.page-about {
  --about-hair: rgba(53, 230, 216, .3);
  --about-soft: rgba(123, 97, 255, .22);
  display: block;
  padding-bottom: var(--sp-6);
}

.page-about .crumbs {
  padding-top: var(--sp-4);
  font-size: .82rem;
  letter-spacing: .04em;
}

/* ---------------- 首屏 ---------------- */
.page-about .about-hero {
  position: relative;
  padding: var(--sp-4) 0 var(--sp-6);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan), var(--violet) 46%, transparent 92%);
  opacity: .75;
}

.page-about .about-hero__stamp {
  margin: 0 0 var(--sp-3);
  font-family: var(--mono);
  font-size: .74rem;
  letter-spacing: .2em;
  color: var(--muted);
}

.page-about .about-hero__title {
  margin: 0;
  font-size: clamp(2.8rem, 13vw, 6.6rem);
  line-height: .98;
  font-weight: 700;
  letter-spacing: -.03em;
  color: var(--text);
}

@supports (-webkit-background-clip: text) {
  .page-about .about-hero__title {
    background: linear-gradient(118deg, #FFFFFF 10%, var(--cyan) 56%, var(--violet) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    -webkit-text-fill-color: transparent;
  }
}

.page-about .about-hero__lede {
  margin: var(--sp-4) 0 0;
  max-width: 44ch;
  color: var(--muted);
}

.page-about .about-metrics {
  display: grid;
  gap: var(--sp-3);
  margin-top: var(--sp-5);
  grid-template-columns: 1fr;
}

.page-about .about-metric {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
  padding: var(--sp-4);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(158deg, rgba(20, 26, 63, .92), rgba(10, 15, 44, .55));
  box-shadow: var(--shadow-soft);
}

.page-about .about-metric .metric__value {
  font-family: var(--mono);
  font-size: clamp(1.9rem, 7vw, 2.6rem);
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-metric .metric__label {
  font-size: .82rem;
  letter-spacing: .05em;
  color: var(--muted);
}

/* ---------------- 章节骨架 ---------------- */
.page-about .section {
  padding: var(--sp-6) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .section:last-of-type {
  border-bottom: 0;
}

.page-about .section__head {
  max-width: 58ch;
}

.page-about .about-duties__intro,
.page-about .about-flow__intro,
.page-about .about-stages__intro {
  margin: var(--sp-3) 0 0;
  color: var(--muted);
  line-height: 1.9;
}

/* ---------------- 职能分工 ---------------- */
.page-about .about-filter {
  margin-top: var(--sp-4);
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
}

.page-about .about-filter-status {
  margin-top: var(--sp-2);
  font-family: var(--mono);
  font-size: .78rem;
  letter-spacing: .04em;
  color: var(--muted);
}

.page-about [data-filter-item][hidden] {
  display: none;
}

.page-about .about-duties__grid {
  display: grid;
  gap: var(--sp-4);
  margin-top: var(--sp-5);
}

.page-about .duty-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--sp-3);
}

.page-about .duty {
  position: relative;
  padding: var(--sp-4) var(--sp-4) var(--sp-4) var(--sp-5);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--panel);
  overflow: hidden;
}

.page-about .duty::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 4px;
  background: linear-gradient(180deg, var(--cyan), var(--violet));
}

.page-about .duty:nth-child(2)::before {
  background: linear-gradient(180deg, var(--violet), var(--cyan));
}

.page-about .duty:nth-child(3)::before {
  background: linear-gradient(180deg, var(--amber), var(--coral));
}

.page-about .duty:nth-child(4)::before {
  background: linear-gradient(180deg, var(--mint), var(--cyan));
}

.page-about .duty__no {
  margin: 0 0 var(--sp-1);
  font-family: var(--mono);
  font-size: .8rem;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .duty__title {
  margin: 0;
  font-size: 1.18rem;
  font-weight: 700;
  letter-spacing: .01em;
}

