.page-about {
  background: var(--color-white);
  color: var(--color-black);
  overflow-x: hidden;
}

/* ===== 首屏 Hero ===== */
.page-about .about-hero {
  position: relative;
  background: var(--color-black);
  color: var(--color-white);
  padding: 3rem 1rem 2.5rem;
  overflow: hidden;
}
.page-about .about-hero::before {
  content: "";
  position: absolute;
  right: -22%;
  top: -12%;
  width: 78%;
  height: 135%;
  background: var(--color-red);
  transform: skewX(-14deg);
  pointer-events: none;
}
.page-about .about-hero-progress {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--color-red);
  z-index: 3;
}
.page-about .about-hero-inner {
  position: relative;
  z-index: 2;
  max-width: var(--content-max);
  margin: 0 auto;
  display: grid;
  gap: 2.5rem;
}
.page-about .about-breadcrumb {
  margin-bottom: 1.5rem;
  color: var(--color-silver);
  font-family: var(--font-ui);
  font-size: 0.75rem;
}
.page-about .about-breadcrumb a {
  color: var(--color-silver);
  text-decoration: none;
}
.page-about .about-breadcrumb a:hover {
  color: var(--color-white);
}
.page-about .about-eyebrow {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.8125rem;
  letter-spacing: 0.16em;
  color: var(--color-white);
  border-left: 4px solid var(--color-red);
  padding-left: 0.75rem;
  margin: 0 0 1rem;
}
.page-about .about-hero h1 {
  margin: 0 0 1.25rem;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(2.4rem, 7vw, 4.6rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
}
.page-about .about-hero h1 span {
  display: block;
  color: var(--color-red);
}
.page-about .about-hero-lead {
  margin: 0;
  max-width: 34em;
  font-size: clamp(1rem, 0.9rem + 0.3vw, 1.125rem);
  line-height: 1.75;
  color: var(--color-silver);
}
.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-top: 1.75rem;
}
.page-about .about-hero-link {
  color: var(--color-white);
  text-decoration: none;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.875rem;
  border-bottom: 2px solid var(--color-red);
  padding-bottom: 0.2rem;
}
.page-about .about-hero-media {
  position: relative;
}
.page-about .about-hero-img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
  aspect-ratio: 4 / 3;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
  filter: saturate(0.85) contrast(1.05);
}
.page-about .about-hero-tag {
  position: absolute;
  top: 1rem;
  left: 1rem;
  background: var(--color-red);
  color: var(--color-white);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  padding: 0.4rem 0.7rem;
}
.page-about .about-hero-tag-alt {
  left: auto;
  right: 1rem;
  background: var(--color-black);
  border: 1px solid rgba(255,255,255,0.4);
}

/* ===== Hero 滚动标签 ===== */
.page-about .about-marquee {
  position: relative;
  z-index: 2;
  margin-top: 2.5rem;
  overflow: hidden;
  border-top: 1px solid rgba(255,255,255,0.18);
  border-bottom: 1px solid rgba(255,255,255,0.18);
  padding: 0.85rem 0;
  color: var(--color-silver);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.875rem;
  letter-spacing: 0.06em;
}
.page-about .about-marquee-track {
  display: flex;
  width: max-content;
  animation: about-marquee-scroll 32s linear infinite;
}
.page-about .about-marquee-group {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  padding-right: 2.5rem;
}
.page-about .about-marquee-group span {
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
}
.page-about .about-marquee-group span + span::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 2.5rem;
  background: var(--color-red);
  transform: skewX(-8deg);
}
@keyframes about-marquee-scroll {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

/* ===== 左右分屏骨架 ===== */
.page-about .about-shell {
  display: grid;
  gap: 2rem;
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 2rem 1rem 0;
}
.page-about .about-rail {
  background: var(--color-black);
  color: var(--color-white);
  padding: 1.25rem;
  border-left: 6px solid var(--color-red);
}
.page-about .about-rail-title {
  margin: 0 0 0.85rem;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--color-silver);
  line-height: 1.5;
}
.page-about .about-rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.page-about .about-rail-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-white);
  text-decoration: none;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.875rem;
  padding: 0.45rem 0.75rem;
  border: 1px solid rgba(255,255,255,0.22);
}
.page-about .about-rail-link span {
  color: var(--color-red);
  font-variant-numeric: tabular-nums;
}
.page-about .about-rail-note {
  margin-top: 1rem;
  background: var(--color-red-tint);
  color: var(--color-black);
  padding: 0.85rem 1rem;
  font-size: 0.8125rem;
  line-height: 1.6;
}
.page-about .about-rail-note-mark {
  color: var(--color-red);
  font-size: 0.625rem;
  vertical-align: middle;
  margin-right: 0.25rem;
}
.page-about .about-rail-note p {
  margin: 0;
}

