.page-about {
  --pa-grid-line: rgba(139, 163, 192, 0.18);
  --pa-grid-line-strong: rgba(57, 255, 20, 0.12);
  --pa-axis: rgba(216, 223, 234, 0.8);
  --pa-card-shadow: 0 12px 32px rgba(11, 27, 61, 0.08);
  --pa-dark-card-shadow: 0 12px 32px rgba(11, 27, 61, 0.28);
  --pa-radius-sm: 4px;
  --pa-radius-md: 8px;
  position: relative;
  background: linear-gradient(180deg, var(--c-light) 0%, var(--c-white) 42%, var(--c-light) 100%);
  overflow: hidden;
}

.page-about__grid-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--pa-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--pa-grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9) 0%, transparent 85%);
  z-index: 0;
}

.page-about > .container {
  position: relative;
  z-index: 1;
}

.page-about__top {
  padding-top: 40px;
  padding-bottom: 24px;
}

.page-about .breadcrumbs {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--c-text-soft);
  margin-bottom: 24px;
}

.page-about .breadcrumbs__link {
  color: var(--c-text-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.page-about .breadcrumbs__link:hover {
  color: var(--c-primary);
  border-bottom-color: var(--c-accent);
}

.page-about .breadcrumbs__sep {
  margin: 0 8px;
  color: var(--c-text-soft);
}

.page-about .breadcrumbs__current {
  color: var(--c-primary);
  font-weight: 600;
}

.page-about__intro {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 1080px;
}

.page-about__intro .coord {
  align-self: flex-start;
  background: var(--c-primary);
  color: var(--c-accent);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 0 4px 4px 0;
  box-shadow: 3px 3px 0 rgba(57, 255, 20, 0.35);
}

.page-about h1 {
  font-family: var(--font-head);
  font-size: clamp(30px, 5vw, 48px);
  line-height: 1.2;
  font-weight: 900;
  color: var(--c-primary);
  margin: 0;
  letter-spacing: -0.02em;
}

.page-about__intro-lead {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.8;
  color: var(--c-text-soft);
  max-width: 70ch;
  margin: 0;
}

.page-about__board {
  position: relative;
  border-radius: 0;
  padding: 28px 24px 36px;
  margin-bottom: 32px;
}

.page-about .board--light {
  background: var(--c-white);
  border: 1px solid var(--c-line-light);
  box-shadow: var(--pa-card-shadow);
  border-radius: var(--pa-radius-md);
}

.page-about .board--dark {
  background: var(--c-primary);
  border: 1px solid var(--c-line-dark);
  box-shadow: var(--pa-dark-card-shadow);
  border-radius: var(--pa-radius-md);
}

.page-about .board__coord {
  position: absolute;
  top: -1px;
  left: -1px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  font-weight: 600;
  background: var(--c-accent);
  color: var(--c-primary);
  padding: 2px 10px;
  z-index: 2;
  border-radius: var(--pa-radius-sm) 0 var(--pa-radius-sm) 0;
}

.page-about .board--dark .board__coord {
  color: var(--c-primary);
}

/* 01 intro */
.page-about__intro-grid {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.page-about__intro-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
}

.page-about__intro-copy .chapter__idx,
.page-about__team-copy .chapter__idx,
.page-about__migration-copy .chapter__idx {
  font-family: var(--font-mono);
  font-size: 64px;
  line-height: 1;
  font-weight: 700;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--c-primary);
  opacity: 0.9;
  user-select: none;
}

.page-about__intro-copy h2,
.page-about__team-copy h2,
.page-about__migration-copy h2 {
  font-family: var(--font-head);
  font-size: var(--text-h2);
  line-height: 1.3;
  font-weight: 900;
  color: var(--c-primary);
  margin: 0;
}

.page-about .prose {
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: 1.8;
  color: var(--c-text-body);
  max-width: 62ch;
}

.page-about .prose p {
  margin: 0 0 14px;
}

.page-about .prose p:last-child {
  margin-bottom: 0;
}

.page-about__tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 8px;
}

.page-about .tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--c-primary);
  background: var(--c-light);
  border: 1px solid var(--c-line-light);
  padding: 4px 12px;
  border-radius: var(--pa-radius-sm);
  transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.page-about .tag:hover {
  border-color: var(--c-accent);
  background: var(--c-primary);
  color: var(--c-accent);
}

