.page-about {
  --about-body: #C8D4E6;
  --about-line: rgba(43, 64, 102, 0.9);
  --about-hair: rgba(11, 23, 48, 0.16);
  --about-axis-w: 200px;
}

.page-about .band--paper {
  color: var(--ink);
}

.page-about .band--ink,
.page-about .band--ink2 {
  color: var(--paper);
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-top: clamp(18px, 3vw, 28px);
  margin-bottom: clamp(26px, 5vw, 52px);
}

.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--slate);
}

.page-about .breadcrumb__list li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--grid);
}

.page-about .breadcrumb__list a {
  color: var(--slate);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) ease, border-color var(--dur) ease;
}

.page-about .breadcrumb__list a:hover,
.page-about .breadcrumb__list a:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.page-about .breadcrumb__list [aria-current="page"] {
  color: var(--paper);
}

/* 封面 */
.page-about .about-cover {
  position: relative;
  padding-bottom: clamp(48px, 7vw, 92px);
  background-color: var(--ink);
  background-image:
    repeating-linear-gradient(to right, rgba(43, 64, 102, 0.55) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(to bottom, rgba(43, 64, 102, 0.35) 0 1px, transparent 1px 96px);
}

.page-about .about-cover__grid {
  display: grid;
  gap: clamp(32px, 5vw, 64px);
}

.page-about .about-kicker {
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-cover h1 {
  margin: 0 0 22px;
  font-family: var(--font-head);
  font-size: clamp(32px, 7vw, 58px);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-lead {
  margin: 0 0 30px;
  max-width: 34em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-body);
}

.page-about .about-cover__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-cover__side {
  display: grid;
  gap: 20px;
}

.page-about .about-cover__figure {
  margin: 0;
  border: 1px solid var(--about-line);
}

.page-about .about-cover__figure .figure__media {
  display: block;
  overflow: hidden;
}

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

.page-about .about-cover__figure .figure__caption {
  display: block;
  padding: 12px 14px;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--slate);
  border-top: 1px solid var(--about-line);
}

.page-about .about-spec {
  margin: 0;
  padding: 6px 20px;
  background: var(--panel);
  border-left: 3px solid var(--amber);
}

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

.page-about .about-spec__row:last-child {
  border-bottom: 0;
}

.page-about .about-spec dt {
  font-size: 13px;
  color: var(--slate);
}

.page-about .about-spec dd {
  margin: 0;
  font-size: 15px;
  color: var(--amber);
}

/* 章节标题 */
.page-about .about-head {
  margin-bottom: clamp(32px, 5vw, 56px);
  max-width: 46em;
}

.page-about .about-head .eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-head h2 {
  margin: 0 0 16px;
  font-family: var(--font-head);
  font-size: clamp(25px, 4.4vw, 38px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-head--dark h2 {
  color: var(--ink);
}

.page-about .about-head--dark .eyebrow {
  color: var(--amber-deep);
}

.page-about .about-sub {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-body);
}

.page-about .about-head--dark .about-sub {
  color: #3C4A63;
}

/* 时间线 */
.page-about .about-timeline {
  padding-block: clamp(52px, 8vw, 96px);
  background-color: var(--ink-2);
  background-image:
    repeating-linear-gradient(to bottom, rgba(43, 64, 102, 0.4) 0 1px, transparent 1px 120px);
}

.page-about .about-track {
  display: grid;
  gap: 24px;
}

.page-about .about-axis {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: none;
}

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

.page-about .about-axis__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex: 0 0 auto;
  padding: 9px 12px;
  font-size: 13px;
  color: var(--slate);
  text-decoration: none;
  background: rgba(22, 41, 77, 0.55);
  border-bottom: 2px solid transparent;
  transition: color var(--dur) ease, border-color var(--dur) ease, background var(--dur) ease;
}

.page-about .about-axis__link:hover,
.page-about .about-axis__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--celadon);
}

.page-about .about-axis__link[data-active] {
  color: var(--ink);
  background: var(--amber);
  border-bottom-color: var(--amber-deep);
}

