/* Stage 2 insertion: existing Stage 1 element styles remain unchanged. */
main.wrap { flex-direction: column; }
.concepts { width: 100%; padding-bottom: 36px; }
.primary-frame { min-height: 260px; display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 36px; padding: 30px; border: 1px solid var(--line); border-radius: 16px; background: #f5fafb; }
.concept-label, .selector-number { color: var(--teal); font-size: .75rem; }
.concept-label { margin: 0 0 18px; font-weight: 700; letter-spacing: .04em; }
.concept-copy h2 { margin: 0 0 18px; font-size: 2rem; line-height: 1.15; font-weight: 400; letter-spacing: -.025em; }
.concept-description { margin: 0; color: var(--muted); font-size: 1rem; line-height: 1.6; }
.process { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); }
.process li { position: relative; text-align: center; }
.process li:not(:last-child)::before { content: ''; position: absolute; top: 22px; left: 50%; width: 100%; height: 1px; background: var(--line); }
.step-number { position: relative; display: grid; place-items: center; width: 44px; height: 44px; margin: 0 auto 20px; border: 1px solid var(--line); border-radius: 50%; background: white; color: var(--teal); font-size: .75rem; }
.process h3 { font-size: .875rem; font-weight: 400; margin: 0; }
.primary-frame .process p { display: none; }
.concept-cards { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin-top: 18px; }
.concept-card { min-width: 0; }
button.concept-selector { width: 100%; height: 126px; display: flex; flex-direction: column; align-items: flex-start; justify-content: center; gap: 9px; position: relative; padding: 16px; border: 1px solid var(--line); border-radius: 10px; color: var(--navy); font-family: inherit; text-align: left; cursor: pointer; }
.selector-name { font-size: 1.125rem; }
.selector-summary { font-size: .875rem; color: var(--muted); line-height: 1.4; }
.concept-selector[aria-pressed="true"] { border-color: var(--teal); background: #f5fafb; }
.concept-selector[aria-pressed="true"]::after { content: ''; position: absolute; bottom: 8px; left: 16px; width: 34px; height: 2px; background: var(--teal); }
.concept-selector:hover { border-color: var(--teal); }
.concept-selector:focus-visible { outline: 2px solid var(--teal); outline-offset: 4px; }
.expand-symbol { display: none; }
[hidden] { display: none !important; }
@media (max-width: 700px) {
  .concept-cards { grid-template-columns: 1fr; gap: 12px; margin-top: 0; }
  .concept-card { border: 1px solid var(--line); border-radius: 10px; overflow: clip; }
  button.concept-selector { border: 0; border-radius: 0; min-height: 80px; height: auto; padding: 15px 42px 15px 16px; gap: 6px; background: #f5fafb; }
  .selector-number { display: none; }
  .expand-symbol { display: block; position: absolute; right: 16px; top: 26px; font-size: 1.25rem; color: var(--teal); }
  .mobile-detail { padding: 24px 20px 30px; }
  .concept-copy h2 { font-size: 1.75rem; }
  .process { grid-template-columns: 1fr; gap: 26px; margin-top: 30px; }
  .process li { display: flex; align-items: flex-start; gap: 18px; text-align: left; }
  .process li:not(:last-child)::before { top: 22px; left: 22px; width: 1px; height: calc(100% + 26px); }
  .step-number { margin: 0; flex-shrink: 0; }
  .process h3 { font-size: 1.125rem; margin: 1px 0 8px; }
  .process p { margin: 0; color: var(--muted); font-size: .875rem; line-height: 1.5; }
}

@media (min-width: 701px) {
  .primary-frame { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .concepts { overflow-wrap: anywhere; }
  button.concept-selector { height: auto; min-height: 126px; padding-bottom: 20px; }
}