.page-about {
  --ab-track-w: 232px;
  --ab-card-bg: rgba(31, 40, 51, 0.66);
  --ab-blue-line: rgba(0, 229, 255, 0.35);
  --ab-red-line: rgba(230, 57, 70, 0.55);
  --ab-gap: clamp(28px, 5vw, 64px);
  position: relative;
  z-index: 0;
  overflow-x: hidden;
  padding-bottom: clamp(40px, 9vw, 88px);
}

.about-breadcrumb {
  margin-bottom: clamp(16px, 3vw, 28px);
}

.about-hero {
  position: relative;
  margin-bottom: clamp(36px, 7vw, 56px);
  padding: clamp(28px, 5vw, 56px);
  background:
    linear-gradient(135deg, rgba(230, 57, 70, 0.95) 0%, rgba(11, 12, 16, 0.82) 62%),
    linear-gradient(45deg, rgba(255, 255, 255, 0.04) 25%, transparent 25%, transparent 50%, rgba(255, 255, 255, 0.04) 50%, rgba(255, 255, 255, 0.04) 75%, transparent 75%);
  background-size: auto, 22px 22px;
  border-left: 4px solid var(--blue);
  overflow: hidden;
}

.about-hero::after {
  content: '';
  position: absolute;
  right: 0;
  bottom: 0;
  width: 120px;
  height: 24px;
  background: var(--black);
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.about-hero__idx {
  display: inline-block;
  font-family: var(--font-data);
  letter-spacing: 0.24em;
  font-size: 12px;
  color: var(--blue);
  border: 1px solid var(--ab-blue-line);
  padding: 6px 10px;
  margin-bottom: 18px;
}

.about-hero__title {
  margin: 0 0 12px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.8rem, 4vw, 2.9rem);
  letter-spacing: -0.02em;
  line-height: 1.18;
  color: var(--white);
  max-width: 720px;
}

.about-hero__lead {
  margin: 0 0 24px;
  max-width: 660px;
  color: var(--smoke);
  font-size: clamp(0.95rem, 1.6vw, 1.06rem);
  line-height: 1.8;
}

.about-hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.about-layout {
  display: grid;
  gap: var(--ab-gap);
}

.about-doc {
  min-width: 0;
}

.about-track {
  position: relative;
  padding: 20px;
  background: var(--gray);
  border-left: 3px solid var(--red);
}

.about-track__heading {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.about-track__index {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--blue);
  letter-spacing: 0.2em;
}

.about-track__rule {
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--ab-red-line), transparent);
}

.about-track__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

.about-track__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 4px;
  color: var(--smoke);
  text-decoration: none;
  font-size: 0.92rem;
  border-bottom: 2px solid transparent;
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

.about-track__num {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--red);
  opacity: 0.75;
}

.about-track__link:hover {
  color: var(--white);
}

.about-track__link.is-active {
  color: var(--white);
  border-bottom-color: var(--blue);
  background: rgba(0, 229, 255, 0.06);
  padding-left: 8px;
  padding-right: 8px;
}

.about-track__link.is-active .about-track__num {
  opacity: 1;
  color: var(--blue);
}

.about-track__meta {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid rgba(197, 198, 199, 0.14);
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.about-track__meta .data-figure {
  color: var(--white);
  font-size: 0.92rem;
}

.about-track__meta-label {
  font-size: 12px;
  color: var(--smoke);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.about-section {
  position: relative;
  margin-bottom: clamp(48px, 10vh, 96px);
  scroll-margin-top: calc(var(--header-h) + 18px);
}

.about-chapter {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.about-chapter__idx {
  font-family: var(--font-data);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--red);
}

.about-chapter__line {
  width: 42px;
  height: 2px;
  background: var(--ab-red-line);
  transform: skewX(-28deg);
}

.about-chapter__label {
  font-family: var(--font-data);
  font-size: 0.82rem;
  letter-spacing: 0.1em;
  color: var(--blue);
  text-transform: uppercase;
}

.about-section__title {
  margin: 0 0 10px;
  font-size: clamp(1.4rem, 2.6vw, 1.85rem);
  color: var(--white);
  line-height: 1.3;
}

.about-section__lede {
  margin: 0 0 24px;
  color: var(--smoke);
}

.about-copy p {
  margin: 0 0 14px;
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--smoke);
}