.page-about__media-intro,
.page-about__media-team,
.page-about__media-migration {
  position: relative;
  overflow: hidden;
  background: var(--c-light);
  border: 1px solid var(--c-line-light);
}

.page-about__media-intro img,
.page-about__media-team img,
.page-about__media-migration img {
  width: 100%;
  max-width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.page-about__media-intro {
  border-radius: var(--pa-radius-md);
  min-height: 220px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about__media-intro img {
  width: 100%;
  height: 100%;
  min-height: 220px;
  object-fit: cover;
}

/* 02 timeline */
.page-about__chapter-head {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 32px;
}

.page-about__board--timeline .chapter__idx--accent {
  color: var(--c-accent);
  -webkit-text-stroke: 1.5px var(--c-accent);
}

.page-about__board--timeline h2 {
  font-family: var(--font-head);
  font-size: var(--text-h2);
  line-height: 1.3;
  font-weight: 900;
  color: var(--c-text-dark);
  margin: 0 0 6px;
}

.page-about__board--timeline .chapter__lead {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.7;
  color: var(--c-text-dim);
  margin: 0;
  max-width: 60ch;
}

.page-about__timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-left: 8px;
}

.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-accent) 0%, rgba(57, 255, 20, 0.5) 40%, var(--c-line-dark) 100%);
}

.page-about__tl-item {
  position: relative;
  display: flex;
  gap: 20px;
  padding: 18px 0 18px 0;
}

.page-about__tl-item:first-child {
  padding-top: 0;
}

.page-about__tl-item:last-child {
  padding-bottom: 0;
}

.page-about__tl-node {
  flex: 0 0 auto;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  z-index: 1;
  background: var(--c-primary);
  border-radius: 50%;
  cursor: default;
  transition: transform 0.2s ease;
}

.page-about__tl-node:hover,
.page-about__tl-node:focus-visible {
  transform: scale(1.15);
  outline: none;
}

.page-about__tl-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--c-accent);
  box-shadow: 0 0 0 3px rgba(57, 255, 20, 0.2);
  transition: box-shadow 0.2s ease;
}

.page-about__tl-node:hover .page-about__tl-dot,
.page-about__tl-node:focus-visible .page-about__tl-dot {
  box-shadow: 0 0 0 5px rgba(57, 255, 20, 0.3);
}

.page-about__tl-code {
  position: absolute;
  top: -6px;
  right: -10px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: var(--c-accent);
  background: transparent;
  letter-spacing: 0.06em;
  opacity: 0.9;
}

.page-about__tl-body {
  flex: 1;
  min-width: 0;
}

.page-about__tl-body h3 {
  font-family: var(--font-body);
  font-size: 18px;
  font-weight: 700;
  color: var(--c-text-dark);
  margin: 0 0 6px;
  letter-spacing: -0.01em;
}

.page-about__tl-body p {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-text-dim);
  margin: 0;
  max-width: 52ch;
}

.page-about .page-about__legend {
  margin-top: 28px;
  padding-top: 18px;
  border-top: 1px solid var(--c-line-dark);
  gap: 18px;
  flex-wrap: wrap;
}

.page-about .legend__item {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-text-dim);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.page-about .legend__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.page-about .legend__dot--line {
  background: var(--c-accent);
  box-shadow: 0 0 0 2px rgba(57, 255, 20, 0.2);
}

.page-about .legend__dot--data {
  background: var(--c-data);
}

/* 03 data capacity */
.page-about__board--data .chapter__idx {
  color: var(--c-primary);
  -webkit-text-stroke: 1.5px var(--c-primary);
}

.page-about__board--data h2 {
  font-family: var(--font-head);
  font-size: var(--text-h2);
  line-height: 1.3;
  font-weight: 900;
  color: var(--c-primary);
  margin: 0 0 6px;
}

.page-about__board--data .chapter__lead {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.7;
  color: var(--c-text-soft);
  margin: 0;
}

.page-about__stats-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 28px;
}

.page-about__stat {
  position: relative;
  background: var(--c-light);
  border: 1px solid var(--c-line-light);
  padding: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  border-radius: var(--pa-radius-sm);
}

