.page-about {
  --about-hero-dec: #FF6B00;
  --about-muted-line: rgba(17,17,17,0.14);
  --about-dark-line: rgba(255,255,255,0.18);
  --about-card-bg: #FFFFFF;
  --about-milestone-bg: #0A192F;
  --about-commitment-bg: #EDEDED;
}

.page-about .breadcrumb {
  font-size: 0.875rem;
  color: var(--color-muted);
  padding-top: 28px;
}

.page-about .breadcrumb a {
  color: var(--color-ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.page-about .breadcrumb a:hover {
  border-color: var(--color-orange);
}

/* ========== Hero ========== */
.about-hero {
  position: relative;
  background: var(--color-bg);
  padding: 40px 0 24px;
  overflow: hidden;
}

.about-hero__bg {
  position: absolute;
  top: -0.18em;
  right: -0.12em;
  z-index: 0;
  font-family: var(--font-mono);
  font-size: 16rem;
  font-weight: 700;
  line-height: 1;
  color: rgba(17,17,17,0.045);
  user-select: none;
  pointer-events: none;
}

.about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 28px;
  align-items: start;
}

.about-hero__eyebrow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

.about-hero__period {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--color-muted);
}

.about-hero__title {
  margin: 0 0 20px;
  font-family: var(--font-heading);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  font-size: clamp(2rem, 7vw, 3.5rem);
}

.about-hero__title-sub {
  display: block;
  margin-top: 12px;
  font-family: var(--font-sub);
  font-size: clamp(1.05rem, 3.4vw, 1.6rem);
  font-weight: 700;
  color: var(--color-orange);
  letter-spacing: -0.01em;
}

.about-hero__lead {
  margin: 0 0 28px;
  max-width: 46em;
  font-size: 1rem;
  line-height: 1.85;
  color: #333333;
}

.about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  border-top: 1px solid var(--about-muted-line);
  border-bottom: 1px solid var(--about-muted-line);
  padding: 18px 0;
}

.about-hero__fact {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.about-hero__fact-num {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-ink);
  letter-spacing: -0.03em;
}

.about-hero__fact span:last-child {
  font-size: 0.8125rem;
  color: var(--color-muted);
}

.about-hero__media {
  position: relative;
  margin: 0;
}

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

.about-hero__caption {
  padding-top: 10px;
  font-size: 0.8125rem;
  color: var(--color-muted);
  border-bottom: 1px solid var(--about-muted-line);
  padding-bottom: 12px;
}

/* ========== 章节索引 ========== */
.about-index {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 22px 0 6px;
  scrollbar-width: thin;
}

.about-index__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-white);
  color: var(--color-muted);
  font-size: 0.875rem;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.about-index__link span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-orange);
}

.about-index__link:hover {
  color: var(--color-ink);
  border-color: var(--color-orange);
  background: rgba(255, 107, 0, 0.06);
}

/* ========== 里程碑 ========== */
.about-milestones {
  background: var(--about-milestone-bg);
  padding: 72px 0;
  color: #FFFFFF;
}

.about-milestones .section-title {
  color: #FFFFFF;
}

.about-milestones__intro {
  margin: 0;
  max-width: 42em;
  line-height: 1.8;
  color: rgba(255,255,255,0.72);
  font-size: 0.9375rem;
}

.about-milestones__head {
  margin-bottom: 40px;
}

.about-timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.about-timeline__item {
  position: relative;
  padding-left: 24px;
  padding-bottom: 28px;
  border-left: 1px solid var(--about-dark-line);
}

.about-timeline__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.about-timeline__item::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 8px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--color-orange);
  box-shadow: 0 0 0 5px rgba(255,107,0,0.22);
}

.about-timeline__toggle {
  width: 100%;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-sub);
}

.about-timeline__year {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-lime);
  letter-spacing: -0.02em;
}

.about-timeline__title {
  font-size: 1.125rem;
  font-weight: 700;
  color: #FFFFFF;
  letter-spacing: 0.01em;
}

.about-timeline__mark {
  width: 28px;
  height: 28px;
  margin-left: auto;
  border: 1px solid rgba(255,255,255,0.32);
  border-radius: 50%;
  position: relative;
  flex-shrink: 0;
}

.about-timeline__mark::before,
.about-timeline__mark::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: var(--color-orange);
  border-radius: 2px;
}

.about-timeline__mark::before {
  width: 10px;
  height: 2px;
}

.about-timeline__mark::after {
  width: 2px;
  height: 10px;
}

.about-timeline__panel {
  padding-top: 12px;
  max-width: 56em;
}

.about-timeline__panel p {
  margin: 0;
  line-height: 1.85;
  color: rgba(255,255,255,0.76);
  font-size: 0.9375rem;
}

/* ========== 数据底盘 ========== */
.about-foundation {
  background: var(--color-bg);
  padding: 72px 0 48px;
}

.about-foundation__lead {
  max-width: 46em;
  line-height: 1.8;
  color: #333333;
  margin: 20px 0 36px;
}

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

.about-foundation__media {
  margin: 0;
}

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

.about-foundation__media figcaption {
  padding-top: 10px;
  font-size: 0.8125rem;
  color: var(--color-muted);
}

