.page-about {
  --about-rail-w: 210px;
  --about-gap: clamp(2rem, 5vw, 4.5rem);
  padding-bottom: clamp(3rem, 8vw, 7rem);
}

/* 面包屑 */
.page-about .about-crumb {
  padding-top: clamp(1.25rem, 4vw, 2.25rem);
  padding-bottom: clamp(1.25rem, 4vw, 2.25rem);
}

/* 首屏 */
.page-about .about-hero {
  padding-block: clamp(.5rem, 2vw, 1rem) clamp(2.5rem, 6vw, 4rem);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 3.25rem);
  align-items: end;
}

.page-about .about-hero__title {
  margin-top: .85rem;
  margin-bottom: 1.25rem;
}

.page-about .about-hero__title em {
  font-family: var(--kj-font-display);
  font-style: normal;
  font-weight: 700;
  color: var(--kj-gold-light);
}

.page-about .about-hero__lede {
  max-width: 34em;
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(1.5rem, 4vw, 3rem);
  margin-top: clamp(1.75rem, 4vw, 2.75rem);
  padding-top: 1.5rem;
  border-top: 1px solid var(--kj-line);
}

.page-about .about-hero__figure {
  margin: 0;
  border-radius: var(--kj-radius-lg);
  overflow: hidden;
}

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

/* 左轨道 + 右叙事 */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 2.5rem);
}

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

.page-about .about-rail__inner {
  position: relative;
  border-radius: var(--kj-radius);
  padding: 1rem 1.15rem;
  background: linear-gradient(160deg, rgba(47, 107, 82, .32) 0%, rgba(11, 33, 27, .9) 70%);
  border: 1px solid var(--kj-line);
  overflow: hidden;
}

.page-about .about-rail__inner::after {
  content: "";
  position: absolute;
  right: -40px;
  top: -40px;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background-image: repeating-radial-gradient(
    circle at center,
    transparent 0 12px,
    rgba(178, 102, 60, .18) 12px 13px
  );
  pointer-events: none;
}

.page-about .about-rail__cap {
  display: block;
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--kj-gold);
  margin-bottom: .75rem;
}

.page-about .about-rail__ticks {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.15rem;
  overflow-x: auto;
  position: relative;
  z-index: 1;
}

.page-about .about-rail__ticks li {
  display: flex;
  align-items: baseline;
  gap: .4rem;
  font-size: 13px;
  color: var(--kj-text-2);
  white-space: nowrap;
  padding-bottom: .25rem;
  border-bottom: 1px solid transparent;
}

.page-about .about-rail__ticks span {
  font-size: 11px;
  color: var(--kj-gold);
}

/* 章节 */
.page-about .about-body {
  min-width: 0;
}

.page-about .about-chapter {
  position: relative;
  padding-block: clamp(2rem, 5vw, 3.5rem);
  border-top: 1px solid var(--kj-hair);
}

.page-about .about-chapter:first-child {
  border-top: none;
  padding-top: 0;
}

.page-about .about-chapter--pattern::before {
  content: "";
  position: absolute;
  left: -8%;
  top: 14%;
  width: min(340px, 60%);
  aspect-ratio: 1;
  border-radius: 50%;
  background-image: repeating-radial-gradient(
    circle at center,
    transparent 0 20px,
    rgba(178, 102, 60, .09) 20px 21px
  );
  pointer-events: none;
  z-index: 0;
}

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

.page-about .about-chapter__head {
  display: flex;
  flex-direction: column;
  gap: .55rem;
  margin-bottom: 1.35rem;
}

.page-about .about-chapter__num {
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--kj-gold);
}

.page-about .about-chapter__body p {
  margin: 0 0 1rem;
  color: var(--kj-text-2);
  font-size: 1rem;
  line-height: 1.9;
  max-width: 40em;
}

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

.page-about .about-link {
  color: var(--kj-gold-light);
  text-decoration: none;
  border-bottom: 1px solid var(--kj-line-strong);
  padding-bottom: 1px;
  transition: color .2s var(--kj-ease), border-color .2s var(--kj-ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--kj-action);
  border-color: var(--kj-action);
}

