.page-about {
  --about-body: 33rem;
  padding-bottom: clamp(3rem, 8vw, 6rem);
  background:
    radial-gradient(120% 55% at 82% 0%, rgba(200, 16, 46, 0.16), transparent 62%),
    radial-gradient(85% 45% at 0% 10%, rgba(46, 230, 214, 0.07), transparent 66%);
}

.page-about a {
  color: inherit;
}

/* ---------- 面包屑与首屏 ---------- */

.page-about .about-topbar {
  padding-top: clamp(1rem, 3vw, 1.75rem);
}

.page-about .about-hero {
  padding-top: clamp(1.5rem, 4vw, 3rem);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(1.75rem, 5vw, 3rem);
}

.page-about .about-hero__kicker {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-hero__kicker::before {
  content: "";
  width: 26px;
  height: 3px;
  background: var(--red);
  transform: skewX(-24deg);
}

.page-about .about-hero__title {
  margin: 0 0 1.15rem;
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 6vw, 3.6rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--ivory);
}

.page-about .about-hero__lede {
  max-width: 34rem;
  color: var(--mist);
}

.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  overflow: hidden;
}

.page-about .about-stats__cell {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 1rem 1.05rem;
  background: var(--ink-2);
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-size: clamp(1.55rem, 5vw, 2.05rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--cyan);
}

.page-about .about-stats__unit {
  margin-left: 0.12em;
  font-size: 0.55em;
}

.page-about .about-stats__label {
  font-size: 0.78rem;
  line-height: 1.5;
  letter-spacing: 0.03em;
  color: var(--mist);
}

/* ---------- 右侧章节索引 ---------- */

.page-about .about-index {
  display: none;
}

/* ---------- 章节骨架 ---------- */

.page-about .about-chapter {
  display: grid;
  gap: clamp(1rem, 2.5vw, 1.6rem);
  padding-block: clamp(2.5rem, 7vw, 4.75rem);
}

.page-about .about-chapter__head {
  display: grid;
  gap: 0.35rem;
  align-content: start;
}

.page-about .about-chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(3rem, 10vw, 5.4rem);
  font-weight: 700;
  line-height: 0.8;
  letter-spacing: -0.05em;
  color: var(--ivory);
  opacity: 0.13;
  user-select: none;
}

.page-about .about-chapter__label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .about-chapter__label::before {
  content: "";
  display: block;
  width: 58px;
  height: 3px;
  margin-bottom: 0.6rem;
  background: linear-gradient(90deg, var(--red), var(--red-deep));
  transform: skewX(-24deg);
}

.page-about .about-chapter__title {
  max-width: 20ch;
  margin: 0.3rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 4.2vw, 2.15rem);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--ivory);
}

.page-about .about-chapter__body {
  max-width: var(--about-body);
  font-size: 1rem;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .about-chapter__body p {
  margin: 0 0 0.9rem;
}

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

/* ---------- 时间轴 ---------- */

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(0.9rem, 3vw, 1.4rem);
}

.page-about .about-node {
  position: relative;
  padding-left: 2.5rem;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 1.5rem;
  bottom: calc(-1 * clamp(0.9rem, 3vw, 1.4rem) - 2px);
  width: 2px;
  background: linear-gradient(180deg, var(--red) 0%, var(--line) 100%);
}

.page-about .about-node:last-child::before {
  display: none;
}

.page-about .about-node::after {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.4rem;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: radial-gradient(circle at 34% 34%, var(--red) 0 46%, var(--ink-2) 48% 100%);
  border: 2px solid var(--red-deep);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-node:hover::after,
.page-about .about-node:focus-within::after {
  transform: scale(1.18);
  box-shadow: 0 0 0 5px rgba(46, 230, 214, 0.16);
}

.page-about .about-node__year {
  display: block;
  margin-bottom: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .about-node__card {
  padding: 1rem 1.15rem;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-node:hover .about-node__card,
.page-about .about-node:focus-within .about-node__card {
  border-color: var(--cyan);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.page-about .about-node__title {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ivory);
}

.page-about .about-node__card p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-node__meta {
  display: block;
  margin-top: 0.6rem;
  padding-top: 0.55rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

/* ---------- 图片框 ---------- */

.page-about .about-frame {
  margin-block: clamp(0.5rem, 2vw, 1.25rem);
}

.page-about .about-frame__media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--r-lg);
  border: 1px solid var(--line);
}

.page-about .about-frame__cap {
  margin-top: 0.7rem;
  font-size: 0.78rem;
  line-height: 1.75;
  letter-spacing: 0.02em;
  color: var(--mist);
}

/* ---------- 三步流程 ---------- */

.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.1rem;
}

.page-about .about-step {
  position: relative;
  padding: 1.15rem 1.2rem 1.25rem;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

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

.page-about .about-step__num {
  display: inline-block;
  margin-bottom: 0.7rem;
  padding: 0.16rem 0.6rem;
  border-radius: var(--r-pill);
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
}

