.page-about {
  --about-card: rgba(16, 42, 66, 0.55);
  --about-text: rgba(238, 246, 251, 0.84);
  --about-text-soft: rgba(238, 246, 251, 0.76);
  --about-grid-line: rgba(159, 182, 201, 0.1);
  background:
    linear-gradient(180deg, #0a1a2b 0%, #06101f 26%, #06101f 100%);
  color: var(--white);
  font-family: var(--font-body);
  padding-bottom: clamp(40px, 8vw, 88px);
}

.page-about a:focus-visible,
.page-about button:focus-visible,
.page-about [tabindex="0"]:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .about-crumbs {
  padding-top: clamp(16px, 3vw, 28px);
}

.page-about .about-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

.page-about .about-crumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(159, 182, 201, 0.45);
}

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

.page-about .about-crumbs a:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .breadcrumb__current {
  color: var(--amber);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(18px, 3vw, 30px) 0 clamp(32px, 5vw, 56px);
}

.page-about .about-hero__grid {
  position: relative;
  display: grid;
  gap: clamp(22px, 4vw, 40px);
  padding: clamp(20px, 4vw, 44px);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-m);
  background:
    linear-gradient(158deg, rgba(57, 242, 208, 0.08), rgba(57, 242, 208, 0) 48%),
    linear-gradient(180deg, rgba(16, 42, 66, 0.72), rgba(6, 16, 31, 0.6));
  overflow: hidden;
}

.page-about .about-hero__grid::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--about-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-grid-line) 1px, transparent 1px);
  background-size: 56px 56px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 78%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 78%);
}

.page-about .about-hero__lead,
.page-about .about-summary {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(30px, 7vw, 58px);
  line-height: 1.08;
  letter-spacing: 0.01em;
  color: var(--white);
}

.page-about .about-hero__intro {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--about-text);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-summary {
  align-self: start;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--amber);
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
  background: rgba(6, 16, 31, 0.6);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
}

.page-about .about-summary__title {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-summary__list {
  margin: 0;
}

.page-about .about-summary__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px dashed rgba(159, 182, 201, 0.18);
}

.page-about .about-summary__row:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-summary__row dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .about-summary__row dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 600;
  color: var(--amber);
}

/* ---------- 长卷布局 ---------- */

.page-about .about-layout {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  padding: clamp(4px, 2vw, 12px) 0 0;
}

.page-about .about-index {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  -webkit-overflow-scrolling: touch;
}

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

.page-about .about-index a {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  color: var(--mist);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-index a:hover {
  color: var(--cyan);
  border-color: var(--teal);
  background: rgba(15, 175, 154, 0.1);
}

.page-about .about-index__num {
  color: var(--amber);
  font-size: 11px;
}

.page-about .about-body {
  min-width: 0;
}

/* ---------- 章节 ---------- */

.page-about .about-sec {
  scroll-margin-top: 110px;
}

.page-about .about-sec + .about-sec {
  margin-top: clamp(36px, 6vw, 68px);
  padding-top: clamp(28px, 5vw, 52px);
  border-top: 1px solid var(--line);
}

.page-about .about-sec__head {
  margin-bottom: clamp(16px, 3vw, 26px);
}

.page-about .about-sec__num {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--amber);
}

.page-about .about-sec__num::after {
  content: "";
  flex: 0 1 56px;
  height: 1px;
  background: linear-gradient(90deg, var(--amber), transparent);
}

.page-about .about-sec h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(23px, 4.4vw, 36px);
  line-height: 1.18;
  letter-spacing: 0.01em;
  color: var(--white);
}

.page-about .about-sec__note {
  margin: 12px 0 0;
  max-width: 58ch;
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-p {
  margin: 0 0 16px;
  max-width: 70ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--about-text);
}

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

.page-about .about-p--note {
  margin-top: 18px;
  padding-left: 14px;
  border-left: 2px solid var(--teal);
  font-size: 14.5px;
  color: var(--about-text-soft);
}

/* ---------- 图片 ---------- */

.page-about .about-plate {
  margin: clamp(22px, 4vw, 34px) 0 0;
}

.page-about .about-plate--tight {
  margin-top: clamp(16px, 3vw, 24px);
  margin-bottom: clamp(20px, 3.5vw, 30px);
}

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

.page-about .about-plate figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 四条主线 ---------- */