.page-about .duty__body {
  margin: var(--sp-2) 0 0;
  color: var(--text);
  line-height: 1.9;
}

.page-about .duty__meta {
  margin: var(--sp-3) 0 0;
  font-family: var(--mono);
  font-size: .76rem;
  letter-spacing: .04em;
  color: var(--cyan);
}

.page-about .about-duties__fig {
  margin: 0;
  border-radius: var(--r-lg);
  overflow: hidden;
}

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

/* ---------------- 两套编排 ---------------- */
.page-about .about-band {
  margin: 0 0 var(--sp-5);
  border-radius: var(--r-lg);
  overflow: hidden;
}

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

.page-about .about-seq__body {
  display: grid;
  gap: var(--sp-5);
  margin-top: var(--sp-4);
}

.page-about .about-prose p {
  margin: 0 0 var(--sp-3);
  max-width: 42ch;
  line-height: 1.9;
}

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

.page-about .about-seq__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-seq__list .spec-list__row {
  display: grid;
  gap: var(--sp-1);
  padding: var(--sp-3) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-seq__list .spec-list__key {
  font-family: var(--mono);
  font-size: .8rem;
  letter-spacing: .08em;
  color: var(--mint);
}

.page-about .about-seq__list .spec-list__val {
  color: var(--text);
  line-height: 1.85;
}

/* ---------------- 复核流程 ---------------- */
.page-about .steps {
  list-style: none;
  margin: var(--sp-5) 0 0;
  padding: 0;
  display: grid;
  gap: var(--sp-3);
  position: relative;
}

.page-about .steps::before {
  content: "";
  position: absolute;
  top: 2.2rem;
  bottom: 2.2rem;
  left: 1.6rem;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--violet) 62%, transparent);
  opacity: .6;
}

.page-about .step {
  position: relative;
  padding: var(--sp-4) var(--sp-4) var(--sp-4) 3.6rem;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(150deg, rgba(20, 26, 63, .96), rgba(10, 15, 44, .72));
  box-shadow: var(--shadow-soft);
}

.page-about .step__no {
  position: absolute;
  top: 1.1rem;
  left: .95rem;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: var(--r-pill);
  font-family: var(--mono);
  font-size: .92rem;
  color: var(--bg);
  background: linear-gradient(140deg, var(--cyan), var(--violet));
  box-shadow: var(--glow-cyan);
}

.page-about .step__title {
  margin: 0;
  font-size: 1.12rem;
  font-weight: 700;
}

.page-about .step__body {
  margin: var(--sp-2) 0 0;
  line-height: 1.9;
  color: var(--text);
}

.page-about .step .accordion {
  margin-top: var(--sp-3);
  border-top: 1px solid var(--line);
  padding-top: var(--sp-2);
}

.page-about .step .accordion__summary {
  cursor: pointer;
  font-size: .86rem;
  letter-spacing: .04em;
  color: var(--cyan);
  list-style: none;
}

.page-about .step .accordion__summary::-webkit-details-marker {
  display: none;
}

.page-about .step .accordion__summary::after {
  content: " ＋";
  font-family: var(--mono);
}

.page-about .step .accordion[open] .accordion__summary::after {
  content: " －";
}

.page-about .step .accordion__body p {
  margin: var(--sp-2) 0 0;
  max-width: 46ch;
  color: var(--muted);
  line-height: 1.9;
}

/* ---------------- 迭代轨迹 ---------------- */
.page-about .about-track {
  list-style: none;
  margin: var(--sp-5) 0 0;
  padding: 0 0 var(--sp-3);
  display: flex;
  gap: var(--sp-3);
  overflow-x: auto;
  scroll-snap-type: x proximity;
  border-bottom: 1px solid var(--line);
}

.page-about .about-track > li {
  flex: 0 0 auto;
  scroll-snap-align: start;
}

.page-about .about-node {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  min-width: 178px;
  padding: var(--sp-3);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(20, 26, 63, .6);
  color: var(--text);
  text-decoration: none;
  transition: border-color .3s ease, transform .3s ease, background-color .3s ease;
}

