.page-about {
  --about-grid-line: rgba(248, 249, 250, 0.055);
  --about-card-bg: rgba(59, 31, 75, 0.32);
  --about-card-bg-strong: rgba(59, 31, 75, 0.48);
  scroll-margin-top: calc(var(--header-height) + 16px);
}

/* ===== Hero ===== */
.page-about-hero {
  position: relative;
  background:
    linear-gradient(var(--about-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-grid-line) 1px, transparent 1px),
    linear-gradient(160deg, var(--color-primary) 0%, var(--color-secondary) 68%, rgba(255, 77, 0, 0.32) 100%);
  background-size: 32px 32px, 32px 32px, 100% 100%;
  padding: 40px 0 64px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), 0 100%);
  margin-bottom: 8px;
}

.page-about-hero .breadcrumb {
  margin-bottom: 28px;
}

.page-about-hero-grid {
  display: grid;
  gap: 32px;
  align-items: center;
}

.page-about-hero-copy .section-index {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.18em;
}

.page-about-hero-copy h1 {
  font-family: var(--font-title);
  font-size: 30px;
  line-height: 1.2;
  color: var(--color-text);
  margin: 14px 0 16px;
}

.page-about-h1-sub {
  display: block;
  font-size: 0.68em;
  color: var(--color-accent-alt);
  margin-top: 6px;
}

.page-about-hero-lead {
  color: var(--color-text-sub);
  font-size: 16px;
  line-height: 1.75;
  margin: 0;
  max-width: 48em;
}

.page-about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about-hero-coord {
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about-hero-coord-card {
  background: rgba(26, 11, 46, 0.55);
  border: 1px solid var(--line-thin);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
  max-width: 340px;
  position: relative;
  overflow: hidden;
}

.page-about-hero-coord-card::after {
  content: '+';
  position: absolute;
  right: 10px;
  top: 0;
  font-family: var(--font-mono);
  font-size: 54px;
  line-height: 1;
  color: rgba(255, 77, 0, 0.28);
  pointer-events: none;
}

.page-about-hero-coord-card .route-coord {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0.08em;
}

.page-about-hero-coord-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--color-text-sub);
}

.page-about-hero-coord-line {
  height: 1px;
  background: var(--line-thin);
  margin: 10px 0;
}

/* ===== Body layout ===== */
.page-about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  padding-top: 24px;
  padding-bottom: 72px;
}

/* ===== TOC ===== */
.page-about-toc {
  border-left: 2px solid rgba(255, 77, 0, 0.5);
  padding-left: 16px;
}

.page-about-toc-title {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--color-text-sub);
  margin-bottom: 12px;
}

.page-about-toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.page-about-toc-list li {
  margin: 0;
}

.page-about-toc-list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  text-decoration: none;
  color: var(--color-text-sub);
  font-size: 14px;
  padding: 6px 10px;
  border: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.page-about-toc-list a:hover,
.page-about-toc-list a:focus {
  color: var(--color-text);
  border-color: var(--line-thin);
  background: rgba(255, 77, 0, 0.08);
}

.page-about-toc-index {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-accent);
}

/* ===== Section base ===== */
.page-about-section {
  padding: 40px 0 8px;
  border-top: 1px solid var(--line-thin);
  scroll-margin-top: calc(var(--header-height) + 16px);
}

.page-about-section:first-of-type {
  border-top: none;
  padding-top: 4px;
}

.page-about-section .section-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  border-bottom: 1px solid var(--line-thin);
  padding-bottom: 12px;
}

.page-about-section .section-index {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
}

.page-about-section h2 {
  font-family: var(--font-title);
  font-size: 26px;
  line-height: 1.2;
  color: var(--color-text);
  margin: 0;
}

.page-about-section-lead {
  color: var(--color-accent-alt);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.08em;
  margin: 14px 0 0;
}

/* ===== Origin section ===== */
.page-about-origin-grid {
  display: grid;
  gap: 24px;
  margin-top: 24px;
}

.page-about .prose p {
  margin: 0 0 14px;
  color: var(--color-text-sub);
  line-height: 1.75;
}

.page-about-origin-figure {
  margin: 0;
}

.page-about-img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-thin);
  box-shadow: var(--shadow-card);
}

.page-about-origin-figure figcaption,
.page-about-cap-figure figcaption {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-text-sub);
  padding-top: 8px;
  border-bottom: 1px solid var(--line-thin);
}

/* ===== Timeline section ===== */
.page-about-timeline-hero {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line-thin);
  margin-top: 24px;
}

.page-about-timeline-bg {
  display: block;
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.page-about-timeline-hero-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: flex-end;
  background: linear-gradient(0deg, rgba(26, 11, 46, 0.88) 0%, rgba(26, 11, 46, 0.22) 100%);
  padding: 20px;
}

