.page-about {
  --about-clip: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 16px 100%, 0 calc(100% - 16px));
  --about-clip-sm: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
  --about-line-grid: repeating-linear-gradient(0deg, transparent 0 32px, rgba(245, 245, 245, 0.04) 32px 33px), repeating-linear-gradient(90deg, transparent 0 32px, rgba(245, 245, 245, 0.04) 32px 33px);

  background: var(--carbon);
  color: var(--white);
  overflow-x: hidden;
}

.page-about .section {
  margin: 0;
}

.page-about .section__head {
  display: flex;
  align-items: flex-start;
  gap: 1.2rem;
}

.page-about .section__head .section__title {
  font-size: clamp(1.8rem, 4vw, 3rem);
  margin-bottom: 0.4rem;
}

/* ===== 区块编号 ===== */
.about-who__index,
.about-milestones__index,
.about-tech__index,
.about-community__index,
.about-credential__index {
  font-family: var(--font-heading);
  font-size: 3.4rem;
  line-height: 0.85;
  color: transparent;
  -webkit-text-stroke: 1px var(--mir-red);
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

/* ===== Hero ===== */
.about-hero {
  position: relative;
  min-height: 82vh;
  display: flex;
  align-items: center;
  padding: 4rem 0;
  background: linear-gradient(135deg, var(--extreme-black) 0%, var(--carbon) 48%, var(--dark-gray) 100%);
  isolation: isolate;
}

.about-hero__bg-layer {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
}

.about-hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.16;
  clip-path: polygon(0 0, 74% 0, 52% 100%, 0 100%);
  filter: saturate(0.35);
}

.about-hero__inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 2.2rem;
}

.about-hero__content {
  max-width: 62rem;
}

.about-hero__kicker {
  display: inline-block;
  color: var(--bright-gold);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  padding-bottom: 0.55rem;
  border-bottom: 2px solid var(--mir-red);
  margin-bottom: 1.6rem;
}

.about-hero__title {
  font-family: var(--font-heading);
  font-size: clamp(2.6rem, 7vw, 5.8rem);
  line-height: 1.04;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  margin-bottom: 1.7rem;
}

.about-hero__title::after {
  content: "";
  display: block;
  width: 72px;
  height: 6px;
  margin-top: 1.4rem;
  background: linear-gradient(90deg, var(--mir-red), var(--bright-gold));
  clip-path: polygon(0 0, 100% 0, calc(100% - 8px) 100%, 0 100%);
}

.about-hero__lead {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--light-gray);
  max-width: 46em;
  margin-bottom: 2.4rem;
}

.about-hero__stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem 2.8rem;
  padding-top: 1.8rem;
  border-top: 1px solid var(--mid-gray);
  max-width: 46em;
}

.about-hero__stat {
  position: relative;
}

.about-hero__stat + .about-hero__stat::before {
  content: "";
  position: absolute;
  left: -1.4rem;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 1px;
  background: var(--mid-gray);
}

.about-hero__stat-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 2.4rem;
  line-height: 1.1;
  color: var(--bright-gold);
}

.about-hero__stat-label {
  font-size: 0.85rem;
  color: var(--light-gray);
  letter-spacing: 0.06em;
}

.about-hero__rail {
  position: absolute;
  right: 1.5rem;
  bottom: 3rem;
  z-index: 3;
  display: none;
  align-items: baseline;
  gap: 0.6rem;
  background: var(--dark-gray);
  padding: 0.7rem 1.1rem;
  border-left: 4px solid var(--mir-red);
  clip-path: var(--about-clip-sm);
}

.about-hero__rail-num {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  color: var(--bright-gold);
  line-height: 1;
}

.about-hero__rail-label {
  font-size: 0.68rem;
  letter-spacing: 0.3em;
  color: var(--light-gray);
}

@media (min-width: 1200px) {
  .about-hero__rail {
    display: flex;
  }
}

/* ===== 我们是谁 ===== */
.about-who {
  padding: 4.5rem 0;
  background: var(--carbon);
}

.about-who__grid {
  display: grid;
  gap: 2.5rem;
  align-items: center;
  margin-top: 2.6rem;
}

.about-who__text p {
  color: var(--light-gray);
  line-height: 1.85;
  margin-bottom: 1.2rem;
}

.about-who__first {
  font-size: 1.12rem;
  font-weight: 500;
  color: var(--white);
  border-left: 3px solid var(--mir-red);
  padding-left: 1rem;
}

.about-who__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2rem;
}

.about-who__visual {
  position: relative;
  max-width: 520px;
  margin-inline: auto;
  width: 100%;
}

.about-who__img {
  width: 100%;
  aspect-ratio: 1 / 1;
}

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

.about-who__badge {
  position: absolute;
  right: -10px;
  bottom: 26px;
  background: var(--extreme-black);
  border: 1px solid var(--gold);
  padding: 1rem 1.2rem;
  text-align: center;
  clip-path: var(--about-clip-sm);
  box-shadow: var(--shadow);
}