.page-about .about-step__title {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ivory);
}

.page-about .about-step p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-step .about-step__role {
  margin-top: 0.8rem;
  padding-top: 0.65rem;
  border-top: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--amber);
}

/* ---------- 每周节奏 ---------- */

.page-about .about-week {
  list-style: none;
  margin: 0;
  padding: 0.4rem;
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 0.3rem;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
}

.page-about .about-week__day {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 0.15rem;
  border-radius: var(--r-sm);
  font-size: 0.76rem;
  letter-spacing: 0.02em;
  color: var(--mist);
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-week__day--on {
  background: var(--red);
  color: var(--ivory);
  font-weight: 700;
}

.page-about .about-week__note {
  margin: 0;
  max-width: var(--about-body);
  font-size: 0.82rem;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 团队分工 ---------- */

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-role {
  display: grid;
  grid-template-columns: 4.4rem minmax(0, 1fr);
  gap: 1rem;
  align-items: start;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-role__num {
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 6vw, 2.7rem);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.05em;
  color: var(--ivory);
  transition: color var(--dur) var(--ease);
}

.page-about .about-role:hover .about-role__num {
  color: var(--cyan);
}

.page-about .about-role__title {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ivory);
}

.page-about .about-role__text p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-roles__total {
  margin: 0.9rem 0 0;
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .about-roles__totalnum {
  margin-inline: 0.2rem;
  font-family: var(--font-mono);
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--amber);
}

/* ---------- 合作生态 ---------- */

.page-about .about-partners {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  overflow: hidden;
}

.page-about .about-partner {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1.2rem 1.1rem;
  background: var(--ink-2);
}

.page-about .about-partner__num {
  font-family: var(--font-mono);
  font-size: clamp(2.1rem, 7vw, 3rem);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.05em;
  color: var(--cyan);
}

.page-about .about-partner__label {
  font-size: 0.82rem;
  line-height: 1.65;
  color: var(--mist);
}

.page-about .about-award {
  padding: 0.35rem 0 0.35rem 1rem;
  border-left: 3px solid var(--amber);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
  background: linear-gradient(90deg, rgba(255, 176, 32, 0.09), transparent 72%);
}

.page-about .about-award__tag {
  display: inline-block;
  margin-bottom: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-award p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--ivory);
}

/* ---------- 选择理由与下一步 ---------- */

.page-about .about-reasons {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.page-about .about-reason {
  padding: 1.1rem 1.2rem;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

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

.page-about .about-reason__idx {
  display: block;
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--red);
}

.page-about .about-reason h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ivory);
}

.page-about .about-reason p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-next {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.page-about .about-next__hint {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-next__hint a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-next__hint a:hover,
.page-about .about-next__hint a:focus-visible {
  border-bottom-color: var(--cyan);
}

/* ---------- 响应式 ---------- */

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

@media (min-width: 820px) {
  .page-about .about-flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 2.4rem;
  }

  .page-about .about-step::after {
    content: "";
    position: absolute;
    right: -1.55rem;
    top: 2.1rem;
    width: 0.7rem;
    height: 0.7rem;
    border-top: 3px solid var(--red);
    border-right: 3px solid var(--red);
    transform: rotate(45deg) skew(-12deg, -12deg);
  }

  .page-about .about-step:last-child::after {
    display: none;
  }
}

@media (min-width: 900px) {
  .page-about .about-chapter {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: clamp(1rem, 2.5vw, 2rem);
  }

  .page-about .about-chapter > * {
    grid-column: 1 / span 7;
  }

  .page-about .about-chapter--shift > * {
    grid-column: 6 / span 7;
  }

  .page-about .about-hero__grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    align-items: end;
    gap: clamp(1.5rem, 3vw, 2.5rem);
  }

  .page-about .about-hero__lead {
    grid-column: 1 / span 7;
  }

  .page-about .about-hero__aside {
    grid-column: 9 / span 4;
  }

  .page-about .about-chapter__num {
    opacity: 0.16;
  }
}

@media (min-width: 1500px) {
  .page-about .about-index {
    display: grid;
    position: fixed;
    right: 1.6rem;
    top: 50%;
    transform: translateY(-50%);
    gap: 0.5rem;
    z-index: 5;
  }

  .page-about .about-index a {
    display: grid;
    place-items: center;
    width: 38px;
    height: 38px;
    border-radius: 50%;
    border: 1px solid var(--line);
    background: var(--ink-2);
    font-family: var(--font-mono);
    font-size: 0.68rem;
    letter-spacing: 0.06em;
    color: var(--mist);
    text-decoration: none;
    transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), transform var(--dur) var(--ease);
  }

  .page-about .about-index a:hover,
  .page-about .about-index a:focus-visible {
    border-color: var(--cyan);
    color: var(--cyan);
    transform: translateX(-3px);
  }
}