/* ===== 品牌一览 · 页面专属样式（作用域 .page-about） ===== */
.page-about {
  --about-line: var(--edge);
  --about-soft: rgba(20, 28, 63, .62);
  background: var(--deep);
  color: var(--text);
  font-family: var(--font-body);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(2.6rem, 7vw, 4.2rem) 0 clamp(2.2rem, 5vw, 3.4rem);
  background:
    radial-gradient(110% 85% at 88% -12%, rgba(95, 227, 222, .18), transparent 60%),
    radial-gradient(90% 70% at 0% 112%, rgba(59, 42, 90, .55), transparent 62%),
    linear-gradient(180deg, var(--deep) 0%, var(--chapter) 100%);
  border-bottom: 1px solid var(--edge);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(140, 154, 192, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(140, 154, 192, .07) 1px, transparent 1px);
  background-size: 68px 68px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, .85), transparent 76%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, .85), transparent 76%);
  pointer-events: none;
}

.page-about .about-hero .page-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumbs a {
  color: var(--mist);
  text-decoration: none;
}

.page-about .about-hero .eyebrow {
  margin: 1.1rem 0 0;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-hero h1 {
  margin: .45rem 0 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(2.1rem, 6.4vw, 3.4rem);
  line-height: 1.06;
  letter-spacing: -.01em;
  color: var(--text);
}

.page-about .about-hero .lede {
  max-width: 48ch;
  margin: 1rem 0 0;
  font-size: clamp(1rem, 2.2vw, 1.1rem);
  line-height: 1.9;
  color: var(--text-soft);
}

.page-about .about-stats {
  list-style: none;
  margin: clamp(1.6rem, 4vw, 2.4rem) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--edge);
  border: 1px solid var(--edge);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stats li {
  padding: 1rem 1.05rem;
  background: rgba(20, 28, 63, .78);
}

.page-about .about-stats b {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.12rem;
  font-weight: 500;
  letter-spacing: .02em;
  color: var(--cyan);
}

.page-about .about-stats span {
  display: block;
  margin-top: .32rem;
  font-size: .8rem;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 双栏骨架 ---------- */
.page-about .about-body {
  padding: clamp(1.8rem, 4.5vw, 3.2rem) 0 clamp(3rem, 8vw, 5.5rem);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.6rem, 4vw, 3rem);
}

/* ---------- 左侧索引 ---------- */
.page-about .about-aside {
  padding: .95rem;
  border: 1px solid var(--edge);
  border-radius: var(--radius);
  background: rgba(20, 28, 63, .5);
}

.page-about .about-aside .toc__title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-aside .toc__list {
  list-style: none;
  margin: .6rem 0 0;
  padding: 0 0 .2rem;
  display: flex;
  gap: .35rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-aside .toc__link {
  display: block;
  white-space: nowrap;
  padding: .45rem .7rem;
  border-bottom: 2px solid transparent;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  color: var(--mist);
  font-size: .9rem;
  text-decoration: none;
  transition: color .2s var(--ease), background .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-aside .toc__link:hover {
  color: var(--text);
  background: rgba(20, 28, 63, .8);
}

.page-about .about-aside .toc__link[aria-current] {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
  background: rgba(95, 227, 222, .08);
}

.page-about .about-anchors {
  margin-top: 1.1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--edge);
}

.page-about .about-anchors__title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-anchors__list {
  list-style: none;
  margin: .6rem 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
}

.page-about .about-anchors__list a {
  display: inline-block;
  padding: .32rem .62rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .08em;
  color: var(--amber);
  text-decoration: none;
  border: 1px solid rgba(255, 196, 107, .35);
  border-radius: 999px;
  transition: background .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-anchors__list a:hover {
  background: rgba(255, 196, 107, .12);
  border-color: var(--amber);
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  --band: var(--cyan);
  --band-soft: rgba(95, 227, 222, .09);
  position: relative;
  padding: clamp(1.8rem, 4.5vw, 2.9rem) 1rem clamp(1.8rem, 4.5vw, 2.9rem) 1.25rem;
  border-top: 1px solid var(--edge);
  background-image: linear-gradient(180deg, var(--band-soft), transparent 62%);
  scroll-margin-top: calc(var(--header-h) + 1.2rem);
}

.page-about .about-section::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 100%;
  background: linear-gradient(180deg, var(--band), transparent 86%);
}

.page-about .about-section--teal {
  --band: var(--cyan);
  --band-soft: rgba(31, 78, 74, .55);
}

.page-about .about-section--violet {
  --band: var(--amber);
  --band-soft: rgba(59, 42, 90, .50);
}

.page-about .about-head {
  display: grid;
  gap: .5rem;
  margin-bottom: 1.05rem;
}

.page-about .about-head__top {
  display: flex;
  align-items: center;
  gap: .75rem;
  margin: 0;
}

.page-about .about-section .index-num {
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .16em;
  color: var(--band);
}

