.faq-hero {
  overflow: hidden;
  border-bottom: var(--line-thin) solid var(--color-border);
  background:
    linear-gradient(var(--color-grid) var(--line-thin), var(--color-transparent) var(--line-thin)),
    linear-gradient(90deg, var(--color-grid) var(--line-thin), var(--color-transparent) var(--line-thin)),
    var(--color-bg);
  background-size: 32px 32px;
}

.faq-hero::after {
  position: absolute;
  top: 12%;
  right: -8%;
  width: 42vw;
  height: 42vw;
  pointer-events: none;
  border: var(--line-thin) dashed var(--color-border);
  border-radius: var(--radius-pill);
  opacity: 0.55;
  content: "";
}

.faq-hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(340px, 0.7fr);
  gap: clamp(36px, 7vw, 96px);
  align-items: center;
}

.faq-hero-copy {
  min-width: 0;
}

.faq-hero-copy h1 {
  max-width: 800px;
  margin-bottom: 22px;
}

.faq-hero-copy .lead {
  margin-bottom: 28px;
}

.faq-observation {
  position: relative;
  border-top: 4px solid var(--color-success);
  background: var(--color-paper-glass);
}

.faq-observation::before {
  position: absolute;
  top: 18px;
  right: 18px;
  width: 11px;
  height: 11px;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  content: "";
}

.faq-observation h2 {
  margin-top: 10px;
  font-size: clamp(26px, 3vw, 36px);
}

.diagnostic-sequence {
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  list-style: none;
}

.diagnostic-sequence li {
  min-width: 0;
  padding: 13px 0;
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 13px;
  align-items: start;
  border-top: var(--line-thin) solid var(--color-border-soft);
}

.diagnostic-sequence li > span {
  color: var(--color-success);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
}

.diagnostic-sequence p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 14px;
  line-height: 1.65;
}

.diagnostic-sequence strong {
  display: block;
  color: var(--color-text);
}

.faq-index-section {
  padding-top: 34px;
  padding-bottom: 20px;
}

.faq-index-section .toc-tabs {
  margin-bottom: 24px;
}

.faq-category {
  overflow: clip;
}

.faq-category-layout {
  display: grid;
  grid-template-columns: minmax(230px, 0.42fr) minmax(0, 1fr);
  gap: clamp(32px, 7vw, 88px);
  align-items: start;
}

.faq-category-head {
  position: sticky;
  top: calc(var(--header-height) + 28px);
  min-width: 0;
}

.faq-category-number {
  display: block;
  margin-bottom: 20px;
  color: var(--color-border);
  font-family: var(--font-display);
  font-size: clamp(74px, 10vw, 132px);
  font-weight: 200;
  line-height: 0.72;
  letter-spacing: -0.09em;
}

.faq-category-head .mono-label {
  display: block;
  margin-bottom: 12px;
  color: var(--color-accent-dark);
}

.faq-category-head h2 {
  margin-bottom: 15px;
}

.faq-category-head p {
  margin-bottom: 0;
  color: var(--color-text-muted);
  font-size: 15px;
}

.faq-category .faq-list {
  position: relative;
}

.faq-category .faq-list::before {
  position: absolute;
  top: -24px;
  right: 18px;
  color: var(--color-border);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.08em;
  content: "OPEN RECORD ↓";
}

.faq-category .faq-item {
  box-shadow: 0 9px 24px var(--color-shadow-soft);
}

.faq-category .faq-item summary {
  font-size: 16px;
  line-height: 1.55;
}

.faq-category .faq-answer p {
  line-height: 1.9;
}

.faq-final-note {
  grid-column: 2;
  margin-top: 30px;
  margin-bottom: 0;
}

@media (max-width: 900px) {
  .faq-hero-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .faq-observation {
    max-width: 680px;
  }

  .faq-category-layout {
    grid-template-columns: minmax(180px, 0.34fr) minmax(0, 1fr);
    gap: 30px;
  }
}

@media (max-width: 700px) {
  .faq-hero::after {
    width: 76vw;
    height: 76vw;
  }

  .faq-category-layout {
    grid-template-columns: minmax(0, 1fr);
  }

  .faq-category-head {
    position: static;
  }

  .faq-category-number {
    margin-bottom: 15px;
    font-size: 72px;
  }

  .faq-category-head p {
    max-width: 560px;
  }

  .faq-category .faq-list {
    margin-top: 18px;
  }

  .faq-final-note {
    grid-column: 1;
  }
}

@media (max-width: 420px) {
  .faq-observation {
    padding: 18px;
  }

  .diagnostic-sequence li {
    grid-template-columns: 31px minmax(0, 1fr);
    gap: 9px;
  }

  .faq-category .faq-item summary {
    padding-right: 48px;
    font-size: 15px;
  }
}