.page-about {
  --about-rail: 200px;
  --about-cut: 18px;
  --about-soft: rgba(232, 237, 245, .8);
  --about-panel: rgba(18, 32, 58, .72);
  --about-slot: rgba(10, 18, 32, .55);
}

.page-about .about-topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 20px;
  align-items: baseline;
  justify-content: space-between;
  padding: 20px 0 0;
}

.page-about .about-topbar__note {
  color: var(--steel);
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 32px 0 44px;
}

.page-about .about-hero__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 44px 44px;
  pointer-events: none;
}

.page-about .about-hero > * {
  position: relative;
}

.page-about .about-hero__kicker {
  color: var(--cyan);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 15ch;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.3rem, 8.4vw, 5rem);
  line-height: 1.04;
  letter-spacing: -.02em;
  color: var(--mist);
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  max-width: 66ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--about-soft);
}

.page-about .about-figures {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin: 32px 0 0;
  padding: 0;
}

.page-about .about-figures__item {
  margin: 0;
  padding: 14px 16px;
  background: var(--about-panel);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-cut)), calc(100% - var(--about-cut)) 100%, 0 100%);
  transition: border-color .16s var(--ease), transform .16s var(--ease);
}

.page-about .about-figures__item:hover {
  border-color: var(--orange);
  transform: translateY(-2px);
}

.page-about .about-figures__label {
  margin: 0;
  color: var(--steel);
}

.page-about .about-figures__value {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.4rem, 3.6vw, 2rem);
  color: var(--mist);
}

.page-about .about-figures__unit {
  margin-left: 6px;
  font-size: .5em;
  font-weight: 600;
  color: var(--steel);
}

/* 主体骨架：左旁注栏 + 主栏 */
.page-about .about-shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  padding-bottom: 52px;
}

.page-about .about-rail {
  padding: 18px 16px;
  background: var(--about-panel);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-cut)), calc(100% - var(--about-cut)) 100%, 0 100%);
}

.page-about .about-rail__title {
  margin: 0;
  color: var(--steel);
}

.page-about .about-rail__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 14px 0 0;
  padding: 0 0 0 16px;
  list-style: none;
}

.page-about .about-rail__list::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 5px;
  background-image: repeating-linear-gradient(45deg, var(--line-strong) 0 2px, transparent 2px 7px);
}

.page-about .about-rail__node {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 7px 0;
  font-size: 13.5px;
  color: var(--steel);
  text-decoration: none;
  transition: color .16s var(--ease);
}

.page-about .about-rail__node:hover,
.page-about .about-rail__node:focus-visible {
  color: var(--mist);
}

.page-about .about-rail__code {
  font-size: 12px;
  color: var(--orange);
}

.page-about .about-rail__hint {
  margin: 14px 0 0;
  font-size: 12px;
  line-height: 1.6;
  color: var(--steel);
}

.page-about .about-flow {
  display: flex;
  flex-direction: column;
  gap: 30px;
  min-width: 0;
}

.page-about .about-block {
  padding: 24px 20px;
  background: var(--about-panel);
  border: 1px solid var(--line);
  scroll-margin-top: 96px;
}

.page-about .about-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  margin-bottom: 18px;
}

.page-about .about-head .panel__index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--orange);
}

.page-about .about-head h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.35rem, 3.4vw, 2rem);
  line-height: 1.15;
  letter-spacing: -.01em;
  color: var(--mist);
}

.page-about .about-text {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 66ch;
}

.page-about .about-text p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--about-soft);
}

.page-about .about-text a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(33, 230, 193, .38);
}

.page-about .about-text a:hover {
  color: var(--orange);
  border-bottom-color: rgba(255, 106, 43, .5);
}

/* 字段清单 */
.page-about .about-fields {
  display: grid;
  gap: 8px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-fields .field {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 12px 14px;
  background: var(--about-slot);
  border-left: 2px solid var(--orange);
}

.page-about .about-fields .field__name {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--orange);
}

.page-about .about-fields .field__value {
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--mist);
}

/* 暖纸旁注 */
.page-about .marginalia {
  margin: 22px 0 0;
  padding: 14px 16px;
  background: var(--paper);
  color: #16202F;
  border: 1px solid rgba(10, 18, 32, .2);
}

.page-about .marginalia__title {
  cursor: pointer;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .08em;
  color: #0A1220;
  list-style: none;
}

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

.page-about .marginalia__title::after {
  content: " +";
  color: #C2400E;
}

.page-about .marginalia[open] .marginalia__title::after {
  content: " −";
}

.page-about .marginalia p {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.8;
}

