.page-about {
  --about-hero-rule: 6px solid var(--c-primary-accent);
  --about-card-border: 4px solid var(--c-border-strong);
  --about-timeline-width: 1080px;
  --about-diamond-size: 14px;
  --about-grid-gap: 3rem;
  background: var(--c-primary-bg);
  color: var(--c-text-light);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about a:focus-visible,
.page-about button:focus-visible,
.page-about summary:focus-visible {
  outline: var(--focus-outline);
  outline-offset: 2px;
}

.page-about [id] {
  scroll-margin-top: 5rem;
}

/* 面包屑 */
.page-about .about-breadcrumb {
  max-width: 1080px;
  margin: 0 auto;
  padding: 1rem 1.25rem 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.875rem;
  color: var(--c-text-muted);
}

.page-about .about-breadcrumb__link {
  color: var(--c-primary-accent);
  text-decoration: none;
}

.page-about .about-breadcrumb__link:hover {
  text-decoration: underline;
}

.page-about .about-breadcrumb__sep {
  color: var(--c-text-muted);
}

.page-about .about-breadcrumb__current {
  color: var(--c-text-light);
}

/* 框景首屏 */
.page-about .about-hero {
  position: relative;
  padding: 3rem 1.25rem 4.5rem;
  background:
    linear-gradient(135deg, rgba(10, 17, 40, 0.82), rgba(26, 58, 58, 0.75)),
    repeating-linear-gradient(-45deg, transparent 0 22px, rgba(0, 232, 120, 0.07) 22px 24px);
  border-bottom: var(--about-hero-rule);
}

.page-about .about-hero__frame {
  position: relative;
  max-width: 1080px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  border: 4px solid var(--c-border-strong);
  background: rgba(10, 17, 40, 0.82);
  box-shadow: var(--shadow-panel);
}

.page-about .about-hero__frame::before,
.page-about .about-hero__frame::after {
  content: "";
  position: absolute;
  width: 2rem;
  height: 2rem;
  border: 4px solid var(--c-primary-accent);
  pointer-events: none;
}

.page-about .about-hero__frame::before {
  top: -0.5rem;
  left: -0.5rem;
  border-right: none;
  border-bottom: none;
}

.page-about .about-hero__frame::after {
  right: -0.5rem;
  bottom: -0.5rem;
  border-left: none;
  border-top: none;
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  justify-content: space-between;
  margin-bottom: 1.75rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px dashed var(--c-border-strong);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--c-primary-accent);
}

.page-about .about-hero__title {
  margin: 0 0 1.25rem;
  max-width: 20ch;
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: clamp(1.75rem, 5vw, 3.25rem);
  line-height: 1.18;
  color: var(--c-text-light);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 58ch;
  font-size: 1.0625rem;
  color: var(--c-text-muted);
}

.page-about .about-hero__anchors {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 2rem;
}

.page-about .about-hero__anchor {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 0.9rem;
  border: 2px solid var(--c-border);
  background: rgba(10, 17, 40, 0.6);
  color: var(--c-text-light);
  text-decoration: none;
  font-size: 0.875rem;
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease;
}

.page-about .about-hero__anchor:hover {
  border-color: var(--c-primary-accent);
  background: rgba(0, 232, 120, 0.12);
  transform: translateY(-2px);
}

/* 章节框架 */
.page-about .about-section {
  position: relative;
  padding: 4rem 1.25rem;
}

.page-about .about-section__head {
  display: flex;
  align-items: center;
  gap: 1rem 1.5rem;
  flex-wrap: wrap;
  max-width: 1080px;
  margin: 0 auto 1.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 4px solid var(--c-border-strong);
}

.page-about .about-section__head h2 {
  margin: 0;
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  line-height: 1.2;
}

.page-about .about-section__lead {
  max-width: 1080px;
  margin: 0 auto 2rem;
  font-size: 1rem;
  color: var(--c-text-muted);
}