.page-about .about-node:hover,
.page-about .about-node:focus-visible {
  border-color: var(--cyan);
  background: rgba(20, 26, 63, .95);
  transform: translateY(-2px);
}

.page-about .about-node__dot {
  width: 10px;
  height: 10px;
  border-radius: var(--r-pill);
  background: var(--mint);
  box-shadow: 0 0 12px rgba(91, 231, 169, .7);
}

.page-about .about-node__label {
  font-size: .74rem;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .about-node__name {
  font-size: 1rem;
  font-weight: 700;
}

.page-about .about-node__hint {
  font-size: .78rem;
  color: var(--muted);
}

.page-about .stage-grid {
  display: grid;
  gap: var(--sp-3);
  margin-top: var(--sp-4);
}

.page-about .stage-card {
  padding: var(--sp-4);
  border-radius: var(--r-lg);
}

.page-about .stage-card .card__meta {
  font-family: var(--mono);
  font-size: .76rem;
  letter-spacing: .12em;
  color: var(--amber);
}

.page-about .stage-card .card__title {
  margin: var(--sp-2) 0 0;
  font-size: 1.08rem;
}

.page-about .stage-card .card__body {
  margin: var(--sp-2) 0 0;
  color: var(--text);
  line-height: 1.9;
}

.page-about .stage-card:target {
  border-color: var(--cyan);
  box-shadow: var(--glow-cyan);
}

.page-about #stage-1,
.page-about #stage-2,
.page-about #stage-3,
.page-about #stage-4 {
  scroll-margin-top: 120px;
}

.page-about .about-stages__fig {
  margin: var(--sp-5) 0 0;
  border-radius: var(--r-lg);
  overflow: hidden;
}

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

/* ---------------- 内容边界 ---------------- */
.page-about .about-boundary__card {
  padding: var(--sp-4);
  border-radius: var(--r-lg);
}

.page-about .about-boundary__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-boundary__list .spec-list__row {
  display: grid;
  gap: var(--sp-1);
  padding: var(--sp-3) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-boundary__list .spec-list__key {
  font-family: var(--mono);
  font-size: .8rem;
  letter-spacing: .1em;
  color: var(--coral);
}

.page-about .about-boundary__list .spec-list__val {
  color: var(--text);
  line-height: 1.85;
}

.page-about .about-boundary__note {
  margin: var(--sp-4) 0 0;
  max-width: 52ch;
  color: var(--muted);
  line-height: 1.9;
}

.page-about .about-boundary__note a {
  color: var(--mint);
  text-decoration: none;
  border-bottom: 1px solid rgba(91, 231, 169, .45);
}

.page-about .about-boundary__note a:hover,
.page-about .about-boundary__note a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------------- 断点 ---------------- */
@media (min-width: 620px) {
  .page-about .duty-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .about-metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 960px) {
  .page-about .about-hero {
    padding: var(--sp-5) 0 var(--sp-6);
  }

  .page-about .about-duties__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, .9fr);
    align-items: start;
  }

  .page-about .about-seq__body {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    align-items: start;
  }

  .page-about .about-seq__list .spec-list__row {
    grid-template-columns: 12rem minmax(0, 1fr);
    gap: var(--sp-3);
    align-items: baseline;
  }

  .page-about .about-boundary__list .spec-list__row {
    grid-template-columns: 12rem minmax(0, 1fr);
    gap: var(--sp-3);
    align-items: baseline;
  }

  .page-about .steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--sp-4);
  }

  .page-about .steps::before {
    display: none;
  }

  .page-about .about-track {
    gap: var(--sp-4);
  }
}

@media (min-width: 1200px) {
  .page-about .stage-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-node,
  .page-about .step,
  .page-about .duty {
    transition: none;
  }
}