/* 读者画像 */
.page-about .about-readers {
  display: grid;
  gap: 24px;
}

.page-about .about-readers__side {
  display: grid;
  gap: 12px;
}

.page-about .about-readers__stat {
  padding: 14px 16px;
  background: var(--about-slot);
  border: 1px solid var(--line);
  border-top: 2px solid var(--cyan);
}

.page-about .about-readers__num {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.8rem, 4.6vw, 2.6rem);
  color: var(--cyan);
}

.page-about .about-readers__cap {
  margin: 6px 0 0;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--steel);
}

/* 图片基座 */
.page-about .about-media {
  margin: 0 0 24px;
}

.page-about .about-media--inset {
  margin: 24px 0 0;
}

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

/* 六道工序 */
.page-about .about-steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-step {
  padding: 14px 16px;
  background: var(--about-slot);
  border: 1px solid var(--line);
  outline-offset: 3px;
  transition: border-color .16s var(--ease), transform .16s var(--ease);
}

.page-about .about-step:is(:hover, :focus-visible) {
  border-color: var(--orange);
  transform: translateY(-2px);
}

.page-about .about-step__num {
  display: inline-block;
  padding: 2px 7px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--ink);
  background: var(--orange);
}

.page-about .about-step__name {
  display: block;
  margin: 10px 0 0;
  font-size: 15px;
  font-weight: 700;
  color: var(--mist);
}

.page-about .about-step__note {
  margin: 8px 0 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--steel);
}

/* 阶段 */
.page-about .about-stages {
  display: grid;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  padding: 16px;
  background: var(--about-slot);
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  transition: border-color .16s var(--ease);
}

.page-about .about-stage:hover {
  border-color: var(--line-strong);
  border-left-color: var(--orange);
}

.page-about .about-stage__ver {
  align-self: start;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  white-space: nowrap;
  color: var(--ink);
  background: var(--cyan);
}

.page-about .about-stage h3 {
  margin: 0;
  font-size: 15.5px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--mist);
}

.page-about .about-stage p {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--steel);
}

/* 边界 */
.page-about .about-boundary {
  display: grid;
  gap: 12px;
  max-width: 70ch;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-boundary li {
  position: relative;
  padding: 2px 0 2px 22px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-soft);
}

.page-about .about-boundary li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 9px;
  height: 9px;
  background: var(--orange);
  clip-path: polygon(0 0, 100% 50%, 0 100%);
}

.page-about .about-boundary a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(33, 230, 193, .38);
}

.page-about .about-boundary a:hover {
  color: var(--orange);
  border-bottom-color: rgba(255, 106, 43, .5);
}

/* 服务地区 */
.page-about .about-region {
  display: grid;
  gap: 22px;
}

.page-about .about-region__facts {
  margin: 18px 0 0;
  padding: 0;
}

.page-about .about-region__facts div {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-region__facts dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--steel);
}

.page-about .about-region__facts dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--mist);
}

/* 收束动作 */
.page-about .about-cta {
  position: relative;
  overflow: hidden;
  margin: 0 0 56px;
  padding: 24px 20px;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-cut)), calc(100% - var(--about-cut)) 100%, 0 100%);
}

.page-about .about-cta::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(45deg, rgba(124, 141, 166, .1) 0 2px, transparent 2px 10px);
  pointer-events: none;
}

.page-about .about-cta__inner {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
}

.page-about .about-cta__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  letter-spacing: -.01em;
  color: var(--mist);
}

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

/* 断点 */
@media (min-width: 640px) {
  .page-about .about-fields .field {
    grid-template-columns: 110px minmax(0, 1fr);
  }
}

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

@media (min-width: 860px) {
  .page-about .about-readers {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr);
    align-items: start;
  }

  .page-about .about-region {
    grid-template-columns: minmax(0, 1fr) minmax(0, .85fr);
    align-items: center;
  }

  .page-about .about-block {
    padding: 30px 28px;
  }
}

@media (min-width: 900px) {
  .page-about .about-figures__item:nth-child(even) {
    transform: translateY(12px);
  }

  .page-about .about-figures__item:nth-child(even):hover {
    transform: translateY(10px);
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
    align-self: start;
  }
}

@media (min-width: 1080px) {
  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-step__note {
    max-height: 0;
    margin-top: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height .24s var(--ease), opacity .2s var(--ease), margin-top .2s var(--ease);
  }

  .page-about .about-step:is(:hover, :focus-visible) .about-step__note {
    max-height: 8rem;
    margin-top: 8px;
    opacity: 1;
  }
}

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

  .page-about .about-step__note {
    transition: none;
  }
}