.page-about {
  --ab-rule: rgba(147, 168, 161, .20);
  --ab-rule-strong: rgba(79, 227, 193, .30);
  --ab-pad: clamp(18px, 3.4vw, 38px);
  padding-bottom: clamp(56px, 9vw, 104px);
}

/* ---------- 首屏框景 ---------- */

.page-about .about-hero {
  padding-top: clamp(18px, 3vw, 34px);
}

.page-about .about-hero-frame {
  position: relative;
  display: grid;
  gap: var(--gap);
  padding: clamp(28px, 4.4vw, 56px) 0 clamp(30px, 4.6vw, 52px);
  border-top: 1px solid var(--ab-rule-strong);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-hero-frame::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 7px;
  background-image: repeating-linear-gradient(to right, var(--c-tick) 0 1px, transparent 1px 28px);
  opacity: .55;
  pointer-events: none;
}

.page-about .about-hero-copy {
  min-width: 0;
}

.page-about .about-hero-copy .display {
  margin: 16px 0 0;
  font-weight: 200;
  line-height: .98;
  letter-spacing: -.02em;
}

.page-about .about-lede {
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  color: var(--c-text);
  opacity: .86;
}

.page-about .about-facts {
  margin: clamp(24px, 3.4vw, 38px) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--ab-rule);
  border-top: 1px solid var(--ab-rule);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-fact {
  display: flex;
  flex-direction: column-reverse;
  gap: 5px;
  padding: 14px 12px 16px;
  background: var(--c-canvas);
  min-width: 0;
}

.page-about .about-fact dt {
  font-size: var(--fs-index);
  letter-spacing: .08em;
  color: var(--c-muted);
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1;
  letter-spacing: .04em;
  color: var(--c-text);
}

.page-about .about-hero-media {
  margin: 0;
  min-width: 0;
}

.page-about .about-hero-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(.5) contrast(1.1) brightness(.9);
}

/* ---------- 内容边界 ---------- */

.page-about .about-bounds {
  display: grid;
  gap: 1px;
  margin-top: clamp(24px, 3.4vw, 38px);
  background: var(--ab-rule);
  border-top: 1px solid var(--ab-rule);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-bound {
  padding: var(--ab-pad);
  min-width: 0;
}

.page-about .about-bound--do {
  background: var(--c-layer);
}

.page-about .about-bound--dont {
  background: rgba(255, 255, 255, .03);
}

.page-about .about-bound-title {
  margin: 0 0 18px;
  font-size: var(--fs-h4);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--c-text);
}

.page-about .about-bound ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-bound li {
  position: relative;
  padding-left: 22px;
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--c-muted);
  overflow-wrap: anywhere;
}

.page-about .about-bound li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .74em;
  width: 11px;
  height: 1px;
  background: var(--c-accent);
}

.page-about .about-bound--dont li::before {
  background: var(--c-tick);
}

.page-about .about-bound-note {
  margin: 20px 0 0;
  font-size: var(--fs-index);
  line-height: 1.8;
  color: var(--c-muted);
}

.page-about .about-bound-note a {
  color: var(--c-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-rule-strong);
  transition: border-color 140ms var(--ease);
}

.page-about .about-bound-note a:hover {
  border-bottom-color: var(--c-accent);
}

/* ---------- 团队分工：技能树 ---------- */

.page-about .about-team-grid {
  display: grid;
  gap: clamp(28px, 4vw, 52px);
  margin-top: clamp(26px, 4vw, 42px);
}

.page-about .skill-tree {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  display: grid;
  gap: 2px;
  min-width: 0;
}

.page-about .skill-tree::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: var(--c-line);
  transition: background 160ms var(--ease);
}

.page-about .skill-tree:hover::before {
  background: var(--c-accent);
}

.page-about .skill-node {
  position: relative;
  padding: 16px 18px 18px;
  border-left: 2px solid transparent;
  transition: opacity 160ms var(--ease), background 160ms var(--ease), border-color 160ms var(--ease);
  min-width: 0;
}

.page-about .skill-node::before {
  content: "";
  position: absolute;
  left: -20px;
  top: 28px;
  width: 20px;
  height: 1px;
  background: var(--c-line);
  transition: background 160ms var(--ease);
}

