.page-about {
  --about-gap: clamp(20px, 4vw, 44px);
  --about-ch-home: #145C7A;
  --about-ch-download: #F28A2E;
  --about-ch-news: #2C7C9A;
  --about-ch-help: #8AA6B2;
  --about-ch-feedback: #E45B4F;
  --about-ch-brand: #0B3B52;
  background: var(--yl-porcelain);
  color: var(--yl-ink);
  font-family: var(--yl-font-body);
  line-height: 1.8;
  overflow-x: hidden;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--yl-font-head);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.12;
  margin: 0;
}

.page-about h1 {
  font-size: clamp(2rem, 5.4vw, 3.4rem);
}

.page-about h2 {
  font-size: clamp(1.6rem, 3.4vw, 2.25rem);
}

.page-about h3 {
  font-size: clamp(1.08rem, 2vw, 1.3rem);
}

.page-about p {
  margin: 0 0 0.9em;
}

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

.page-about img {
  max-width: 100%;
  height: auto;
  display: block;
}

.page-about .media-frame__img {
  object-fit: cover;
  border-radius: var(--yl-radius-md);
}

/* ---------- 首屏 ---------- */
.about-hero {
  position: relative;
  padding: clamp(84px, 12vw, 128px) 0 clamp(44px, 7vw, 80px);
  color: var(--yl-porcelain);
  background:
    radial-gradient(circle at 84% 8%, rgba(44, 124, 154, 0.55), transparent 56%),
    linear-gradient(158deg, #0B3B52 0%, #145C7A 58%, #1B6B8C 100%);
  border-bottom-left-radius: var(--yl-radius-lg);
  border-bottom-right-radius: var(--yl-radius-lg);
  overflow: hidden;
}

.about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 auto;
  width: 46%;
  height: 62%;
  background-image: repeating-linear-gradient(45deg, rgba(247, 244, 236, 0.07) 0 2px, transparent 2px 16px);
  pointer-events: none;
}

.about-hero__inner {
  position: relative;
  z-index: 1;
}

.about-crumbs {
  margin-bottom: clamp(20px, 3vw, 32px);
  color: rgba(247, 244, 236, 0.72);
}

.about-crumbs .crumbs__item[aria-current="page"] {
  color: var(--yl-orange-soft);
}

.about-hero__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: end;
}

.about-hero__eyebrow {
  color: var(--yl-orange-soft);
  letter-spacing: 0.14em;
  font-size: 0.78rem;
  margin-bottom: 0.8em;
}

.about-hero__lede {
  margin-top: 1em;
  max-width: 34em;
  font-size: clamp(1rem, 1.6vw, 1.12rem);
  color: rgba(247, 244, 236, 0.9);
}

.about-hero__facts {
  list-style: none;
  margin: clamp(24px, 4vw, 36px) 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: clamp(16px, 3vw, 34px);
}

.about-hero__facts li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 14px;
  border-left: 3px solid rgba(242, 138, 46, 0.8);
}

.about-num {
  font-family: var(--yl-font-mono);
  font-size: clamp(1.6rem, 3.4vw, 2.35rem);
  font-weight: 600;
  line-height: 1;
  color: var(--yl-orange);
  letter-spacing: -0.02em;
}

.about-fact__label {
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: rgba(247, 244, 236, 0.78);
}

.about-hero__figure {
  margin: 0;
}

.about-hero__frame {
  border-radius: var(--yl-radius-lg);
  overflow: hidden;
  box-shadow: 0 24px 60px rgba(4, 26, 38, 0.42);
}

.page-about .about-hero__figure .media-frame__caption {
  margin-top: 12px;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  color: rgba(247, 244, 236, 0.7);
}

/* ---------- 通用分栏 ---------- */
.about-section {
  position: relative;
}

.about-split {
  display: grid;
  gap: clamp(20px, 3.5vw, 40px);
}

.about-sign {
  border-top: 3px solid var(--yl-orange);
  padding-top: 14px;
}

.about-sign .exhibit {
  display: block;
  margin-bottom: 8px;
  color: var(--yl-blue);
}