.page-about .section-symbol {
  display: inline-block;
  padding: 0.25rem 0.6rem;
  border: 4px solid var(--c-primary-accent);
  color: var(--c-primary-accent);
  background: rgba(0, 232, 120, 0.06);
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(1.5rem, 4vw, 2.6rem);
  line-height: 1;
}

.page-about .section-symbol--orange {
  border-color: var(--c-secondary-accent);
  color: var(--c-secondary-accent);
  background: rgba(255, 107, 53, 0.07);
}

/* 01 始于观赛需求 */
.page-about .about-origin {
  background: var(--c-section-bg-1);
  border-top: 4px solid var(--c-primary-accent);
}

.page-about .about-origin__body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  max-width: 1080px;
  margin: 0 auto;
}

.page-about .about-origin__copy p + p {
  margin-top: 1rem;
}

.page-about .about-origin__summary {
  margin-top: 2rem;
  padding: 1.25rem 1.5rem;
  border-left: 6px solid var(--c-primary-accent);
  background: rgba(10, 17, 40, 0.35);
  font-size: 1.0625rem;
}

.page-about .about-origin__summary .mono-data {
  color: var(--c-primary-accent);
  font-weight: 700;
}

.page-about .about-origin__summary a {
  color: var(--c-primary-accent);
  text-decoration: underline;
}

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

.page-about .about-origin__media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 4px solid var(--c-border-strong);
  box-shadow: var(--shadow-panel);
}

.page-about .about-origin__media figcaption,
.page-about .about-team__media figcaption,
.page-about .about-commitment__media figcaption {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--c-text-muted);
}

/* 02 发展里程碑 */
.page-about .about-milestones {
  background: var(--c-primary-bg);
  border-top: 4px solid var(--c-border-strong);
}

.page-about .topic-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  max-width: 1080px;
  margin: 0 auto 0.75rem;
}

.page-about .topic-tabs button {
  padding: 0.45rem 1.15rem;
  border: 2px solid var(--c-border);
  background: transparent;
  color: var(--c-text-light);
  font-family: var(--font-body);
  font-size: 0.925rem;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.page-about .topic-tabs button:hover {
  border-color: var(--c-primary-accent);
}

.page-about .topic-tabs button.is-active {
  border-color: var(--c-primary-accent);
  color: var(--c-primary-accent);
  background: rgba(0, 232, 120, 0.1);
}

.page-about .topic-status {
  display: inline-block;
  max-width: 1080px;
  margin: 0 auto 2rem;
  padding: 0.3rem 0.75rem;
  border-left: 3px solid var(--c-primary-accent);
  background: rgba(0, 232, 120, 0.06);
  font-family: var(--font-data);
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  color: var(--c-text-muted);
}

.page-about .about-milestones__more {
  max-width: 1080px;
  margin: 3rem auto 0;
  padding: 1rem 0 0;
  border-top: 1px dashed var(--c-border-strong);
  font-size: 0.95rem;
  color: var(--c-text-muted);
}

.page-about .about-milestones__more a {
  color: var(--c-primary-accent);
  text-decoration: underline;
}

.page-about .about-timeline {
  position: relative;
  max-width: 1080px;
  margin: 0 auto;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: repeating-linear-gradient(to bottom, var(--c-primary-accent) 0 10px, transparent 10px 18px);
  opacity: 0.45;
}

.page-about .about-timeline__track {
  display: none;
  pointer-events: none;
}

.page-about .about-milestone {
  position: relative;
  padding-left: 2.75rem;
  margin-top: calc(var(--rise, 0) * 30px + 1.25rem);
}

.page-about .about-milestone::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 1.5rem;
  width: var(--about-diamond-size);
  height: var(--about-diamond-size);
  border: 3px solid var(--c-primary-accent);
  background: var(--c-primary-bg);
  transform: rotate(45deg);
  z-index: 1;
}

.page-about .about-milestone[hidden] {
  display: none !important;
}

.page-about .about-milestone__card {
  display: block;
  margin: 0;
  border: 4px solid var(--c-border-strong);
  background: rgba(10, 17, 40, 0.65);
  box-shadow: var(--shadow-panel);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.page-about .about-milestone__card:hover {
  border-color: var(--c-primary-accent);
  transform: translateY(-2px);
}