.page-about .about-head h2 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(1.4rem, 3.6vw, 1.95rem);
  line-height: 1.28;
  letter-spacing: -.01em;
  color: var(--text);
}

.page-about .about-section > p {
  margin: 0;
  font-size: 1rem;
  line-height: 1.9;
  color: var(--text-soft);
}

/* ---------- 01 场景卡 ---------- */
.page-about .about-cases {
  display: grid;
  grid-template-columns: 1fr;
  gap: .85rem;
  margin-top: 1.3rem;
}

.page-about .about-case {
  padding: 1.05rem 1.1rem;
  border: 1px solid var(--edge);
  border-radius: var(--radius-sm);
  background: linear-gradient(155deg, rgba(20, 28, 63, .92), rgba(11, 16, 38, .88));
}

.page-about .about-case h3 {
  margin: 0 0 .45rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--cyan);
}

.page-about .about-case p {
  margin: 0;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--text-soft);
}

/* ---------- 02 角色卡 ---------- */
.page-about .about-roles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-top: 1.35rem;
}

.page-about .about-role {
  position: relative;
  padding: 1.2rem 1.1rem 1.25rem;
  border: 1px solid var(--edge);
  border-radius: var(--radius);
  background: linear-gradient(160deg, rgba(20, 28, 63, .95), rgba(11, 16, 38, .92));
  overflow: hidden;
  outline: none;
  transition: border-color .25s var(--ease), transform .25s var(--ease);
}

.page-about .about-role:hover,
.page-about .about-role:focus-visible {
  border-color: rgba(95, 227, 222, .55);
  transform: translateY(-2px);
}

.page-about .about-role::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(115deg, transparent 32%, rgba(95, 227, 222, .14) 50%, transparent 68%);
  transform: translateX(-125%);
  transition: transform .75s var(--ease);
  pointer-events: none;
}

.page-about .about-role:hover::after,
.page-about .about-role:focus-visible::after {
  transform: translateX(125%);
}

.page-about .about-role__code {
  display: block;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .16em;
  color: var(--amber);
}

.page-about .about-role h3 {
  margin: .5rem 0 .5rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.14rem;
  color: var(--text);
}

.page-about .about-role > p {
  margin: 0;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--text-soft);
}

.page-about .about-role__duties {
  list-style: none;
  margin: .9rem 0 0;
  padding: 0;
  display: grid;
  gap: .45rem;
}

.page-about .about-role__duties li {
  position: relative;
  padding-left: .95rem;
  font-size: .86rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-role__duties li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--cyan);
}

.page-about .about-note {
  margin-top: 1.15rem;
}

.page-about .about-note p {
  margin: 0;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--text-soft);
}

/* ---------- 03 大区 ---------- */
.page-about .about-regions {
  display: grid;
  grid-template-columns: 1fr;
  gap: .55rem;
  margin-top: 1.25rem;
}

.page-about .about-region {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .7rem;
  padding: .68rem .85rem;
  border: 1px solid var(--edge);
  border-left: 2px solid rgba(95, 227, 222, .45);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: rgba(20, 28, 63, .58);
}

.page-about .about-region__key {
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .1em;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .about-region__val {
  font-size: .9rem;
  line-height: 1.7;
  color: var(--text-soft);
}

.page-about .about-regions__foot {
  margin: 1.1rem 0 0;
  font-size: .94rem;
  line-height: 1.85;
  color: var(--text-soft);
}

/* ---------- 04 版本 ---------- */
.page-about .about-timeline {
  display: grid;
  grid-template-columns: 1fr;
  gap: .9rem;
  margin-top: 1.35rem;
}

.page-about .about-tl {
  padding: 1.05rem 1.05rem 1.15rem;
  border-left: 2px solid var(--violet);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: linear-gradient(180deg, rgba(59, 42, 90, .40), rgba(20, 28, 63, .55));
  scroll-margin-top: calc(var(--header-h) + 1.5rem);
}

.page-about .about-tl__code {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .12em;
  color: var(--cyan);
}

.page-about .about-tl h3 {
  margin: .45rem 0 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.04rem;
  color: var(--text);
}

.page-about .about-tl ul {
  list-style: none;
  margin: .75rem 0 0;
  padding: 0;
  display: grid;
  gap: .5rem;
}

.page-about .about-tl li {
  position: relative;
  padding-left: 1rem;
  font-size: .9rem;
  line-height: 1.75;
  color: var(--text-soft);
}

.page-about .about-tl li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 6px;
  height: 1px;
  background: var(--amber);
}

/* ---------- 05 复核步骤 ---------- */
.page-about .about-steps {
  list-style: none;
  counter-reset: step;
  margin: 1.3rem 0 0;
  padding: 0;
  display: grid;
  gap: .7rem;
}

