.page-about {
  --about-gap: 1.5rem;
  padding-top: calc(var(--header-h) + 2rem);
  padding-bottom: 4rem;
}

.page-about [id] {
  scroll-margin-top: calc(var(--header-h) + 1.25rem);
}

.page-about__breadcrumb {
  margin-bottom: 1.25rem;
}

.page-about__layout {
  display: grid;
  gap: 2rem;
}

.page-about__content {
  min-width: 0;
}

/* ===== 章节索引 ===== */
.page-about__chapters {
  display: none;
}

.page-about__chapters-label {
  display: block;
  font-family: var(--font-data), monospace;
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--c-orange);
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.page-about__chapters-nav {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.page-about__chapters-nav a {
  display: flex;
  align-items: baseline;
  gap: 0.625rem;
  padding: 0.45rem 0;
  color: var(--c-silver);
  text-decoration: none;
  border-bottom: 1px solid rgba(192, 200, 208, 0.12);
  font-size: 0.95rem;
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.page-about__chapters-nav a span {
  font-family: var(--font-data), monospace;
  font-size: 0.75rem;
  color: var(--c-green);
}

.page-about__chapters-nav a:hover {
  color: var(--c-white);
  padding-left: 0.35rem;
}

.page-about__chapters-note {
  margin-top: 2rem;
  padding: 1rem 1.125rem;
  background: var(--c-dblue);
  clip-path: var(--clip-cut);
}

.page-about__chapters-note .data-value {
  font-family: var(--font-data), monospace;
  font-size: 1.75rem;
  font-weight: 700;
}

.page-about__chapters-note p {
  margin: 0.35rem 0 0;
  color: var(--c-silver);
  font-family: var(--font-data), monospace;
  font-size: 0.7rem;
  line-height: 1.6;
  letter-spacing: 0.08em;
}

/* ===== Hero ===== */
.page-about__hero {
  position: relative;
  display: grid;
  background: var(--c-ocean);
  clip-path: var(--clip-cut);
  overflow: hidden;
  margin-bottom: 2.5rem;
}

.page-about__hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 28px 28px;
}

.page-about__hero-inner {
  position: relative;
  display: grid;
  gap: 1.5rem;
  padding: 2rem 1.25rem;
}

.page-about__hero-copy {
  min-width: 0;
}

.page-about__hero-eyebrow {
  font-family: var(--font-data), monospace;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--c-green);
  text-transform: uppercase;
  margin: 0 0 0.75rem;
}

.page-about__hero-copy h1 {
  margin: 0 0 1.125rem;
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-weight: 900;
  font-size: clamp(2.1rem, 5vw, 3.6rem);
  line-height: 1.14;
  color: var(--c-white);
}

.page-about__hero-lead {
  margin: 0 0 1.75rem;
  max-width: 36rem;
  color: var(--c-silver);
  font-size: 1rem;
  line-height: 1.85;
}

.page-about__hero-meta {
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 0.35rem 1.6rem;
  justify-content: start;
  margin-bottom: 1.5rem;
}

.page-about__hero-meta div {
  position: relative;
  padding-left: 0.75rem;
  border-left: 2px solid var(--c-green);
}

.page-about__hero-meta dt {
  font-family: var(--font-data), monospace;
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  color: var(--c-silver);
  text-transform: uppercase;
  margin-bottom: 0.2rem;
}

.page-about__hero-meta dd {
  margin: 0;
  font-family: var(--font-data), monospace;
  font-size: 1rem;
  font-weight: 700;
  color: var(--c-white);
}

.page-about__hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.625rem;
}

.page-about__hero-media {
  margin: 0;
  position: relative;
  min-width: 0;
}

.page-about__hero-media img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  clip-path: var(--clip-cut);
}

.page-about__hero-coords {
  position: absolute;
  right: 1rem;
  bottom: 0.75rem;
  display: none;
  gap: 1rem;
  font-family: var(--font-data), monospace;
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  color: rgba(0, 255, 163, 0.6);
  pointer-events: none;
}