/* ===== 章节通用 ===== */
.page-about .about-section {
  position: relative;
  padding: 3.25rem 0 1.5rem;
  scroll-margin-top: calc(var(--header-h) + 1rem);
}
.page-about .about-section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 14px;
  background: var(--color-red);
  clip-path: polygon(0 0, calc(100% - 36px) 0, 100% 14px, 100% 100%, 0 100%);
}
.page-about .about-section:first-child::before {
  display: none;
}
.page-about .about-section-head {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  margin: 0 0 1.75rem;
}
.page-about .about-section-num {
  flex-shrink: 0;
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: 0.8125rem;
  color: var(--color-white);
  background: var(--color-red);
  padding: 0.4rem 0.6rem;
  line-height: 1;
  transform: skewX(-8deg);
  letter-spacing: 0.06em;
}
.page-about .about-section-head h2 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
}
.page-about .about-section-head p {
  margin: 0.4rem 0 0;
  color: var(--color-gray);
  font-size: 0.9375rem;
  max-width: 46em;
}

/* ===== 01 品牌起点 ===== */
.page-about .about-origin-grid {
  display: grid;
  gap: 1.5rem;
}
.page-about .about-origin-main p {
  margin: 0 0 1em;
}
.page-about .about-origin-main strong {
  color: var(--color-red);
}
.page-about .about-origin-side {
  display: grid;
  gap: 1rem;
  align-content: start;
}
.page-about .about-origin-card {
  position: relative;
  background: var(--color-black);
  color: var(--color-white);
  padding: 1.5rem;
  margin-left: 1rem;
}
.page-about .about-origin-card::before {
  content: "";
  position: absolute;
  left: -1rem;
  top: 0;
  width: 4px;
  height: 100%;
  background: var(--color-red);
}
.page-about .about-origin-card-label {
  display: inline-block;
  background: var(--color-red);
  color: var(--color-white);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  padding: 0.2rem 0.5rem;
  margin-bottom: 0.75rem;
}
.page-about .about-origin-card p {
  margin: 0;
  line-height: 1.7;
}
.page-about .about-origin-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 1px solid var(--color-silver);
}
.page-about .about-origin-list li {
  display: flex;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--color-silver);
  font-size: 0.9375rem;
}
.page-about .about-origin-list li:last-child {
  border-bottom: none;
}
.page-about .about-origin-list li span {
  color: var(--color-red);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.75rem;
}

/* ===== 02 数字能力 ===== */
.page-about .about-section-data {
  background: var(--color-black);
  color: var(--color-white);
  padding: 3rem 1.25rem 2rem;
}
.page-about .about-section-data .about-section-head p {
  color: var(--color-silver);
}
.page-about .about-data-grid {
  display: grid;
  gap: 1rem;
}
.page-about .about-data-card {
  background: var(--color-deep);
  color: var(--color-white);
  padding: 1.5rem;
  position: relative;
}
.page-about .about-data-card-red {
  background: var(--color-red);
}
.page-about .about-data-num {
  display: inline-block;
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: clamp(2.8rem, 8vw, 4.25rem);
  line-height: 1;
  color: var(--color-white);
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
  border-bottom: 5px solid var(--color-red);
  padding-bottom: 0.15rem;
}
.page-about .about-data-card-red .about-data-num {
  border-bottom-color: var(--color-white);
}
.page-about .about-data-suffix {
  font-size: 0.55em;
  vertical-align: top;
}
.page-about .about-data-label {
  display: block;
  margin: 0.75rem 0 0.5rem;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--color-silver);
}
.page-about .about-data-card-red .about-data-label {
  color: rgba(255,255,255,0.85);
}
.page-about .about-data-card p {
  margin: 0;
  color: var(--color-silver);
  font-size: 0.875rem;
  line-height: 1.6;
}
.page-about .about-data-card-red p {
  color: var(--color-white);
}
.page-about .about-data-strip {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--color-silver);
  border-top: 4px solid var(--color-red);
  margin-top: 1.5rem;
}
.page-about .about-data-strip-item {
  background: var(--color-black);
  padding: 1rem;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  color: var(--color-silver);
}
.page-about .about-data-strip-key {
  display: block;
  color: var(--color-white);
  font-weight: 900;
  font-size: 1.5rem;
  line-height: 1.2;
}

