.page-about {
  background: var(--c-bg);
  color: var(--c-text);
  overflow-x: clip;
}

.page-about__hero {
  position: relative;
  padding: 56px 0 0;
  border-bottom: 1px solid var(--c-border-soft);
  overflow: hidden;
  background:
    radial-gradient(ellipse at 90% 10%, rgba(157, 78, 221, 0.18), transparent 40%),
    radial-gradient(ellipse at 10% 90%, rgba(255, 42, 109, 0.12), transparent 40%);
}

.page-about__hero::before {
  content: 'PROFILE';
  position: absolute;
  top: 20px;
  right: -24px;
  z-index: 0;
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
  font-size: clamp(80px, 16vw, 180px);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.04em;
  color: transparent;
  -webkit-text-stroke: 1px rgba(255, 255, 255, 0.05);
  pointer-events: none;
}

.page-about__hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  padding-bottom: 48px;
}

.page-about__crumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  margin-bottom: 18px;
}

.page-about__crumb {
  color: var(--c-text-dim);
  text-decoration: none;
  transition: color 0.3s var(--ease-out);
}

.page-about__crumb:hover {
  color: var(--c-gold);
}

.page-about__crumb-sep {
  color: var(--c-border);
}

.page-about__crumb-current {
  color: var(--c-gold);
}

.page-about__kicker {
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-pink);
  margin: 0 0 10px;
}

.page-about__title {
  margin: 0 0 18px;
  font-size: clamp(28px, 5vw, 54px);
  line-height: 1.06;
  font-weight: 900;
  color: var(--c-white);
  letter-spacing: 0.01em;
  text-transform: uppercase;
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
}

.page-about__lead {
  margin: 0 0 12px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--c-text);
  max-width: 640px;
}

.page-about__desc {
  margin: 0 0 20px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-text-dim);
  max-width: 640px;
}

.page-about__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about__hero-art {
  position: relative;
  box-shadow: 0 24px 50px rgba(0, 0, 0, 0.35);
}

.page-about__hero-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--c-border-soft);
  clip-path: polygon(0 0, calc(100% - 30px) 0, 100% 22%, 100% 100%, 30px 100%, 0 calc(100% - 22%));
}

.page-about__shell {
  padding-top: 44px;
  padding-bottom: 40px;
}

.page-about__toc {
  margin-bottom: 40px;
  border-left: 2px solid var(--c-border);
  padding-left: 14px;
}

.page-about__toc-label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-gold);
  margin: 0 0 12px;
  text-transform: uppercase;
}

.page-about__toc-nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about__toc-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  line-height: 1.4;
  color: var(--c-text-dim);
  text-decoration: none;
  padding: 8px 10px;
  transition: color 0.3s var(--ease-out), transform 0.3s var(--ease-out);
}

.page-about__toc-link:hover {
  color: var(--c-white);
  transform: translateX(4px);
}

.page-about__toc-num {
  color: var(--c-pink);
  font-weight: 700;
}

.page-about__toc-foot {
  display: inline-block;
  margin-top: 14px;
  font-size: 13px;
  color: var(--c-gold);
  text-decoration: none;
  border-bottom: 1px solid var(--c-gold);
  padding-bottom: 2px;
}

.page-about__toc-foot:hover {
  color: var(--c-white);
  border-color: var(--c-white);
}

.page-about__content {
  min-width: 0;
  display: grid;
  gap: 0;
}

.page-about__chapter {
  scroll-margin-top: calc(var(--header-h) + 24px);
  padding: 36px 0 0;
}

.page-about__chapter::after {
  content: '';
  display: block;
  height: 2px;
  margin-top: 44px;
  background: var(--grad-gold-line);
  opacity: 0.55;
}

.page-about__chapter-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 20px;
  border-top: 1px solid var(--c-border);
  padding-top: 20px;
  position: relative;
}

.page-about__chapter-head::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 0;
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, var(--c-pink), var(--c-purple));
}

.page-about__chapter-no {
  display: block;
  font-size: 48px;
  font-weight: 900;
  line-height: 0.9;
  color: transparent;
  -webkit-text-stroke: 1px var(--c-pink);
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', sans-serif;
  flex-shrink: 0;
}

.page-about__chapter-kicker {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-gold);
}

.page-about__chapter-title {
  margin: 0;
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 900;
  line-height: 1.15;
  color: var(--c-white);
  text-transform: uppercase;
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
}

.page-about__chapter-copy {
  max-width: 720px;
}

.page-about__chapter-copy p {
  margin: 0 0 14px;
  color: var(--c-text-dim);
  font-size: 15px;
  line-height: 1.8;
}

.page-about__chapter-copy p:first-child {
  color: var(--c-text);
}

.page-about__note {
  margin: 18px 0 0;
  font-size: 13px;
  color: var(--c-purple);
  border-left: 2px solid var(--c-purple);
  padding-left: 12px;
  line-height: 1.7;
}

.page-about__timeline {
  margin: 28px 0 0;
}

.page-about__timeline-img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--c-border-soft);
}

.page-about__timeline-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin-top: 16px;
}

.page-about__milestone {
  padding: 0;
  border: 1px solid var(--c-border);
  border-left: 2px solid var(--c-pink);
  background: var(--c-surface);
}

