/* =========================================================
   PAGE: 站点介绍 / about
   Scope: .page-about
   ========================================================= */

.page-about {
  --about-rail-w: 290px;
  --about-gutter: clamp(32px, 5vw, 88px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--ink);
  border-bottom: 1px solid var(--rule);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.55;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(102deg,
    rgba(11, 11, 11, 0.96) 0%,
    rgba(11, 11, 11, 0.84) 44%,
    rgba(11, 11, 11, 0.42) 100%);
}

.page-about .about-hero__slash {
  position: absolute;
  z-index: 1;
  top: -18%;
  right: 4%;
  width: 20%;
  height: 136%;
  background: linear-gradient(180deg,
    rgba(201, 162, 39, 0.22),
    rgba(201, 162, 39, 0) 78%);
  transform: rotate(9deg);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  padding-top: 56px;
  padding-bottom: 72px;
}

.page-about .about-hero .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 30px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--ash);
}

.page-about .about-hero .crumbs a {
  color: var(--ash);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 200ms ease, border-color 200ms ease;
}

.page-about .about-hero .crumbs a:hover {
  color: var(--gold-lift);
  border-bottom-color: var(--gold-lift);
}

.page-about .about-hero .crumbs__sep {
  color: var(--rule);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gold);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 15em;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(32px, 5.2vw, 62px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-hero__lead {
  margin: 26px 0 0;
  max-width: 34em;
  font-size: var(--fs-17);
  line-height: 1.9;
  color: var(--paper);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 22px 32px;
  max-width: 660px;
  margin: 42px 0 0;
  padding: 26px 0 0;
  border-top: 1px solid var(--rule);
  list-style: none;
}

.page-about .hero-stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .hero-stat__num {
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--gold);
}

.page-about .hero-stat__key {
  font-size: var(--fs-14);
  letter-spacing: 0.04em;
  color: var(--ash);
}

/* ---------- 主体：左轨 + 右章节 ---------- */

.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  padding-top: 24px;
  padding-bottom: 64px;
}

.page-about .about-rail {
  position: relative;
  z-index: 6;
  margin-bottom: 8px;
}

.page-about .about-rail__inner {
  padding: 20px 0 26px;
}

.page-about .about-rail__label {
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--ash);
}

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

.page-about .rail-item {
  position: relative;
}

.page-about .rail-link {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 10px 8px 10px 0;
  text-decoration: none;
  color: var(--ash);
}

.page-about .rail-node {
  position: relative;
  z-index: 1;
  flex: 0 0 11px;
  width: 11px;
  height: 11px;
  margin-top: 5px;
  background: var(--ink);
  border: 1px solid var(--rule);
  transition: background-color 200ms ease, border-color 200ms ease;
}

.page-about .rail-text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--ash);
  transition: color 200ms ease;
}

.page-about .rail-name {
  font-size: var(--fs-14);
  line-height: 1.4;
  color: var(--ash);
  transition: color 200ms ease;
}

.page-about .rail-link:hover .rail-node {
  border-color: var(--gold);
}

.page-about .rail-link:hover .rail-name {
  color: var(--gold-lift);
}

.page-about .rail-link:hover .rail-num {
  color: var(--gold);
}

.page-about .rail-link[aria-current="true"] .rail-node {
  background: var(--gold);
  border-color: var(--gold);
}

.page-about .rail-link[aria-current="true"] .rail-name {
  color: var(--paper);
}

.page-about .rail-link[aria-current="true"] .rail-num {
  color: var(--gold);
}

.page-about .rail-link:focus-visible {
  outline: 2px solid var(--gold-lift);
  outline-offset: 2px;
}

/* ---------- 章节 ---------- */

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

.page-about .chapter {
  position: relative;
  padding: 48px 0 56px;
}

.page-about .chapter + .chapter {
  border-top: 1px solid var(--rule);
}

.page-about .chapter__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-40);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--gold);
}