.about-sign p {
  font-size: 0.86rem;
  line-height: 1.75;
  letter-spacing: 0.02em;
  color: #4A6470;
  max-width: 22em;
}

.about-sign--dark {
  border-top-color: var(--yl-orange);
}

.about-sign--dark .exhibit,
.about-sign--dark p {
  color: rgba(247, 244, 236, 0.75);
}

.about-sign--dark .exhibit {
  color: var(--yl-orange-soft);
}

.about-body > h2 {
  margin-bottom: 0.6em;
  color: var(--yl-deep);
}

.page-about .lede {
  font-size: clamp(1rem, 1.5vw, 1.08rem);
  color: #3A5663;
  max-width: 40em;
}

.about-subhead {
  margin: clamp(26px, 4vw, 38px) 0 0.6em;
  color: var(--yl-deep);
}

.about-inline-cta {
  margin-top: clamp(18px, 3vw, 26px);
}

/* ---------- 定位要点 ---------- */
.about-points {
  display: grid;
  gap: clamp(16px, 2.5vw, 24px);
  margin-top: clamp(20px, 3vw, 30px);
}

.about-point {
  padding-left: 18px;
  border-left: 2px solid var(--yl-mist);
}

.about-point h3 {
  margin-bottom: 0.35em;
  color: var(--yl-blue);
}

.about-point p {
  font-size: 0.94rem;
  color: #3A5663;
}

/* ---------- 设备族群 ---------- */
.about-device-list {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.about-device {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  gap: 4px 14px;
  padding: 14px 16px;
  background: rgba(255, 255, 255, 0.72);
  border-radius: var(--yl-radius-sm);
  border-left: 4px solid var(--yl-mid);
}

.about-device:nth-child(2) { border-left-color: var(--yl-orange); }
.about-device:nth-child(3) { border-left-color: var(--yl-deep); }
.about-device:nth-child(4) { border-left-color: var(--yl-coral); }
.about-device:nth-child(5) { border-left-color: var(--yl-line); }

.about-device__name {
  font-family: var(--yl-font-head);
  font-weight: 900;
  font-size: 1.06rem;
  color: var(--yl-deep);
}

.about-device__count {
  font-family: var(--yl-font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--yl-blue);
  background: var(--yl-mist);
  padding: 2px 10px;
  border-radius: var(--yl-radius-pill);
  white-space: nowrap;
}

.about-device p {
  grid-column: 1 / -1;
  font-size: 0.88rem;
  color: #44606D;
  margin: 0;
}

/* ---------- 频道色标 ---------- */
.about-channels {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.about-channel {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.8);
  border-radius: var(--yl-radius-pill);
  font-size: 0.9rem;
}

.about-channel__swatch {
  position: relative;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border-radius: 8px;
  cursor: help;
  outline-offset: 3px;
}

.about-channel--home .about-channel__swatch { background: var(--about-ch-home); }
.about-channel--download .about-channel__swatch { background: var(--about-ch-download); }
.about-channel--news .about-channel__swatch { background: var(--about-ch-news); }
.about-channel--help .about-channel__swatch { background: var(--about-ch-help); }
.about-channel--feedback .about-channel__swatch { background: var(--about-ch-feedback); }
.about-channel--brand .about-channel__swatch { background: var(--about-ch-brand); }

.about-channel__tip {
  position: absolute;
  left: 50%;
  bottom: calc(100% + 10px);
  transform: translate(-50%, 6px);
  width: 15em;
  padding: 8px 11px;
  font-size: 0.76rem;
  line-height: 1.55;
  letter-spacing: 0.02em;
  color: var(--yl-porcelain);
  background: rgba(11, 59, 82, 0.96);
  border-radius: var(--yl-radius-sm);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.18s ease, transform 0.18s ease;
  pointer-events: none;
  z-index: 3;
}

.about-channel__swatch:hover .about-channel__tip,
.about-channel__swatch:focus-visible .about-channel__tip {
  opacity: 1;
  visibility: visible;
  transform: translate(-50%, 0);
}

