.page-about {
  --about-line: rgba(220, 227, 220, 0.14);
  --about-line-strong: rgba(220, 227, 220, 0.28);
  --about-soft: rgba(220, 227, 220, 0.78);
  background: var(--ink-green);
  color: var(--stand);
  overflow-x: hidden;
}

.page-about a {
  color: var(--signal);
  text-decoration: none;
  border-bottom: 1px solid rgba(201, 255, 61, 0.4);
}

.page-about a:hover {
  border-bottom-color: var(--signal);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding: 20px 0 0;
  font-size: 13px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 22px 0 0;
  background:
    radial-gradient(130% 80% at 88% -20%, rgba(201, 255, 61, 0.10), transparent 62%),
    radial-gradient(95% 75% at -10% 115%, rgba(30, 91, 69, 0.55), transparent 70%);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(32px, 8vw, 66px);
  line-height: 1.03;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero__lead {
  margin: 18px 0 0;
  max-width: 44em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  color: var(--about-soft);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--about-line-strong);
  border: 1px solid var(--about-line-strong);
}

.page-about .about-hero__stats li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 15px 18px;
  background: var(--ink-green);
}

.page-about .about-hero__num {
  font-family: var(--font-mono);
  font-size: clamp(25px, 4.6vw, 40px);
  font-weight: 700;
  line-height: 1;
  color: var(--signal);
  font-variant-numeric: tabular-nums;
}

.page-about .about-hero__cap {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .about-tickline {
  height: 12px;
  margin-top: 34px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--about-line-strong) 0 1px,
    transparent 1px 20px
  );
  border-bottom: 2px solid var(--about-line-strong);
}

/* ---------- 通用区块骨架 ---------- */
.page-about .about-sec {
  padding: 42px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-sec--last {
  border-bottom: 0;
  padding-bottom: 76px;
}

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

.page-about .about-sec__rail {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .about-sec__idx {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .about-sec__label {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-sec__body {
  min-width: 0;
}

.page-about .about-sec__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 4.6vw, 36px);
  line-height: 1.12;
  color: var(--paper);
}

.page-about .about-sec__body > p {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.78;
  color: var(--about-soft);
}

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

/* ---------- 图片 ---------- */
.page-about .about-media {
  margin: 24px 0 0;
  border: 2px solid var(--about-line-strong);
  background: var(--midnight);
}

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

.page-about .about-media--banner {
  margin: 18px 0 0;
  border-color: var(--edge);
}

/* ---------- 流程四步 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-flow li {
  position: relative;
  padding: 18px 16px;
  background: var(--midnight);
  border: 2px solid var(--about-line-strong);
  box-shadow: var(--hard-shadow-sm);
}

.page-about .about-flow__n {
  display: inline-block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--signal);
}

.page-about .about-flow h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  color: var(--paper);
}

.page-about .about-flow p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(220, 227, 220, 0.72);
}

/* ---------- 暖纸面板 ---------- */
.page-about .about-paper {
  margin-top: 18px;
  padding: 24px 20px;
  background: var(--paper);
  color: var(--paper-ink);
  border: 2px solid var(--deep-ink);
  box-shadow: var(--hard-shadow);
}

.page-about .about-paper p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--paper-ink);
}

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

.page-about .about-paper a {
  color: var(--pitch);
  border-bottom-color: rgba(30, 91, 69, 0.4);
}

.page-about .about-scope {
  list-style: none;
  margin: 20px 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: rgba(22, 34, 29, 0.16);
  border: 1px solid rgba(22, 34, 29, 0.16);
}

.page-about .about-scope li {
  padding: 14px 12px;
  background: var(--paper);
}

.page-about .about-scope__v {
  display: block;
  font-family: var(--font-mono);
  font-size: 23px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--paper-ink);
  font-variant-numeric: tabular-nums;
}

.page-about .about-scope__l {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  line-height: 1.5;
  color: rgba(22, 34, 29, 0.66);
}

/* ---------- 版本演进时间轴 ---------- */
.page-about .about-tl {
  margin-top: 24px;
}

.page-about .about-tl__item {
  border-top: 1px solid var(--about-line-strong);
}

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

.page-about .about-tl__item summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 0;
  list-style: none;
  cursor: pointer;
}

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

.page-about .about-tl__item summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--signal);
}

.page-about .about-tl__item[open] summary::after {
  content: "\2212";
}

.page-about .about-tl__yr {
  min-width: 54px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--signal);
  font-variant-numeric: tabular-nums;
}

.page-about .about-tl__ttl {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-tl__body {
  padding: 0 0 18px 0;
}

.page-about .about-tl__body p {
  margin: 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(220, 227, 220, 0.75);
}

/* ---------- 使用场景 ---------- */
.page-about .about-users {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-users li {
  padding: 18px 16px;
  border: 2px solid var(--about-line-strong);
  background: linear-gradient(180deg, rgba(220, 227, 220, 0.045), transparent 70%);
}

.page-about .about-users h3 {
  margin: 14px 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-users p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: rgba(220, 227, 220, 0.75);
}

/* ---------- 合作 ---------- */
.page-about .about-collab {
  list-style: none;
  margin: 22px 0 28px;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-collab li {
  padding: 4px 0 4px 15px;
  border-left: 3px solid var(--signal);
}

.page-about .about-collab h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  color: var(--paper);
}

.page-about .about-collab p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: rgba(220, 227, 220, 0.76);
}

.page-about .about-sec--last .btn {
  border-bottom: 0;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-hero__stats li {
    display: block;
    padding: 18px 20px;
  }

  .page-about .about-hero__cap {
    margin-top: 8px;
  }

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

@media (min-width: 760px) {
  .page-about .about-sec {
    padding: 54px 0;
  }

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

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

  .page-about .about-paper {
    padding: 32px 30px;
  }

  .page-about .about-tl__body {
    padding-left: 68px;
  }
}

@media (min-width: 860px) {
  .page-about .about-sec__grid {
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 44px;
  }

  .page-about .about-sec__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .page-about .about-sec__body {
    position: relative;
    padding-left: 36px;
    border-left: 2px solid var(--about-line-strong);
  }

  .page-about .about-sec__body::before {
    content: "";
    position: absolute;
    left: -8px;
    top: 12px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--signal);
    box-shadow: 0 0 0 5px var(--ink-green);
  }

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

@media (min-width: 900px) {
  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-flow li + li::before {
    content: "";
    position: absolute;
    left: -22px;
    top: 26px;
    width: 22px;
    height: 2px;
    background: var(--signal);
  }
}