/* 配管ラボ（pipeline.html）と鉄道ラボ（railway.html）が共有する解説まわりの部品。
   導入・4原則・実験の目次・各実験の見出し・末尾ノートをここで持ち、
   実験本体（操作パネル・ステージ・SVG）は pipeline.css / railway.css が持つ。 */

/* --- 導入 ------------------------------------------------------------ */
.lab-intro {
  align-items: start;
  margin-bottom: 20px;
}

.lab-intro .build-stamp { align-self: start; }

.lab-kicker {
  margin: 0 0 8px;
  color: var(--cyan);
  font: 600 11px/1.4 var(--mono);
  letter-spacing: .16em;
  text-transform: uppercase;
}

.lab-sequence {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 18px;
  margin-top: 18px;
}

.lab-sequence__label {
  color: var(--muted);
  font-size: 12px;
  font-weight: 600;
}

.lab-sequence ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lab-sequence li {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--fg);
  font-size: 13px;
  line-height: 1.5;
}

.lab-sequence li b {
  color: var(--accent-strong);
  font: 600 11px/1 var(--mono);
}

.lab-sequence li + li::before {
  margin: 0 4px 0 12px;
  color: var(--faint);
  font: 500 13px/1 var(--mono);
  content: "→";
}

/* --- 4原則 ------------------------------------------------------------ */
.lab-principles {
  margin: 0 0 20px;
  border: 1px solid var(--line);
  background: var(--bg-raised);
}

.lab-principles__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0;
  padding: 10px 18px;
  border-bottom: 1px solid var(--line);
  background: var(--bg-panel);
  color: var(--fg-strong);
  font-size: 13px;
  font-weight: 600;
}

.lab-principles__head span {
  color: var(--cyan);
  font: 600 10px/1.4 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
}

/* 1px の gap に下地の線色を透かして、枠を重ねずに罫線で区切る。 */
.lab-principles__grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
}

.lab-principle {
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto;
  gap: 8px;
  min-width: 0;
  padding: 18px 18px 16px;
  background: var(--bg-raised);
}

.lab-principle__index {
  display: flex;
  align-items: baseline;
  gap: 10px;
  color: var(--accent-strong);
  font: 500 24px/1 var(--mono);
}

.lab-principle__index small {
  color: var(--cyan);
  font: 600 10px/1.4 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
}

.lab-principle__title {
  display: block;
  color: var(--fg-strong);
  font-size: 15px;
  line-height: 1.4;
}

.lab-principle p {
  margin: 0;
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.7;
}

.lab-principle code {
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  color: var(--accent-strong);
  font: 500 11px/1.5 var(--mono);
  overflow-wrap: anywhere;
}

/* --- 実験の目次 ------------------------------------------------------- */
.lab-jump {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  margin: 0 0 22px;
  border: 1px solid var(--line);
  background: var(--bg-panel);
}

.lab-jump__label {
  display: flex;
  align-items: center;
  padding: 0 16px;
  border-right: 1px solid var(--line);
  color: var(--faint);
  font: 600 10px/1.4 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
}

.lab-jump ol {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  background: var(--line);
  list-style: none;
}

.lab-jump li { min-width: 0; }

.lab-jump a {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 8px 16px;
  background: var(--bg-panel);
  box-shadow: inset 0 -2px 0 transparent;
  color: var(--muted);
  font-size: 12.5px;
  text-decoration: none;
  transition: box-shadow .15s ease, color .15s ease;
}

.lab-jump a:hover,
.lab-jump a:focus-visible {
  box-shadow: inset 0 -2px 0 var(--accent);
  color: var(--fg-strong);
  outline: 0;
}

.lab-jump b {
  color: var(--accent-strong);
  font: 600 11px/1 var(--mono);
}

/* --- 各実験の見出し --------------------------------------------------- */
.lab {
  scroll-margin-top: 20px;
  margin-top: 18px;
  border: 1px solid var(--line-strong);
  border-top: 3px solid var(--accent);
  background: var(--bg-raised);
  box-shadow: 0 18px 46px var(--shadow);
}

.lab + .lab { margin-top: 26px; }

.lab__header {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 10px 22px;
  align-items: start;
  padding: 22px clamp(18px, 3vw, 30px) 20px;
  border-bottom: 1px solid var(--line);
  background: var(--bg-panel);
}

.lab__index {
  display: grid;
  gap: 4px;
  padding-top: 2px;
  color: var(--accent-strong);
  font: 500 clamp(30px, 4vw, 40px)/1 var(--mono);
  letter-spacing: -.02em;
}

.lab__index small {
  color: var(--faint);
  font: 600 9px/1.2 var(--mono);
  letter-spacing: .16em;
  text-transform: uppercase;
}

.lab__header h3 {
  margin: 0;
  color: var(--fg-strong);
  font-size: clamp(21px, 2.6vw, 28px);
  line-height: 1.25;
  letter-spacing: -.01em;
}