/* ===== 品牌概览 ===== */
.page-about__overview {
  margin-top: 2.5rem;
}

.page-about__overview-grid {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.page-about__overview-text p {
  margin: 0 0 1rem;
  color: var(--c-silver);
  line-height: 1.85;
}

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

.page-about__overview-aside {
  min-width: 0;
}

.page-about__overview-card {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  padding: 1.75rem 1.5rem;
  background: var(--c-dblue);
}

.page-about__overview-card-label {
  font-family: var(--font-data), monospace;
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--c-orange);
  text-transform: uppercase;
}

.page-about__overview-card-value {
  font-family: var(--font-data), monospace;
  font-size: 2rem;
  font-weight: 700;
  background: var(--grad-silver);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about__overview-card-note {
  color: var(--c-silver);
  font-size: 0.875rem;
  line-height: 1.65;
}

/* ===== 品牌里程碑 ===== */
.page-about__milestone {
  margin-top: 3rem;
}

.milestone-track {
  position: relative;
  display: grid;
  gap: 1.25rem;
  margin-top: 1.75rem;
}

.milestone-track__item {
  position: relative;
  background: var(--c-dblue);
  clip-path: var(--clip-cut);
  padding: 1.75rem 1.25rem 1.375rem 3.5rem;
  min-width: 0;
}

.milestone-track__item::after {
  content: "";
  position: absolute;
  left: 0;
  top: 1.5rem;
  bottom: 1.5rem;
  width: 2px;
  background: linear-gradient(180deg, var(--c-green), var(--c-orange));
  opacity: 0.7;
}

.milestone-track__year {
  position: absolute;
  top: 1.25rem;
  left: 1rem;
  z-index: 1;
  font-family: var(--font-data), monospace;
  font-size: 1.375rem;
  font-weight: 700;
  line-height: 1;
  color: var(--c-green);
  transform: rotate(-6deg);
  background: var(--c-deep);
  padding: 0.4rem 0.45rem;
  border: 1px solid rgba(0, 255, 163, 0.35);
}

.milestone-track__content {
  min-width: 0;
}

.milestone-track__content .tag {
  display: inline-block;
  margin-bottom: 0.625rem;
}

.milestone-track__content h3 {
  margin: 0 0 0.5rem;
  color: var(--c-white);
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-size: 1.125rem;
  font-weight: 800;
  line-height: 1.4;
}

.milestone-track__content p {
  margin: 0;
  color: var(--c-silver);
  font-size: 0.875rem;
  line-height: 1.7;
}

/* ===== 安全体系 ===== */
.page-about__security {
  margin-top: 3rem;
}

.page-about__security-grid {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.page-about__security-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.security-item {
  padding: 1.375rem 1.25rem;
  background: var(--c-dblue);
}

.security-item__icon {
  width: 2rem;
  height: 2rem;
  margin-bottom: 0.75rem;
  color: var(--c-green);
}

.security-item h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-size: 1.0625rem;
  font-weight: 800;
  color: var(--c-white);
}

.security-item p {
  margin: 0;
  color: var(--c-silver);
  font-size: 0.875rem;
  line-height: 1.7;
}

.page-about__security-figure {
  margin: 0;
  min-width: 0;
}

.page-about__security-figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ===== 用户与覆盖 ===== */
.page-about__coverage {
  margin-top: 3rem;
}

.page-about__coverage-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-top: 1.75rem;
}

.coverage-stat {
  padding: 1.25rem 1.125rem;
  background: var(--c-dblue);
}

.coverage-stat .data-line {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.coverage-stat .data-line > span:first-child {
  font-size: 0.75rem;
  color: var(--c-silver);
  font-family: var(--font-data), monospace;
  letter-spacing: 0.06em;
}

.coverage-stat__desc {
  margin: 0.625rem 0 0;
  color: var(--c-silver);
  font-size: 0.8125rem;
  line-height: 1.5;
}

.coverage-tabs {
  margin-top: 2rem;
  background: var(--c-ocean);
  clip-path: var(--clip-cut);
  padding: 1.25rem;
}

.coverage-tabs .tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid rgba(192, 200, 208, 0.18);
}