.page-about .skill-tree:hover .skill-node {
  opacity: .4;
}

.page-about .skill-tree .skill-node:hover {
  opacity: 1;
  background: var(--c-accent-soft);
  border-left-color: var(--c-accent);
}

.page-about .skill-tree .skill-node:hover::before {
  background: var(--c-accent);
}

.page-about .skill-index {
  display: block;
  font-size: var(--fs-index);
  letter-spacing: .1em;
  color: var(--c-muted);
}

.page-about .skill-count {
  display: block;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: clamp(28px, 3.6vw, 40px);
  line-height: 1;
  letter-spacing: .04em;
  color: var(--c-accent);
}

.page-about .skill-name {
  margin: 8px 0 0;
  font-size: var(--fs-h4);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--c-text);
}

.page-about .skill-out {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--c-muted);
  max-width: 42ch;
}

.page-about .about-team-media {
  margin: 0;
  min-width: 0;
}

.page-about .about-team-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 10 / 7;
  object-fit: cover;
  filter: saturate(.4) contrast(1.12) brightness(.82);
}

/* ---------- 生产流程 ---------- */

.page-about .flow-track {
  list-style: none;
  margin: clamp(26px, 4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--ab-rule);
  border-top: 1px solid var(--ab-rule);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .flow-step {
  position: relative;
  background: var(--c-canvas);
  padding: clamp(20px, 2.8vw, 30px) var(--ab-pad) clamp(22px, 3vw, 32px);
  min-width: 0;
  transition: background 140ms var(--ease);
}

.page-about .flow-step:hover {
  background: rgba(255, 255, 255, .035);
}

.page-about .flow-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1;
  letter-spacing: .04em;
  color: var(--c-accent);
}

.page-about .flow-name {
  margin: 14px 0 0;
  font-size: var(--fs-h4);
  font-weight: 700;
  color: var(--c-text);
  letter-spacing: -.01em;
}

.page-about .flow-text {
  margin: 9px 0 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--c-muted);
}

.page-about .flow-text a {
  color: var(--c-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-rule-strong);
}

.page-about .flow-text a:hover {
  border-bottom-color: var(--c-accent);
}

/* ---------- 四阶段 ---------- */

.page-about .about-phase-visual {
  position: relative;
  margin: clamp(24px, 3.6vw, 40px) 0 0;
  overflow: hidden;
  border-radius: var(--radius-panel);
}

.page-about .about-phase-visual img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 5;
  object-fit: cover;
  filter: saturate(.35) contrast(1.15) brightness(.72);
}

.page-about .about-phase-visual::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, var(--c-base) 0%, transparent 28%, transparent 72%, var(--c-base) 100%);
  pointer-events: none;
}

.page-about .phase-track {
  display: grid;
  gap: 1px;
  margin-top: clamp(20px, 2.6vw, 28px);
  background: var(--ab-rule);
  border-top: 1px solid var(--ab-rule);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .phase {
  background: var(--c-canvas);
  min-width: 0;
}

.page-about .phase > summary {
  position: relative;
  list-style: none;
  cursor: pointer;
  display: grid;
  gap: 8px;
  padding: clamp(18px, 2.6vw, 26px);
  transition: background 140ms var(--ease);
}

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

.page-about .phase > summary:hover {
  background: var(--c-accent-soft);
}

.page-about .phase[open] > summary {
  background: rgba(255, 255, 255, .045);
}

.page-about .phase > summary::after {
  content: "+";
  position: absolute;
  top: clamp(16px, 2.4vw, 22px);
  right: clamp(16px, 2.4vw, 22px);
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--c-accent);
}

.page-about .phase[open] > summary::after {
  content: "–";
}

.page-about .phase > summary:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: -2px;
}

.page-about .phase-num {
  font-family: var(--font-mono);
  font-size: var(--fs-index);
  letter-spacing: .1em;
  color: var(--c-muted);
}

.page-about .phase-name {
  font-family: var(--font-display);
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 200;
  line-height: 1.05;
  letter-spacing: -.02em;
  color: var(--c-text);
}

.page-about .phase-body {
  padding: 0 clamp(18px, 2.6vw, 26px) clamp(22px, 3vw, 30px);
}