.lab__header p {
  max-width: 56em;
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.75;
}

/* 再生ボタンのクラス名は tools/test_*.mjs が数えているので、ページごとの名前のまま共通で装う。 */
.pipeline-lab__motion,
.rail-lab__motion {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-width: 124px;
  min-height: 44px;
  padding: 9px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 0;
  background: var(--bg-sunk);
  color: var(--fg-strong);
  font-size: 13px;
  font-weight: 700;
  transition: border-color .15s ease, background-color .15s ease;
}

.pipeline-lab__motion::before,
.rail-lab__motion::before {
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 5px 0 5px 8px;
  border-color: transparent transparent transparent var(--cyan);
  content: "";
}

.pipeline-lab__motion:hover,
.pipeline-lab__motion:focus-visible,
.rail-lab__motion:hover,
.rail-lab__motion:focus-visible {
  border-color: var(--cyan);
  background: var(--cyan-soft);
  outline: 0;
}

.pipeline-lab__motion[aria-pressed="true"],
.rail-lab__motion[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--on-accent);
}

.pipeline-lab__motion[aria-pressed="true"]::before,
.rail-lab__motion[aria-pressed="true"]::before {
  box-sizing: content-box;
  width: 3px;
  height: 11px;
  border-width: 0 3px;
  border-color: currentColor;
}

/* --- 末尾ノート ------------------------------------------------------- */
.lab-notes {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(280px, .7fr);
  gap: 14px;
  margin-top: 26px;
}

.lab-note {
  min-width: 0;
  padding: 20px 22px 22px;
  border: 1px solid var(--line);
  background: var(--bg-raised);
}

.lab-note__kicker {
  margin: 0 0 6px;
  color: var(--cyan);
  font: 600 10px/1.4 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
}

.lab-note h3 {
  margin: 0 0 12px;
  color: var(--fg-strong);
  font-size: 17px;
  line-height: 1.3;
}

.lab-note p,
.lab-note li {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

.lab-note p { margin: 12px 0 0; }
.lab-note h3 + p { margin-top: 0; }

.lab-note code {
  padding: 1px 6px;
  border: 1px solid var(--line);
  background: var(--bg-sunk);
  color: var(--fg);
  font-size: 11.5px;
  overflow-wrap: anywhere;
}

.lab-checklist,
.lab-steps,
.lab-sources {
  margin: 0;
  padding: 0;
  list-style: none;
}

.lab-checklist {
  display: grid;
  gap: 7px;
}

.lab-checklist li {
  display: grid;
  grid-template-columns: 16px minmax(0, 1fr);
  gap: 10px;
}

.lab-checklist li::before {
  color: var(--cyan);
  font: 700 12px/1.7 var(--mono);
  content: "✓";
}

.lab-steps {
  display: grid;
  gap: 10px;
  counter-reset: lab-step;
}

.lab-steps li {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 12px;
  counter-increment: lab-step;
}

.lab-steps li::before {
  padding-top: 2px;
  color: var(--accent-strong);
  font: 500 18px/1.2 var(--mono);
  content: counter(lab-step, decimal-leading-zero);
}

.lab-sources {
  display: grid;
  gap: 7px;
  margin-top: 12px;
}

.lab-sources a {
  color: var(--accent-strong);
  text-decoration: none;
  overflow-wrap: anywhere;
}

.lab-sources a::after {
  margin-left: 6px;
  color: var(--faint);
  font: 600 11px var(--mono);
  content: "↗";
}

.lab-sources a:hover,
.lab-sources a:focus-visible {
  color: var(--cyan);
  text-decoration: underline;
}

.lab-note .lab-caveat {
  margin-top: 16px;
  padding: 12px 14px;
  border-left: 3px solid var(--accent);
  background: var(--bg-sunk);
  color: var(--fg);
  font-size: 12.5px;
}

.lab-note .lab-note__back {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
}

@media (max-width: 1000px) {
  .lab-principles__grid,
  .lab-jump ol { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 780px) {
  .lab-notes { grid-template-columns: 1fr; }
  .lab__header { grid-template-columns: auto minmax(0, 1fr); }
  .pipeline-lab__motion,
  .rail-lab__motion { grid-column: 1 / -1; width: 100%; }
}

@media (max-width: 520px) {
  .lab-principles__grid,
  .lab-jump,
  .lab-jump ol { grid-template-columns: 1fr; }
  .lab-jump__label { padding: 8px 14px; border-right: 0; border-bottom: 1px solid var(--line); }
  .lab-principle { padding: 14px; }
  .lab__header { gap: 8px 12px; padding: 16px 14px; }
  .lab__index { font-size: 26px; }
  .lab-note { padding: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  .lab-jump a,
  .pipeline-lab__motion,
  .rail-lab__motion { transition: none; }
}