.page-about .about-milestone__card summary {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 1rem 1.25rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-milestone__card summary .mono-data {
  flex-shrink: 0;
  padding: 0.15rem 0.4rem;
  border: 2px solid rgba(0, 232, 120, 0.35);
  color: var(--c-primary-accent);
  font-size: 0.9rem;
  font-weight: 700;
}

.page-about .about-milestone__card summary h3 {
  min-width: 0;
  margin: 0;
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: 1.125rem;
  line-height: 1.3;
  color: var(--c-text-light);
}

.page-about .about-milestone__card summary::after {
  content: "+";
  margin-left: auto;
  flex-shrink: 0;
  font-family: var(--font-data);
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1;
  color: var(--c-primary-accent);
  transition: transform 0.25s ease;
}

.page-about .about-milestone__card[open] summary::after {
  transform: rotate(45deg);
}

.page-about .about-milestone__body {
  padding: 0 1.25rem 1.25rem;
  border-top: 1px dashed var(--c-border);
}

.page-about .about-milestone__body p {
  margin: 0.9rem 0 0.6rem;
}

.page-about .about-milestone__body ul {
  margin: 0;
  padding-left: 1.2rem;
}

.page-about .about-milestone__body li {
  margin: 0.35rem 0;
}

/* 03 技术与数据团队 */
.page-about .about-team {
  background: var(--c-section-bg-3);
  border-top: 4px solid var(--c-primary-accent);
}

.page-about .about-team__grid {
  max-width: 1080px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-team__copy > p {
  margin: 0 0 1rem;
}

.page-about .about-team__copy > p:last-of-type {
  margin-bottom: 0;
}

.page-about .about-team__copy .mono-data {
  color: var(--c-primary-accent);
  font-weight: 700;
}

.page-about .about-team__subtitle {
  margin: 2rem 0 1rem;
  padding-left: 0.75rem;
  border-left: 4px solid var(--c-primary-accent);
  font-family: var(--font-headline);
  font-size: 1.25rem;
  color: var(--c-primary-accent);
}

.page-about .about-team__steps {
  margin: 0 0 1.25rem;
  padding: 0;
  list-style: none;
}

.page-about .about-team__steps li {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.65rem 0;
  border-bottom: 1px dashed var(--c-border);
}

.page-about .about-team__steps .mono-data {
  flex-shrink: 0;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--c-primary-accent);
}

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

.page-about .about-team__media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 4px solid var(--c-border-strong);
  box-shadow: var(--shadow-panel);
}

.page-about .about-team__stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  max-width: 1080px;
  margin: 3rem auto 0;
}

.page-about .about-team__stat {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  min-height: 110px;
  padding: 1.25rem;
  border-top: 4px solid var(--c-primary-accent);
  background: rgba(10, 17, 40, 0.45);
}

.page-about .about-team__stat .mono-data {
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--c-primary-accent);
}

.page-about .about-team__stat-label {
  margin-top: 0.35rem;
  font-size: 0.875rem;
  color: var(--c-text-muted);
}

/* 04 服务承诺 */
.page-about .about-commitment {
  background: var(--c-bg-light);
  color: var(--c-text-dark);
  border-top: 6px solid var(--c-secondary-accent);
}

.page-about .about-commitment .about-section__head {
  border-bottom-color: rgba(10, 17, 40, 0.2);
}

.page-about .about-commitment .about-section__head h2 {
  color: var(--c-text-dark);
}

.page-about .about-commitment__body {
  max-width: 1080px;
  margin: 0 auto;
}

.page-about .about-commitment__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-commitment__copy > p {
  margin: 0 0 1.25rem;
  color: var(--c-text-dark);
}

.page-about .about-commitment__list {
  margin: 0 0 2rem;
  padding: 0;
  list-style: none;
}