/* ===== 03 技术路线 ===== */
.page-about .about-tech-list {
  display: grid;
  gap: 1rem;
}
.page-about .about-tech-card {
  position: relative;
  background: var(--color-black);
  color: var(--color-white);
  padding: 1.75rem 1.25rem 1.25rem;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.page-about .about-tech-card:hover {
  transform: translateY(-4px);
  box-shadow: 6px 6px 0 var(--color-red);
}
.page-about .about-tech-index {
  position: absolute;
  top: 0;
  right: 0;
  background: var(--color-red);
  color: var(--color-white);
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  padding: 0.5rem 0.75rem;
}
.page-about .about-tech-card h3 {
  margin: 0.5rem 0 0.6rem;
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: 1.2rem;
  line-height: 1.3;
}
.page-about .about-tech-card p {
  margin: 0 0 1rem;
  color: var(--color-silver);
  font-size: 0.9375rem;
  line-height: 1.7;
}
.page-about .about-tech-tag {
  display: inline-block;
  font-family: var(--font-ui);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-white);
  background: var(--color-red);
  padding: 0.2rem 0.5rem;
  letter-spacing: 0.08em;
}

/* ===== 04 社区协作 ===== */
.page-about .about-community-grid {
  display: grid;
  gap: 2rem;
}
.page-about .about-community-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  border-top: 3px solid var(--color-red);
}
.page-about .about-community-list li {
  padding: 0.8rem 0;
  border-bottom: 1px solid var(--color-silver);
  font-size: 0.9375rem;
}
.page-about .about-community-list li::before {
  content: "—";
  color: var(--color-red);
  margin-right: 0.5rem;
}
.page-about .about-community-media {
  margin: 0;
}
.page-about .about-community-media img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
  aspect-ratio: 9 / 5;
  border: 1px solid var(--color-black);
}
.page-about .about-community-media figcaption,
.page-about .about-timeline-media figcaption {
  margin-top: 0.5rem;
  font-family: var(--font-ui);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--color-gray);
}

/* ===== 05 发展历程 ===== */
.page-about .about-timeline {
  position: relative;
  margin: 2rem 0;
  padding-left: 1.75rem;
}
.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--color-red) 0%, var(--color-blue) 100%);
}
.page-about .about-timeline-item {
  position: relative;
  margin-bottom: 1.25rem;
}
.page-about .about-timeline-dot {
  position: absolute;
  left: -1.75rem;
  top: 1rem;
  width: 12px;
  height: 12px;
  background: var(--color-red);
  border: 3px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-red);
  border-radius: 50%;
}
.page-about .about-timeline-card {
  background: var(--color-white);
  border: 1px solid var(--color-silver);
  padding: 1.25rem;
}
.page-about .about-timeline-card h3,
.page-about .about-timeline-title {
  display: block;
  margin: 0.5rem 0 0.25rem;
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: 1.25rem;
  color: var(--color-black);
  line-height: 1.3;
}
.page-about .about-timeline-card p {
  margin: 0.6rem 0 0;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-gray);
}
.page-about .about-timeline-phase {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--color-red);
}
.page-about .about-timeline-details summary {
  display: block;
  position: relative;
  cursor: pointer;
  list-style: none;
  padding-right: 2.5rem;
}
.page-about .about-timeline-details summary::-webkit-details-marker {
  display: none;
}
.page-about .about-timeline-details summary:hover .about-timeline-title {
  color: var(--color-red);
}
.page-about .about-timeline-more {
  position: absolute;
  top: 0.35rem;
  right: 0.5rem;
  display: inline-block;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-red);
  transition: transform 0.25s ease;
}
.page-about .about-timeline-details[open] .about-timeline-more {
  transform: rotate(45deg);
}
.page-about .about-timeline-media {
  margin: 2.25rem 0 0;
}
.page-about .about-timeline-media img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
  aspect-ratio: 7 / 4;
}