.about-who__badge-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 2.2rem;
  line-height: 1;
  color: var(--bright-gold);
}

.about-who__badge-text {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.78rem;
  color: var(--light-gray);
}

@media (min-width: 800px) {
  .about-who__grid {
    grid-template-columns: 1.1fr 0.9fr;
  }
}

/* ===== 发展里程碑 ===== */
.about-milestones {
  position: relative;
  padding: 5rem 0;
  background: var(--dark-gray);
  background-image: var(--about-line-grid);
}

.about-milestones__filter {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 2.2rem;
}

.about-milestones__filter .filter-bar__btn.is-active {
  box-shadow: inset 0 -3px 0 var(--mir-red);
  color: var(--bright-gold);
}

.about-milestones__timeline {
  position: relative;
  margin: 3rem 0 0;
  padding: 0;
  list-style: none;
}

.about-milestones__timeline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(to bottom, var(--mir-red) 0%, var(--gold) 45%, var(--mid-gray) 100%);
}

.about-milestones__item {
  position: relative;
  padding-left: 3.2rem;
  margin-bottom: 1.8rem;
}

.about-milestones__node {
  position: absolute;
  left: 0;
  top: 1.4rem;
  width: 16px;
  height: 16px;
  background: var(--mir-red);
  border: 2px solid var(--bright-gold);
  transform: rotate(45deg);
  box-shadow: 0 0 0 5px rgba(230, 25, 44, 0.18);
  transition: transform var(--transition), background var(--transition);
}

.about-milestones__item:hover .about-milestones__node {
  transform: rotate(45deg) scale(1.22);
  background: var(--bright-red);
}

.about-milestones__card {
  background: var(--carbon);
  padding: 1.4rem 1.4rem 1.5rem;
  clip-path: var(--about-clip);
  border-left: 3px solid transparent;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.about-milestones__card:hover {
  background: #242424;
  border-left-color: var(--mir-red);
  transform: translateX(4px);
}

.about-milestones__tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 0.18rem 0.6rem;
  margin-bottom: 0.6rem;
  background: var(--dark-gray);
  color: var(--light-gray);
}

.about-milestones__tag--history {
  border-left: 3px solid var(--gold);
}

.about-milestones__tag--tech {
  border-left: 3px solid var(--mir-red);
}

.about-milestones__tag--community {
  border-left: 3px solid var(--bright-gold);
}

.about-milestones__title {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  margin-bottom: 0.5rem;
}

.about-milestones__desc {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--light-gray);
}

.about-milestones__note {
  margin-top: 2.5rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--mid-gray);
}

.about-milestones__track {
  display: block;
  width: 100%;
  height: 40px;
  margin-bottom: 1rem;
}

.about-milestones__note p {
  font-size: 0.9rem;
  color: var(--light-gray);
}

.about-milestones__note a {
  color: var(--bright-gold);
  text-decoration: underline;
  text-underline-offset: 4px;
}

@media (min-width: 640px) {
  .about-milestones__item {
    padding-left: 4rem;
  }
  .about-milestones__timeline::before {
    left: 16px;
  }
  .about-milestones__node {
    left: 4px;
    width: 20px;
    height: 20px;
  }
  .about-milestones__card {
    padding: 1.6rem 1.8rem 1.7rem;
  }
}

@media (min-width: 1024px) {
  .about-milestones__timeline {
    margin-left: 4rem;
  }
  .about-milestones__item {
    padding-left: 4.8rem;
  }
  .about-milestones__timeline::before {
    left: 22px;
  }
  .about-milestones__node {
    left: 6px;
    width: 24px;
    height: 24px;
  }
  .about-milestones__card {
    max-width: 780px;
  }
}

/* ===== 数据与技术支持 ===== */
.about-tech {
  padding: 4.5rem 0;
  background: var(--carbon);
}

.about-tech__grid {
  display: grid;
  gap: 2.5rem;
  align-items: start;
  margin-top: 2.6rem;
}

.about-tech__block {
  position: relative;
  padding: 1.5rem 1.5rem 1.5rem 1.8rem;
  margin-bottom: 1.4rem;
  background: var(--dark-gray);
  clip-path: var(--about-clip);
  overflow: hidden;
}

.about-tech__block::before {
  content: "";
  position: absolute;
  right: 16px;
  top: 16px;
  width: 10px;
  height: 10px;
  background: var(--bright-gold);
  transform: rotate(45deg);
  opacity: 0.55;
}

.about-tech__heading {
  font-family: var(--font-heading);
  font-size: 1.18rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 0.7rem;
}

.about-tech__heading::after {
  content: "";
  display: block;
  width: 36px;
  height: 3px;
  margin-top: 0.5rem;
  background: var(--mir-red);
}

.about-tech__block p {
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--light-gray);
  margin-bottom: 0.6rem;
}