/* 图片框 */
.page-about .about-figure {
  margin: clamp(1.5rem, 4vw, 2.25rem) 0;
  border-radius: var(--kj-radius-lg);
  overflow: hidden;
}

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

/* 四次定型 */
.page-about .about-steps {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 1rem;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .about-steps__item {
  position: relative;
  padding: 1.25rem 1.25rem 1.25rem 1.4rem;
  border-radius: var(--kj-radius);
  background: var(--kj-felt-800);
  border: 1px solid var(--kj-line);
  transition: border-color .24s var(--kj-ease), transform .24s var(--kj-ease);
}

.page-about .about-steps__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.25rem;
  bottom: 1.25rem;
  width: 3px;
  border-radius: 3px;
  background: var(--kj-gold);
  opacity: .55;
}

.page-about .about-steps__item:hover {
  border-color: var(--kj-line-strong);
  transform: translateY(-2px);
}

.page-about .about-steps__idx {
  display: inline-block;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--kj-gold-light);
  margin-bottom: .4rem;
}

.page-about .about-steps__title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--kj-text);
  margin: 0 0 .5rem;
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: .95rem;
  line-height: 1.85;
  color: var(--kj-text-2);
}

/* 档位对照折叠 */
.page-about .about-tier-toggle {
  margin-top: 1.5rem;
  border: 1px solid var(--kj-line);
  border-radius: var(--kj-radius);
  background: rgba(243, 238, 228, .03);
  overflow: hidden;
}

.page-about .about-tier-toggle summary {
  cursor: pointer;
  list-style: none;
  padding: 1rem 1.25rem;
  font-size: .95rem;
  color: var(--kj-gold-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  transition: background-color .22s var(--kj-ease);
}

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

.page-about .about-tier-toggle summary::after {
  content: "+";
  font-family: var(--kj-font-mono);
  font-size: 1.1rem;
  color: var(--kj-gold);
  transition: transform .22s var(--kj-ease);
}

.page-about .about-tier-toggle[open] summary::after {
  content: "−";
}

.page-about .about-tier-toggle summary:hover {
  background: rgba(199, 162, 44, .07);
}

.page-about .about-tier-compare {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
  padding: 0 1.25rem 1.25rem;
}

.page-about .about-tier-compare__col {
  padding: .9rem 1rem;
  border-radius: 18px;
  border: 1px solid var(--kj-hair);
  background: rgba(20, 56, 44, .55);
}

.page-about .about-tier-compare__cap {
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--kj-gold);
  margin: 0 0 .4rem;
}

.page-about .about-tier-compare__col p:last-child {
  margin: 0;
  color: var(--kj-text);
  font-size: .95rem;
  line-height: 1.8;
}

/* 团队角色 */
.page-about .about-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
  margin: 1.5rem 0;
}

.page-about .about-roles__card {
  padding: 1.35rem 1.25rem;
}

.page-about .about-roles__tag {
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--kj-gold);
  margin: 0 0 .6rem;
}

.page-about .about-roles__title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--kj-text);
  margin: 0 0 .5rem;
}

.page-about .about-roles__card p:last-child {
  margin: 0;
  font-size: .95rem;
  line-height: 1.85;
  color: var(--kj-text-2);
}

/* 里程碑时间轴 */
.page-about .about-tl {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: .6rem;
  bottom: 1.5rem;
  width: 1px;
  background: linear-gradient(
    to bottom,
    var(--kj-gold) 0%,
    var(--kj-gold) 65%,
    rgba(199, 162, 44, .16) 100%
  );
}

.page-about .about-tl__item {
  position: relative;
  padding-left: 2.25rem;
  padding-bottom: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .about-tl__item:last-child {
  padding-bottom: 0;
}