.page-about .about-steps li {
  position: relative;
  padding: 1rem 1.05rem 1rem 3.1rem;
  border: 1px solid var(--edge);
  border-radius: var(--radius-sm);
  background: rgba(20, 28, 63, .55);
}

.page-about .about-steps li::before {
  counter-increment: step;
  content: "0" counter(step);
  position: absolute;
  left: 1rem;
  top: 1.05rem;
  font-family: var(--font-mono);
  font-size: .82rem;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-about .about-steps h3 {
  margin: 0 0 .35rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
}

.page-about .about-steps p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--text-soft);
}

/* ---------- FAQ ---------- */
.page-about .about-faq {
  margin-top: clamp(1.8rem, 4vw, 2.6rem);
  padding-top: 1.4rem;
  border-top: 1px solid var(--edge);
}

.page-about .about-faq__title {
  margin: 0 0 .9rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.06rem;
  color: var(--text);
}

.page-about .about-faq .faq__item {
  border-bottom: 1px solid var(--edge);
}

.page-about .about-faq summary {
  padding: .85rem 0;
  cursor: pointer;
  font-size: .96rem;
  font-weight: 500;
  color: var(--text);
  list-style: none;
}

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

.page-about .about-faq summary::after {
  content: "+";
  float: right;
  margin-left: 1rem;
  font-family: var(--font-mono);
  color: var(--cyan);
}

.page-about .about-faq details[open] summary::after {
  content: "—";
}

.page-about .about-faq .faq__body p {
  margin: 0 0 .95rem;
  font-size: .9rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 结尾入口 ---------- */
.page-about .about-next-wrap {
  margin-top: clamp(2rem, 5vw, 3rem);
  padding-top: 1.6rem;
  border-top: 1px solid var(--edge);
}

.page-about .about-next-wrap h2 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(1.25rem, 3vw, 1.6rem);
  color: var(--text);
}

.page-about .about-next {
  display: grid;
  grid-template-columns: 1fr;
  gap: .7rem;
  margin-top: 1.1rem;
}

.page-about .about-next a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--edge);
  border-radius: var(--radius-sm);
  background: rgba(20, 28, 63, .62);
  color: var(--text);
  text-decoration: none;
  transition: border-color .25s var(--ease), transform .25s var(--ease), background .25s var(--ease);
}

.page-about .about-next a:hover {
  border-color: var(--cyan);
  background: rgba(20, 28, 63, .92);
  transform: translateY(-2px);
}

.page-about .about-next strong {
  font-size: .96rem;
  font-weight: 600;
}

.page-about .about-next span {
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .06em;
  color: var(--amber);
  white-space: nowrap;
}

/* ---------- 图片容器 ---------- */
.page-about .about-media {
  margin: 1.5rem 0 0;
}

.page-about .about-media .media__frame {
  overflow: hidden;
  border: 1px solid var(--edge);
  border-radius: var(--radius);
  background: linear-gradient(150deg, rgba(31, 78, 74, .45), rgba(11, 16, 38, .9));
}

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

.page-about .about-media .media__caption {
  margin-top: .6rem;
  font-size: .82rem;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 中屏 ---------- */
@media (min-width: 640px) {
  .page-about .about-cases {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-regions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-next {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 桌面：左窄右宽 + 粘性索引 ---------- */
@media (min-width: 1000px) {
  .page-about .about-split {
    grid-template-columns: 268px minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 4rem);
    align-items: start;
  }

  .page-about .about-aside {
    padding: 1.1rem;
    background: rgba(20, 28, 63, .42);
  }

  .page-about .about-aside .sticky-aside {
    position: sticky;
    top: calc(var(--header-h) + 1.6rem);
  }

  .page-about .about-aside .toc__list {
    display: grid;
    gap: .12rem;
    overflow: visible;
  }

  .page-about .about-aside .toc__link {
    border-bottom: 0;
    border-left: 2px solid transparent;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  }

  .page-about .about-aside .toc__link[aria-current] {
    border-bottom-color: transparent;
    border-left-color: var(--cyan);
  }

  .page-about .about-section {
    padding: clamp(2.2rem, 4vw, 3.2rem) 1.6rem clamp(2.2rem, 4vw, 3.2rem) 1.9rem;
  }

  .page-about .about-cases {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
  }
}

/* ---------- 悬停展开职责（仅指针设备） ---------- */
@media (hover: hover) and (min-width: 960px) {
  .page-about .about-role__duties {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height .5s var(--ease), opacity .35s var(--ease), margin-top .5s var(--ease);
  }

  .page-about .about-role:hover .about-role__duties,
  .page-about .about-role:focus-within .about-role__duties,
  .page-about .about-role:focus-visible .about-role__duties {
    max-height: 18rem;
    margin-top: .9rem;
    opacity: 1;
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-role,
  .page-about .about-role::after,
  .page-about .about-next a,
  .page-about .about-aside .toc__link {
    transition: none;
  }

  .page-about .about-role:hover {
    transform: none;
  }
}
</main>