.page-about .about-commitment__list li {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.4rem;
  padding: 1rem 0;
  border-bottom: 1px dashed rgba(10, 17, 40, 0.25);
  color: var(--c-text-dark);
}

.page-about .about-commitment__list .data-chip {
  display: inline-block;
  margin-bottom: 0.25rem;
}

.page-about .about-commitment__contact {
  padding: 1.5rem;
  border: 4px solid var(--c-border-strong);
  border-top: 6px solid var(--c-primary-accent);
  background: var(--c-primary-bg);
  color: var(--c-text-light);
  box-shadow: var(--shadow-panel);
}

.page-about .about-commitment__contact h3 {
  margin: 0 0 1rem;
  font-family: var(--font-headline);
  font-size: 1.25rem;
}

.page-about .about-commitment__contact-line {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  margin: 0.5rem 0;
}

.page-about .about-commitment__contact-line .mono-data {
  min-width: 3.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--c-primary-accent);
}

.page-about .about-commitment__note {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--c-border-strong);
  font-size: 0.875rem;
  color: var(--c-text-muted);
}

.page-about .about-commitment__cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1.25rem;
  padding: 0.6rem 1.25rem;
  border: 2px solid var(--c-primary-accent);
  background: rgba(0, 232, 120, 0.12);
  color: var(--c-text-light);
  text-decoration: none;
  font-weight: 600;
  transition: background 0.2s ease, transform 0.2s ease;
}

.page-about .about-commitment__cta:hover {
  background: rgba(0, 232, 120, 0.24);
  transform: translateY(-2px);
}

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

.page-about .about-commitment__media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 4px solid rgba(10, 17, 40, 0.2);
  box-shadow: var(--shadow-panel);
}

/* 桌面布局 */
@media (min-width: 820px) {
  .page-about .about-hero {
    padding: 4rem 2rem 6rem;
  }

  .page-about .about-hero__frame {
    padding: 2.5rem 3rem;
  }

  .page-about .about-section {
    padding: 5.5rem 2rem;
  }

  .page-about .about-origin__body {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: var(--about-grid-gap);
    align-items: center;
  }

  .page-about .about-timeline {
    display: grid;
    grid-template-columns: 1fr 1fr;
    column-gap: var(--about-grid-gap);
    align-items: start;
  }

  .page-about .about-timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .page-about .about-timeline__track {
    display: block;
    position: absolute;
    left: 50%;
    top: 0;
    width: 220px;
    height: 100%;
    transform: translateX(-50%);
    z-index: 0;
  }

  .page-about .about-milestone {
    grid-column: 1;
    padding-left: 0;
    padding-right: var(--about-grid-gap);
    text-align: right;
    margin-top: calc(var(--rise, 0) * 90px);
    z-index: 1;
  }

  .page-about .about-milestone:nth-of-type(even) {
    grid-column: 2;
    padding-right: 0;
    padding-left: var(--about-grid-gap);
    text-align: left;
  }

  .page-about .about-milestone::before {
    left: auto;
    right: calc(-1.5rem - 7px);
  }

  .page-about .about-milestone:nth-of-type(even)::before {
    right: auto;
    left: calc(-1.5rem - 7px);
  }

  .page-about .about-milestone:nth-of-type(odd) .about-milestone__card summary {
    justify-content: flex-end;
  }

  .page-about .about-milestone:nth-of-type(odd) .about-milestone__card summary::after {
    margin-left: 1rem;
  }

  .page-about .about-milestone:nth-of-type(odd) .about-milestone__body {
    text-align: right;
  }

  .page-about .about-milestone:nth-of-type(odd) .about-milestone__body ul {
    padding-left: 0;
    padding-right: 1.2rem;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: var(--about-grid-gap);
    align-items: start;
  }

  .page-about .about-team__stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 1.25rem;
    margin-top: 3.5rem;
  }

  .page-about .about-commitment__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: var(--about-grid-gap);
    align-items: start;
  }
}

.page-about {
  --rise: 1rem;
}