.page-about {
  --about-axis: 18px;
  --about-pad: 3.5rem;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-top: clamp(1.5rem, 4vw, 2.75rem);
  padding-bottom: clamp(3rem, 8vw, 6rem);
}

.page-about .about-hero__slant {
  position: absolute;
  top: 0;
  right: -4%;
  width: 54%;
  height: 68px;
  background: linear-gradient(120deg, var(--cyan-deep), #0d414c 78%);
  clip-path: polygon(22% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__lead {
  margin-top: clamp(1.25rem, 4vw, 2rem);
}

.page-about .about-hero__lead .lede {
  margin-top: 1.1rem;
  max-width: 60ch;
}

.page-about .about-hero__stats {
  list-style: none;
  margin: clamp(2rem, 6vw, 3.5rem) 0 0;
  padding: 1.5rem 0 0;
  border-top: 1px solid var(--sand);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem 1rem;
}

.page-about .stat-num {
  display: block;
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  line-height: 1.1;
  color: var(--cyan-deep);
  font-weight: 700;
}

.page-about .stat-cap {
  display: block;
  margin-top: .35rem;
  font-size: 13px;
  color: var(--rock);
  line-height: 1.5;
}

/* ---------- 时间线骨架 ---------- */

.page-about .about-body {
  padding-bottom: clamp(2.5rem, 6vw, 4.5rem);
}

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

.page-about .tl::before {
  content: "";
  position: absolute;
  top: .5rem;
  bottom: 2rem;
  left: var(--about-axis);
  width: 2px;
  background: linear-gradient(to bottom, transparent, var(--sand) 5%, var(--sand) 95%, transparent);
}

.page-about .tl__item {
  position: relative;
  padding: 0 0 clamp(3rem, 8vw, 4.5rem) var(--about-pad);
}

.page-about .tl__dot {
  position: absolute;
  top: 0;
  left: var(--about-axis);
  transform: translateX(-50%);
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--sand);
  color: var(--rock);
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .02em;
  z-index: 2;
  transition: background-color .3s var(--ease), border-color .3s var(--ease),
              color .3s var(--ease), transform .3s var(--ease);
}

.page-about .tl__item.is-inview .tl__dot,
.page-about .tl__item:hover .tl__dot {
  background: var(--cyan-deep);
  border-color: var(--lime);
  color: var(--lime);
  transform: translateX(-50%) scale(1.12);
}

.page-about .tl__dot .num {
  font-size: inherit;
  color: inherit;
}

/* ---------- 面板通用 ---------- */

.page-about .tl__panel--left .data-heading {
  margin: .55rem 0 .9rem;
}

.page-about .tl__panel--left p {
  margin: 0 0 1rem;
}

.page-about .tl__panel--right {
  margin-top: 1.75rem;
}

.page-about .about-fig {
  margin: 1.25rem 0 0;
}

.page-about .about-fig--tight {
  margin-top: 1.5rem;
}

.page-about .about-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 20px 0 20px 0;
  background: var(--paper-deep);
}

.page-about .about-fig .caption {
  display: block;
  margin-top: .7rem;
}

/* ---------- 事实卡 ---------- */

.page-about .fact {
  background: var(--paper-deep);
  border-radius: var(--radius-card) 0 var(--radius-card) 0;
  padding: 1.25rem 1.35rem;
}

.page-about .fact__row {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  padding: .85rem 0;
  border-bottom: 1px solid var(--sand);
}

.page-about .fact__row:first-child { padding-top: 0; }
.page-about .fact__row:last-child { padding-bottom: 0; border-bottom: 0; }

.page-about .fact__key {
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--rock);
}

.page-about .fact__val {
  font-size: .98rem;
  line-height: 1.6;
  color: var(--text);
}

/* ---------- 三层内容 ---------- */

.page-about .layer {
  border-bottom: 1px solid var(--sand);
}

.page-about .layer:first-of-type {
  border-top: 1px solid var(--sand);
}

.page-about .layer__head {
  display: flex;
  align-items: center;
  gap: .7rem;
  padding: .9rem 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .layer__head::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 1rem;
  line-height: 1;
  color: var(--cyan-deep);
}

