.page-about {
  --about-line: rgba(44, 90, 66, .6);
  --about-soft: rgba(143, 163, 150, .26);
  display: block;
  background: var(--deep);
  color: var(--paper);
  padding: clamp(24px, 3vw, 42px) var(--pad) clamp(52px, 7vw, 92px);
  overflow-x: clip;
}

.page-about .section {
  margin: 0 0 clamp(48px, 6vw, 84px);
}

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

.page-about h2 {
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(26px, 3.6vw, 42px);
  line-height: 1.2;
  letter-spacing: -.01em;
  margin: 0;
  color: var(--paper);
}

.page-about .section-head {
  display: grid;
  gap: 14px;
  padding-bottom: 18px;
  margin-bottom: clamp(24px, 3vw, 36px);
  border-bottom: 2px solid var(--about-line);
}

.page-about .section-head p {
  margin: 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--sage);
  max-width: 62ch;
}

/* ---------- 首屏定位 ---------- */
.page-about .about-hero {
  position: relative;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
}

.page-about .about-hero h1 {
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(34px, 7.4vw, 74px);
  line-height: 1.08;
  letter-spacing: -.022em;
  margin: 14px 0 20px;
  color: var(--paper);
}

.page-about .about-hero .lede {
  font-size: clamp(17px, 2vw, 21px);
  line-height: 1.62;
  color: var(--gilt-lift);
  max-width: 30ch;
  margin: 0 0 18px;
}

.page-about .about-hero__body {
  margin: 0 0 26px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--paper);
  max-width: 62ch;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero__metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 2px solid var(--pine);
  align-content: start;
}

.page-about .about-hero__metrics .metric {
  background: var(--panel);
  padding: 18px 16px 16px;
  transition: background var(--t-fast);
}

.page-about .about-hero__metrics .metric:hover {
  background: var(--deep);
}

.page-about .metric-num {
  display: block;
  font-family: var(--mono);
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1.1;
  letter-spacing: .05em;
  color: var(--gilt);
}

.page-about .metric-label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--sage);
}

/* ---------- 三种使用场景 ---------- */
.page-about .what-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .what-item {
  display: grid;
  align-content: start;
  gap: 12px;
  padding: 24px 0 0;
  border-top: 4px solid var(--pine);
  transition: border-color var(--t-mid), transform var(--t-mid);
}

.page-about .what-item:hover {
  border-color: var(--gilt);
  transform: translateY(-3px);
}

.page-about .what-step {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: .32em;
  color: var(--gilt);
}

.page-about .what-item h3 {
  font-family: var(--serif);
  font-weight: 900;
  font-size: 21px;
  line-height: 1.32;
  margin: 0;
  color: var(--paper);
}

.page-about .what-item p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--paper);
}

.page-about .what-item .what-for {
  margin-top: 4px;
  padding-top: 12px;
  border-top: 1px dashed var(--about-line);
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.6;
  letter-spacing: .04em;
  color: var(--amber);
}

/* ---------- 区服分布 ---------- */
.page-about .zone-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

.page-about .zone-figure {
  margin: 0;
}

.page-about .zone-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 3px solid var(--pine);
  box-shadow: 10px 10px 0 rgba(11, 20, 16, .55);
}

.page-about .zone-figure figcaption {
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--sage);
}

.page-about .zone-copy h2 {
  margin: 12px 0 18px;
}

.page-about .zone-lede {
  margin: 0;
  font-size: 16.5px;
  line-height: 1.8;
  color: var(--paper);
  max-width: 60ch;
}

.page-about .zone-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 2px;
  background: var(--about-line);
  border: 2px solid var(--pine);
}

.page-about .zone-item {
  display: grid;
  gap: 5px;
  padding: 14px 18px;
  background: var(--panel);
  border-left: 4px solid transparent;
  transition: background var(--t-fast), border-color var(--t-fast), padding-left var(--t-fast);
}

.page-about .zone-item:hover {
  background: var(--deep);
  border-left-color: var(--gilt);
  padding-left: 24px;
}

.page-about .zone-name {
  font-family: var(--mono);
  font-size: 14px;
  letter-spacing: .08em;
  color: var(--gilt);
}

.page-about .zone-desc {
  font-size: 15px;
  line-height: 1.65;
  color: var(--paper);
}

/* ---------- 版本时间轴 ---------- */
.page-about .version-figure {
  margin: 0 0 clamp(24px, 3vw, 34px);
}

.page-about .version-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 3px solid var(--pine);
}

.page-about .vtl {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: flex;
  gap: 0;
  border-top: 2px solid var(--pine);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: var(--pine) transparent;
}

.page-about .vtl-node {
  position: relative;
  flex: 0 0 min(80vw, 300px);
  scroll-snap-align: start;
  padding: 32px 20px 24px;
  border-right: 1px solid var(--about-line);
  border-bottom: 1px solid var(--about-line);
  background: linear-gradient(180deg, rgba(28, 58, 44, .55), rgba(18, 36, 28, 0));
  transition: background var(--t-mid), border-color var(--t-mid);
}

