/* ===== 品牌介绍页专属样式 ===== */
.page-about {
  background-color: var(--color-bg);
  background-image:
    linear-gradient(rgba(31, 58, 82, 0.1) 1px, transparent 1px),
    linear-gradient(90deg, rgba(31, 58, 82, 0.1) 1px, transparent 1px);
  background-size: 2.5rem 2.5rem;
  overflow-x: hidden;
}

/* ---------- HERO ---------- */
.page-about .about-hero {
  position: relative;
  padding: 1.25rem 0 2.75rem;
  border-bottom: 1px solid var(--color-line);
  background:
    radial-gradient(ellipse at 82% 18%, rgba(57, 255, 136, 0.09) 0%, transparent 52%),
    linear-gradient(145deg, rgba(26, 58, 82, 0.62) 0%, rgba(11, 27, 43, 0.18) 58%, rgba(6, 15, 26, 0.85) 100%);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "V4";
  position: absolute;
  top: 1.25rem;
  right: -1.5rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(7rem, 24vw, 20rem);
  line-height: 0.8;
  color: transparent;
  -webkit-text-stroke: 1px rgba(57, 255, 136, 0.14);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-data), var(--color-accent));
  z-index: 1;
}

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

.page-about .about-hero .breadcrumb {
  margin-bottom: 2rem;
}

.page-about .about-hero__layout {
  display: grid;
  gap: 2rem;
  align-items: end;
}

.page-about .about-hero__kicker {
  display: inline-block;
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  color: var(--color-data);
  margin-bottom: 0.85rem;
}

.page-about .about-hero h1 {
  margin: 0 0 1.25rem;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2rem, 8vw, 4.5rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.page-about .about-hero__version-mark {
  display: inline-block;
  margin-left: 0.5rem;
  font-size: 0.42em;
  font-weight: 400;
  color: var(--color-accent);
  vertical-align: super;
  letter-spacing: 0;
}

.page-about .about-hero__lead {
  margin: 0 0 1.75rem;
  max-width: 33rem;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--color-text-muted);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.page-about .about-hero__board {
  border: 1px solid var(--color-line);
  background: var(--color-line);
  padding: 1px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  max-width: 30rem;
}

.page-about .about-hero__board-row {
  background: var(--color-bg-lift);
  padding: 0.85rem 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.page-about .about-hero__board-label {
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
}

.page-about .about-hero__board-value {
  font-size: 1rem;
  font-family: var(--font-head);
  color: var(--color-text);
  line-height: 1.2;
}

.page-about .about-hero__board-row:first-child .about-hero__board-value {
  color: var(--color-accent);
  font-size: 1.4rem;
}

.page-about .about-hero__board-row:nth-child(2) .about-hero__board-value {
  color: var(--color-data);
}

.page-about .about-hero__board-note {
  grid-column: 1 / -1;
  margin: 0;
  padding: 0.6rem 0.9rem 0.2rem;
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  background: var(--color-bg-lift);
}

/* ---------- 品牌愿景 ---------- */
.page-about .about-vision {
  padding: 3rem 0;
}

.page-about .about-vision .section__head {
  margin-bottom: 1.5rem;
}

.page-about .about-vision__body {
  max-width: 42rem;
}

.page-about .about-vision__lead {
  margin: 0 0 1.5rem;
  padding-left: 1rem;
  border-left: 3px solid var(--color-accent);
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.65;
  color: var(--color-text);
}

.page-about .about-vision__body p {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--color-text-muted);
}

.page-about .about-vision__body a {
  color: var(--color-data);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .about-vision__body a:hover {
  color: var(--color-accent);
}

.page-about .about-vision__principles {
  display: grid;
  gap: 0.875rem;
  margin-top: 2.25rem;
}

.page-about .about-vision__principle {
  background: var(--color-bg-lift);
  border: 1px solid var(--color-line);
  border-left: 2px solid var(--color-accent);
  padding: 1.1rem 1.1rem 1.15rem;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.page-about .about-vision__principle:hover {
  border-left-color: var(--color-accent);
  border-color: rgba(255, 107, 0, 0.45);
  box-shadow: var(--shadow-card);
  transform: translateY(-2px);
}

.page-about .about-vision__principle-index {
  display: block;
  font-size: 0.66rem;
  letter-spacing: 0.1em;
  color: var(--color-data);
  margin-bottom: 0.55rem;
}