.page-about__milestone summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 14px 16px;
}

.page-about__milestone summary::-webkit-details-marker {
  display: none;
}

.page-about__milestone-year {
  font-size: 16px;
  font-weight: 700;
  color: var(--c-gold);
}

.page-about__milestone-hint {
  font-size: 11px;
  color: var(--c-text-dim);
}

.page-about__milestone[open] .page-about__milestone-hint::before {
  content: '− ';
}

.page-about__milestone:not([open]) .page-about__milestone-hint::before {
  content: '+ ';
}

.page-about__milestone p {
  margin: 0;
  padding: 0 16px 14px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-text-dim);
}

.page-about__steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.page-about__step {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 12px;
  padding: 18px 16px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
}

.page-about__step-num {
  font-size: 16px;
  font-weight: 700;
  color: var(--c-pink);
}

.page-about__step-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--c-white);
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
}

.page-about__step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--c-text-dim);
}

.page-about__tiers {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin: 24px 0 0;
}

.page-about__tier {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 18px 16px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
}

.page-about__tier--active {
  border-color: var(--c-gold);
  box-shadow: inset 0 2px 0 var(--c-gold);
}

.page-about__tier-name {
  font-size: 14px;
  color: var(--c-text-dim);
}

.page-about__tier-res {
  margin-left: auto;
  font-size: 20px;
  font-weight: 900;
  color: var(--c-white);
  font-family: 'Courier New', 'SF Mono', monospace;
}

.page-about__tier-default {
  margin-left: auto;
}

.page-about__chapter-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about__team-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin: 24px 0 0;
}

.page-about__team-stat {
  padding: 18px 14px;
  border: 1px solid var(--c-border);
  border-top: 2px solid var(--c-purple);
  background: var(--c-surface);
  border-radius: var(--radius);
}

.page-about__team-count {
  display: block;
  font-size: 36px;
  font-weight: 900;
  line-height: 1.1;
  color: var(--c-white);
  font-family: 'Courier New', 'SF Mono', monospace;
}

.page-about__team-label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: var(--c-text-dim);
}

.page-about__team-img {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 24px;
  border: 1px solid var(--c-border-soft);
}

.page-about__team-note {
  margin: 18px 0 0;
  font-size: 14px;
  color: var(--c-text-dim);
  line-height: 1.8;
  max-width: 720px;
}

.page-about__team-note a {
  color: var(--c-gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(249, 194, 46, 0.4);
}

.page-about__team-note a:hover {
  color: var(--c-white);
  border-color: var(--c-white);
}

.page-about__outro {
  position: relative;
  margin-top: 56px;
  padding: 32px 22px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(255, 42, 109, 0.09), rgba(157, 78, 221, 0.09));
  overflow: hidden;
}

.page-about__outro::after {
  content: '続く';
  position: absolute;
  right: 12px;
  bottom: 4px;
  font-size: 72px;
  font-weight: 900;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(255, 255, 255, 0.06);
  font-family: 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
  pointer-events: none;
}

.page-about__outro-kicker {
  position: relative;
  z-index: 1;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-pink);
  margin: 0 0 10px;
}

.page-about__outro-title {
  position: relative;
  z-index: 1;
  margin: 0 0 10px;
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 900;
  color: var(--c-white);
  font-family: 'Arial Black', 'Impact', 'Hiragino Kaku Gothic Std', 'Noto Sans CJK SC', sans-serif;
}

.page-about__outro-text {
  position: relative;
  z-index: 1;
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-text-dim);
  max-width: 640px;
}

.page-about__outro-sign {
  position: relative;
  z-index: 1;
  font-size: 13px;
  color: var(--c-gold);
  margin: 0 0 22px;
}

.page-about__outro-links {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about__backtop {
  position: fixed;
  right: 16px;
  bottom: 20px;
  z-index: 20;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  font-size: 12px;
  color: var(--c-text);
  text-decoration: none;
  background: var(--c-bg-2);
  border: 1px solid var(--c-border);
  border-radius: 999px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  transition: color 0.3s var(--ease-out), border-color 0.3s var(--ease-out), transform 0.3s var(--ease-out);
}

.page-about__backtop:hover {
  color: var(--c-gold);
  border-color: var(--c-gold);
  transform: translateY(-2px);
}

@media (min-width: 680px) {
  .page-about__hero-inner {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: center;
    gap: 40px;
  }

  .page-about__hero-art {
    order: 2;
  }

  .page-about__timeline-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-about__steps {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-about__tiers {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about__team-stats {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (min-width: 920px) {
  .page-about__hero {
    padding-top: 72px;
  }

  .page-about__shell {
    display: grid;
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .page-about__toc {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    margin-bottom: 0;
  }

  .page-about__chapter {
    padding-top: 48px;
  }

  .page-about__chapter-head {
    gap: 24px;
  }

  .page-about__chapter-no {
    font-size: 64px;
  }

  .page-about__timeline-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about__tiers {
    grid-template-columns: repeat(5, 1fr);
  }
}

@media (min-width: 1200px) {
  .page-about__hero-inner {
    gap: 64px;
  }

  .page-about__outro {
    padding: 40px 36px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about__toc-link,
  .page-about__backtop {
    transition: none;
  }
}