.page-about .vtl-node::before {
  content: "";
  position: absolute;
  top: -7px;
  left: 20px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--gilt);
  box-shadow: 0 0 0 4px var(--deep);
  transition: background var(--t-fast), box-shadow var(--t-fast);
}

.page-about .vtl-node:hover,
.page-about .vtl-node:focus {
  background: var(--panel);
  border-color: var(--gilt);
}

.page-about .vtl-node:hover::before,
.page-about .vtl-node:focus::before {
  background: var(--gilt-lift);
  box-shadow: 0 0 0 4px var(--deep), 0 0 0 7px rgba(228, 200, 120, .28);
}

.page-about .vtl-node:focus-visible {
  outline: 2px solid var(--gilt-lift);
  outline-offset: -2px;
}

.page-about .vtl-num {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .26em;
  color: var(--amber);
}

.page-about .vtl-node h3 {
  font-family: var(--serif);
  font-weight: 900;
  font-size: 20px;
  line-height: 1.34;
  margin: 12px 0 10px;
  color: var(--paper);
}

.page-about .vtl-node p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--paper);
}

.page-about .vtl-more {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  margin-top: 0;
  padding-top: 0;
  border-top: 1px dashed var(--about-line);
  font-size: 14px;
  line-height: 1.68;
  color: var(--sage);
  transition: max-height var(--t-mid), opacity var(--t-mid), margin-top var(--t-mid), padding-top var(--t-mid);
}

.page-about .vtl-node:hover .vtl-more,
.page-about .vtl-node:focus .vtl-more {
  max-height: 240px;
  opacity: 1;
  margin-top: 12px;
  padding-top: 12px;
}

@media (hover: none) {
  .page-about .vtl-more {
    max-height: none;
    opacity: 1;
    margin-top: 12px;
    padding-top: 12px;
  }
}

/* ---------- 服务支撑（纸面区） ---------- */
.page-about .about-support {
  margin-inline: calc(var(--pad) * -1);
  padding: clamp(36px, 6vw, 76px) var(--pad);
  background: var(--paper);
  color: var(--inktype);
  border-top: 4px solid var(--gilt);
  border-bottom: 4px solid var(--gilt);
}

.page-about .support-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

.page-about .about-support h2 {
  color: var(--inktype);
  margin: 12px 0 18px;
}

.page-about .about-support .eyebrow {
  color: var(--cinnabar);
}

.page-about .support-copy > p {
  margin: 0 0 16px;
  font-size: 16.5px;
  line-height: 1.82;
  color: #33403A;
  max-width: 62ch;
}

.page-about .support-list {
  list-style: none;
  margin: 26px 0 26px;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .support-list li {
  padding: 14px 18px;
  background: transparent;
  border: 3px solid var(--inktype);
  border-left-width: 9px;
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.72;
  letter-spacing: .02em;
  color: var(--inktype);
  transition: border-color var(--t-fast), background var(--t-fast), transform var(--t-fast);
}

.page-about .support-list li:hover {
  border-color: var(--cinnabar);
  background: rgba(178, 58, 46, .07);
  transform: translateX(4px);
}

.page-about .about-support .btn--solid {
  background: var(--inktype);
  border-color: var(--inktype);
  color: var(--paper);
}

.page-about .about-support .btn--solid:hover {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
}

.page-about .support-figure {
  margin: 0;
}

.page-about .support-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 3px solid var(--inktype);
  box-shadow: 10px 10px 0 rgba(16, 26, 20, .22);
}

/* ---------- 更新节奏 ---------- */
.page-about .cadence-inner {
  border: 3px solid var(--pine);
  border-left-width: 10px;
  padding: clamp(24px, 4vw, 46px);
  background: var(--panel);
}

.page-about .cadence-lede {
  margin: 16px 0 0;
  font-size: 16.5px;
  line-height: 1.82;
  color: var(--paper);
  max-width: 66ch;
}

.page-about .cadence-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .cadence-list li {
  display: grid;
  gap: 6px;
  padding: 14px 0 0;
  border-top: 1px solid var(--about-line);
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--paper);
}

.page-about .cadence-list .num {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: .22em;
  color: var(--gilt);
}

.page-about .cadence-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .zone-item {
    grid-template-columns: 13ch minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }
}

@media (min-width: 780px) {
  .page-about .what-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .section-head {
    grid-template-columns: 5fr 7fr;
    align-items: end;
    gap: 36px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: 7fr 5fr;
    gap: 52px;
    align-items: start;
  }

  .page-about .zone-grid {
    grid-template-columns: 5fr 7fr;
    gap: 46px;
    align-items: start;
  }

  .page-about .support-grid {
    grid-template-columns: 7fr 5fr;
    gap: 46px;
    align-items: start;
  }
}

@media (min-width: 960px) {
  .page-about .vtl {
    overflow-x: visible;
    padding-bottom: 0;
  }

  .page-about .vtl-node {
    flex: 1 1 0;
    min-width: 0;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero::after {
    content: "";
    position: absolute;
    top: 6px;
    right: -26px;
    bottom: 6px;
    width: 8px;
    background-image: repeating-linear-gradient(to bottom, var(--gilt) 0 2px, transparent 2px 12px);
    opacity: .45;
    pointer-events: none;
  }
}
</style>