.page-about .about-vision__principle h3 {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text);
}

.page-about .about-vision__principle p {
  margin: 0;
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--color-text-muted);
}

/* ---------- 版本演进里程碑 ---------- */
.page-about .about-milestones {
  padding: 3rem 0;
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
  background: rgba(6, 15, 26, 0.4);
}

.page-about .about-milestones__fig {
  margin: 2rem 0 2.5rem;
  border: 1px solid var(--color-line);
  background: var(--color-bg-lift);
}

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

.page-about .about-milestones__fig .figure__caption {
  padding: 0.7rem 1rem;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  display: grid;
  gap: 1.4rem;
  margin: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 1.5rem;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--color-line);
  z-index: 0;
}

.page-about .about-timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 0.85rem;
  align-items: start;
}

.page-about .about-timeline__node {
  width: 3rem;
  height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.78rem;
  position: relative;
  z-index: 1;
}

.page-about .about-timeline__node--v1 {
  background: rgba(26, 58, 82, 0.55);
  color: var(--color-text-muted);
  border: 1px solid var(--color-line);
}

.page-about .about-timeline__node--v2 {
  background: var(--color-bg-glow);
  color: var(--color-text);
}

.page-about .about-timeline__node--v3 {
  background: var(--color-data);
  color: var(--color-bg);
}

.page-about .about-timeline__node--v4 {
  background: var(--color-accent);
  color: var(--color-bg);
  box-shadow: 0 0 0 4px rgba(255, 107, 0, 0.2);
}

.page-about .about-timeline__card {
  background: var(--color-bg-lift);
  border: 1px solid var(--color-line);
  padding: 1.15rem 1.15rem 0.9rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.page-about .about-timeline__card:hover {
  border-color: rgba(57, 255, 136, 0.35);
  box-shadow: var(--shadow-card);
  transform: translateY(-2px);
}

.page-about .about-timeline__item--current .about-timeline__card {
  border-color: rgba(255, 107, 0, 0.45);
}

.page-about .about-timeline__header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 0.7rem;
}

.page-about .about-timeline__version {
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--color-data);
}

.page-about .about-timeline__card h3 {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text);
}

.page-about .about-timeline__card > p {
  margin: 0 0 0.75rem;
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--color-text-muted);
}

.page-about .about-timeline__detail {
  border-top: 1px solid var(--color-line);
  margin-top: 0.2rem;
}

.page-about .about-timeline__detail summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.05em;
  color: var(--color-data);
  padding: 0.6rem 0;
  list-style: none;
  user-select: none;
  outline-offset: 4px;
}

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

.page-about .about-timeline__detail summary::before {
  content: "[+] ";
  color: var(--color-accent);
}

.page-about .about-timeline__detail[open] summary::before {
  content: "[–] ";
}

.page-about .about-timeline__detail ul {
  margin: 0;
  padding: 0 0 0.7rem;
  list-style: none;
}

.page-about .about-timeline__detail li {
  position: relative;
  padding-left: 1.1rem;
  font-size: 0.78rem;
  line-height: 1.6;
  color: var(--color-text-muted);
  margin-bottom: 0.3rem;
}

.page-about .about-timeline__detail li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--color-accent);
}

/* ---------- V4 技术升级 ---------- */
.page-about .about-tech {
  display: grid;
  gap: 1.75rem;
  margin-top: 2.5rem;
  padding: 1.25rem;
  background: linear-gradient(135deg, rgba(255, 107, 0, 0.05), rgba(57, 255, 136, 0.04));
  border: 1px solid var(--color-line);
  border-left: 3px solid var(--color-accent);
}

.page-about .about-tech__figure {
  margin: 0;
  border: 1px solid var(--color-line);
  background: var(--color-bg-lift);
}

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

.page-about .about-tech__content .exhibit-tag {
  display: inline-block;
  margin-bottom: 0.6rem;
}

.page-about .about-tech__content h3 {
  margin: 0 0 0.9rem;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--color-text);
}

.page-about .about-tech__list {
  margin: 0 0 1.4rem;
  padding: 0;
  list-style: none;
}

.page-about .about-tech__list li {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding: 0.6rem 0;
  border-bottom: 1px dashed var(--color-line);
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--color-text-muted);
}