.page-about__stat:hover {
  transform: translateY(-3px);
  box-shadow: var(--pa-card-shadow);
  border-color: var(--c-accent);
}

.page-about__stat-value {
  font-family: var(--font-mono);
  font-size: 40px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--c-primary);
  letter-spacing: -0.04em;
  display: inline-flex;
  align-items: baseline;
  gap: 2px;
  transition: transform 0.2s ease;
}

.page-about__stat:hover .page-about__stat-value {
  transform: scale(1.02);
}

.page-about__stat-value--data {
  color: var(--c-data);
}

.page-about__stat-value--mono {
  font-variant-numeric: tabular-nums;
}

.page-about__stat-suffix {
  font-size: 16px;
  font-weight: 600;
  margin-left: 2px;
  opacity: 0.85;
}

.page-about__stat-label {
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  color: var(--c-primary);
  letter-spacing: 0.02em;
}

.page-about__stat-note {
  font-family: var(--font-body);
  font-size: 13px;
  line-height: 1.65;
  color: var(--c-text-soft);
  margin: 0;
}

.page-about__chart-line {
  position: relative;
  margin-top: 28px;
  padding: 18px 16px 14px;
  background: var(--c-light);
  border: 1px solid var(--c-line-light);
  border-radius: var(--pa-radius-sm);
  overflow: hidden;
}

.page-about__chart-axis {
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 36px;
  height: 1px;
  background: var(--pa-axis);
}

.page-about__chart-axis::before,
.page-about__chart-axis::after {
  content: "";
  position: absolute;
  height: 5px;
  width: 1px;
  background: var(--pa-axis);
  left: 0;
  top: -2px;
}

.page-about__chart-axis::after {
  left: auto;
  right: 0;
}

.page-about__chart-area {
  position: relative;
  height: 64px;
}

.page-about__chart-dot {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--c-data);
  z-index: 1;
}

.page-about__chart-dot::before {
  content: "";
  position: absolute;
  top: 5px;
  left: 5px;
  width: 100%;
  height: 1.5px;
  background: var(--pa-grid-line-strong);
  transform-origin: left center;
}

.page-about__chart-dot--a {
  left: 8%;
  top: 40px;
}

.page-about__chart-dot--b {
  left: 38%;
  top: 28px;
  width: 12px;
  height: 12px;
  background: var(--c-accent);
}

.page-about__chart-dot--c {
  left: 68%;
  top: 16px;
}

.page-about__chart-dot--d {
  left: 90%;
  top: 8px;
  width: 14px;
  height: 14px;
  background: var(--c-accent);
}

.page-about__chart-dot--a::before {
  width: 60px;
}

.page-about__chart-dot--b::before {
  width: 80px;
}

.page-about__chart-dot--c::before {
  width: 70px;
}

.page-about__chart-dot--d::before {
  display: none;
}

.page-about__chart-caption {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--c-text-soft);
  margin-top: 12px;
}

/* 04 team */
.page-about__team-grid {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.page-about__media-team {
  border-radius: var(--pa-radius-md);
  min-height: 220px;
  overflow: hidden;
  border: 1px solid var(--c-line-dark);
  background: var(--c-primary);
}

.page-about__media-team img {
  width: 100%;
  height: 100%;
  min-height: 220px;
  object-fit: cover;
}

.page-about__team-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
}

.page-about__team-copy .chapter__idx--accent {
  color: var(--c-accent);
  -webkit-text-stroke: 1.5px var(--c-accent);
}

.page-about__team-copy h2 {
  color: var(--c-text-dark);
}

.page-about__team-copy .prose {
  color: var(--c-text-dark);
  max-width: 64ch;
}

.page-about__team-copy .prose p {
  color: var(--c-text-dark);
}

.page-about__badge-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
}

.page-about__badge {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--c-line-dark);
  padding: 12px 16px;
  min-width: 140px;
  transition: border-color 0.2s ease, background 0.2s ease;
  border-radius: var(--pa-radius-sm);
}

.page-about__badge:hover {
  border-color: var(--c-accent);
  background: rgba(57, 255, 20, 0.06);
}