.page-about-timeline-hero-overlay span {
  font-family: var(--font-mono);
  color: var(--color-text);
  font-size: 13px;
  letter-spacing: 0.18em;
}

.page-about-timeline {
  position: relative;
  margin-top: 24px;
  padding-left: 32px;
}

.page-about-timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-accent-alt) 62%, transparent 100%);
}

.page-about-milestone {
  position: relative;
  padding: 0 0 28px;
}

.page-about-milestone:last-child {
  padding-bottom: 0;
}

.page-about-milestone::before {
  content: '';
  position: absolute;
  left: -28px;
  top: 10px;
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border: 2px solid var(--color-primary);
  border-radius: 2px;
  transform: rotate(45deg);
}

.page-about-milestone-year {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 20px;
  color: var(--color-accent);
  display: block;
}

.page-about-milestone-card {
  background: var(--about-card-bg);
  border: 1px solid var(--line-thin);
  border-left: 3px solid var(--color-accent);
  padding: 16px;
  margin-top: 8px;
}

.page-about-milestone-card h3 {
  font-family: var(--font-title);
  font-size: 16px;
  color: var(--color-text);
  margin: 0 0 8px;
}

.page-about-milestone-card p {
  font-size: 14px;
  line-height: 1.65;
  color: var(--color-text-sub);
  margin: 0;
}

/* ===== Capabilities section ===== */
.page-about-cap-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 24px;
}

.page-about-cap-grid .data-card {
  background: var(--about-card-bg);
  border: 1px solid var(--line-thin);
  padding: 20px;
  position: relative;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
  box-shadow: var(--shadow-card);
}

.page-about-cap-grid .data-card[data-coord]::before {
  content: attr(data-coord);
  position: absolute;
  top: 8px;
  right: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: rgba(248, 249, 250, 0.35);
}

.page-about-cap-num {
  font-family: var(--font-mono);
  font-size: 36px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-accent);
  display: block;
}

.page-about-cap-grid h3 {
  font-family: var(--font-title);
  font-size: 16px;
  color: var(--color-text);
  margin: 10px 0 8px;
}

.page-about-cap-grid p {
  font-size: 14px;
  line-height: 1.65;
  color: var(--color-text-sub);
  margin: 0;
}

.page-about-cap-figure {
  margin: 24px 0 0;
}

.page-about-cap-img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-thin);
  box-shadow: var(--shadow-card);
}

/* ===== Security section ===== */
.page-about-sec-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 24px;
}

.page-about-sec-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .btn-accent {
  color: #1A0B2E;
}

.page-about-sec-contact {
  background: var(--about-card-bg-strong);
  border: 1px dashed rgba(248, 249, 250, 0.22);
  padding: 20px;
  align-self: start;
}

.page-about-sec-contact h3 {
  font-family: var(--font-title);
  font-size: 16px;
  color: var(--color-text);
  margin: 0 0 12px;
  border-bottom: 1px solid var(--line-thin);
  padding-bottom: 8px;
}

.page-about-sec-contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about-sec-contact-list li {
  border-bottom: 1px solid var(--line-thin);
  padding: 12px 0;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.5;
  color: var(--color-text-sub);
  display: flex;
  flex-direction: column;
  gap: 2px;
  overflow-wrap: break-word;
}

.page-about-sec-contact-list li:last-child {
  border-bottom: none;
}

.page-about-sec-contact-list .contact-label {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent-alt);
}

/* ===== Desktop responsive ===== */
@media (min-width: 768px) {
  .page-about-hero {
    padding: 64px 0 88px;
  }

  .page-about-hero-copy h1 {
    font-size: 42px;
  }

  .page-about-body {
    grid-template-columns: 200px 1fr;
    gap: 40px;
    padding-top: 32px;
  }

  .page-about-toc {
    position: sticky;
    top: calc(var(--header-height) + 24px);
    align-self: start;
  }

  .page-about-toc-list {
    flex-direction: column;
  }

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

  .page-about-timeline-bg {
    height: 220px;
  }
}

@media (min-width: 1024px) {
  .page-about-hero-grid {
    grid-template-columns: 1.3fr 0.9fr;
  }

  .page-about-hero-copy h1 {
    font-size: 48px;
  }

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

  .page-about-sec-grid {
    grid-template-columns: 1.2fr 0.8fr;
  }

  .page-about-timeline-bg {
    height: 240px;
  }

  .page-about-section {
    padding: 48px 0 16px;
  }

  .page-about-section h2 {
    font-size: 32px;
  }

  .page-about-cap-grid .data-card {
    padding: 24px;
  }

  .page-about-cap-num {
    font-size: 42px;
  }
}