.page-about .chapter__title {
  margin: 14px 0 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(23px, 2.6vw, 32px);
  line-height: 1.3;
  color: var(--white);
}

.page-about .chapter__lead {
  margin: 20px 0 0;
  max-width: 34em;
  font-size: var(--fs-17);
  line-height: 1.9;
  color: var(--paper);
}

.page-about .chapter__note {
  margin: 30px 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--gold-deep);
  max-width: 38em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--ash);
}

.page-about .chapter__note a,
.page-about .archive-item__text a {
  color: var(--gold);
  text-decoration: none;
  border-bottom: 1px solid var(--gold-deep);
  transition: color 200ms ease, border-color 200ms ease;
}

.page-about .chapter__note a:hover,
.page-about .archive-item__text a:hover {
  color: var(--gold-lift);
  border-bottom-color: var(--gold-lift);
}

.page-about .chapter__note a:focus-visible,
.page-about .archive-item__text a:focus-visible {
  outline: 2px solid var(--gold-lift);
  outline-offset: 2px;
}

/* ---------- 01 阶段 ---------- */

.page-about .stages {
  margin: 34px 0 0;
  padding: 0;
  border-top: 1px solid var(--rule);
  list-style: none;
}

.page-about .stage {
  padding: 24px 0 26px 22px;
  border-bottom: 1px solid var(--rule);
  border-left: 2px solid var(--gold-deep);
}

.page-about .stage__mark {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .stage__title {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  color: var(--white);
}

.page-about .stage__text {
  margin: 0;
  max-width: 36em;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--paper);
}

/* ---------- 02 资料分类 ---------- */

.page-about .chapter__cols {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  margin-top: 34px;
}

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

.page-about .archive-item {
  padding: 20px 0 22px;
  border-bottom: 1px solid var(--rule);
}

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

.page-about .archive-item__tag {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--gold);
}

.page-about .archive-item__title {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  color: var(--white);
}

.page-about .archive-item__text {
  margin: 0;
  max-width: 34em;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--paper);
}

.page-about .archive-figure {
  margin: 0;
}

.page-about .archive-figure .figure__frame {
  overflow: hidden;
  border: 1px solid var(--rule);
  background: var(--graphite);
  aspect-ratio: 4 / 3;
}

.page-about .archive-figure .figure__frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .archive-figure .figure__cap {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--rule);
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--ash);
}

/* ---------- 03 团队 ---------- */

.page-about .team {
  margin-top: 34px;
  border-top: 1px solid var(--rule);
}

.page-about .team-row {
  border-bottom: 1px solid var(--rule);
}

.page-about .team-row__sum {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 20px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .team-row__sum::after {
  content: "+";
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-17);
  line-height: 1;
  color: var(--gold);
}

.page-about .team-row[open] .team-row__sum::after {
  content: "−";
}

.page-about .team-row__name {
  flex: 1 1 auto;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  color: var(--white);
  transition: color 200ms ease;
}

.page-about .team-row__meta {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--gold);
}

.page-about .team-row__sum:hover .team-row__name {
  color: var(--gold-lift);
}

.page-about .team-row__sum:focus-visible {
  outline: 2px solid var(--gold-lift);
  outline-offset: -2px;
}

.page-about .team-row__body {
  max-width: 38em;
  padding: 0 0 24px;
}

.page-about .team-row__body p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--paper);
}

/* ---------- 04 流程 ---------- */

.page-about .flow {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .flow__step {
  padding: 20px 18px 22px;
  background: var(--graphite);
  border: 1px solid var(--rule);
  border-top: 2px solid var(--gold);
}

.page-about .flow__idx {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .flow__title {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-17);
  line-height: 1.4;
  color: var(--white);
}

.page-about .flow__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--paper);
}

.page-about .fold {
  margin-top: 30px;
  padding-left: 18px;
  border-left: 2px solid var(--gold-deep);
}

.page-about .fold__sum {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 4px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-17);
  line-height: 1.5;
  color: var(--gold);
}

