/* =========================================================
   page-about — 品牌介绍
   纵向时间轴 + 分工矩阵 + 流程四步 + 场景并排
   ========================================================= */

.page-about {
  --about-sec-pad: clamp(44px, 6.5vw, 88px);
  --about-sec-pad-tight: clamp(32px, 4.5vw, 60px);
  display: block;
  color: var(--cool-white);
}

.page-about .about-sec__inner {
  padding-block: var(--about-sec-pad);
}

.page-about .about-sec--tight .about-sec__inner {
  padding-block: var(--about-sec-pad-tight);
}

/* ---------- 正文链接 ---------- */
.page-about .about-open__body a,
.page-about .flow__body a,
.page-about .about-network__body a {
  color: var(--signal-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 224, 210, .45);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-open__body a:hover,
.page-about .flow__body a:hover,
.page-about .about-network__body a:hover {
  color: var(--signal-orange);
  border-bottom-color: currentColor;
}

/* ---------- 开篇 ---------- */
.page-about .about-open {
  padding-block: clamp(26px, 4.5vw, 56px) clamp(18px, 2.6vw, 30px);
}

.page-about .about-open__eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--signal-cyan);
}

.page-about .about-open__lead {
  display: grid;
  gap: 22px;
}

.page-about .about-open__title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(28px, 5.6vw, 54px);
  line-height: 1.1;
  letter-spacing: .012em;
  color: var(--cool-white);
  text-wrap: balance;
}

.page-about .about-open__body p {
  margin: 0 0 1.05em;
  max-width: 44ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--mist);
}

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

.page-about .about-open__body strong {
  color: var(--cool-white);
  font-weight: 600;
}

@media (min-width: 900px) {
  .page-about .about-open__lead {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
    column-gap: clamp(32px, 5vw, 80px);
    align-items: start;
  }
}

/* ---------- 关键数字条 ---------- */
.page-about .about-facts {
  margin: clamp(28px, 4vw, 46px) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  overflow: hidden;
}

@media (min-width: 780px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-facts > div {
  background: var(--charcoal);
  padding: 18px 16px 20px;
  display: grid;
  gap: 8px;
  align-content: start;
}

.page-about .about-facts dt {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mist);
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  line-height: 1;
  color: var(--cool-white);
  letter-spacing: .01em;
}

.page-about .about-facts dd span {
  margin-left: 4px;
  font-size: .5em;
  font-weight: 500;
  color: var(--mist);
  letter-spacing: .06em;
}

/* ---------- 内容索引 ---------- */
.page-about .about-index {
  margin-top: clamp(26px, 3.4vw, 40px);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

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

@media (min-width: 1060px) {
  .page-about .about-index__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-index__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 14px;
  padding: 15px 16px;
  background: var(--ink-navy);
  color: var(--cool-white);
  text-decoration: none;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  background: var(--charcoal);
  color: var(--signal-cyan);
}

.page-about .about-index__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--signal-cyan);
}

.page-about .about-index__label {
  font-size: 15px;
  letter-spacing: .01em;
}

.page-about .about-index__mark {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--mist);
  transition: color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-index__link:hover .about-index__mark {
  color: var(--signal-orange);
  transform: translateY(2px);
}

/* ---------- 首图 ---------- */
.page-about .about-hero {
  margin: clamp(26px, 3.6vw, 46px) 0 0;
}

.page-about .about-hero__frame {
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--charcoal);
}

.page-about .about-hero__frame img {
  display: block;
  width: 100%;
  height: clamp(170px, 32vw, 400px);
  object-fit: cover;
}

.page-about .about-hero__cap {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
  letter-spacing: .02em;
}

/* ---------- 章节标题 ---------- */
.page-about .about-head {
  display: grid;
  gap: 12px;
  max-width: 66ch;
  margin-bottom: clamp(26px, 3.8vw, 46px);
}

.page-about .about-head__kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--signal-cyan);
}

.page-about .about-head__title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(24px, 3.8vw, 40px);
  line-height: 1.14;
  letter-spacing: .02em;
  color: var(--cool-white);
  text-wrap: balance;
}

