.tier-section { border-bottom: 1px solid var(--line); }
.tier-section .section-title { align-items: center; margin-bottom: 42px; }
.tier-section .section-title > p { max-width: 410px; margin: 0; font-size: 16px; }
.tier-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border: 1px solid var(--line); background: #faf9f5; }
.tier-grid article { min-width: 0; padding: 28px; }
.tier-grid article + article { border-left: 1px solid var(--line); }
.tier-heading { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 8px 12px; }
.tier-number { font-size: 10px; font-weight: 700; letter-spacing: 1.2px; color: var(--blue); }
.tier-scope { font-size: 12px; color: var(--muted); }
.tier-grid h3 { margin: 32px 0 18px; font-size: 46px; line-height: 1.1; letter-spacing: -1.5px; }
.tier-description { min-height: 104px; margin: 0; color: var(--muted); font-size: 15px; line-height: 1.7; }
.test-spec { margin: 22px 0 0; }
.test-spec > div { border-top: 1px solid var(--line); padding: 18px 0 0; margin-top: 18px; }
.test-spec dt { margin-bottom: 8px; font-size: 11px; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; }
.test-spec dd { margin: 0; font-size: 14px; line-height: 1.65; color: var(--muted); }
.test-spec > div:first-child dd { min-height: 70px; }
.tier-principle { display: grid; grid-template-columns: 240px 1fr; gap: 32px; padding: 25px 0; border-bottom: 1px solid var(--line); }
.tier-principle .eyebrow { align-self: start; line-height: 1.7; color: var(--blue); }
.tier-principle p { max-width: 790px; margin: 0; font-size: 14px; line-height: 1.7; color: var(--muted); }
.framework-footer { display: flex; align-items: center; justify-content: space-between; gap: 28px; padding-top: 18px; font-size: 13px; line-height: 1.7; color: var(--muted); }
.framework-footer a { flex-shrink: 0; color: var(--ink); }
.evolution .section-title > p { max-width: 410px; }
.evolution-flow { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 36px; list-style: none; margin: 40px 0; padding: 0; }
.evolution-flow li { position: relative; min-width: 0; padding-top: 22px; border-top: 2px solid var(--blue); }
.evolution-flow li:first-child { border-top-style: dashed; }
.evolution-flow li:not(:last-child)::after { content: '→'; position: absolute; right: -28px; top: 55px; font-size: 24px; color: var(--blue); }
.evolution-flow .eyebrow { color: var(--blue); }
.evolution-flow h3 { margin: 12px 0; font-size: 29px; line-height: 1.2; }
.evolution-flow p { margin: 0; font-size: 14px; line-height: 1.7; color: var(--muted); }
.evolution-rules { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 36px; padding-top: 20px; border-top: 1px solid var(--line); }
.evolution-rules h3 { font-size: 24px; }
.evolution-rules p { font-size: 14px; line-height: 1.75; color: var(--muted); }
.evolution-note { max-width: 900px; margin: 30px 0 0; font-size: 13px; line-height: 1.7; color: var(--muted); }

@media (min-width: 901px) and (max-width: 1150px) {
  .tier-grid article { padding: 22px; }
  .tier-heading { align-items: flex-start; flex-direction: column; gap: 8px; }
  .tier-description { min-height: 130px; }
  .test-spec > div:first-child dd { min-height: 94px; }
}
@media (max-width: 900px) {
  .tier-grid { grid-template-columns: 1fr; }
  .tier-grid article { padding: 28px; }
  .tier-grid article + article { border-left: 0; border-top: 1px solid var(--line); }
  .tier-grid h3 { margin-top: 24px; font-size: 42px; }
  .tier-description, .test-spec > div:first-child dd { min-height: 0; }
  .test-spec { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; margin-top: 4px; }
  .tier-principle { grid-template-columns: 1fr; gap: 12px; }
  .evolution-flow { gap: 28px; }
  .evolution-flow h3 { font-size: 24px; }
  .evolution-flow li:not(:last-child)::after { right: -24px; font-size: 20px; }
  .evolution-rules { gap: 24px; }
}
@media (max-width: 700px) {
  .evolution-flow { grid-template-columns: 1fr; gap: 28px; margin: 30px 0; }
  .evolution-flow li { padding: 6px 0 14px 22px; border-top: 0; border-left: 2px solid var(--blue); }
  .evolution-flow li:first-child { border-left-style: dashed; }
  .evolution-flow li:not(:last-child)::after { content: '↓'; top: auto; right: auto; left: 20px; bottom: -27px; font-size: 22px; }
  .evolution-flow h3 { font-size: 29px; margin: 8px 0; }
  .evolution-rules { grid-template-columns: 1fr; gap: 0; }
  .evolution-rules h3 { margin-bottom: 8px; }
  .evolution-rules p { margin-top: 0; }
  .evolution-note { margin-top: 22px; }
}
@media (max-width: 600px) {
  .tier-section .section-title { margin-bottom: 30px; }
  .tier-section .section-title > p { font-size: 15px; }
  .tier-grid article { padding: 24px; }
  .tier-scope { font-size: 11px; }
  .tier-grid h3 { font-size: 40px; }
  .test-spec { grid-template-columns: 1fr; gap: 0; }
  .framework-footer { align-items: flex-start; flex-direction: column; gap: 10px; }
}