.about-foundation__block {
  background: var(--about-card-bg);
  border-top: 4px solid var(--color-orange);
  border-radius: var(--radius-md);
  padding: 28px;
  box-shadow: var(--shadow-sm);
}

.about-foundation__block h3 {
  margin: 0 0 12px;
  font-family: var(--font-sub);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-ink);
}

.about-foundation__block p {
  margin: 0 0 18px;
  line-height: 1.75;
  color: #444444;
  font-size: 0.9375rem;
}

.about-foundation__dl {
  display: grid;
  gap: 8px;
  margin: 0;
}

.about-foundation__dl > div {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-line);
}

.about-foundation__dl > div:last-child {
  border-bottom: none;
}

.about-foundation__dl dt {
  font-size: 0.875rem;
  color: var(--color-muted);
}

.about-foundation__dl dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-ink);
}

.about-foundation__certs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.about-foundation__certs span {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  background: var(--about-milestone-bg);
  color: var(--color-white);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.about-foundation__certs span::before {
  content: "";
  width: 7px;
  height: 7px;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--color-lime);
}

.about-foundation__foot {
  margin-top: 36px;
  padding: 28px;
  border-radius: var(--radius-md);
  background: var(--about-milestone-bg);
  color: rgba(255,255,255,0.84);
}

.about-foundation__foot p {
  margin: 0;
  line-height: 1.85;
  font-size: 0.9375rem;
}

/* ========== 透明承诺 ========== */
.about-commitment {
  background: var(--about-commitment-bg);
  padding: 72px 0;
}

.about-commitment__grid {
  display: grid;
  gap: 20px;
  margin-bottom: 24px;
}

.about-commitment__card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--about-card-bg);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 32px 28px 28px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.about-commitment__card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.about-commitment__num {
  position: absolute;
  top: 18px;
  right: 22px;
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1;
  color: rgba(17,17,17,0.07);
  letter-spacing: -0.04em;
}

.about-commitment__card h3 {
  margin: 0 0 14px;
  padding-right: 44px;
  font-family: var(--font-sub);
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--color-ink);
}

.about-commitment__card p {
  margin: 0 0 22px;
  line-height: 1.85;
  color: #444444;
  font-size: 0.9375rem;
}

.about-commitment__card .btn {
  align-self: flex-start;
  margin-top: auto;
}

.about-commitment__band {
  display: flex;
  flex-direction: column;
  gap: 20px;
  background: var(--about-milestone-bg);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  color: #FFFFFF;
  box-shadow: var(--shadow-md);
}

.about-commitment__band-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-lime);
  margin-bottom: 10px;
}

.about-commitment__band p {
  margin: 0;
  line-height: 1.85;
  color: rgba(255,255,255,0.8);
  font-size: 0.9375rem;
}

.about-commitment__band .btn {
  align-self: flex-start;
  flex-shrink: 0;
}

/* ========== 收尾 ========== */
.about-outro {
  background: var(--color-white);
  padding: 64px 0;
}

.about-outro__inner {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.about-outro__copy h2 {
  margin: 0 0 14px;
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 900;
  color: var(--color-ink);
  letter-spacing: -0.02em;
}

.about-outro__copy p {
  margin: 0;
  max-width: 40em;
  line-height: 1.8;
  color: var(--color-muted);
}

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

/* ========== 桌面端增强 ========== */
@media (min-width: 640px) {
  .about-hero {
    padding: 56px 0 40px;
  }

  .about-milestones,
  .about-foundation,
  .about-commitment {
    padding-top: 96px;
    padding-bottom: 96px;
  }

  .about-timeline__item {
    padding-left: 32px;
  }

  .about-commitment__band {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 36px 40px;
  }

  .about-commitment__band .btn {
    margin: 0;
  }

  .about-outro__inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

@media (min-width: 980px) {
  .about-hero__grid {
    grid-template-columns: repeat(12, 1fr);
    gap: 40px;
  }

  .about-hero__copy {
    grid-column: 1 / 8;
    padding-top: 20px;
  }

  .about-hero__media {
    grid-column: 9 / 13;
  }

  .about-hero__media img {
    max-height: 640px;
    object-fit: cover;
  }

  .about-hero__bg {
    font-size: 24rem;
  }

  .about-index {
    justify-content: flex-start;
    gap: 12px;
    padding: 28px 0 8px;
  }

  .about-milestones__head {
    display: grid;
    grid-template-columns: auto 1fr 1.2fr;
    gap: 28px;
    align-items: center;
  }

  .about-milestones__intro {
    margin: 0;
  }

  .about-timeline {
    padding-left: 8px;
  }

  .about-foundation__grid {
    grid-template-columns: repeat(12, 1fr);
    gap: 28px;
  }

  .about-foundation__media--team {
    grid-column: 1 / 6;
  }

  .about-foundation__block--team {
    grid-column: 7 / 13;
  }

  .about-foundation__block--tech {
    grid-column: 1 / 6;
  }

  .about-foundation__media--tech {
    grid-column: 7 / 13;
  }

  .about-foundation__block {
    margin-top: 12px;
  }

  .about-commitment__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }

  .about-outro {
    padding: 80px 0;
  }
}