.page-about {
  --about-nav-w: 236px;
  --about-text: #b9c6d9;
  --about-gap: clamp(28px, 4vw, 64px);
  display: block;
  overflow-x: clip;
  background:
    linear-gradient(180deg, var(--ink-900) 0%, var(--ink-800) 38%, var(--ink-900) 72%, #04060b 100%);
  color: var(--paper);
}

/* ============ 刊头 ============ */
.page-about .about-masthead {
  position: relative;
  padding-top: clamp(22px, 3.6vw, 44px);
  padding-bottom: clamp(28px, 4vw, 52px);
}

.page-about .about-masthead::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  width: min(1400px, 130%);
  height: 100%;
  transform: translateX(-50%);
  background:
    repeating-linear-gradient(
      -6deg,
      rgba(42, 58, 85, 0.34) 0 1px,
      transparent 1px 46px
    );
  opacity: 0.55;
  pointer-events: none;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
}

.page-about .about-masthead .container {
  position: relative;
  z-index: 1;
}

.page-about .about-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 20px 0 0;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--signal);
}

.page-about .about-kicker::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--signal);
}

.page-about .about-title {
  margin: 18px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(34px, 6.4vw, 68px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 16em;
}

.page-about .about-lede {
  margin: 22px 0 0;
  max-width: 64ch;
  font-size: clamp(16px, 1.5vw, 17.5px);
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .about-stamp {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  margin-top: clamp(24px, 3.4vw, 38px);
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mute);
}

.page-about .about-stamp span {
  position: relative;
  padding-left: 14px;
}

.page-about .about-stamp span::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
}

/* ============ 通栏氛围图 ============ */
.page-about .about-banner {
  position: relative;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-banner figure {
  position: relative;
  margin: 0;
  overflow: hidden;
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  height: clamp(180px, 30vw, 400px);
  object-fit: cover;
  filter: saturate(0.68) brightness(0.72);
}

.page-about .about-banner figure::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(5, 7, 13, 0.78), rgba(11, 18, 32, 0.38) 46%, rgba(5, 7, 13, 0.92)),
    linear-gradient(90deg, rgba(5, 7, 13, 0.7), transparent 55%);
  pointer-events: none;
}

/* ============ 双栏骨架 ============ */
.page-about .about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 44px);
  padding-top: clamp(38px, 5vw, 76px);
  padding-bottom: clamp(48px, 7vw, 104px);
}

@media (min-width: 1000px) {
  .page-about .about-grid {
    grid-template-columns: var(--about-nav-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }
}

/* ============ 章节索引 ============ */
.page-about .about-index__label {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mute);
  text-transform: uppercase;
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 6px;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
  scrollbar-width: none;
}

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

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 10px 14px;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  font-size: 14px;
  color: var(--mute);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.page-about .about-index__link .mono {
  font-size: 11.5px;
  color: var(--signal);
  letter-spacing: 0.08em;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--signal);
  background: rgba(200, 255, 61, 0.06);
}

@media (min-width: 1000px) {
  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-bottom: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-index__link {
    white-space: normal;
    border-bottom: 0;
    border-left: 2px solid transparent;
    margin-left: -1px;
    padding: 9px 14px;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-bottom-color: transparent;
    border-left-color: var(--signal);
  }
}

/* ============ 正文列 ============ */
.page-about .about-body {
  display: grid;
  gap: clamp(46px, 6vw, 88px);
  min-width: 0;
}

.page-about .chapter {
  min-width: 0;
  scroll-margin-top: calc(var(--header-h) + 26px);
}

.page-about .chapter__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 12px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.page-about .chapter__no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13.5px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .chapter__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .chapter__body > p {
  margin: 0 0 1.2em;
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--about-text);
}

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

/* ============ 01 三块切角面板 ============ */
.page-about .pillars {
  display: grid;
  gap: 16px;
}

@media (min-width: 780px) {
  .page-about .pillars {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .pillar {
  position: relative;
  padding: 24px 22px 26px;
  background: linear-gradient(158deg, rgba(20, 28, 44, 0.94), rgba(11, 18, 32, 0.68));
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .pillar__no {
  display: block;
  margin-bottom: 12px;
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .pillar h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .pillar p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--mute);
}

/* ============ 02 四条内容线 ============ */
.page-about .lines {
  display: grid;
  gap: 14px;
  margin-top: 20px;
}

@media (min-width: 760px) {
  .page-about .lines {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .line {
  display: grid;
  gap: 9px;
  padding: 22px;
  background: rgba(20, 28, 44, 0.55);
  border: 1px solid var(--line);
  border-left: 3px solid var(--line);
  transition: border-color 0.25s ease, background 0.25s ease, transform 0.25s ease;
}

.page-about .line:hover,
.page-about .line:focus-within {
  border-left-color: var(--signal);
  background: rgba(20, 28, 44, 0.88);
  transform: translateX(2px);
}

.page-about .line__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
}

.page-about .line__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  color: var(--paper);
}

.page-about .line__rate {
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mute);
  white-space: nowrap;
  transition: color 0.25s ease;
}

.page-about .line:hover .line__rate {
  color: var(--signal);
}

.page-about .line p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--mute);
}

.page-about .line__for {
  font-size: 13px;
  line-height: 1.6;
  color: var(--cyan);
}