.about-link {
  color: var(--blue);
  text-decoration: underline;
  text-decoration-color: rgba(0, 229, 255, 0.4);
  text-underline-offset: 3px;
}

.about-link:hover {
  color: var(--white);
}

.about-section__grid {
  display: grid;
  gap: clamp(20px, 4vw, 32px);
}

.about-section__grid--system {
  align-items: center;
}

.about-media {
  position: relative;
  margin: 0;
  overflow: hidden;
  background: var(--gray);
  border: 1px solid rgba(197, 198, 199, 0.14);
  transform: translateZ(0);
}

.about-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.about-media--origin {
  width: min(100%, 500px);
  margin-inline: auto;
  border-left: 4px solid var(--red);
}

.about-media--system {
  width: min(100%, 700px);
  margin-inline: auto;
}

.about-media--team {
  width: min(100%, 400px);
  margin-inline: auto;
  border-left: 4px solid var(--blue);
}

.about-tl {
  position: relative;
  display: grid;
  gap: 22px;
  color: rgba(230, 57, 70, 0.35);
}

.about-tl__line {
  position: absolute;
  left: 6px;
  top: 6px;
  width: 2px;
  height: calc(100% - 12px);
  pointer-events: none;
}

.milestone {
  position: relative;
  padding: clamp(18px, 3vw, 24px);
  margin-left: 26px;
  background: var(--ab-card-bg);
  border-left: 3px solid var(--red);
  transition: border-color var(--transition), background var(--transition);
}

.milestone::before {
  content: '';
  position: absolute;
  right: 0;
  bottom: 0;
  width: 24px;
  height: 24px;
  background: var(--black);
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.milestone:hover {
  border-left-color: var(--blue);
  background: rgba(31, 40, 51, 0.9);
}

.milestone__dot {
  position: absolute;
  left: -24px;
  top: 22px;
  width: 10px;
  height: 10px;
  background: var(--red);
  transform: rotate(45deg);
  box-shadow: 0 0 10px rgba(230, 57, 70, 0.7);
  z-index: 1;
}

.milestone__year {
  display: inline-block;
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(1.5rem, 3vw, 2rem);
  line-height: 1.15;
  color: var(--white);
  margin-bottom: 8px;
}

.milestone__title {
  margin: 0 0 8px;
  font-size: 1.12rem;
  color: var(--white);
  line-height: 1.4;
}

.milestone__desc {
  margin: 0;
  color: var(--smoke);
  font-size: 0.93rem;
  line-height: 1.7;
}

.about-syslist {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.about-syslist__item {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 12px 14px;
  background: rgba(31, 40, 51, 0.48);
  border-left: 2px solid transparent;
  transition: border-color var(--transition);
}

.about-syslist__item:hover {
  border-left-color: var(--red);
}

.about-syslist__tag {
  flex-shrink: 0;
}

.about-syslist__item > span:last-child {
  min-width: 0;
  color: var(--smoke);
  font-size: 0.92rem;
  line-height: 1.65;
}

.about-next {
  margin-top: 24px;
  padding: clamp(24px, 4vw, 40px);
  background:
    linear-gradient(135deg, rgba(230, 57, 70, 0.16), rgba(0, 229, 255, 0.06) 70%),
    var(--gray);
  border: 1px solid rgba(197, 198, 199, 0.12);
  display: grid;
  gap: 18px;
}

.about-next__idx {
  font-family: var(--font-data);
  font-size: 0.82rem;
  letter-spacing: 0.14em;
  color: var(--blue);
}

.about-next__head p {
  margin: 8px 0 0;
  color: var(--smoke);
}

.about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

@media (min-width: 720px) {
  .about-track__nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .about-section__grid--origin {
    grid-template-columns: 1fr minmax(260px, 420px);
  }

  .about-section__grid--team {
    grid-template-columns: 1fr minmax(220px, 340px);
  }

  .about-next {
    grid-template-columns: 1fr auto;
    align-items: end;
  }
}

@media (min-width: 1100px) {
  .about-layout {
    grid-template-columns: var(--ab-track-w) minmax(0, 1fr);
    align-items: start;
  }

  .about-track {
    position: sticky;
    top: calc(var(--header-h) + 22px);
  }

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

  .about-doc {
    max-width: 920px;
  }

  .about-section__grid--system {
    grid-template-columns: minmax(0, 1fr) minmax(300px, 440px);
  }
}