.about-channel__name {
  font-weight: 600;
  color: var(--yl-deep);
}

/* ---------- 区域对照 ---------- */
.about-regions {
  margin-top: clamp(20px, 3vw, 28px);
  display: grid;
  gap: 8px;
}

.about-region {
  background: #fff;
  border-radius: var(--yl-radius-md);
  border: 1px solid rgba(138, 166, 178, 0.32);
  overflow: hidden;
}

.about-region[open] {
  border-color: rgba(20, 92, 122, 0.42);
  box-shadow: var(--yl-shadow-soft);
}

.about-region__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  padding: 14px 18px;
  cursor: pointer;
  list-style: none;
  background: linear-gradient(90deg, rgba(220, 239, 245, 0.85), rgba(220, 239, 245, 0));
}

.about-region__summary::-webkit-details-marker {
  display: none;
}

.about-region__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--yl-font-mono);
  font-size: 1.1rem;
  color: var(--yl-blue);
}

.about-region[open] .about-region__summary::after {
  content: "−";
  color: var(--yl-coral);
}

.about-region__name {
  font-family: var(--yl-font-head);
  font-weight: 900;
  font-size: 1rem;
  color: var(--yl-deep);
}

.about-region__meta {
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: #5B7684;
}

.about-region__body {
  margin: 0;
  padding: 4px 18px 16px;
  font-size: 0.9rem;
  color: #3A5663;
}

.about-regions__note {
  margin-top: 14px;
  font-size: 0.82rem;
  letter-spacing: 0.03em;
  color: #5B7684;
}

/* ---------- 时间线 ---------- */
.about-section--timeline {
  background: linear-gradient(180deg, #0B3B52 0%, #10465F 100%);
  color: var(--yl-porcelain);
  border-radius: var(--yl-radius-lg);
  margin: 0 clamp(8px, 2vw, 20px);
}

.about-section--timeline .about-body > h2 {
  color: var(--yl-porcelain);
}

.about-section--timeline .lede {
  color: rgba(247, 244, 236, 0.82);
}

.about-timeline {
  list-style: none;
  margin: clamp(22px, 3.5vw, 34px) 0 0;
  padding: 0 0 0 22px;
  border-left: 2px dashed rgba(138, 166, 178, 0.55);
}

.about-timeline__item {
  position: relative;
  padding-bottom: clamp(14px, 2.4vw, 22px);
}

.about-timeline__item::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 16px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--yl-orange);
  box-shadow: 0 0 0 4px rgba(242, 138, 46, 0.18);
}

.about-timeline__item--mid::before {
  background: var(--yl-mid);
  box-shadow: 0 0 0 4px rgba(44, 124, 154, 0.24);
}

.about-stage {
  background: rgba(247, 244, 236, 0.06);
  border-radius: var(--yl-radius-md);
  border: 1px solid rgba(247, 244, 236, 0.14);
  transition: background 0.2s ease;
}

.about-stage[open] {
  background: rgba(247, 244, 236, 0.1);
  border-color: rgba(242, 138, 46, 0.5);
}

.about-stage__summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 13px 18px;
  cursor: pointer;
  list-style: none;
}

.about-stage__summary::-webkit-details-marker {
  display: none;
}

.about-stage__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--yl-font-mono);
  color: var(--yl-orange-soft);
}

.about-stage[open] .about-stage__summary::after {
  content: "−";
}

.about-stage__year {
  font-family: var(--yl-font-mono);
  font-size: clamp(1rem, 2vw, 1.22rem);
  font-weight: 600;
  color: var(--yl-orange);
  letter-spacing: 0.02em;
}

.about-stage__title {
  font-family: var(--yl-font-head);
  font-weight: 900;
  font-size: 1.02rem;
  color: var(--yl-porcelain);
}

.about-stage__body {
  padding: 0 18px 16px;
}

.about-stage__body p {
  font-size: 0.9rem;
  color: rgba(247, 244, 236, 0.82);
}

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

.about-figure__frame {
  border-radius: var(--yl-radius-lg);
  overflow: hidden;
}

.about-section--timeline .media-frame__caption {
  margin-top: 12px;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: rgba(247, 244, 236, 0.65);
}

