.page-about {
  --about-card: #fffcf6;
  --about-shadow: 5px 5px 0 rgba(231, 223, 210, 0.92);
  --about-deep-line: #12514f;
  --about-indigo-line: #453a6b;
  --about-ink-line: #3a302b;
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--paper);
  overflow-x: clip;
  padding-bottom: 56px;
}

/* ---- 面包屑 ---- */
.page-about .crumbs {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 18px 18px 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  letter-spacing: 0.02em;
}

.page-about .crumbs__link {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .crumbs__link:hover,
.page-about .crumbs__link:focus-visible {
  color: var(--tiger);
  border-bottom-color: var(--tiger);
}

.page-about .crumbs__sep {
  color: var(--line);
}

.page-about .crumbs__current {
  color: var(--ink);
  font-weight: 800;
}

/* ---- 首屏 ---- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 26px 18px 40px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -6px;
  right: -14vw;
  width: 82vw;
  height: 260px;
  background: repeating-linear-gradient(
    112deg,
    rgba(242, 96, 26, 0.15) 0 15px,
    rgba(242, 96, 26, 0) 15px 38px
  );
  clip-path: polygon(28% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-kicker {
  display: inline-block;
  margin: 0 0 16px;
  padding: 5px 12px;
  background: var(--ink);
  color: var(--sand);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.14em;
  transform: rotate(-2deg);
}

.page-about .about-hero h1 {
  max-width: 15em;
  margin: 0 0 18px;
  font-size: clamp(2rem, 8.4vw, 4.1rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.02em;
  transform: rotate(-2.4deg);
  transform-origin: left bottom;
}

.page-about .about-hero__lead {
  max-width: 34em;
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--charcoal);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  max-width: 760px;
}

.page-about .about-hero__stat {
  background: var(--about-card);
  border: 2px solid var(--line);
  border-left: 5px solid var(--tiger);
  box-shadow: var(--about-shadow);
  padding: 10px 12px 12px;
}

.page-about .about-hero__stat:nth-child(2) {
  border-left-color: var(--cyan);
}

.page-about .about-hero__stat:nth-child(3) {
  border-left-color: var(--sand);
}

.page-about .about-hero__stat:nth-child(4) {
  border-left-color: var(--teal);
}

.page-about .about-hero__num {
  display: block;
  font-size: clamp(1.5rem, 5.4vw, 2rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.01em;
}

.page-about .about-hero__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

/* ---- 主体两栏 ---- */
.page-about .about-body {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 18px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

/* ---- 左侧演进轨道 ---- */
.page-about .about-rail {
  border-top: 2px solid var(--ink);
  padding-top: 14px;
  min-width: 0;
}

.page-about .about-rail__cap {
  margin: 0 0 12px;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.2em;
  color: var(--tiger);
}

.page-about .about-rail__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
}

.page-about .about-rail__list::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(to bottom, var(--tiger) 0%, var(--tiger) 20%, var(--line) 20%, var(--line) 100%);
}

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

.page-about .about-rail__link {
  position: relative;
  display: block;
  padding: 8px 6px 10px 0;
  text-decoration: none;
  color: var(--ink);
  transition: color 0.18s ease;
}

.page-about .about-rail__dot {
  position: absolute;
  left: -21px;
  top: 12px;
  width: 12px;
  height: 12px;
  background: var(--paper);
  border: 2px solid var(--line);
  transform: rotate(45deg);
  transition: background 0.18s ease, border-color 0.18s ease;
}

.page-about .about-rail__num {
  display: block;
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.14em;
  color: var(--muted);
  transition: color 0.18s ease;
}

.page-about .about-rail__text {
  display: block;
  margin-top: 2px;
  font-size: 15px;
  font-weight: 800;
  line-height: 1.35;
}

.page-about .about-rail__note {
  display: block;
  margin-top: 3px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
}

.page-about .about-rail__link:hover .about-rail__dot,
.page-about .about-rail__link:focus-visible .about-rail__dot {
  background: var(--tiger);
  border-color: var(--tiger);
}

.page-about .about-rail__link:hover .about-rail__num,
.page-about .about-rail__link:focus-visible .about-rail__num {
  color: var(--tiger);
}

