.page-about {
  --about-rail-w: 264px;
  --about-gap: 40px;
  background: var(--ink-900);
  color: var(--white-100);
  padding-bottom: 88px;
  overflow-x: clip;
}

.page-about .breadcrumbs {
  padding: 20px 0 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 26px;
  margin: 22px auto 56px;
}

.page-about .about-hero__media {
  margin: 0;
  border: var(--line);
  background: var(--ink-800);
  aspect-ratio: 16 / 10;
  overflow: hidden;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.88) contrast(1.04);
}

.page-about .about-hero__title {
  margin: 12px 0 16px;
  font-family: var(--font-head);
  font-size: clamp(32px, 7.2vw, 54px);
  line-height: 1.12;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--white-100);
}

.page-about .about-hero__text .lead {
  max-width: 40em;
  color: var(--mist-300);
}

.page-about .about-hero__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: center;
    gap: 52px;
    margin: 32px auto 88px;
  }
  .page-about .about-hero__media {
    aspect-ratio: 1 / 1;
  }
}

/* ---------- 左右分栏 ---------- */
.page-about .about-layout {
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-rail__pitch {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist-300);
}

.page-about .about-rail__nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  margin: 20px 0;
  padding-bottom: 10px;
  border-bottom: var(--line);
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

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

.page-about .about-rail__nav a {
  flex: 0 0 auto;
  padding: 7px 14px;
  border: 1px solid var(--ink-600);
  border-radius: var(--radius-pill);
  font-size: 14px;
  line-height: 1.4;
  color: var(--mist-300);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease), background 0.25s var(--ease);
}

.page-about .about-rail__nav a:hover {
  color: var(--cyan-300);
  border-color: var(--cyan-500);
}

.page-about .about-rail__nav a.is-active {
  color: var(--ink-900);
  background: var(--cyan-500);
  border-color: var(--cyan-500);
  font-weight: 600;
}

.page-about .about-rail__cta {
  display: inline-flex;
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
  }
  .page-about .about-rail__inner {
    position: sticky;
    top: 104px;
  }
  .page-about .about-rail__nav {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-bottom: 0;
    border-left: var(--line);
    padding-bottom: 0;
  }
  .page-about .about-rail__nav a {
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    margin-left: -1px;
    padding: 9px 0 9px 18px;
    background: transparent;
    white-space: normal;
  }
  .page-about .about-rail__nav a.is-active {
    color: var(--cyan-300);
    background: transparent;
    border-left-color: var(--cyan-500);
  }
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding: 44px 0;
  border-top: var(--line);
}

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

.page-about .about-sec .h2 {
  margin: 10px 0 18px;
  font-size: clamp(23px, 3.4vw, 34px);
  line-height: 1.24;
}

.page-about .about-sec__lead {
  margin: 0 0 22px;
  max-width: 42em;
  color: var(--mist-300);
}

.page-about .about-sec__foot {
  margin: 26px 0 0;
}

.page-about .about-sec__note {
  margin: 18px 0 0;
  max-width: 46em;
}

/* ---------- 媒体块 ---------- */
.page-about .about-media {
  margin: 0 0 24px;
  border: var(--line);
  background: var(--ink-800);
  overflow: hidden;
}

.page-about .about-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.85) contrast(1.05);
}

.page-about .about-media--wide {
  aspect-ratio: 14 / 7;
}

.page-about .about-media--portrait {
  aspect-ratio: 4 / 3;
  margin: 0;
}

@media (min-width: 720px) {
  .page-about .about-media--wide {
    aspect-ratio: 21 / 8;
  }
}

/* ---------- 产品线卡片 ---------- */
.page-about .about-lines {
  display: grid;
  gap: 16px;
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 640px) {
  .page-about .about-lines {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  }
}

.page-about .about-line {
  border: var(--line);
  background: var(--ink-800);
  display: flex;
  flex-direction: column;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease);
}

.page-about .about-line:hover {
  transform: translateY(-4px);
  border-color: var(--cyan-500);
}

.page-about .about-line__toggle {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 20px 0;
  border: 0;
  background: transparent;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .about-line__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--cyan-500);
  flex: none;
}

.page-about .about-line__name {
  font-size: 17px;
  font-weight: 650;
  color: var(--white-100);
}

.page-about .about-line__icon {
  position: relative;
  width: 14px;
  height: 14px;
  margin-left: auto;
  flex: none;
}

.page-about .about-line__icon::before,
.page-about .about-line__icon::after {
  content: "";
  position: absolute;
  background: var(--cyan-300);
  transition: transform 0.25s var(--ease);
}

.page-about .about-line__icon::before {
  top: 6px;
  left: 0;
  width: 14px;
  height: 2px;
}

.page-about .about-line__icon::after {
  top: 0;
  left: 6px;
  width: 2px;
  height: 14px;
}

