.page-about {
  --pa-hair: rgba(143, 163, 196, .16);
  --pa-cyan-soft: rgba(47, 230, 214, .08);
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
}

/* ---------- 面包屑与首屏 ---------- */

.page-about .breadcrumbs {
  margin-bottom: 1.4rem;
}

.page-about .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .45rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .04em;
  color: var(--mist);
}

.page-about .breadcrumbs li + li::before {
  content: "/";
  margin-right: .45rem;
  color: var(--graphite);
}

.page-about .breadcrumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

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

.page-about .pa-hero {
  position: relative;
  padding: 2.6rem 0 0;
  background:
    linear-gradient(158deg, rgba(5, 7, 15, .96) 0%, rgba(5, 7, 15, 0) 52%),
    linear-gradient(115deg, var(--ink-deep) 0 38%, var(--ink) 38% 100%);
  border-bottom: 1px solid var(--pa-hair);
}

.page-about .pa-hero::before {
  content: "";
  position: absolute;
  top: -30%;
  right: -12%;
  width: 68vw;
  height: 160%;
  background: linear-gradient(148deg, rgba(47, 230, 214, .13), rgba(11, 18, 48, 0) 62%);
  transform: skewX(-15deg);
  pointer-events: none;
}

.page-about .pa-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 2rem;
}

.page-about .pa-hero h1 {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(2.05rem, 6vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: -.005em;
  margin: .5rem 0 1rem;
  color: var(--paper);
  max-width: 18ch;
}

.page-about .pa-hero .lead {
  color: var(--mist);
  font-size: 1rem;
  line-height: 1.78;
  margin: 0 0 1.6rem;
  max-width: 54ch;
}

.page-about .pa-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
}

.page-about .pa-hero__media {
  border: 1px solid var(--pa-hair);
  overflow: hidden;
}

.page-about .pa-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

/* ---------- 关键数据条 ---------- */

.page-about .pa-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 2.6rem 0 0;
  padding: 0;
  list-style: none;
  background: var(--pa-hair);
  border: 1px solid var(--pa-hair);
}

.page-about .pa-stat {
  display: flex;
  flex-direction: column;
  gap: .28rem;
  padding: 1.05rem 1.05rem 1.15rem;
  background: var(--ink);
}

.page-about .pa-stat__num {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -.01em;
}

.page-about .pa-stat__label {
  font-size: .78rem;
  line-height: 1.5;
  color: var(--mist);
}

/* ---------- 主体两栏 ---------- */

.page-about .pa-body {
  display: grid;
  gap: 2.2rem;
  padding-top: 3rem;
  padding-bottom: 4.5rem;
}

.page-about .pa-main {
  min-width: 0;
}

/* ---------- 左侧章节轨道 ---------- */

.page-about .pa-rail__title {
  margin: 0 0 .7rem;
  font-family: var(--font-head);
  font-size: .72rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .rail__list {
  display: flex;
  gap: .9rem;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .rail__link {
  display: block;
  padding: .38rem 0;
  white-space: nowrap;
  font-size: .85rem;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .rail__link:hover {
  color: var(--paper);
}

.page-about .rail__link[aria-current="true"] {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 章节结构 ---------- */

.page-about .pa-section {
  margin-bottom: 4.2rem;
}

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

.page-about .section__head {
  margin-bottom: 1.7rem;
}

.page-about .section__index {
  display: block;
  font-family: var(--font-head);
  font-size: clamp(2.4rem, 7vw, 3.9rem);
  line-height: 1;
  margin-bottom: .15rem;
  color: transparent;
  -webkit-text-stroke: 1px var(--graphite);
}

.page-about .section__title {
  margin: 0 0 .5rem;
  font-family: var(--font-head);
  font-size: clamp(1.45rem, 4vw, 2.1rem);
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .section__sub {
  margin: 0;
  max-width: 64ch;
  font-size: .96rem;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 纵向时间轴 ---------- */

.page-about .pa-timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 1.4rem;
  list-style: none;
}

.page-about .pa-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: .6rem;
  bottom: .6rem;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(47, 230, 214, .1));
}

.page-about .pa-node {
  position: relative;
  padding-bottom: 2.5rem;
}

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

.page-about .pa-node__dot {
  position: absolute;
  left: -1.4rem;
  top: .55rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(47, 230, 214, .1);
  transform: translateX(-50%);
}

.page-about .pa-node__year {
  margin: 0 0 .3rem;
  font-family: var(--font-mono);
  font-size: .8rem;
  letter-spacing: .09em;
  color: var(--amber);
}

.page-about .pa-node__title {
  margin: 0 0 .5rem;
  font-family: var(--font-head);
  font-size: 1.25rem;
  color: var(--paper);
}

.page-about .pa-node__text {
  margin: 0 0 .8rem;
  max-width: 68ch;
  font-size: .96rem;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .pa-node__btn {
  margin-bottom: .6rem;
}