.page-about .phase-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-muted);
}

.page-about .phase-body ul {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .phase-body li {
  position: relative;
  padding-left: 18px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--c-text);
  opacity: .84;
  overflow-wrap: anywhere;
}

.page-about .phase-body li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 9px;
  height: 1px;
  background: var(--c-accent);
}

.page-about .phase-body a {
  color: var(--c-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-rule-strong);
}

.page-about .phase-body a:hover {
  border-bottom-color: var(--c-accent);
}

/* ---------- 更新节奏表 ---------- */

.page-about .cadence-wrap {
  margin-top: clamp(24px, 3.4vw, 38px);
  overflow-x: auto;
  border-top: 1px solid var(--ab-rule-strong);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .cadence-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .cadence-table th,
.page-about .cadence-table td {
  text-align: left;
  padding: 16px 18px;
  border-bottom: 1px solid var(--ab-rule);
  vertical-align: baseline;
  white-space: nowrap;
}

.page-about .cadence-table thead th {
  font-size: var(--fs-index);
  font-weight: 500;
  letter-spacing: .1em;
  color: var(--c-muted);
}

.page-about .cadence-table tbody tr {
  transition: background 140ms var(--ease);
}

.page-about .cadence-table tbody tr:hover {
  background: rgba(79, 227, 193, .07);
}

.page-about .cadence-table tbody tr:hover th[scope="row"] {
  box-shadow: inset 2px 0 0 0 var(--c-accent);
}

.page-about .cadence-table tbody tr:last-child th,
.page-about .cadence-table tbody tr:last-child td {
  border-bottom: 0;
}

.page-about .cadence-table th[scope="row"] {
  font-weight: 600;
  color: var(--c-text);
}

.page-about .cadence-table td {
  color: var(--c-muted);
}

.page-about .cadence-table .num {
  font-family: var(--font-mono);
  letter-spacing: .04em;
  color: var(--c-accent);
}

.page-about .cadence-foot {
  margin: 20px 0 0;
  font-size: var(--fs-index);
  line-height: 1.85;
  color: var(--c-muted);
}

.page-about .cadence-foot a {
  color: var(--c-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-rule-strong);
  transition: border-color 140ms var(--ease);
}

.page-about .cadence-foot a:hover {
  border-bottom-color: var(--c-accent);
}

/* ---------- 备案与服务 ---------- */

.page-about .about-records {
  padding-top: clamp(6px, 1.5vw, 14px);
}

.page-about .about-records-grid {
  display: grid;
  gap: clamp(24px, 3.4vw, 44px);
  padding-top: clamp(26px, 4vw, 42px);
  border-top: 1px solid var(--ab-rule-strong);
}

.page-about .about-records-head {
  min-width: 0;
}

.page-about .about-records-note {
  margin: 18px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--c-muted);
  max-width: 44ch;
}

.page-about .about-record-list {
  margin: 0;
  display: grid;
  gap: 1px;
  background: var(--ab-rule);
  border-block: 1px solid var(--ab-rule);
  min-width: 0;
}

.page-about .about-record {
  display: grid;
  gap: 6px;
  padding: 14px 16px;
  background: var(--c-canvas);
}

.page-about .about-record dt {
  font-size: var(--fs-index);
  letter-spacing: .09em;
  color: var(--c-muted);
}

.page-about .about-record dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-text);
  overflow-wrap: anywhere;
}

.page-about .about-record dd.num {
  font-family: var(--font-mono);
  font-size: 14.5px;
  letter-spacing: .04em;
  color: var(--c-accent);
}

/* ---------- 响应式 ---------- */

@media (min-width: 560px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 820px) {
  .page-about .about-bounds {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .flow-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 880px) {
  .page-about .phase-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .about-records-grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-frame {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    align-items: center;
    gap: clamp(28px, 4vw, 64px);
  }

  .page-about .about-team-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .about-team-media {
    position: sticky;
    top: 96px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .skill-node,
  .page-about .skill-tree::before,
  .page-about .skill-node::before,
  .page-about .flow-step,
  .page-about .phase > summary,
  .page-about .cadence-table tbody tr {
    transition: none;
  }
}
<<<END>>>