.page-about {
  --a-bg-deep: #0A192F;
  --a-bg-panel: #112240;
  --a-bg-soft: #F5F7FA;
  --a-text-main: #F0F6FC;
  --a-text-muted: #8892B0;
  --a-line: #233554;
  --a-green: #39FF14;
  --a-orange: #FF6C00;
  --a-violet: #B537F2;
  --a-font-head: "Inter Tight", "Noto Sans SC", system-ui, sans-serif;
  --a-font-body: "Noto Sans SC", "PingFang SC", system-ui, sans-serif;
  --a-font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, monospace;
  background-color: var(--a-bg-soft);
}

.page-about a {
  color: inherit;
  text-decoration: none;
}

.page-about .container {
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: 20px;
}

.page-about .button {
  display: inline-block;
  padding: 12px 28px;
  border: 1px solid var(--a-line);
  border-radius: 8px;
  font-family: var(--a-font-head);
  font-weight: 600;
  font-size: 0.95rem;
  line-height: 1.4;
  color: var(--a-bg-deep);
  background-color: transparent;
  transition: border-color 0.3s, color 0.3s, background-color 0.3s, box-shadow 0.3s;
  cursor: pointer;
}

.page-about .button--primary {
  border-color: var(--a-green);
  color: var(--a-bg-deep);
  background-color: var(--a-green);
  box-shadow: 0 6px 24px rgba(57, 255, 20, 0.22);
}

.page-about .button--primary:hover {
  background-color: transparent;
  color: var(--a-bg-deep);
  border-color: var(--a-green);
  box-shadow: 0 0 0 1px var(--a-green), 0 6px 24px rgba(57, 255, 20, 0.3);
}

.page-about .section__header {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 28px;
}

.page-about .section__index {
  font-family: var(--a-font-mono);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--a-green);
  background-color: var(--a-bg-deep);
  padding: 4px 12px;
  border-radius: 4px;
  line-height: 1.6;
}

.page-about .section__heading {
  font-family: var(--a-font-head);
  font-size: clamp(1.6rem, 3vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--a-bg-deep);
  line-height: 1.2;
  margin: 0;
}

.page-about .section__lead {
  font-size: 1.05rem;
  color: var(--a-text-muted);
}

/* Hero */
.page-about .about-hero {
  background-color: var(--a-bg-deep);
  color: var(--a-text-main);
  padding: 64px 0 72px;
  position: relative;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -80px;
  bottom: -80px;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  border: 32px solid var(--a-green);
  opacity: 0.08;
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
}

.page-about .about-hero__content {
  position: relative;
  z-index: 1;
  max-width: 640px;
}

.page-about .about-hero__index {
  font-family: var(--a-font-mono);
  font-size: 1rem;
  color: var(--a-green);
  margin: 0 0 18px;
  letter-spacing: 0.15em;
}

.page-about .about-hero__title {
  font-family: var(--a-font-head);
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 24px;
}

.page-about .about-hero__lead {
  font-size: 1.1rem;
  color: var(--a-text-muted);
  max-width: 42ch;
  margin: 0 0 36px;
  line-height: 1.7;
}

.page-about .about-hero__ctrl {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

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

.page-about .about-hero__visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--a-line);
  box-shadow: 0 28px 60px rgba(0, 0, 0, 0.35);
}

/* Breadcrumb */
.page-about .breadcrumb {
  margin-bottom: 24px;
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 0.9rem;
  color: var(--a-text-muted);
}

.page-about .breadcrumb li::after {
  content: "/";
  margin-left: 8px;
  opacity: 0.5;
}

.page-about .breadcrumb li:last-child::after {
  content: "";
  margin-left: 0;
}

.page-about .breadcrumb a:hover {
  color: var(--a-green);
}

/* Layout */
.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  padding-top: 56px;
  padding-bottom: 80px;
}

/* Chapter nav */
.page-about .about-chapter-nav {
  position: sticky;
  top: 96px;
  align-self: start;
  z-index: 5;
}

.page-about .about-chapter-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--a-line);
}

.page-about .about-chapter-nav__list li {
  margin: 0;
}

.page-about .about-chapter-nav__list a {
  display: block;
  padding: 8px 16px;
  font-size: 0.92rem;
  font-family: var(--a-font-head);
  font-weight: 500;
  color: var(--a-bg-deep);
  border-left: 2px solid transparent;
  margin-left: -2px;
  transition: color 0.2s, border-color 0.2s, background-color 0.2s;
}

.page-about .about-chapter-nav__list a:hover {
  color: var(--a-orange);
  border-left-color: var(--a-orange);
}

/* Article */
.page-about .about-article {
  display: flex;
  flex-direction: column;
  gap: 80px;
  min-width: 0;
}

.page-about .about-section {
  scroll-margin-top: 100px;
}

.page-about .about-section__body,
.page-about .about-data__desc,
.page-about .about-partner__content {
  max-width: 60ch;
}