.page-about .pa-node--media {
  padding-bottom: 2.5rem;
}

.page-about .pa-node__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
}

/* ---------- 档案构成 ---------- */

.page-about .pa-fields {
  display: grid;
  gap: 1.5rem;
}

.page-about .pa-fields__table {
  overflow-x: auto;
  border: 1px solid var(--pa-hair);
}

.page-about .pa-table {
  width: 100%;
  min-width: 420px;
  border-collapse: collapse;
  font-size: .89rem;
}

.page-about .pa-table th,
.page-about .pa-table td {
  padding: .68rem .85rem;
  text-align: left;
  border-bottom: 1px solid var(--pa-hair);
}

.page-about .pa-table th {
  font-family: var(--font-head);
  font-size: .74rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--mist);
  border-bottom-color: rgba(58, 67, 88, .9);
}

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

.page-about .pa-table tbody tr {
  transition: background .2s ease;
}

.page-about .pa-table tbody tr:hover {
  background: var(--pa-cyan-soft);
}

.page-about .pa-table td:first-child {
  color: var(--cyan);
  border-right: 1px solid var(--pa-hair);
}

.page-about .pa-table td:nth-child(2) {
  color: var(--paper);
}

.page-about .pa-table td:nth-child(3) {
  color: var(--mist);
}

.page-about .pa-fields__side {
  display: grid;
  gap: .9rem;
  align-content: start;
}

/* ---------- 桌台分类 ---------- */

.page-about .pa-bar {
  display: flex;
  height: 54px;
  margin-bottom: 1.7rem;
  border: 1px solid var(--pa-hair);
  overflow: hidden;
}

.page-about .pa-bar__seg {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  min-width: 0;
  padding: 0 .8rem;
  font-size: .84rem;
  font-weight: 600;
  letter-spacing: .04em;
}

.page-about .pa-bar__seg b {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
}

.page-about .pa-bar__seg--v {
  flex: 4;
  background: linear-gradient(120deg, var(--cyan), rgba(47, 230, 214, .7));
  color: var(--ink-deep);
}

.page-about .pa-bar__seg--e {
  flex: 4;
  background: linear-gradient(120deg, var(--amber), rgba(242, 179, 74, .72));
  color: var(--ink-deep);
}

.page-about .pa-bar__seg--c {
  flex: 3;
  background: var(--graphite);
  color: var(--paper);
}

.page-about .pa-cats {
  gap: 1.2rem;
}

.page-about .pa-cat {
  padding-top: 1.05rem;
  border-top: 2px solid var(--graphite);
}

.page-about .pa-cat--v {
  border-top-color: var(--cyan);
}

.page-about .pa-cat--e {
  border-top-color: var(--amber);
}

.page-about .pa-cat--c {
  border-top-color: var(--green);
}

.page-about .pa-cat h3 {
  margin: 0 0 .9rem;
  font-family: var(--font-head);
  font-size: 1.05rem;
  letter-spacing: .06em;
  color: var(--paper);
}

.page-about .pa-cat ul {
  display: grid;
  gap: .85rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .pa-cat li {
  display: grid;
  gap: .16rem;
}

.page-about .pa-cat b {
  font-size: .94rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .pa-cat span {
  font-size: .84rem;
  line-height: 1.62;
  color: var(--mist);
}

/* ---------- 青海本地服务 ---------- */

.page-about .pa-qh {
  display: grid;
  gap: 1.6rem;
}

.page-about .pa-qh__fig {
  border: 1px solid var(--pa-hair);
  overflow: hidden;
}

.page-about .pa-qh__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.page-about .pa-qh__copy p {
  margin: 0 0 1.2rem;
  max-width: 62ch;
  font-size: .96rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .pa-qh__list {
  display: grid;
  gap: 0;
  margin: 0 0 1.3rem;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--pa-hair);
}

.page-about .pa-qh__list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: .9rem;
  padding: .8rem 0;
  border-bottom: 1px solid var(--pa-hair);
}

.page-about .pa-qh__k {
  font-family: var(--font-mono);
  font-size: .95rem;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .pa-qh__list li span:last-child {
  font-size: .9rem;
  line-height: 1.65;
  color: var(--paper);
}

.page-about .pa-qh__note {
  padding-left: .95rem;
  border-left: 2px solid var(--cyan);
  font-size: .9rem !important;
  color: var(--mist);
}

/* ---------- 团队四象限 ---------- */

.page-about .pa-quad {
  display: grid;
  gap: 1px;
  margin-bottom: 1.6rem;
  background: var(--pa-hair);
  border: 1px solid var(--pa-hair);
}

.page-about .pa-quad__item {
  position: relative;
  padding: 1.35rem 1.25rem 1.45rem;
  background: var(--ink);
  transition: background .25s ease;
}

.page-about .pa-quad__item::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .3s ease;
}

.page-about .pa-quad__item:hover,
.page-about .pa-quad__item:focus-within {
  background: var(--panel);
}