.page-about .about-axis__num {
  font-size: 11px;
  opacity: 0.75;
}

.page-about .about-stages {
  display: grid;
  gap: 18px;
}

.page-about .about-stage {
  position: relative;
  padding: 22px 20px 24px;
  background: var(--panel);
  border: 1px solid var(--about-line);
  border-top: 2px solid var(--celadon-deep);
  transition: transform var(--dur) ease, border-color var(--dur) ease;
}

.page-about .about-stage:hover {
  transform: translateY(-2px);
  border-top-color: var(--amber);
}

.page-about .about-stage__meta {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--celadon);
}

.page-about .about-stage h3 {
  margin: 0 0 12px;
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-stage p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-body);
}

.page-about .about-stage__list {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.page-about .about-stage__list li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-body);
}

.page-about .about-stage__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 10px;
  height: 1px;
  background: var(--amber);
}

.page-about .about-stage__link {
  display: inline-block;
  margin-top: 16px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid var(--amber-deep);
  padding-bottom: 2px;
}

.page-about .about-stage__link:hover,
.page-about .about-stage__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--paper);
}

.page-about .about-timeline__figure {
  margin: clamp(32px, 5vw, 56px) 0 0;
  border: 1px solid var(--about-line);
}

.page-about .about-timeline__figure .figure__media {
  display: block;
  overflow: hidden;
}

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

.page-about .about-timeline__figure .figure__caption {
  display: block;
  padding: 12px 14px;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--slate);
  border-top: 1px solid var(--about-line);
}

/* 认证与频道 */
.page-about .about-certify {
  padding-block: clamp(52px, 8vw, 96px);
  background: var(--paper);
}

.page-about .about-certify__grid {
  display: grid;
  gap: 36px;
}

.page-about .about-certs {
  display: grid;
  gap: 12px;
  align-content: start;
}

.page-about .about-cert {
  background: #FFFFFF;
  border: 1px solid var(--about-hair);
  border-left: 3px solid var(--celadon-deep);
}

.page-about .about-cert[open] {
  border-left-color: var(--amber-deep);
}

.page-about .about-cert > summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

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

.page-about .about-cert > summary:focus-visible {
  outline: 2px solid var(--amber-deep);
  outline-offset: -2px;
}

.page-about .about-cert__code {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--celadon-deep);
}

.page-about .about-cert__name {
  flex: 1 1 auto;
}

.page-about .about-cert__plus {
  position: relative;
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
}

.page-about .about-cert__plus::before,
.page-about .about-cert__plus::after {
  content: "";
  position: absolute;
  background: var(--amber-deep);
}

.page-about .about-cert__plus::before {
  left: 0;
  top: 5px;
  width: 12px;
  height: 2px;
}

.page-about .about-cert__plus::after {
  left: 5px;
  top: 0;
  width: 2px;
  height: 12px;
  transition: transform var(--dur) ease;
}

.page-about .about-cert[open] .about-cert__plus::after {
  transform: scaleY(0);
}

.page-about .about-cert p {
  margin: 0;
  padding: 0 18px 18px;
  font-size: 14px;
  line-height: 1.8;
  color: #3C4A63;
}

.page-about .about-cert__figure {
  margin: 8px 0 0;
  border: 1px solid var(--about-hair);
}

.page-about .about-cert__figure .figure__media {
  display: block;
  overflow: hidden;
}

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

.page-about .about-cert__figure .figure__caption {
  display: block;
  padding: 10px 12px;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: #5A6885;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-channels__title {
  margin: 0 0 16px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--amber-deep);
}

.page-about .about-channels__list {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .about-channel {
  padding: 16px 16px 18px;
  background: #FFFFFF;
}

.page-about .about-channel__num {
  display: block;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--celadon-deep);
  margin-bottom: 6px;
}

.page-about .about-channel h3 {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-channel p {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: #3C4A63;
}

.page-about .about-channels__link {
  display: inline-block;
  margin-top: 18px;
  font-size: 14px;
  font-weight: 500;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid var(--amber);
  padding-bottom: 2px;
}

.page-about .about-channels__link:hover,
.page-about .about-channels__link:focus-visible {
  color: var(--amber-deep);
  border-bottom-color: var(--amber-deep);
}

/* 团队 */
.page-about .about-team {
  padding-block: clamp(52px, 8vw, 96px);
  background: var(--ink-2);
}