.about-tech__visual {
  position: relative;
}

.about-tech__map {
  width: 100%;
  aspect-ratio: 3 / 2;
}

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

.about-tech__map-caption {
  margin-top: 1.2rem;
  padding: 1rem 1.2rem;
  background: var(--dark-gray);
  border-left: 3px solid var(--gold);
}

@media (min-width: 880px) {
  .about-tech__grid {
    grid-template-columns: 1.05fr 0.95fr;
  }
}

/* ===== 社区与互动 ===== */
.about-community {
  padding: 4.5rem 0;
  background: var(--dark-gray);
  background-image: var(--about-line-grid);
}

.about-community__grid {
  display: grid;
  gap: 1.5rem;
  margin-top: 2.6rem;
}

.about-community__card {
  background: var(--carbon);
  padding: 1.6rem;
  clip-path: var(--about-clip);
  border-top: 3px solid var(--mid-gray);
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.about-community__card:hover {
  border-top-color: var(--mir-red);
  background: #242424;
  transform: translateY(-4px);
}

.about-community__header {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  margin-bottom: 0.9rem;
}

.about-community__icon {
  width: 40px;
  height: 40px;
  color: var(--mir-red);
  flex-shrink: 0;
}

.about-community__title {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

.about-community__desc {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--light-gray);
}

.about-community__quote {
  margin-top: 2.5rem;
  padding: 1.4rem 1.6rem;
  background: linear-gradient(90deg, rgba(230, 25, 44, 0.12), transparent 70%);
  border-left: 4px solid var(--mir-red);
}

.about-community__quote p {
  font-size: 1rem;
  line-height: 1.7;
}

.about-community__quote a {
  color: var(--bright-gold);
  text-decoration: underline;
  text-underline-offset: 4px;
}

@media (min-width: 768px) {
  .about-community__grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ===== 资质与合作 ===== */
.about-credential {
  padding: 4.5rem 0;
  background: var(--carbon);
}

.about-credential__grid {
  display: grid;
  gap: 1.5rem;
  margin-top: 2.6rem;
}

.about-credential__item {
  position: relative;
  padding: 1.6rem 1.4rem 1.6rem 1.8rem;
  background: var(--dark-gray);
  overflow: hidden;
  clip-path: var(--about-clip-sm);
}

.about-credential__item::after {
  content: "";
  position: absolute;
  right: -20px;
  bottom: -20px;
  width: 80px;
  height: 80px;
  border: 2px solid var(--mid-gray);
  transform: rotate(45deg);
  pointer-events: none;
}

.about-credential__num {
  display: block;
  font-family: var(--font-heading);
  font-size: 1.4rem;
  color: var(--bright-gold);
  margin-bottom: 0.5rem;
}

.about-credential__heading {
  font-family: var(--font-heading);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.6rem;
}

.about-credential__text {
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--light-gray);
}

@media (min-width: 640px) {
  .about-credential__grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1100px) {
  .about-credential__grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ===== 团队与联系方式 ===== */
.about-team {
  padding: 4.5rem 0 5.5rem;
  background: var(--extreme-black);
}

.about-team__inner {
  display: grid;
  gap: 2.5rem;
}

.about-team__index {
  display: block;
  font-family: var(--font-heading);
  font-size: 3.4rem;
  line-height: 0.85;
  color: transparent;
  -webkit-text-stroke: 1px var(--bright-gold);
  margin-bottom: 0.8rem;
}

.about-team__title {
  font-family: var(--font-heading);
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.about-team__desc {
  color: var(--light-gray);
  line-height: 1.75;
  margin-bottom: 1.8rem;
  max-width: 42em;
}

.about-team__contact {
  list-style: none;
  margin: 0 0 1.6rem;
  padding: 0;
}

.about-team__contact li {
  display: flex;
  gap: 1rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid rgba(61, 61, 61, 0.6);
  font-size: 0.95rem;
}

.about-team__label {
  min-width: 3.6em;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--bright-gold);
}

.about-team__note {
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--light-gray);
  margin-bottom: 1.8rem;
}

.about-team__content a {
  color: var(--bright-gold);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.about-team__side {
  display: grid;
  gap: 1.2rem;
  align-content: start;
}

.about-team__stat {
  background: var(--dark-gray);
  padding: 1.4rem 1.6rem;
  border-right: 4px solid var(--mir-red);
  clip-path: var(--about-clip-sm);
}

.about-team__stat-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 2.4rem;
  line-height: 1;
  color: var(--bright-gold);
}

.about-team__stat-label {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.85rem;
  color: var(--light-gray);
}

@media (min-width: 880px) {
  .about-team__inner {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: start;
  }

  .about-team__side {
    grid-template-columns: repeat(3, 1fr);
    position: sticky;
    top: 2rem;
  }
}

@media (min-width: 1100px) {
  .about-team__side {
    grid-template-columns: 1fr;
  }
}