.page-about .layer[open] .layer__head::after {
  content: "−";
}

.page-about .layer__swatch {
  width: 10px;
  height: 10px;
  flex: none;
  border-radius: 2px;
}

.page-about .layer--db .layer__swatch { background: var(--cyan); }
.page-about .layer--purple .layer__swatch { background: var(--purple); }
.page-about .layer--sunset .layer__swatch { background: var(--sunset); }

.page-about .layer__title {
  font-size: .98rem;
  font-weight: 500;
  color: var(--text);
}

.page-about .layer__num {
  margin-left: auto;
  font-size: .78rem;
  color: var(--rock);
}

.page-about .layer__body {
  padding: 0 0 1.1rem;
}

.page-about .layer__body p {
  margin: 0;
  font-size: .95rem;
  color: var(--text);
}

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

/* ---------- 层级示意图 ---------- */

.page-about .layer-map {
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  display: grid;
  gap: .55rem;
}

.page-about .layer-map__row {
  display: flex;
  align-items: center;
  gap: .7rem;
  padding: .75rem .9rem;
  font-size: .9rem;
  color: var(--ink);
  border-radius: 0 14px 14px 0;
}

.page-about .layer-map__idx {
  font-size: .75rem;
  color: var(--rock);
}

.page-about .layer-map__row--a {
  width: 100%;
  background: color-mix(in srgb, var(--cyan) 22%, var(--paper));
  border-left: 4px solid var(--cyan-deep);
}

.page-about .layer-map__row--b {
  width: 84%;
  background: color-mix(in srgb, var(--purple) 16%, var(--paper));
  border-left: 4px solid var(--purple);
}

.page-about .layer-map__row--c {
  width: 68%;
  background: color-mix(in srgb, var(--sunset) 18%, var(--paper));
  border-left: 4px solid var(--sunset);
}

/* ---------- 生产流程 ---------- */

.page-about .flow {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
}

.page-about .flow__step {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .5rem .8rem;
  font-size: .85rem;
  background: var(--lime-soft);
  color: var(--ink);
  border-radius: 999px;
}

.page-about .flow__num {
  font-size: .72rem;
  color: var(--cyan-deep);
}

/* ---------- 年份演进 ---------- */

.page-about .years {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .years__row {
  display: grid;
  grid-template-columns: 4.6rem minmax(0, 1fr);
  gap: .9rem;
  padding: .95rem 0;
  border-bottom: 1px solid var(--sand);
}

.page-about .years__row:first-child { padding-top: 0; }

.page-about .years__y {
  font-size: 1rem;
  color: var(--cyan-deep);
  font-weight: 700;
}

.page-about .years__t {
  font-size: .95rem;
  line-height: 1.65;
  color: var(--text);
}

/* ---------- 合作生态卡 ---------- */

.page-about .part {
  display: grid;
  gap: 1rem;
}

.page-about .part__card {
  padding: 1.3rem 1.35rem 1.4rem;
  background: var(--paper-deep);
  border-radius: var(--radius-card) 0 var(--radius-card) 0;
  border-top: 4px solid var(--cyan-deep);
}

.page-about .part__card--alt {
  border-top-color: var(--purple);
}

.page-about .part__num {
  font-size: 1.85rem;
  color: var(--ink);
  line-height: 1;
}

.page-about .part__title {
  margin: .6rem 0 .7rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .part__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .part__list li {
  position: relative;
  padding-left: 1rem;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--text);
}

.page-about .part__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .7em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--sand);
}

/* ---------- 服务区域点阵 ---------- */

.page-about .geo {
  list-style: none;
  margin: 0;
  padding: 1.25rem 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.25rem;
  background: var(--paper-deep);
  border-radius: 0 var(--radius-card) 0 var(--radius-card);
}

.page-about .geo__pt {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  min-width: 6.5rem;
  max-width: 100%;
}