.page-about .about-tl__dot {
  position: absolute;
  left: 0;
  top: .45rem;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--kj-felt-900);
  border: 1px solid var(--kj-line-strong);
  transition: border-color .24s var(--kj-ease), background-color .24s var(--kj-ease);
}

.page-about .about-tl__item--now .about-tl__dot {
  background: var(--kj-action);
  border-color: var(--kj-action);
  box-shadow: 0 0 0 5px rgba(255, 90, 43, .14);
}

.page-about .about-tl__item:hover .about-tl__dot {
  border-color: var(--kj-gold);
}

.page-about .about-tl__time {
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--kj-gold);
  margin: 0 0 .45rem;
}

.page-about .about-tl__title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--kj-text);
  margin: 0 0 .5rem;
}

.page-about .about-tl__item > p {
  margin: 0 0 .5rem;
  font-size: .95rem;
  line-height: 1.85;
  color: var(--kj-text-2);
  max-width: 38em;
}

.page-about .about-tl__more {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: .9rem !important;
  color: var(--kj-text-3) !important;
  padding-left: .9rem;
  border-left: 2px solid var(--kj-line);
  transition: max-height .3s var(--kj-ease), opacity .3s var(--kj-ease), margin .3s var(--kj-ease);
}

.page-about .about-tl__item:hover .about-tl__more,
.page-about .about-tl__item:focus-within .about-tl__more {
  max-height: 8rem;
  opacity: 1;
  margin-top: .6rem;
}

/* 铜鼓纹章节 */
.page-about .about-chapter--drum {
  overflow: hidden;
}

.page-about .about-drumband {
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  height: 72px;
  border-radius: var(--kj-radius);
  background-image: repeating-radial-gradient(
      circle at 50% 50%,
      transparent 0 26px,
      rgba(178, 102, 60, .22) 26px 27px
    ),
    linear-gradient(90deg, rgba(47, 107, 82, .35), rgba(11, 33, 27, .9));
  border: 1px solid var(--kj-line);
}

/* 收尾 */
.page-about .about-closing {
  margin-top: clamp(2.5rem, 6vw, 4rem);
  padding: clamp(1.75rem, 4vw, 2.75rem);
  border-radius: var(--kj-radius-lg);
  border: 1px solid var(--kj-line);
  background: linear-gradient(155deg, rgba(20, 56, 44, .95) 0%, rgba(11, 33, 27, .95) 100%);
}

.page-about .about-closing__title {
  margin: 0 0 .85rem;
}

.page-about .about-closing__text {
  margin: 0 0 1.5rem;
  color: var(--kj-text-2);
  font-size: 1rem;
  line-height: 1.9;
  max-width: 42em;
}

.page-about .about-closing__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}

/* 平板 */
@media (min-width: 640px) {
  .page-about .about-steps,
  .page-about .about-roles,
  .page-about .about-tier-compare {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* 桌面 */
@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
  }

  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-rail__inner {
    position: sticky;
    top: 6rem;
    padding: 1.5rem 1.15rem;
  }

  .page-about .about-rail__ticks {
    flex-direction: column;
    gap: .85rem;
    overflow: visible;
  }

  .page-about .about-rail__ticks li {
    font-size: 13px;
    padding-bottom: .55rem;
    border-bottom: 1px dashed var(--kj-hair);
  }

  .page-about .about-rail__ticks li:last-child {
    border-bottom: none;
  }

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

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

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

@media (min-width: 1200px) {
  .page-about .about-hero__grid {
    gap: clamp(2.5rem, 5vw, 4.5rem);
  }
}

/* 窄屏兜底 */
@media (max-width: 480px) {
  .page-about .about-hero__title {
    font-size: clamp(2rem, 10vw, 2.75rem);
  }

  .page-about .about-hero__meta {
    gap: 1.25rem;
  }

  .page-about .about-steps__item {
    padding: 1.1rem 1rem 1.1rem 1.2rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-steps__item,
  .page-about .about-tl__dot,
  .page-about .about-tl__more,
  .page-about .about-link {
    transition: none;
  }
}
<<<END>>>