/* ============ 03 流程 ============ */
.page-about .flow-figure {
  position: relative;
  margin: 0 0 26px;
  overflow: hidden;
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .flow-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.6) brightness(0.76);
}

.page-about .flow-figure::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(5, 7, 13, 0.2), rgba(11, 18, 32, 0.74));
  pointer-events: none;
}

.page-about .flow-figure figcaption {
  position: absolute;
  left: 16px;
  bottom: 12px;
  z-index: 1;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--paper);
  text-shadow: 0 1px 6px rgba(5, 7, 13, 0.9);
}

.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
}

.page-about .flow-step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 16px;
  padding: 20px 0;
  border-top: 1px dashed var(--line);
}

.page-about .flow-step:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .flow-step__no {
  padding-top: 4px;
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .flow-step h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18.5px;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .flow-step p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--mute);
}

/* ============ 04 团队角色 ============ */
.page-about .roles {
  display: grid;
  gap: 12px;
  margin-top: 22px;
}

@media (min-width: 700px) {
  .page-about .roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .role {
  position: relative;
  padding: 20px 20px 22px;
  background: var(--ink-700);
  border: 1px solid var(--line);
}

.page-about .role::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 36px;
  height: 3px;
  background: var(--cyan);
}

.page-about .role__tag {
  display: block;
  margin-bottom: 10px;
  font-size: 10.5px;
  letter-spacing: 0.18em;
  color: var(--mute);
}

.page-about .role h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .role__count {
  font-size: 24px;
  letter-spacing: -0.01em;
  color: var(--signal);
}

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

.page-about .roles-note {
  margin: 22px 0 0;
  padding: 18px 20px;
  border-left: 3px solid var(--signal);
  background: rgba(200, 255, 61, 0.06);
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--about-text);
}

/* ============ 05 版本时间轴 ============ */
.page-about .versions-art {
  position: relative;
  margin: 0 0 16px;
  height: clamp(96px, 15vw, 168px);
  overflow: hidden;
  border: 1px solid var(--line);
}

.page-about .versions-art img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.55;
}

.page-about .versions-art::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(5, 7, 13, 0.24), rgba(5, 7, 13, 0.94));
  pointer-events: none;
}

.page-about .versions-hint {
  margin: 0 0 14px;
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--mute);
}

.page-about .versions {
  display: flex;
  gap: 16px;
  overflow-x: auto;
  padding: 6px 2px 20px;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: var(--line) transparent;
}

.page-about .versions::-webkit-scrollbar {
  height: 6px;
}

.page-about .versions::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 3px;
}

.page-about .version {
  flex: 0 0 min(310px, 80vw);
  scroll-snap-align: start;
  padding: 22px;
  background: linear-gradient(200deg, rgba(20, 28, 44, 0.96), rgba(5, 7, 13, 0.82));
  border: 1px solid var(--line);
}

.page-about .version__rail {
  position: relative;
  display: block;
  height: 1px;
  margin-bottom: 18px;
  background: var(--line);
}

.page-about .version__rail::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--cyan);
  transform: translateY(-50%);
}

.page-about .version--v4 .version__rail::before {
  background: var(--signal);
  box-shadow: 0 0 0 5px rgba(200, 255, 61, 0.16);
}

.page-about .version__tag {
  display: block;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--signal);
}

.page-about .version h3 {
  margin: 8px 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  line-height: 1.35;
  color: var(--paper);
}

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

/* ============ 06 差异点列表 ============ */
.page-about .diffs {
  display: grid;
}

.page-about .diff {
  display: grid;
  gap: 8px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.page-about .diff:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .diff__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18.5px;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .diff__text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--mute);
}

.page-about .diff__link {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--signal);
  text-decoration: none;
  opacity: 0.68;
  transition: opacity 0.2s ease, color 0.2s ease;
}

.page-about .diff__link:hover,
.page-about .diff__link:focus-visible {
  opacity: 1;
  color: var(--signal);
  text-decoration: underline;
  text-underline-offset: 4px;
}

@media (min-width: 900px) {
  .page-about .diff {
    grid-template-columns: 216px minmax(0, 1fr) 156px;
    align-items: baseline;
    gap: 22px;
  }

  .page-about .diff__link {
    justify-self: end;
    text-align: right;
  }
}

/* ============ 07 合作 ============ */
.page-about .partner {
  padding: clamp(24px, 3.6vw, 38px);
  background: linear-gradient(136deg, rgba(200, 255, 61, 0.09), rgba(20, 28, 44, 0.72) 52%, rgba(5, 7, 13, 0.9));
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .partner > p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .partner ul {
  list-style: none;
  margin: 20px 0 24px;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .partner li {
  position: relative;
  padding-left: 22px;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--mute);
}

.page-about .partner li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 9px;
  height: 2px;
  background: var(--signal);
}

.page-about .partner li strong {
  color: var(--paper);
  font-weight: 600;
}

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

/* ============ 窄屏收敛 ============ */
@media (max-width: 520px) {
  .page-about .about-stamp {
    gap: 8px 18px;
  }

  .page-about .flow-step {
    grid-template-columns: 32px minmax(0, 1fr);
    gap: 12px;
  }

  .page-about .version {
    flex-basis: 86vw;
  }
}

/* ============ 动效降级 ============ */
@media (prefers-reduced-motion: reduce) {
  .page-about .line,
  .page-about .line__rate,
  .page-about .diff__link,
  .page-about .about-index__link {
    transition: none;
  }

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