.page-about .about-team__grid {
  display: grid;
  gap: 30px;
}

.page-about .about-team__list {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

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

.page-about .about-team__num {
  display: block;
  font-size: 30px;
  font-weight: 500;
  line-height: 1;
  color: var(--amber);
  margin-bottom: 10px;
}

.page-about .about-team__item h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-team__item p {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--about-body);
}

.page-about .about-partners {
  padding: 24px 20px;
  background: rgba(22, 41, 77, 0.6);
  border: 1px solid var(--about-line);
  border-top: 3px solid var(--celadon);
}

.page-about .about-partners__title {
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--celadon);
}

.page-about .about-partners__row {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-partners__row p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-body);
}

.page-about .about-partners__num {
  flex: 0 0 auto;
  font-size: 24px;
  font-weight: 500;
  color: var(--celadon);
}

.page-about .about-partners__note {
  margin: 18px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--slate);
}

/* 联系收束 */
.page-about .about-reach {
  padding-block: clamp(52px, 8vw, 96px);
  background-color: var(--ink);
  background-image:
    repeating-linear-gradient(to right, rgba(43, 64, 102, 0.5) 0 1px, transparent 1px 96px);
}

.page-about .about-reach__grid {
  display: grid;
  gap: 32px;
}

.page-about .about-reach__copy .eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-reach__copy h2 {
  margin: 0 0 16px;
  font-family: var(--font-head);
  font-size: clamp(25px, 4.4vw, 36px);
  font-weight: 800;
  line-height: 1.2;
  color: var(--paper);
}

.page-about .about-reach__copy p {
  margin: 0 0 26px;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-body);
}

.page-about .about-reach__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-reach__plate {
  padding: 24px 20px;
  background: var(--panel);
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--amber);
}

.page-about .about-reach__label {
  margin: 0 0 16px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-reach__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 13px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-reach__row--stack {
  display: grid;
  gap: 6px;
}

.page-about .about-reach__row .contact-label {
  flex: 0 0 auto;
  min-width: 68px;
  font-size: 12px;
  color: var(--slate);
}

.page-about .about-reach__row .contact-value {
  flex: 1 1 auto;
  font-size: 14px;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

.page-about .about-reach__row .copy-btn {
  flex: 0 0 auto;
  padding: 5px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink);
  background: var(--amber);
  border: 0;
  cursor: pointer;
  transition: background var(--dur) ease;
}

.page-about .about-reach__row .copy-btn:hover,
.page-about .about-reach__row .copy-btn:focus-visible {
  background: var(--amber-deep);
}

.page-about .about-reach__meta {
  margin: 18px 0 0;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

/* 平板 */
@media (min-width: 640px) {
  .page-about .about-stages {
    gap: 20px;
  }

  .page-about .about-certify__grid {
    gap: 40px;
  }

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

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

/* 桌面 */
@media (min-width: 900px) {
  .page-about .about-cover__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

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

  .page-about .about-axis {
    display: grid;
    gap: 0;
    overflow: visible;
    position: sticky;
    top: 96px;
    padding-bottom: 0;
  }

  .page-about .about-axis__link {
    flex-direction: column;
    align-items: flex-start;
    gap: 3px;
    background: transparent;
    border-bottom: 0;
    border-left: 1px solid var(--about-line);
    padding: 12px 0 12px 16px;
  }

  .page-about .about-axis__link:hover,
  .page-about .about-axis__link:focus-visible {
    border-left-color: var(--celadon);
  }

  .page-about .about-axis__link[data-active] {
    background: transparent;
    color: var(--amber);
    border-left: 2px solid var(--amber);
    padding-left: 15px;
  }

  .page-about .about-axis__link[data-active] .about-axis__num {
    color: var(--amber);
    opacity: 1;
  }

  .page-about .about-stage:nth-child(even) {
    margin-left: 36px;
  }

  .page-about .about-certify__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    gap: 56px;
    align-items: start;
  }

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

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-reach__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: 56px;
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage,
  .page-about .about-cert__plus::after,
  .page-about .about-axis__link,
  .page-about .breadcrumb__list a {
    transition: none;
  }

  .page-about .about-stage:hover {
    transform: none;
  }
}