.page-about .about-line__toggle[aria-expanded="true"] .about-line__icon::after {
  transform: scaleY(0);
}

.page-about .about-line__summary {
  margin: 10px 0 0;
  padding: 0 20px 20px;
  font-size: 15px;
  line-height: 1.68;
  color: var(--mist-300);
}

.page-about .about-line__panel {
  padding: 16px 20px 20px;
  border-top: 1px solid var(--ink-600);
  font-size: 15px;
  line-height: 1.72;
  color: var(--white-100);
}

.page-about .about-line__panel[hidden] {
  display: none;
}

.page-about .about-line__panel p {
  margin: 0;
}

/* ---------- 步骤 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
}

.page-about .about-step {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 0;
  border-top: 1px solid var(--ink-600);
}

.page-about .about-step:last-child {
  border-bottom: 1px solid var(--ink-600);
}

.page-about .about-step__key {
  padding-top: 4px;
}

.page-about .about-step__body .h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 650;
  color: var(--white-100);
}

.page-about .about-step__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist-300);
  max-width: 44em;
}

@media (min-width: 720px) {
  .page-about .about-step {
    grid-template-columns: 72px minmax(0, 1fr);
    gap: 20px;
    padding: 22px 0;
  }
}

/* ---------- 呼吸段 ---------- */
.page-about .about-pull {
  position: relative;
  margin: 52px 0;
  padding: 44px 0 40px;
  border-top: var(--line);
  border-bottom: var(--line);
}

.page-about .about-pull::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 108px;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan-500), var(--orange-500));
}

.page-about .about-pull p {
  margin: 0;
  max-width: 26ch;
  font-family: var(--font-head);
  font-size: clamp(19px, 3.6vw, 27px);
  line-height: 1.5;
  font-weight: 650;
  letter-spacing: -0.01em;
  color: var(--white-100);
}

/* ---------- 统计块 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px 18px;
  background: var(--ink-800);
}

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 34px);
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--cyan-500);
}

.page-about .about-stat__unit {
  font-size: 13px;
  line-height: 1.55;
  color: var(--mist-300);
}

/* ---------- 迭代 ---------- */
.page-about .about-iter-head {
  display: grid;
  gap: 22px;
}

@media (min-width: 760px) {
  .page-about .about-iter-head {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
    gap: 28px;
  }
  .page-about .about-media--portrait {
    aspect-ratio: 5 / 4;
  }
}

.page-about .about-stages {
  list-style: none;
  display: flex;
  gap: 14px;
  margin: 28px 0 0;
  padding: 0 0 14px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: var(--ink-600) transparent;
}

.page-about .about-stages::-webkit-scrollbar {
  height: 4px;
}

.page-about .about-stages::-webkit-scrollbar-thumb {
  background: var(--ink-600);
}

.page-about .about-stage {
  position: relative;
  flex: 0 0 244px;
  scroll-snap-align: start;
  padding: 22px 20px 26px;
  border: var(--line);
  background: var(--ink-800);
}

.page-about .about-stage::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 2px;
  background: var(--ink-600);
}

.page-about .about-stage--now::after {
  background: linear-gradient(90deg, var(--cyan-500), var(--orange-500));
}

.page-about .about-stage__key {
  display: block;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cyan-500);
}

.page-about .about-stage--now .about-stage__key {
  color: var(--orange-500);
}

.page-about .about-stage .h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 650;
  color: var(--white-100);
}

.page-about .about-stage p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist-300);
}

/* ---------- 适用人群 ---------- */
.page-about .about-users {
  display: grid;
  gap: 16px;
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 720px) {
  .page-about .about-users {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  }
}

.page-about .about-user {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 24px 22px;
  border: var(--line);
  background: var(--ink-800);
  transition: border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about .about-user:hover {
  transform: translateY(-4px);
  border-color: var(--orange-500);
}

.page-about .about-user .h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 650;
  color: var(--white-100);
}

.page-about .about-user p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist-300);
}

.page-about .about-user__link {
  margin-top: auto;
  padding-top: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--orange-300);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  align-self: flex-start;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-user__link:hover {
  color: var(--orange-500);
  border-bottom-color: var(--orange-500);
}

/* ---------- 收尾 ---------- */
.page-about .about-end {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 44px;
  padding-top: 28px;
  border-top: var(--line);
}

.page-about .about-end__paths {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-end__top {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--cyan-300);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s var(--ease);
}

.page-about .about-end__top:hover {
  border-bottom-color: var(--cyan-300);
}

/* ---------- 显现动效 ---------- */
.page-about.js .page-about [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

.page-about.js .page-about [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
  .page-about.js .page-about [data-reveal] {
    opacity: 1;
    transform: none;
  }
}
</main>