.page-about {
  --about-line: 1px solid var(--grid);
  background-color: var(--ink-900);
  background-image:
    linear-gradient(to right, rgba(47, 74, 94, 0.18) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(47, 74, 94, 0.18) 1px, transparent 1px);
  background-size: 48px 48px;
  color: var(--paper);
  padding-block: 1.5rem 4.5rem;
  overflow-x: hidden;
}

.page-about :focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

.page-about .breadcrumb {
  margin-bottom: 1.75rem;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 2.25rem;
  padding-bottom: 2.5rem;
  border-bottom: var(--about-line);
}

.page-about .about-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.page-about .about-kicker-dot {
  width: 0.5rem;
  height: 0.5rem;
  background: var(--signal);
}

.page-about .about-title {
  margin: 0 0 1.1rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.2rem, 7vw, 4rem);
  line-height: 1.04;
  letter-spacing: -0.01em;
  color: var(--paper-hi);
}

.page-about .about-lead {
  margin: 0;
  max-width: 62ch;
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--paper);
}

.page-about .about-stats {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid);
  border: var(--about-line);
}

.page-about .about-stat {
  background: var(--ink-800);
  padding: 0.85rem 0.9rem;
}

.page-about .about-stat dt {
  margin-bottom: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  color: var(--slate);
}

.page-about .about-stat dd {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 700;
  line-height: 1;
  color: var(--paper-hi);
}

.page-about .about-stat dd span {
  margin-left: 0.2rem;
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--slate);
}

/* ---------- 章节通用 ---------- */
.page-about .section {
  padding-block: 2.75rem;
  border-bottom: var(--about-line);
}

.page-about .about-head {
  margin-bottom: 1.5rem;
}

.page-about .about-head .section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--signal);
}

.page-about .about-head .section-title {
  margin: 0.25rem 0 0.45rem;
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4.4vw, 2.4rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--paper-hi);
}

.page-about .about-head .section-note {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--slate);
}

.page-about p {
  max-width: 72ch;
}

.page-about .about-link {
  color: var(--terminal);
  text-decoration: none;
  border-bottom: 1px solid var(--terminal-deep);
  transition: color var(--dur), border-color var(--dur);
}

.page-about .about-link:hover {
  color: var(--signal);
  border-color: var(--signal);
}

/* ---------- 01 起点 ---------- */
.page-about .about-origin-grid {
  display: grid;
  gap: 1.75rem;
}

.page-about .about-origin-copy p {
  margin: 0 0 1rem;
  font-size: 1rem;
  line-height: 1.82;
  color: var(--paper);
}

.page-about .about-points {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  border-top: var(--about-line);
}

.page-about .about-points li {
  display: grid;
  gap: 0.2rem;
  padding: 0.8rem 0;
  border-bottom: var(--about-line);
}

.page-about .about-points strong {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  color: var(--paper-hi);
}

.page-about .about-points span {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--slate);
}

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

.page-about .about-frame {
  position: relative;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border: var(--about-line);
  background: var(--ink-800);
}

.page-about .about-frame--tall {
  aspect-ratio: 4 / 3;
}

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

.page-about .media-caption {
  display: block;
  margin-top: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  color: var(--slate);
}

/* ---------- 02 时间线 ---------- */
.page-about .about-diagram {
  margin: 0 0 1.5rem;
  padding: 1rem;
  border: var(--about-line);
  background: var(--ink-800);
}

.page-about .about-diagram svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-diagram .d-axis {
  stroke: var(--grid);
  stroke-width: 1;
}

.page-about .about-diagram .d-node {
  fill: var(--ink-900);
  stroke: var(--slate);
  stroke-width: 1;
}

.page-about .about-diagram .d-node--now {
  fill: var(--signal);
  stroke: var(--signal);
}

.page-about .about-diagram .d-branch {
  fill: none;
  stroke: var(--terminal-deep);
  stroke-width: 1;
  stroke-dasharray: 3 4;
}

.page-about .about-diagram .d-dot {
  fill: var(--terminal);
}

.page-about .about-diagram .d-year {
  fill: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
}

.page-about .about-diagram .d-year--inverse {
  fill: var(--ink-900);
}

.page-about .about-diagram .d-label {
  fill: var(--slate);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
}

.page-about .about-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.page-about .about-jump-link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--slate);
  text-decoration: none;
  border: var(--about-line);
  padding: 0.3rem 0.55rem;
  transition: color var(--dur), border-color var(--dur);
}

.page-about .about-jump-link:hover {
  color: var(--signal);
  border-color: var(--signal);
}

.page-about .about-nodes {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.5rem;
  position: relative;
}

.page-about .about-nodes::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 0.6rem;
  bottom: 0.6rem;
  width: 1px;
  background: var(--grid);
}

.page-about .about-node {
  position: relative;
  margin-bottom: 0.75rem;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -1.5rem;
  top: 1.05rem;
  width: 7px;
  height: 7px;
  background: var(--ink-900);
  border: 1px solid var(--terminal);
}

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

.page-about .about-folder {
  border: var(--about-line);
  background: var(--ink-800);
  transition: border-color var(--dur);
}