.page-about .about-tech__list li span {
  flex-shrink: 0;
  font-size: 0.68rem;
  color: var(--color-data);
}

/* ---------- 数据服务能力 ---------- */
.page-about .about-data {
  padding: 3rem 0;
}

.page-about .about-data__grid {
  display: grid;
  gap: 1.75rem;
  margin-top: 1.75rem;
}

.page-about .about-data__figure {
  margin: 0;
  border: 1px solid var(--color-line);
  background: var(--color-bg-lift);
  position: relative;
}

.page-about .about-data__figure::after {
  content: "LIVE DATA";
  position: absolute;
  top: 0.7rem;
  left: 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.14em;
  color: var(--color-data);
  background: rgba(11, 27, 43, 0.78);
  padding: 0.25rem 0.5rem;
  z-index: 1;
}

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

.page-about .about-data__list {
  display: grid;
  gap: 1px;
  border: 1px solid var(--color-line);
  background: var(--color-line);
}

.page-about .about-data__item {
  background: var(--color-bg-lift);
  padding: 1.1rem 1.05rem;
  transition: background 0.2s ease;
}

.page-about .about-data__item:hover {
  background: linear-gradient(135deg, rgba(57, 255, 136, 0.05), var(--color-bg-lift) 70%);
}

.page-about .about-data__num {
  display: block;
  font-size: 0.64rem;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
}

.page-about .about-data__item h3 {
  margin: 0 0 0.4rem;
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--color-text);
}

.page-about .about-data__item p {
  margin: 0;
  font-size: 0.8rem;
  line-height: 1.68;
  color: var(--color-text-muted);
}

/* ---------- 结尾 / NEXT ---------- */
.page-about .about-next {
  padding: 3rem 0;
  border-top: 1px solid var(--color-line);
  position: relative;
}

.page-about .about-next::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-data), var(--color-accent));
}

.page-about .about-next__inner {
  max-width: 40rem;
}

.page-about .about-next .section__index {
  margin-bottom: 0.6rem;
}

.page-about .about-next h2 {
  margin: 0 0 0.75rem;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--color-text);
}

.page-about .about-next__desc {
  margin: 0 0 1.5rem;
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--color-text-muted);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  margin-bottom: 2rem;
}

.page-about .about-next__trust {
  margin: 0;
  padding-left: 0.8rem;
  border-left: 2px solid var(--color-line);
  font-size: 0.75rem;
  line-height: 1.7;
  color: var(--color-text-muted);
}

/* ---------- 适配桌面端 ---------- */
@media (min-width: 768px) {
  .page-about .about-hero {
    padding: 1.5rem 0 4rem;
  }

  .page-about .about-hero .breadcrumb {
    margin-bottom: 3rem;
  }

  .page-about .about-hero__layout {
    grid-template-columns: 1.15fr 0.85fr;
    gap: 3rem;
  }

  .page-about .about-hero h1 {
    font-size: clamp(2.8rem, 6vw, 4.5rem);
  }

  .page-about .about-hero__lead {
    font-size: 1rem;
  }

  .page-about .about-hero__board {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .about-hero__board-row {
    padding: 1rem;
  }

  .page-about .about-vision,
  .page-about .about-milestones,
  .page-about .about-data,
  .page-about .about-next {
    padding: 4.5rem 0;
  }

  .page-about .about-vision__principles {
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
  }

  .page-about .about-timeline {
    gap: 2rem;
  }

  .page-about .about-timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .page-about .about-timeline__item {
    grid-template-columns: 1fr 3rem 1fr;
    gap: 1rem;
  }

  .page-about .about-timeline__node {
    grid-column: 2;
    grid-row: 1;
    justify-self: center;
    align-self: start;
  }

  .page-about .about-timeline__card {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .about-timeline__item:nth-child(even) .about-timeline__card {
    grid-column: 3;
  }

  .page-about .about-tech {
    grid-template-columns: 0.85fr 1.15fr;
    gap: 2rem;
    align-items: center;
    padding: 1.75rem;
  }

  .page-about .about-data__grid {
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
    gap: 2rem;
  }

  .page-about .about-data__list {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .about-next__inner {
    padding-left: 2rem;
    border-left: 3px solid var(--color-line);
  }
}