.page-about .about-lines {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-line {
  padding: 18px 18px 18px 20px;
  border-left: 2px solid var(--line-strong);
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
  background: linear-gradient(180deg, var(--about-card), rgba(16, 42, 66, 0.24));
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-line:hover {
  border-left-color: var(--cyan);
  background: linear-gradient(180deg, rgba(16, 42, 66, 0.78), rgba(16, 42, 66, 0.4));
}

.page-about .about-line__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .about-line h3 {
  margin: 7px 0 8px;
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 700;
  line-height: 1.25;
  color: var(--white);
}

.page-about .about-line p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-text-soft);
}

/* ---------- 时间线 ---------- */

.page-about .about-tl {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(57, 242, 208, 0.12));
}

.page-about .about-tl__item {
  position: relative;
  padding: 0 0 22px 30px;
}

.page-about .about-tl__item:last-child {
  padding-bottom: 0;
}

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--cyan);
  box-shadow: 0 0 0 3px rgba(57, 242, 208, 0.12);
  transition: background-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-tl__item:hover::before {
  background: var(--cyan);
  box-shadow: 0 0 0 5px rgba(57, 242, 208, 0.16);
}

.page-about .about-tl__year {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-tl h3 {
  margin: 5px 0 6px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--white);
}

.page-about .about-tl p {
  margin: 0;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-text-soft);
}

/* ---------- 数字提示 ---------- */

.page-about .about-num {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--amber);
  border-bottom: 1px dashed rgba(255, 178, 74, 0.5);
  cursor: help;
}

.page-about .about-num__tip {
  position: absolute;
  left: 0;
  bottom: calc(100% + 8px);
  z-index: 3;
  width: max-content;
  max-width: min(230px, 68vw);
  padding: 8px 10px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-s);
  background: var(--panel);
  color: var(--white);
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease), visibility var(--dur) var(--ease);
}

.page-about .about-num:hover .about-num__tip,
.page-about .about-num:focus-visible .about-num__tip {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ---------- 协作小组 ---------- */

.page-about .about-groups {
  display: grid;
  gap: 16px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-group {
  padding-top: 14px;
  border-top: 2px solid var(--teal);
}

.page-about .about-group__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-group__name {
  margin: 7px 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-group p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--about-text-soft);
}

/* ---------- 站点信息 ---------- */

.page-about .about-info {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-info__row {
  display: grid;
  gap: 5px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-info__key {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-info__val {
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--white);
  overflow-wrap: anywhere;
}

.page-about .about-copy {
  display: inline-block;
  margin-left: 10px;
  padding: 5px 11px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  background: rgba(16, 42, 66, 0.6);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-copy:hover {
  color: var(--ink);
  background: var(--cyan);
  border-color: var(--cyan);
}

/* ---------- 继续查看 ---------- */

.page-about .about-next {
  display: grid;
  gap: 2px;
  margin-top: clamp(26px, 4vw, 40px);
  padding: clamp(16px, 3vw, 26px);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-m);
  background: linear-gradient(120deg, rgba(16, 42, 66, 0.78), rgba(10, 26, 43, 0.55));
}

.page-about .about-next__link {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 18px;
  padding: 13px 0;
  border-bottom: 1px dashed rgba(159, 182, 201, 0.2);
  color: var(--white);
  font-size: 14.5px;
  line-height: 1.6;
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.page-about .about-next__link:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-next__link .mono {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  transition: color var(--dur) var(--ease);
}

.page-about .about-next__link:hover {
  color: var(--amber);
}

.page-about .about-next__link:hover .mono {
  color: var(--amber);
}

/* ---------- 断点 ---------- */

@media (min-width: 640px) {
  .page-about .about-lines {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .about-groups {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .about-info__row {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(260px, 0.85fr);
    align-items: start;
  }

  .page-about .about-layout {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .about-index {
    display: block;
    position: sticky;
    top: 100px;
    align-self: start;
    overflow: visible;
    padding: 0 0 0 14px;
    border-left: 1px solid var(--line);
  }

  .page-about .about-index__label {
    display: block;
    margin: 0 0 14px;
    font-family: var(--font-mono);
    font-size: 10.5px;
    letter-spacing: 0.2em;
    color: var(--mist);
  }

  .page-about .about-index a {
    display: flex;
    gap: 9px;
    padding: 9px 0;
    border: 0;
    border-radius: 0;
    background: none;
    font-size: 12.5px;
  }

  .page-about .about-index a:hover {
    background: none;
  }

  .page-about .about-line {
    padding: 22px 22px 22px 24px;
  }

  .page-about .about-tl__item {
    padding-left: 34px;
    padding-bottom: 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 1ms !important;
  }
}