 580px; }
}