.page-about {
  background-color: var(--ink-900);
  color: var(--white);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + 48px) 0 52px;
  background-color: var(--ink-850);
  background-image:
    repeating-linear-gradient(to right, var(--line) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(to bottom, var(--line) 0 1px, transparent 1px 88px);
  border-bottom: 1px solid var(--line-strong);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 34px;
}

.page-about .about-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--cool-400);
}

.page-about .about-crumbs a {
  color: var(--cool-300);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

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

.page-about .about-crumbs__sep {
  color: var(--ink-700);
}

.page-about .about-kicker {
  margin: 20px 0 0;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--lime);
}

.page-about .about-hero__title {
  margin: 14px 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.95rem, 6.4vw, 3.65rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.page-about .about-hero__lede {
  max-width: 35em;
  margin: 0;
  color: var(--cool-300);
  font-size: clamp(0.94rem, 1.7vw, 1.0625rem);
  line-height: 1.8;
}

.page-about .about-index {
  margin-top: 34px;
  padding-top: 18px;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-index__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--cool-400);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 9px 10px 9px 0;
  text-decoration: none;
  color: var(--cool-300);
  border-left: 2px solid transparent;
  padding-left: 10px;
  transition: color 0.18s ease, border-color 0.18s ease, background-color 0.18s ease;
}

.page-about .about-index__list a b {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--cool-400);
  transition: color 0.18s ease;
}

.page-about .about-index__list a span {
  font-size: 0.9rem;
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--white);
  border-left-color: var(--lime);
  background-color: rgba(184, 255, 61, 0.07);
}

.page-about .about-index__list a:hover b,
.page-about .about-index__list a:focus-visible b {
  color: var(--lime);
}

/* 首屏右侧视觉 + 坐标刻度 */
.page-about .about-hero__side {
  display: grid;
  gap: 6px;
  align-content: start;
}

.page-about .about-visual {
  position: relative;
  margin: 0;
}

.page-about .about-visual img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
}

.page-about .about-visual::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 54px;
  height: 3px;
  background-color: var(--lime);
  z-index: 1;
}

.page-about .about-visual__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: var(--cool-400);
}

.page-about .about-scale {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-scale li {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 10px;
  align-items: baseline;
  padding: 9px 0;
  border-bottom: 1px dashed var(--line);
}

.page-about .about-scale b {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--lime);
}

.page-about .about-scale span {
  font-size: 0.875rem;
  color: var(--cool-300);
}

/* ---------- 通用章节 ---------- */
.page-about .about-section {
  padding: 56px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-section--alt {
  background-color: var(--ink-850);
}

.page-about .about-head {
  max-width: 60ch;
  margin-bottom: 34px;
}

.page-about .about-head h2 {
  margin: 12px 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.45rem, 4.2vw, 2.2rem);
  line-height: 1.16;
  letter-spacing: -0.005em;
}

.page-about .about-head p:not(.coord-tag) {
  margin: 0;
  color: var(--cool-300);
  font-size: 0.95rem;
  line-height: 1.85;
}

.page-about .coord-tag {
  margin: 0;
}

/* ---------- 01 服务对象 ---------- */
.page-about .about-who {
  display: grid;
  gap: 26px;
}

.page-about .about-who__list {
  display: grid;
  gap: 12px;
}

.page-about .about-card {
  position: relative;
  padding: 20px 18px 22px;
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
}

.page-about .about-card--paper {
  background-color: var(--paper);
  color: var(--ink-900);
  border-color: var(--paper);
  box-shadow: 5px 5px 0 0 rgba(7, 17, 31, 0.55);
}

.page-about .about-card__tag {
  display: inline-block;
  margin: 0 0 10px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.12em;
  background-color: var(--moss);
  color: var(--paper);
}

.page-about .about-card__tag--lime {
  background-color: var(--lime);
  color: var(--ink-900);
}

.page-about .about-card__tag--cyan {
  background-color: var(--cyan);
  color: var(--ink-900);
}

.page-about .about-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.08rem;
  line-height: 1.3;
  letter-spacing: 0.01em;
}

.page-about .about-card p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.75;
}

.page-about .about-card:not(.about-card--paper) p {
  color: var(--cool-300);
}

.page-about .about-card--paper p {
  color: var(--ink-700);
}

.page-about .about-who > .about-visual {
  align-self: start;
}

/* ---------- 02 数据维护 ---------- */
.page-about .about-maint {
  display: grid;
  gap: 26px;
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
}

.page-about .about-steps li {
  position: relative;
  padding: 16px 0 16px 54px;
  border-top: 1px solid var(--line);
}

.page-about .about-steps li:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-steps li::before {
  counter-increment: none;
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 8px;
  height: 8px;
  background-color: var(--lime);
}

.page-about .about-steps li::after {
  content: "";
  position: absolute;
  left: 3.5px;
  top: 26px;
  bottom: 0;
  width: 1px;
  background-color: var(--line-strong);
}

.page-about .about-steps li:last-child::after {
  display: none;
}

.page-about .about-steps h3 {
  margin: 0 0 5px;
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-steps p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.8;
  color: var(--cool-300);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 0;
  padding: 0;
  background-color: var(--line-strong);
  border: 1px solid var(--line-strong);
}

.page-about .about-facts > div {
  padding: 16px 14px;
  background-color: var(--ink-800);
}

.page-about .about-facts dt {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  color: var(--cool-400);
}

.page-about .about-facts dd {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--lime);
}