.page-about .about-head__note {
  margin: 0;
  font-size: 16px;
  line-height: 1.76;
  color: var(--mist);
}

/* ---------- 分段切换：通用面板 ---------- */
.page-about .about-panel[data-tab-panel] {
  display: block;
}

.js .page-about .about-panel[data-tab-panel]:not([data-active]) {
  display: none;
}

/* ---------- 时间轴标签 ---------- */
.page-about .tl-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0 22px;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: clamp(18px, 2.4vw, 28px);
}

.page-about .tl-tab {
  appearance: none;
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  padding: 12px 0 11px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .07em;
  color: var(--mist);
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .tl-tab:hover {
  color: var(--cool-white);
}

.page-about .tl-tab[aria-selected="true"] {
  color: var(--cool-white);
  border-bottom-color: var(--signal-cyan);
}

.page-about .tl-tab:focus-visible {
  outline: 2px solid var(--signal-cyan);
  outline-offset: 3px;
}

/* ---------- 时间轴列表 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-tl__row {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px 0 18px 22px;
  border-left: 1px solid var(--hairline);
}

.page-about .about-tl__row::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 25px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--signal-cyan);
}

.page-about .about-tl__row:last-child {
  padding-bottom: 6px;
}

.page-about .about-tl__mark {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--signal-cyan);
}

.page-about .about-tl__title {
  margin: 0 0 7px;
  font-family: var(--font-head);
  font-size: clamp(17px, 2vw, 20px);
  font-weight: 700;
  letter-spacing: .03em;
  color: var(--cool-white);
}

.page-about .about-tl__text {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.76;
  color: var(--mist);
}

@media (min-width: 760px) {
  .page-about .about-tl__row {
    grid-template-columns: 104px minmax(0, 1fr);
    column-gap: clamp(20px, 3vw, 40px);
    padding: 22px 0 22px 28px;
    align-items: start;
  }

  .page-about .about-tl__row::before {
    top: 30px;
  }

  .page-about .about-tl__mark {
    padding-top: 4px;
  }
}

/* ---------- 团队标签 ---------- */
.page-about .team-tabs {
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: clamp(22px, 3vw, 32px);
}

@media (min-width: 720px) {
  .page-about .team-tabs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .team-tab {
  position: relative;
  appearance: none;
  border: 0;
  background: var(--charcoal);
  text-align: left;
  padding: 18px 18px 20px;
  display: grid;
  gap: 6px;
  align-content: start;
  font-family: inherit;
  color: var(--mist);
  cursor: pointer;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .team-tab::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: transparent;
  transition: background var(--dur) var(--ease);
}

.page-about .team-tab:hover {
  background: #161d26;
}

.page-about .team-tab[aria-selected="true"] {
  background: var(--ink-navy);
}

.page-about .team-tab[aria-selected="true"]::after {
  background: var(--signal-cyan);
}

.page-about .team-tab:focus-visible {
  outline: 2px solid var(--signal-cyan);
  outline-offset: -2px;
}

.page-about .team-tab__num {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--cool-white);
  letter-spacing: .02em;
}

.page-about .team-tab[aria-selected="true"] .team-tab__num {
  color: var(--signal-cyan);
}

.page-about .team-tab__role {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .03em;
  color: var(--cool-white);
}

.page-about .team-tab__hint {
  font-size: 13px;
  color: var(--mist);
}

/* ---------- 团队面板 ---------- */
.page-about .team-panel {
  display: grid;
  gap: 18px;
  border-left: 2px solid var(--deep-teal);
  padding-left: 20px;
}

@media (min-width: 860px) {
  .page-about .team-panel {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    column-gap: clamp(24px, 4vw, 56px);
    align-items: start;
    padding-left: 28px;
  }
}

.page-about .team-panel__text {
  margin: 0;
  max-width: 52ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .team-panel__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 11px;
}

.page-about .team-panel__list li {
  position: relative;
  padding-left: 20px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--cool-white);
}

.page-about .team-panel__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .66em;
  width: 9px;
  height: 1px;
  background: var(--signal-cyan);
}

/* ---------- 流程 ---------- */
.page-about .flow-wrap {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
}

@media (min-width: 960px) {
  .page-about .flow-wrap {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 1fr);
    column-gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }
}