/* ---------- 团队 ---------- */
.about-crew {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.about-crew__item {
  padding: 16px;
  background: #fff;
  border-radius: var(--yl-radius-md);
  border-bottom: 3px solid var(--yl-mist);
}

.about-crew__item:nth-child(2) { border-bottom-color: var(--yl-orange-soft); }
.about-crew__item:nth-child(3) { border-bottom-color: var(--yl-mist); }
.about-crew__item:nth-child(4) { border-bottom-color: rgba(228, 91, 79, 0.45); }

.about-crew__item .about-num {
  color: var(--yl-blue);
  font-size: clamp(1.5rem, 3vw, 1.9rem);
}

.about-crew__name {
  display: block;
  margin-top: 4px;
  font-family: var(--yl-font-head);
  font-weight: 900;
  font-size: 0.98rem;
  color: var(--yl-deep);
}

.about-crew__item p {
  margin: 6px 0 0;
  font-size: 0.84rem;
  color: #4A6470;
}

.about-partners {
  margin-top: clamp(22px, 3.4vw, 32px);
}

.about-partners p {
  font-size: 0.94rem;
  color: #3A5663;
}

.about-figure__frame--tall {
  max-width: 560px;
}

/* ---------- 成果展板 ---------- */
.about-results__head {
  max-width: 46em;
  margin-bottom: clamp(24px, 4vw, 40px);
}

.about-results__head h2 {
  color: var(--yl-deep);
  margin-bottom: 0.5em;
}

.about-results__lede {
  color: #3A5663;
}

.about-board {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
  grid-template-columns: minmax(0, 1fr);
}

.about-board__cell {
  padding: clamp(18px, 3vw, 26px);
  background: #fff;
  border-radius: var(--yl-radius-lg);
  border-top: 4px solid var(--yl-mid);
}

.about-board__cell:nth-child(2) { border-top-color: var(--yl-orange); }
.about-board__cell:nth-child(3) { border-top-color: var(--yl-blue); }
.about-board__cell:nth-child(4) { border-top-color: var(--yl-line); }
.about-board__cell:nth-child(5) { border-top-color: var(--yl-coral); }

.about-board__num {
  display: block;
  font-family: var(--yl-font-mono);
  font-size: clamp(1.9rem, 4.4vw, 2.9rem);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--yl-deep);
}

.about-board__unit {
  font-size: 0.42em;
  margin-left: 4px;
  letter-spacing: 0;
  color: var(--yl-blue);
}

.about-board__label {
  display: block;
  margin-top: 8px;
  font-size: 0.84rem;
  letter-spacing: 0.08em;
  color: var(--yl-blue);
}

.about-board__cell p {
  margin: 10px 0 0;
  font-size: 0.88rem;
  color: #4A6470;
}

.about-observe {
  margin-top: clamp(24px, 4vw, 36px);
  padding-left: 18px;
  border-left: 3px solid var(--yl-orange);
}

.about-observe p {
  font-size: 0.94rem;
  color: #3A5663;
  max-width: 46em;
}

/* ---------- 结尾入口 ---------- */
.about-next__inner {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  padding: clamp(26px, 4vw, 44px);
  background: linear-gradient(140deg, #DCEFF5 0%, #F7F4EC 68%);
  border-radius: var(--yl-radius-lg);
  border: 1px solid rgba(20, 92, 122, 0.16);
}

.about-next__copy h2 {
  color: var(--yl-deep);
  margin-bottom: 0.5em;
}

.about-next__copy p {
  color: #3A5663;
  max-width: 38em;
}

.about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: start;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .about-points {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .about-crew {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .about-hero__grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  }

  .about-split {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .about-sign {
    align-self: start;
    position: sticky;
    top: 96px;
  }

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

  .about-device-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }

  .about-device:first-child {
    grid-column: 1 / -1;
  }

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

  .about-board__cell--wide {
    grid-column: span 2;
  }

  .about-next__inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: center;
  }
}

@media (min-width: 1120px) {
  .about-channels {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .about-channel {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    border-radius: var(--yl-radius-md);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-channel__tip,
  .page-about .about-stage {
    transition: none;
  }
}