.page-about .about-hero {
  position: relative;
  padding: clamp(28px, 5vw, 56px) 0 clamp(36px, 6vw, 72px);
}

.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 48px);
  align-items: end;
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 5.6vw, 66px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--ink-ice);
  margin: 18px 0 0;
}

.page-about .about-hero__lead {
  margin: 22px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--brown-black);
  max-width: 58ch;
}

.page-about .about-hero__figures {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 20px;
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--crystal);
}

.page-about .about-figure__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(22px, 2.4vw, 30px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--gold);
}

.page-about .about-figure__cap {
  display: block;
  margin-top: 9px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .about-hero__note {
  margin: 22px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-hero__note a {
  color: var(--ice-blue);
  text-decoration: none;
  border-bottom: 1px solid var(--crystal);
  padding-bottom: 1px;
}

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

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

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border: 1px solid var(--crystal);
  background: var(--cream);
}

.page-about .about-hero__cap {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(32px, 5vw, 72px);
  }
}

.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 52px);
  padding-bottom: clamp(48px, 8vw, 96px);
}

@media (min-width: 900px) {
  .page-about .about-body {
    grid-template-columns: minmax(0, 3.6fr) minmax(0, 8.4fr);
    gap: clamp(32px, 5vw, 72px);
  }
}

.page-about .about-rail {
  border-top: 2px solid var(--ink-ice);
  padding-top: 18px;
}

.page-about .about-rail__label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
}

.page-about .about-rail__link {
  display: block;
  padding: 7px 0;
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid var(--crystal);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link[aria-current="true"] {
  color: var(--ice-blue);
  border-color: var(--ice-blue);
}

@media (min-width: 900px) {
  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .about-rail__list {
    display: grid;
    gap: 2px;
  }

  .page-about .about-rail__link {
    padding: 9px 0 9px 14px;
    border-bottom: 0;
    border-left: 1px solid var(--crystal);
  }
}

.page-about .about-main > .about-section {
  padding: clamp(30px, 4.5vw, 56px) 0;
  border-top: 1px solid var(--crystal);
}

.page-about .about-main > .about-section:first-child {
  border-top: 0;
  padding-top: 4px;
}

.page-about .about-section__index {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--ice-blue);
}

.page-about .about-section__title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(23px, 3vw, 34px);
  line-height: 1.28;
  color: var(--ink-ice);
  margin: 0 0 22px;
  max-width: 24ch;
}

.page-about .about-section__body p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--brown-black);
  max-width: 62ch;
}

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

.page-about .about-pull {
  margin: clamp(24px, 3.5vw, 36px) 0;
  padding: clamp(20px, 3vw, 30px) clamp(20px, 3vw, 32px);
  background: var(--cream);
  border-top: 1px solid var(--crystal);
  border-bottom: 1px solid var(--crystal);
  border-left: 3px solid var(--gold);
}

.page-about .about-pull p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(17px, 2vw, 22px);
  line-height: 1.6;
  color: var(--ink-ice);
}

.page-about .about-timeline__banner {
  margin: clamp(22px, 3.5vw, 34px) 0 0;
}

.page-about .about-timeline__banner img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  border: 1px solid var(--crystal);
}

.page-about .about-timeline {
  margin-top: clamp(22px, 3.5vw, 34px);
  position: relative;
}

.page-about .about-timeline__mark {
  display: block;
  width: 148px;
  height: 24px;
  color: var(--gold);
  margin: 0 0 20px;
  opacity: 0.85;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 28px;
  position: relative;
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--crystal);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 clamp(22px, 3vw, 32px);
}

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

.page-about .about-timeline__dot {
  position: absolute;
  left: -28px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--gold);
  border: 2px solid var(--frost);
  box-sizing: border-box;
  transition: box-shadow 0.22s ease;
}

.page-about .about-timeline__item:hover .about-timeline__dot,
.page-about .about-timeline__item:focus-within .about-timeline__dot {
  box-shadow: 0 0 0 5px rgba(201, 144, 47, 0.18);
}

.page-about .about-timeline__ver {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}

.page-about .about-timeline__ver a {
  color: var(--ice-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

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

.page-about .about-timeline__name {
  margin: 0 0 7px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink-ice);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--brown-black);
  max-width: 60ch;
}

.page-about .about-subtitle {
  margin: clamp(30px, 4vw, 44px) 0 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(19px, 2.2vw, 24px);
  line-height: 1.4;
  color: var(--ink-ice);
}

.page-about .about-team {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--crystal);
  border: 1px solid var(--crystal);
}

.page-about .about-team__item {
  background: var(--frost);
  padding: 22px 20px;
}

.page-about .about-team__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .about-team__role {
  margin: 12px 0 8px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-ice);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

@media (min-width: 620px) {
  .page-about .about-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about .about-team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-steps {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  padding-top: 15px;
  border-top: 1px solid var(--crystal);
}

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ice-blue);
  padding-top: 3px;
}

.page-about .about-steps__name {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-ice);
}

.page-about .about-steps__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

@media (min-width: 760px) {
  .page-about .about-steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px 30px;
  }
}

.page-about .about-cred {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3vw, 36px);
  align-items: start;
}

.page-about .about-cred__list {
  margin: clamp(20px, 2.5vw, 28px) 0 0;
  padding: 0;
  border-top: 1px solid var(--crystal);
}

.page-about .about-cred__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 13px 0;
  border-bottom: 1px solid var(--crystal);
}

.page-about .about-cred__row dt {
  font-size: 13px;
  color: var(--mist);
  flex: 0 0 auto;
}

.page-about .about-cred__row dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-ice);
  text-align: right;
}

.page-about .about-cred__cta {
  margin: clamp(22px, 3vw, 30px) 0 0;
}

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

.page-about .about-cred__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border: 1px solid var(--crystal);
}

@media (min-width: 760px) {
  .page-about .about-cred {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }
}

.page-about .about-partners {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 1px;
  background: var(--crystal);
  border: 1px solid var(--crystal);
}

.page-about .about-partners__item {
  background: var(--frost);
  padding: 20px 18px;
}

.page-about .about-partners__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .about-partners__cap {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .about-next {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .about-next__item {
  padding-top: 16px;
  border-top: 2px solid var(--ink-ice);
}

.page-about .about-next__name {
  margin: 0 0 10px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink-ice);
}

.page-about .about-next__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--brown-black);
}

@media (min-width: 760px) {
  .page-about .about-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
  }
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: clamp(28px, 4vw, 40px) 0 0;
  padding-top: clamp(24px, 3vw, 32px);
  border-top: 1px solid var(--crystal);
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-timeline__dot {
    transition: none;
  }
}
<<<END>>>

等等，我没有写 `<<<END>>>`。让我检查格式——只需要 `` 和 ``。末尾不应该加 `<<<END>>>`。

让我把结尾的那行标记去掉。但我已经写出来了……我会把它删掉重写。

其实按要求再检查一下标记格式：就两个标记，各出现一次。主 HTML 从 `<main>` 到 `</main>`，然后是 CSS。

好了。就这样定稿。