.page-about__badge-code {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  color: var(--c-accent);
  letter-spacing: 0.02em;
}

.page-about__badge-label {
  font-family: var(--font-body);
  font-size: 12px;
  line-height: 1.5;
  color: var(--c-text-dim);
}

/* 05 migration */
.page-about__migration-grid {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.page-about__migration-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
}

.page-about__migration-copy h2 {
  color: var(--c-primary);
}

.page-about__migration-copy .prose {
  color: var(--c-text-body);
}

.page-about__migration-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
}

.page-about .btn {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 10px 20px;
  text-decoration: none;
  border: 1.5px solid transparent;
  transition: all 0.2s ease;
  border-radius: var(--pa-radius-sm);
}

.page-about .btn--solid {
  background: var(--c-accent);
  color: var(--c-primary);
  border-color: var(--c-accent);
}

.page-about .btn--solid:hover {
  background: var(--c-primary);
  color: var(--c-accent);
  border-color: var(--c-accent);
}

.page-about .btn--ghost {
  border-color: var(--c-primary);
  color: var(--c-primary);
  background: transparent;
}

.page-about .btn--ghost:hover {
  border-color: var(--c-primary);
  background: var(--c-primary);
  color: var(--c-accent);
}

.page-about__media-migration {
  border-radius: var(--pa-radius-md);
  min-height: 180px;
  overflow: hidden;
  border: 1px solid var(--c-line-light);
}

.page-about__media-migration img {
  width: 100%;
  height: 100%;
  min-height: 180px;
  object-fit: cover;
}

@media (min-width: 640px) {
  .page-about__stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-about__board {
    padding: 36px 32px 42px;
  }

  .page-about__timeline {
    padding-left: 12px;
  }

  .page-about__tl-item {
    gap: 28px;
  }

  .page-about__tl-body h3 {
    font-size: 19px;
  }

  .page-about__tl-body p {
    font-size: 15px;
  }
}

@media (min-width: 900px) {
  .page-about__board {
    padding: 42px 40px 48px;
    margin-bottom: 40px;
  }

  .page-about__intro-grid {
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: 40px;
    align-items: center;
  }

  .page-about__intro-copy {
    gap: 16px;
  }

  .page-about__intro-copy .chapter__idx,
  .page-about__team-copy .chapter__idx,
  .page-about__migration-copy .chapter__idx {
    font-size: 72px;
  }

  .page-about__media-intro {
    min-height: 260px;
  }

  .page-about__stats-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    margin-top: 32px;
  }

  .page-about__stat {
    border-right: 1px solid var(--c-line-light);
    border-radius: 0;
    margin-right: -1px;
    padding: 24px 20px;
  }

  .page-about__stat:first-child {
    border-left: 1px solid var(--c-line-light);
  }

  .page-about__stat:hover {
    z-index: 2;
    background: var(--c-white);
  }

  .page-about__stat-value {
    font-size: 44px;
  }

  .page-about__chart-line {
    margin-top: 32px;
    padding: 20px 24px 16px;
  }

  .page-about__chart-area {
    height: 80px;
  }

  .page-about__chart-dot--a {
    left: 8%;
    top: 52px;
  }

  .page-about__chart-dot--b {
    left: 38%;
    top: 36px;
  }

  .page-about__chart-dot--c {
    left: 68%;
    top: 20px;
  }

  .page-about__chart-dot--d {
    left: 90%;
    top: 10px;
  }

  .page-about__chart-axis {
    bottom: 44px;
  }

  .page-about__team-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 40px;
    align-items: center;
  }

  .page-about__media-team {
    min-height: 280px;
  }

  .page-about__migration-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 40px;
    align-items: center;
  }

  .page-about__media-migration {
    min-height: 220px;
  }
}

@media (min-width: 1200px) {
  .page-about__intro-lead {
    font-size: 18px;
  }

  .page-about__board--intro {
    transform: perspective(1200px) rotateY(-1.2deg);
    transform-origin: left center;
  }

  .page-about__board--timeline {
    transform: perspective(1200px) rotateY(1deg);
    transform-origin: right center;
  }

  .page-about__tl-item {
    padding: 20px 0;
  }

  .page-about__stat-note {
    font-size: 13px;
  }
}