.page-about .about-section__body p,
.page-about .about-data__desc,
.page-about .about-partner__content p,
.page-about .about-partner__content ul {
  font-family: var(--a-font-body);
  font-size: 1rem;
  line-height: 1.8;
  color: #2a3a55;
  margin: 0 0 1.2em;
}

.page-about .about-idea__note {
  border-left: 3px solid var(--a-orange);
  padding-left: 18px;
  font-style: normal;
  color: var(--a-text-muted);
}

/* Timeline */
.page-about .about-timeline {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
  background: var(--a-line);
}

.page-about .about-timeline__item {
  position: relative;
  padding-left: 36px;
  padding-bottom: 36px;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--a-green);
  box-shadow: 0 0 0 4px rgba(57, 255, 20, 0.2);
}

.page-about .about-timeline__item:first-child::before {
  background: var(--a-orange);
  box-shadow: 0 0 0 4px rgba(255, 108, 0, 0.2);
}

.page-about .about-timeline__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.page-about .about-timeline__version {
  font-family: var(--a-font-mono);
  font-size: 1rem;
  font-weight: 600;
  color: var(--a-bg-deep);
  background-color: rgba(57, 255, 20, 0.15);
  padding: 3px 10px;
  border-radius: 4px;
}

.page-about .about-timeline__tag {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--a-orange);
  border: 1px solid var(--a-orange);
  padding: 2px 8px;
  border-radius: 999px;
}

.page-about .about-timeline__item h3 {
  font-family: var(--a-font-head);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--a-bg-deep);
  margin: 0 0 8px;
}

.page-about .about-timeline__item p {
  font-size: 0.95rem;
  line-height: 1.7;
  color: #2a3a55;
  margin: 0;
  max-width: 56ch;
}

.page-about .about-timeline__chart img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--a-line);
  margin-top: 8px;
}

/* Data section */
.page-about .about-data__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  align-items: start;
}

.page-about .about-data__panel {
  background-color: var(--a-bg-panel);
  border-radius: 12px;
  padding: 24px;
  border: 1px solid var(--a-line);
}

.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 20px;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
}

.page-about .stat__value {
  font-family: var(--a-font-mono);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--a-green);
  line-height: 1.2;
  margin-bottom: 8px;
}

.page-about .stat__label {
  font-size: 0.9rem;
  color: var(--a-text-muted);
  line-height: 1.5;
}

.page-about .about-data__visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--a-line);
}

.page-about .about-data__desc {
  margin-top: 24px;
}

/* Quote */
.page-about .about-quote__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.page-about .about-quote {
  margin: 0;
  padding: 28px;
  background-color: var(--a-bg-panel);
  border-left: 3px solid var(--a-orange);
  border-radius: 8px;
  transition: box-shadow 0.3s, transform 0.3s;
}

.page-about .about-quote:hover {
  box-shadow: 0 12px 32px rgba(10, 25, 47, 0.12);
  transform: translateY(-2px);
}

.page-about .about-quote p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--a-text-main);
  margin: 0;
}

/* Partner */
.page-about .about-partner__list {
  list-style: none;
  margin: 24px 0;
  padding: 24px;
  border: 1px dashed var(--a-green);
  border-radius: 12px;
}

.page-about .about-partner__list li {
  position: relative;
  padding-left: 28px;
  margin-bottom: 12px;
  line-height: 1.7;
  color: #2a3a55;
}

.page-about .about-partner__list li::before {
  content: "●";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--a-green);
  font-size: 0.85rem;
}

.page-about .about-partner__list li:last-child {
  margin-bottom: 0;
}

@media (min-width: 768px) {
  .page-about .container {
    padding-inline: 32px;
  }

  .page-about .about-hero {
    padding: 96px 0 100px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: center;
    gap: 64px;
  }

  .page-about .about-layout {
    grid-template-columns: 220px 1fr;
    gap: 56px;
    padding-top: 88px;
    padding-bottom: 120px;
  }

  .page-about .about-data__layout {
    grid-template-columns: 1fr 0.8fr;
  }

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

  .page-about .about-timeline {
    flex-direction: row;
    align-items: stretch;
  }

  .page-about .about-timeline__list {
    flex: 1;
  }

  .page-about .about-timeline__chart {
    flex: 0 0 320px;
    display: flex;
    align-items: flex-end;
  }

  .page-about .about-timeline__chart img {
    margin-top: 0;
  }
}

@media (max-width: 640px) {
  .page-about .about-chapter-nav {
    display: none;
  }

  .page-about .about-hero__ctrl {
    flex-direction: column;
    align-items: stretch;
  }

  .page-about .about-hero__ctrl .button {
    text-align: center;
  }

  .page-about .about-stats {
    grid-template-columns: 1fr 1fr;
  }
}