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

.page-about .fold__sum::before {
  content: "▸";
  flex: 0 0 auto;
  font-size: var(--fs-12);
  color: var(--gold);
  transition: transform 200ms ease;
}

.page-about .fold[open] .fold__sum::before {
  transform: rotate(90deg);
}

.page-about .fold__sum:focus-visible {
  outline: 2px solid var(--gold-lift);
  outline-offset: 2px;
}

.page-about .fold__body {
  max-width: 38em;
  padding-top: 14px;
}

.page-about .fold__body p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--paper);
}

/* ---------- 05 规模 ---------- */

.page-about .chapter--scale {
  overflow: hidden;
}

.page-about .scale-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-about .scale-bg img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.12;
}

.page-about .chapter--scale > *:not(.scale-bg) {
  position: relative;
  z-index: 1;
}

.page-about .scale-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  margin: 34px 0 0;
  padding: 0;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .scale-cell {
  margin: 0;
  padding: 20px 18px 22px;
  background: var(--ink);
}

.page-about .scale-cell__key {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--ash);
}

.page-about .scale-cell__val {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.3;
  color: var(--gold);
}

/* ---------- 结尾 ---------- */

.page-about .about-outro {
  position: relative;
  overflow: hidden;
  background: var(--graphite);
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.page-about .about-outro::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 82% 26%, rgba(201, 162, 39, 0.24), rgba(201, 162, 39, 0) 62%);
  pointer-events: none;
}

.page-about .about-outro__inner {
  position: relative;
  z-index: 1;
  padding-top: 72px;
  padding-bottom: 78px;
}

.page-about .about-outro__eyebrow {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-outro__title {
  margin: 0;
  max-width: 20em;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(23px, 2.6vw, 34px);
  line-height: 1.3;
  color: var(--white);
}

.page-about .about-outro__text {
  margin: 18px 0 0;
  max-width: 34em;
  font-size: var(--fs-17);
  line-height: 1.9;
  color: var(--paper);
}

.page-about .about-outro__btn {
  display: inline-flex;
  align-items: center;
  margin-top: 30px;
  text-decoration: none;
}

/* ---------- 桌面端 ---------- */

@media (min-width: 1024px) {

  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: var(--about-gutter);
    align-items: start;
    padding-top: 40px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 36px);
    margin-bottom: 0;
  }

  .page-about .rail-list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 12px;
    bottom: 12px;
    width: 1px;
    background: var(--rule);
  }

  .page-about .chapter__cols {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

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

@media (min-width: 768px) {
  .page-about .flow {
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 14px;
  }
}

/* ---------- 移动端 ---------- */

@media (max-width: 1023px) {

  .page-about .about-rail {
    position: sticky;
    top: var(--header-h);
    margin-bottom: 24px;
    background: var(--ink);
    border-bottom: 1px solid var(--rule);
  }

  .page-about .about-rail__inner {
    padding: 10px 0 12px;
  }

  .page-about .about-rail__label {
    display: none;
  }

  .page-about .rail-list {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    scrollbar-width: none;
  }

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

  .page-about .rail-item {
    flex: 0 0 auto;
  }

  .page-about .rail-link {
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    border: 1px solid var(--rule);
    white-space: nowrap;
  }

  .page-about .rail-node {
    flex: 0 0 9px;
    width: 9px;
    height: 9px;
    margin-top: 0;
  }

  .page-about .rail-text {
    flex-direction: row;
    align-items: baseline;
    gap: 8px;
  }
}

@media (max-width: 640px) {

  .page-about .about-hero__inner {
    padding-top: 40px;
    padding-bottom: 56px;
  }

  .page-about .hero-stats {
    grid-template-columns: 1fr 1fr;
    gap: 20px 22px;
  }

  .page-about .chapter {
    padding: 40px 0 46px;
  }

  .page-about .scale-grid {
    grid-template-columns: 1fr;
  }

  .page-about .about-outro__inner {
    padding-top: 56px;
    padding-bottom: 60px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}