/* ===== 底部收束 ===== */
.page-about .about-outro {
  position: relative;
  background: var(--color-deep);
  color: var(--color-white);
  padding: 3.5rem 1rem;
  margin-top: 3rem;
  overflow: hidden;
}
.page-about .about-outro::before {
  content: "";
  position: absolute;
  right: -8%;
  top: -40%;
  width: 60%;
  height: 150%;
  background: var(--color-red);
  opacity: 0.16;
  transform: rotate(12deg);
  pointer-events: none;
}
.page-about .about-outro-inner {
  position: relative;
  z-index: 1;
  max-width: var(--content-max);
  margin: 0 auto;
}
.page-about .about-outro-kicker {
  margin: 0;
  font-family: var(--font-ui);
  font-weight: 900;
  font-size: 0.8125rem;
  letter-spacing: 0.22em;
  color: var(--color-red);
}
.page-about .about-outro-title {
  margin: 0.5rem 0 1.5rem;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  line-height: 1.2;
}
.page-about .about-outro-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ===== 平板及以上 ===== */
@media (min-width: 640px) {
  .page-about .about-hero-inner {
    grid-template-columns: 1fr;
  }
  .page-about .about-data-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-about .about-tech-list {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-about .about-data-strip {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ===== 桌面布局 ===== */
@media (min-width: 992px) {
  .page-about .about-hero {
    padding: calc(var(--header-h) + 2rem) clamp(1rem, 3vw, 2.5rem) 3rem;
  }
  .page-about .about-hero-inner {
    grid-template-columns: 7fr 5fr;
    gap: 3rem;
    align-items: center;
  }
  .page-about .about-hero h1 {
    font-size: clamp(3rem, 5vw, 4.75rem);
  }
  .page-about .about-shell {
    grid-template-columns: 230px 1fr;
    gap: 3.5rem;
    padding: 3rem clamp(1rem, 3vw, 2.5rem) 0;
  }
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
    align-self: start;
    background: transparent;
    color: var(--color-black);
    border-left: none;
    padding: 0;
  }
  .page-about .about-rail-title {
    color: var(--color-gray);
    border-bottom: 2px solid var(--color-black);
    padding-bottom: 0.5rem;
  }
  .page-about .about-rail-list {
    display: block;
  }
  .page-about .about-rail-item {
    margin-bottom: 0.4rem;
  }
  .page-about .about-rail-link {
    display: flex;
    padding: 0.6rem 0.75rem;
    border: none;
    border-left: 3px solid var(--color-silver);
    font-size: 0.9rem;
    color: var(--color-black);
  }
  .page-about .about-rail-link:hover {
    border-left-color: var(--color-red);
    color: var(--color-red);
  }
  .page-about .about-rail-link span {
    min-width: 2em;
    color: var(--color-gray);
  }
  .page-about .about-rail-note {
    display: block;
    margin-top: 2rem;
  }
  .page-about .about-section {
    padding: 4.5rem 0 2.5rem;
  }
  .page-about .about-section-data {
    padding: 4rem 2.5rem 2.5rem;
  }
  .page-about .about-origin-grid {
    grid-template-columns: 5fr 3fr;
    gap: 2.5rem;
  }
  .page-about .about-community-grid {
    grid-template-columns: 1fr 1.2fr;
    gap: 2.5rem;
    align-items: center;
  }
  .page-about .about-timeline {
    padding-left: 2.5rem;
  }
  .page-about .about-timeline::before {
    left: 10px;
  }
  .page-about .about-timeline-dot {
    left: -2.5rem;
    width: 15px;
    height: 15px;
  }
  .page-about .about-outro {
    padding: 4rem clamp(1rem, 3vw, 2.5rem);
    margin-top: 4rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-marquee-track {
    animation: none;
  }
  .page-about .about-tech-card {
    transition: none;
  }
}