.page-about .pa-quad__item:hover::before,
.page-about .pa-quad__item:focus-within::before {
  transform: scaleY(1);
}

.page-about .pa-quad__no {
  margin: 0 0 .55rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .12em;
  color: var(--cyan);
}

.page-about .pa-quad__item h3 {
  margin: 0 0 .5rem;
  font-family: var(--font-head);
  font-size: 1.1rem;
  color: var(--paper);
}

.page-about .pa-quad__desc {
  margin: 0 0 .8rem;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .pa-quad__keys {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .05em;
  color: var(--graphite);
  transition: color .25s ease;
}

.page-about .pa-quad__item:hover .pa-quad__keys {
  color: var(--amber);
}

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

.page-about .pa-cadence li {
  display: grid;
  grid-template-columns: 5.6rem minmax(0, 1fr);
  gap: .9rem;
  align-items: baseline;
  padding: .78rem 0;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--mist);
  border-bottom: 1px dashed var(--pa-hair);
}

.page-about .pa-cadence li:first-child {
  border-top: 1px dashed var(--pa-hair);
}

.page-about .pa-cadence .mono {
  font-family: var(--font-mono);
  font-size: .82rem;
  color: var(--cyan);
  letter-spacing: .03em;
}

/* ---------- 资料入口 ---------- */

.page-about .pa-docs {
  gap: 1rem;
}

.page-about .pa-doc {
  display: block;
  padding: 1.4rem 1.3rem 1.5rem;
  background: var(--panel);
  border: 1px solid var(--pa-hair);
  text-decoration: none;
  transition: border-color .25s ease, transform .25s ease;
}

.page-about .pa-doc:hover,
.page-about .pa-doc:focus-visible {
  border-color: rgba(47, 230, 214, .55);
  transform: translateY(-2px);
}

.page-about .pa-doc__k {
  margin: 0 0 .6rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .14em;
  color: var(--amber);
}

.page-about .pa-doc h3 {
  margin: 0 0 .55rem;
  font-family: var(--font-head);
  font-size: 1.15rem;
  color: var(--paper);
}

.page-about .pa-doc p {
  margin: 0 0 1rem;
  font-size: .89rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .pa-doc__go {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .1em;
  color: var(--cyan);
  border-bottom: 1px solid rgba(47, 230, 214, .45);
  padding-bottom: .1rem;
}

.page-about .pa-docs__note {
  margin: 1.4rem 0 0;
  font-size: .9rem;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .pa-docs__note a {
  color: var(--paper);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
  padding-bottom: .08rem;
}

.page-about .pa-docs__note a:hover {
  color: var(--cyan);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .pa-hero {
    padding-top: 3.2rem;
  }

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

  .page-about .pa-stat {
    padding: 1.2rem 1.15rem 1.25rem;
  }

  .page-about .pa-stat__num {
    font-size: 1.95rem;
  }
}

@media (min-width: 768px) {
  .page-about .pa-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
    gap: 3rem;
  }

  .page-about .pa-timeline {
    padding-left: 2rem;
  }

  .page-about .pa-node__dot {
    left: -2rem;
  }

  .page-about .pa-cadence li {
    grid-template-columns: 6.5rem minmax(0, 1fr);
  }
}

@media (min-width: 720px) {
  .page-about .pa-quad {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .pa-qh {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
    gap: 2.2rem;
  }
}

@media (min-width: 960px) {
  .page-about .pa-fields {
    grid-template-columns: minmax(0, 8fr) minmax(0, 4fr);
    gap: 1.8rem;
  }
}

@media (min-width: 1024px) {
  .page-about .pa-body {
    grid-template-columns: 172px minmax(0, 1fr);
    gap: 3.5rem;
    align-items: start;
    padding-top: 3.6rem;
  }

  .page-about .pa-rail {
    position: sticky;
    top: var(--head-offset);
  }

  .page-about .rail__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
  }

  .page-about .rail__link {
    padding: .42rem 0 .42rem .85rem;
    border-bottom: 0;
    border-left: 1px solid transparent;
  }

  .page-about .rail__link[aria-current="true"] {
    border-bottom-color: transparent;
    border-left-color: var(--cyan);
  }

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

  .page-about .pa-quad__item {
    padding: 1.5rem 1.3rem 1.6rem;
  }
}

@media (max-width: 599px) {
  .page-about .pa-bar__seg {
    padding: 0 .45rem;
    font-size: 0;
  }

  .page-about .pa-bar__seg b {
    font-size: .95rem;
  }
}

@media (max-width: 420px) {
  .page-about .pa-cadence li {
    grid-template-columns: minmax(0, 1fr);
    gap: .25rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .pa-doc,
  .page-about .pa-quad__item,
  .page-about .pa-quad__item::before,
  .page-about .pa-table tbody tr,
  .page-about .rail__link,
  .page-about .breadcrumbs a {
    transition: none;
  }

  .page-about .pa-doc:hover,
  .page-about .pa-doc:focus-visible {
    transform: none;
  }
}