.page-about .about-folder:hover {
  border-color: var(--terminal);
}

.page-about .about-folder[open] {
  border-color: var(--terminal-deep);
}

.page-about .about-folder-summary {
  position: relative;
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "year code"
    "title title";
  gap: 0.4rem 0.9rem;
  align-items: center;
  padding: 0.85rem 2.4rem 0.85rem 1rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-folder-summary::after {
  content: "+";
  position: absolute;
  right: 0.9rem;
  top: 0.8rem;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  line-height: 1;
  color: var(--signal);
  transition: color var(--dur);
}

.page-about .about-folder[open] .about-folder-summary::after {
  content: "−";
  color: var(--terminal);
}

.page-about .about-year {
  grid-area: year;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--signal);
}

.page-about .about-folder-title {
  grid-area: title;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.25;
  color: var(--paper-hi);
}

.page-about .about-code {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  color: var(--terminal);
  border: 1px solid var(--terminal-deep);
  padding: 0.15rem 0.4rem;
  justify-self: start;
}

.page-about .about-folder-summary .about-code {
  grid-area: code;
}

.page-about .about-folder-body {
  padding: 0 1rem 1.1rem;
  border-top: var(--about-line);
}

.page-about .about-folder-body p {
  margin: 1rem 0 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--paper);
}

.page-about .about-folder-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem;
  margin-top: 1rem;
}

.page-about .about-copy {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  padding: 0.35rem 0.7rem;
}

.page-about .about-copy-status {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--terminal);
}

/* ---------- 03 分类体系 ---------- */
.page-about .about-system-grid {
  display: grid;
  gap: 2rem;
}

.page-about .about-system-copy p {
  margin: 0 0 1rem;
  font-size: 1rem;
  line-height: 1.82;
  color: var(--paper);
}

.page-about .about-cats {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  border-top: var(--about-line);
}

.page-about .about-cat {
  display: grid;
  grid-template-columns: 3.4rem 1fr;
  gap: 0.15rem 0.9rem;
  padding: 0.9rem 0.3rem;
  border-bottom: var(--about-line);
  transition: background-color var(--dur);
}

.page-about .about-cat:hover {
  background: rgba(61, 220, 151, 0.06);
}

.page-about .about-cat-id {
  grid-row: span 2;
  padding-top: 0.2rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  color: var(--signal);
}

.page-about .about-cat-name {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--paper-hi);
}

.page-about .about-cat-desc {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--slate);
}

.page-about .about-ledger {
  align-self: start;
  padding: 1.1rem;
  border: var(--about-line);
  border-left: 3px solid var(--signal);
  background: var(--ink-800);
}

.page-about .about-ledger h3 {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: var(--slate);
}

.page-about .about-ledger dl {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.55rem 1rem;
  margin: 0.9rem 0 0;
}

.page-about .about-ledger dt {
  font-size: 0.875rem;
  color: var(--slate);
}

.page-about .about-ledger dd {
  margin: 0;
  text-align: right;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--terminal);
}

/* ---------- 04 团队 ---------- */
.page-about .about-team-grid {
  display: grid;
  gap: 1.75rem;
}

.page-about .about-roles {
  border-top: var(--about-line);
}

.page-about .about-role {
  padding: 1rem 0;
  border-bottom: var(--about-line);
}

.page-about .about-role h3 {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--paper-hi);
}

.page-about .about-role h3 span {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 400;
  letter-spacing: 0.04em;
  color: var(--signal);
}

.page-about .about-role p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--slate);
}

.page-about .about-team-note {
  margin: 1.75rem 0 0;
  padding-left: 1rem;
  border-left: 2px solid var(--terminal);
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--paper);
}

/* ---------- 05 收获 ---------- */
.page-about .about-take-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.75rem;
}

.page-about .about-take-list li {
  border-top: 3px solid var(--signal);
  padding-top: 0.9rem;
}

.page-about .about-take-list h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--paper-hi);
}

.page-about .about-take-list p {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--slate);
}

.page-about .about-take-list > li > a.about-link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  display: grid;
  gap: 1.25rem;
  margin-top: 3rem;
  padding: 1.75rem 1.25rem;
  border: var(--about-line);
  background: var(--ink-800);
}

.page-about .about-cta-kicker {
  margin: 0 0 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  color: var(--signal);
}

.page-about .about-cta h2 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 5vw, 2.1rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--paper-hi);
}

.page-about .about-cta-copy p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--paper);
}

.page-about .about-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ---------- 桌面 ---------- */
@media (min-width: 640px) {
  .page-about .about-folder-summary {
    grid-template-columns: 4.5rem 1fr auto;
    grid-template-areas: "year title code";
    padding-right: 3rem;
  }

  .page-about .about-folder-summary::after {
    top: 50%;
    margin-top: -0.55rem;
  }
}

@media (min-width: 900px) {
  .page-about {
    padding-block: 2rem 5.5rem;
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 0.55fr);
    align-items: end;
    gap: 3rem;
    padding-bottom: 3rem;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-origin-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    gap: 3rem;
    align-items: start;
  }

  .page-about .about-system-grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 0.55fr);
    gap: 3rem;
  }

  .page-about .about-team-grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 2.75rem;
    align-items: start;
  }

  .page-about .about-take-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 2rem;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 2rem;
    padding: 2.25rem 2rem;
  }

  .page-about .about-cta-actions {
    justify-content: flex-end;
  }
}

@media (min-width: 1180px) {
  .page-about .about-cat {
    grid-template-columns: 4.2rem 9.5rem 1fr;
    align-items: baseline;
  }

  .page-about .about-cat-id {
    grid-row: auto;
    padding-top: 0;
  }
}
<<<END>>>