.page-about .geo__pt:nth-child(odd) { margin-top: 1.35rem; }

.page-about .geo__dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--cyan);
  transition: background-color .25s var(--ease), transform .25s var(--ease);
}

.page-about .geo__pt:hover .geo__dot,
.page-about .geo__pt:focus-within .geo__dot {
  background: var(--cyan-deep);
  transform: scale(1.5);
}

.page-about .geo__name {
  font-size: .95rem;
  color: var(--text);
}

.page-about .geo__meta {
  font-size: 12px;
  line-height: 1.5;
  color: var(--rock);
}

.page-about .tl__panel--right .caption {
  display: block;
  margin-top: .8rem;
}

/* ---------- 收尾 ---------- */

.page-about .about-outro {
  padding-bottom: clamp(3rem, 8vw, 5rem);
}

.page-about .about-outro__card {
  position: relative;
  overflow: hidden;
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--radius-card) 0 var(--radius-card) 0;
  padding: clamp(1.75rem, 5vw, 3rem);
}

.page-about .about-outro__card::after {
  content: "";
  position: absolute;
  right: -6%;
  bottom: -30%;
  width: 46%;
  height: 130%;
  background: var(--cyan-deep);
  opacity: .35;
  clip-path: polygon(38% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-outro__card > * {
  position: relative;
  z-index: 1;
}

.page-about .about-outro__card .index-label {
  color: var(--lime);
}

.page-about .about-outro__title {
  margin: .6rem 0 1rem;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-outro__text {
  margin: 0 0 1.5rem;
  max-width: 52ch;
  font-size: .98rem;
  line-height: 1.75;
  color: color-mix(in srgb, var(--paper) 82%, var(--rock));
}

.page-about .about-outro__links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .9rem 1.4rem;
}

.page-about .about-outro__btn {
  display: inline-block;
  padding: .8rem 1.5rem;
  background: var(--lime);
  color: var(--ink);
  font-weight: 700;
  font-size: .95rem;
  text-decoration: none;
  border-radius: 999px;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease);
}

.page-about .about-outro__btn:hover,
.page-about .about-outro__btn:focus-visible {
  transform: translateY(-3px);
  box-shadow: 0 14px 24px -16px rgba(200, 240, 74, .8);
}

.page-about .about-outro__link {
  color: var(--paper);
  font-size: .95rem;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-color: var(--cyan);
}

/* ---------- 桌面布局 ---------- */

@media (min-width: 900px) {

  .page-about {
    --about-axis: 50%;
    --about-pad: 0px;
  }

  .page-about .about-hero {
    padding-top: clamp(2rem, 4vw, 3.25rem);
    padding-bottom: clamp(3.5rem, 7vw, 5.5rem);
  }

  .page-about .about-hero__slant {
    top: -10%;
    right: -8%;
    width: 46%;
    height: 68%;
    clip-path: polygon(26% 0, 100% 0, 100% 74%, 0 100%);
  }

  .page-about .about-hero__lead {
    max-width: 54%;
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.5rem;
    margin-top: clamp(3.5rem, 8vw, 6rem);
    padding-top: 1.75rem;
  }

  .page-about .tl__item {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    column-gap: clamp(3.5rem, 8vw, 7rem);
    padding-bottom: clamp(4rem, 7vw, 6rem);
  }

  .page-about .tl__panel--left {
    padding-top: .35rem;
  }

  .page-about .tl__panel--right {
    margin-top: 0;
  }

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

  .page-about .geo {
    padding: 1.75rem 1.5rem;
    gap: 1.5rem 1.75rem;
  }

  .page-about .geo__meta {
    opacity: 0;
    transform: translateY(3px);
    transition: opacity .25s var(--ease), transform .25s var(--ease);
  }

  .page-about .geo__pt:hover .geo__meta,
  .page-about .geo__pt:focus-within .geo__meta {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero__lead {
    max-width: 52%;
  }

  .page-about .about-outro__card {
    padding-right: 34%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl__dot,
  .page-about .geo__dot,
  .page-about .geo__meta,
  .page-about .about-outro__btn {
    transition: none;
  }
}