.coverage-tabs .tab {
  appearance: none;
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  padding: 0.625rem 0.875rem;
  color: var(--c-silver);
  font-family: var(--font-body), var(--font-head), sans-serif;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.coverage-tabs .tab:hover {
  color: var(--c-white);
}

.coverage-tabs .tab[aria-selected="true"] {
  color: var(--c-green);
  border-bottom-color: var(--c-green);
}

.coverage-tabs .tab-panel {
  padding-top: 0.25rem;
}

.coverage-tabs .tab-panel h3 {
  margin: 0 0 0.5rem;
  color: var(--c-white);
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-size: 1.125rem;
  font-weight: 800;
}

.coverage-tabs .tab-panel p {
  margin: 0;
  color: var(--c-silver);
  font-size: 0.925rem;
  line-height: 1.8;
}

.page-about__coverage-map {
  margin: 1.75rem 0 0;
}

.page-about__coverage-map img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ===== 品牌理念 ===== */
.page-about__philosophy {
  margin-top: 3rem;
}

.page-about__philosophy-grid {
  display: grid;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.philosophy-card {
  position: relative;
  background: var(--c-ocean);
  clip-path: var(--clip-cut);
  padding: 1.75rem 1.375rem 1.5rem;
}

.philosophy-card__index {
  display: block;
  font-family: var(--font-data), monospace;
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1;
  color: rgba(0, 255, 163, 0.4);
  margin-bottom: 0.875rem;
}

.philosophy-card h3 {
  margin: 0 0 0.625rem;
  color: var(--c-white);
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-size: 1.25rem;
  font-weight: 800;
}

.philosophy-card p {
  margin: 0;
  color: var(--c-silver);
  font-size: 0.875rem;
  line-height: 1.75;
}

/* ===== 相关导航 ===== */
.page-about__related {
  margin-top: 3rem;
}

.page-about__related-panel {
  background: var(--c-dblue);
  clip-path: var(--clip-cut);
  padding: 2.5rem 1.5rem;
  text-align: center;
}

.page-about__related-panel h2 {
  margin: 0 0 0.625rem;
  font-family: var(--font-head), var(--font-body), sans-serif;
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 900;
  color: var(--c-white);
}

.page-about__related-panel p {
  margin: 0 auto;
  max-width: 32rem;
  color: var(--c-silver);
  line-height: 1.7;
}

.page-about__related-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
  justify-content: center;
  margin-top: 1.5rem;
}

/* ===== 平板及以上 ===== */
@media (min-width: 700px) {
  .page-about__hero-inner {
    grid-template-columns: 1fr 0.85fr;
    align-items: center;
    gap: 2rem;
    padding: 2.5rem 2rem;
  }

  .page-about__hero-media img {
    height: 300px;
  }

  .page-about__hero-coords {
    display: flex;
  }

  .page-about__overview-grid {
    grid-template-columns: 1fr 300px;
  }

  .page-about__security-main {
    grid-template-columns: 1fr 1fr;
  }

  .page-about__coverage-stats {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about__philosophy-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ===== 桌面布局 ===== */
@media (min-width: 1024px) {
  .page-about__layout {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 3rem;
  }

  .page-about__chapters {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
    align-self: start;
    border-left: 2px solid var(--c-green);
    padding-left: 1.25rem;
  }

  .page-about__hero-inner {
    padding: 3rem 3rem;
  }

  .page-about__hero-media img {
    height: 340px;
  }

  .page-about__hero-copy h1 {
    font-size: clamp(2.6rem, 4.4vw, 4rem);
  }

  .page-about__security-grid {
    grid-template-columns: 1fr 360px;
    align-items: start;
  }

  .page-about__security-figure {
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
  }

  .milestone-track {
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
  }

  .milestone-track__item:nth-child(even) {
    transform: translateY(1.75rem);
  }

  .milestone-track__item {
    padding: 2.25rem 1.75rem 1.75rem 4rem;
  }

  .milestone-track__year {
    left: 1.25rem;
    font-size: 1.625rem;
  }
}

/* ===== 减少动效偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}