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

.page-about .flow__step {
  display: grid;
  grid-template-columns: 36px minmax(0, 1fr);
  column-gap: 14px;
  padding: 20px 0;
  border-top: 1px solid var(--hairline);
}

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

.page-about .flow__idx {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--signal-orange);
  padding-top: 5px;
}

.page-about .flow__title {
  margin: 0 0 9px;
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--cool-white);
}

.page-about .flow__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.76;
  color: var(--mist);
}

.page-about .flow__detail {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--amber-note);
}

@media (hover: hover) and (min-width: 960px) {
  .page-about .flow__detail {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height .3s var(--ease), opacity .22s var(--ease), margin-top .3s var(--ease);
  }

  .page-about .flow__step:hover .flow__detail,
  .page-about .flow__step:focus-within .flow__detail {
    max-height: 220px;
    margin-top: 10px;
    opacity: 1;
  }
}

.page-about .flow__media {
  margin: 0;
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--charcoal);
}

.page-about .flow__media img {
  display: block;
  width: 100%;
  height: auto;
}

@media (min-width: 960px) {
  .page-about .flow__media {
    position: sticky;
    top: calc(var(--header-h) + 18px);
  }
}

/* ---------- 公告协作网络 ---------- */
.page-about .about-network {
  position: relative;
  overflow: hidden;
}

.page-about .about-network__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .2;
  pointer-events: none;
}

.page-about .about-network::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(6, 13, 26, .74) 0%, rgba(58, 16, 36, .82) 100%);
  pointer-events: none;
}

.page-about .about-network > .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-network__body {
  display: grid;
  gap: 16px;
  max-width: 72ch;
}

.page-about .about-network__body p {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--cool-white);
}

.page-about .about-network__body p:first-child {
  font-size: clamp(17px, 2vw, 19px);
  color: var(--cool-white);
}

@media (min-width: 900px) {
  .page-about .about-network__body {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px clamp(24px, 4vw, 56px);
    max-width: none;
  }

  .page-about .about-network__body p:first-child {
    grid-column: 1 / -1;
    max-width: 62ch;
  }
}

/* ---------- 版本迭代 ---------- */
.page-about .versions {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  overflow: hidden;
}

@media (min-width: 720px) {
  .page-about .versions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1060px) {
  .page-about .versions {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .versions__item {
  position: relative;
  background: var(--ink-navy);
  padding: 24px 20px 28px;
  display: grid;
  gap: 10px;
  align-content: start;
}

.page-about .versions__item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--signal-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .32s var(--ease);
}

.page-about .versions__item:hover::before {
  transform: scaleX(1);
}

.page-about .versions__ver {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--signal-orange);
}

.page-about .versions__name {
  margin: 0;
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--cool-white);
}

.page-about .versions__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--mist);
}

/* ---------- 使用场景 ---------- */
.page-about .scenes {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

@media (min-width: 860px) {
  .page-about .scenes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .scenes__item {
  background: var(--ink-navy);
  padding: clamp(22px, 3vw, 34px) clamp(18px, 2.4vw, 28px);
  display: grid;
  gap: 13px;
  align-content: start;
}

.page-about .scenes__who {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--signal-cyan);
}

.page-about .scenes__title {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(18px, 2.1vw, 22px);
  font-weight: 700;
  line-height: 1.32;
  letter-spacing: .02em;
  color: var(--cool-white);
}

.page-about .scenes__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.76;
  color: var(--mist);
}

.page-about .scenes__link {
  justify-self: start;
  margin-top: 4px;
  font-size: 14px;
  letter-spacing: .02em;
  color: var(--signal-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 224, 210, .45);
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .scenes__link:hover,
.page-about .scenes__link:focus-visible {
  color: var(--signal-orange);
  border-bottom-color: currentColor;
}

/* ---------- 窄屏兜底 ---------- */
@media (max-width: 480px) {
  .page-about .about-facts {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .about-index__link {
    gap: 10px;
    padding: 14px 14px;
  }

  .page-about .flow__step {
    grid-template-columns: 28px minmax(0, 1fr);
    column-gap: 12px;
  }
}
</main>