.page-about .about-facts__note {
  margin: 14px 0 0;
  font-size: 0.8rem;
  color: var(--cool-400);
  border-left: 2px solid var(--clay);
  padding-left: 12px;
}

/* ---------- 03 使用路径 ---------- */
.page-about .about-path {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-path__item {
  position: relative;
  padding: 20px 18px 22px;
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
}

.page-about .about-path__item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--cyan);
  opacity: 0.65;
}

.page-about .about-path__no {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .about-path__item h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  line-height: 1.3;
}

.page-about .about-path__item p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.78;
  color: var(--cool-300);
}

.page-about .about-path__cta {
  margin: 28px 0 0;
}

/* ---------- 04 版本演进 ---------- */
.page-about .about-ver {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-ver__box {
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
}

.page-about .about-ver__box[open] {
  border-color: rgba(184, 255, 61, 0.5);
}

.page-about .about-ver__sum {
  position: relative;
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  align-items: baseline;
  gap: 0 12px;
  padding: 15px 46px 15px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-ver__sum::after {
  content: "+";
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 1.1rem;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-ver__box[open] .about-ver__sum::after {
  content: "−";
}

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

.page-about .about-ver__no {
  grid-row: span 2;
  align-self: center;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--lime);
}

.page-about .about-ver__stage {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  line-height: 1.35;
}

.page-about .about-ver__meta {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: var(--cool-400);
}

.page-about .about-ver__body {
  padding: 14px 16px 18px;
  border-top: 1px dashed var(--line);
}

.page-about .about-ver__body p {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.85;
  color: var(--cool-300);
}

.page-about .about-ver__body a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-ver__body a:hover,
.page-about .about-ver__body a:focus-visible {
  color: var(--lime);
}

/* ---------- 05 服务网络 ---------- */
.page-about .about-support {
  display: grid;
  gap: 14px;
}

.page-about .about-support__card {
  position: relative;
  padding: 22px 18px 24px;
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
  border-top-width: 3px;
}

.page-about .about-support__card--lime {
  border-top-color: var(--lime);
}

.page-about .about-support__card--cyan {
  border-top-color: var(--cyan);
}

.page-about .about-support__card--orange {
  border-top-color: var(--orange);
}

.page-about .about-support__card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.12rem;
}

.page-about .about-support__card p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.8;
  color: var(--cool-300);
}

.page-about .about-support__link {
  display: inline-block;
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(55, 214, 255, 0.4);
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-support__link:hover,
.page-about .about-support__link:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .about-speed {
  margin: 26px 0 0;
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.7;
  color: var(--paper);
  background-color: rgba(111, 143, 94, 0.22);
  border-left: 3px solid var(--moss);
}

/* ---------- 06 合作生态 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-partner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: 16px;
  background-color: var(--ink-800);
  border: 1px solid var(--line-strong);
}

.page-about .about-partner__mark {
  justify-self: start;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  background-color: var(--moss);
  color: var(--paper);
}

.page-about .about-partner:nth-child(2) .about-partner__mark {
  background-color: var(--clay);
}

.page-about .about-partner:nth-child(3) .about-partner__mark {
  background-color: var(--lime);
  color: var(--ink-900);
}

.page-about .about-partner:nth-child(4) .about-partner__mark {
  background-color: var(--cyan);
  color: var(--ink-900);
}

.page-about .about-partner:nth-child(5) .about-partner__mark {
  background-color: var(--paper);
  color: var(--ink-900);
}

.page-about .about-partner p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.78;
  color: var(--cool-300);
}

.page-about .about-promise {
  margin-top: 30px;
  padding: 24px 20px 26px;
  background-color: var(--paper);
  color: var(--ink-900);
  border-left: 4px solid var(--clay);
}

.page-about .about-promise h3 {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--ink-900);
}

.page-about .about-promise ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 9px;
}

.page-about .about-promise li {
  position: relative;
  padding-left: 18px;
  font-size: 0.85rem;
  line-height: 1.75;
  color: var(--ink-700);
}

.page-about .about-promise li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 7px;
  background-color: var(--clay);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  padding: 46px 0 60px;
  background-image: linear-gradient(118deg, rgba(55, 214, 255, 0.09), rgba(184, 255, 61, 0.07) 62%, rgba(7, 17, 31, 0));
  border-top: 1px solid var(--line-strong);
}

.page-about .about-cta__inner {
  display: grid;
  gap: 14px;
  max-width: 760px;
}

.page-about .about-cta__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.35rem, 4vw, 2rem);
  line-height: 1.18;
}

.page-about .about-cta__text {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.85;
  color: var(--cool-300);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

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

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

  .page-about .about-partner {
    grid-template-columns: 150px minmax(0, 1fr);
    align-items: baseline;
  }
}

@media (min-width: 760px) {
  .page-about .about-path {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-top: calc(var(--header-h) + 72px);
    padding-bottom: 72px;
  }

  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .about-index__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 14px;
  }

  .page-about .about-section {
    padding: 84px 0;
  }

  .page-about .about-who {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    gap: 34px;
    align-items: start;
  }

  .page-about .about-maint {
    grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
    gap: 42px;
    align-items: start;
  }

  .page-about .about-path {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    border-left: 1px solid var(--line-strong);
  }

  .page-about .about-path__item {
    border-left: 0;
    margin-left: -1px;
  }

  .page-about .about-support {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about .about-hero__side {
    position: sticky;
    top: calc(var(--header-h) + 26px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .about-crumbs a,
  .page-about .about-support__link {
    transition: none;
  }
}