.page-about .about-rail__link:hover .about-rail__text,
.page-about .about-rail__link:focus-visible .about-rail__text {
  color: var(--tiger);
}

/* ---- 卡片流 ---- */
.page-about .about-stream {
  min-width: 0;
}

.page-about .about-card {
  position: relative;
  scroll-margin-top: 20px;
  background: var(--about-card);
  border: 2px solid var(--line);
  box-shadow: var(--about-shadow);
  padding: 22px 34px 24px 18px;
  margin-bottom: 40px;
  transition: transform 0.18s ease, border-color 0.18s ease;
}

.page-about .about-card:nth-child(2) {
  margin-bottom: 36px;
}

.page-about .about-card:nth-child(3) {
  margin-bottom: 30px;
}

.page-about .about-card:nth-child(4) {
  margin-bottom: 26px;
}

.page-about .about-card:nth-child(5) {
  margin-bottom: 22px;
}

.page-about .about-card:nth-child(6) {
  margin-bottom: 18px;
}

.page-about .about-card:nth-child(7) {
  margin-bottom: 0;
}

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

.page-about .about-card__issue {
  position: absolute;
  top: 16px;
  right: 6px;
  writing-mode: vertical-rl;
  padding: 6px 3px;
  background: var(--sand);
  color: var(--ink);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.18em;
}

.page-about .about-card__title {
  margin: 0 0 12px;
  font-size: clamp(1.28rem, 4.8vw, 1.85rem);
  font-weight: 900;
  line-height: 1.24;
  letter-spacing: -0.01em;
}

.page-about .about-card p {
  margin: 0 0 12px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--charcoal);
}

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

.page-about .about-card__tail {
  margin-top: 16px;
}

.page-about .about-link {
  display: inline-block;
  color: var(--ink);
  font-weight: 800;
  text-decoration: none;
  border-bottom: 2px solid var(--tiger);
  padding-bottom: 1px;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--tiger);
}

/* 深色分区变体 */
.page-about .about-card--teal {
  background: var(--teal);
  border-color: var(--about-deep-line);
  color: #eef3ec;
  box-shadow: 6px 6px 0 rgba(11, 59, 58, 0.24);
}

.page-about .about-card--teal:hover {
  border-color: var(--cyan);
}

.page-about .about-card--teal .about-card__title {
  color: #ffffff;
}

.page-about .about-card--teal p {
  color: #cfe0db;
}

.page-about .about-card--teal .about-link {
  color: var(--cyan);
  border-bottom-color: rgba(18, 214, 196, 0.5);
}

.page-about .about-card--teal .about-link:hover {
  color: #ffffff;
  border-bottom-color: #ffffff;
}

.page-about .about-card--indigo {
  background: var(--indigo);
  border-color: var(--about-indigo-line);
  color: #e8e2f6;
  box-shadow: 6px 6px 0 rgba(46, 35, 80, 0.24);
}

.page-about .about-card--indigo:hover {
  border-color: var(--sand);
}

.page-about .about-card--indigo .about-card__title {
  color: #ffffff;
}

.page-about .about-card--indigo p {
  color: #d6cfeb;
}

.page-about .about-card--indigo .about-link {
  color: var(--sand);
  border-bottom-color: rgba(233, 180, 76, 0.55);
}

.page-about .about-card--indigo .about-link:hover {
  color: #ffffff;
  border-bottom-color: #ffffff;
}

.page-about .about-card--ink {
  background: var(--ink);
  border-color: var(--about-ink-line);
  color: #ece5da;
  box-shadow: 6px 6px 0 rgba(20, 16, 14, 0.2);
}

.page-about .about-card--ink:hover {
  border-color: var(--tiger);
}

.page-about .about-card--ink .about-card__title {
  color: #ffffff;
}

.page-about .about-card--ink p {
  color: #cfc4b8;
}

.page-about .about-card--ink .about-link {
  color: var(--cyan);
  border-bottom-color: rgba(18, 214, 196, 0.45);
}

.page-about .about-card--ink .about-link:hover {
  color: #ffffff;
  border-bottom-color: #ffffff;
}

.page-about .about-card--indigo .about-card__issue,
.page-about .about-card--ink .about-card__issue,
.page-about .about-card--teal .about-card__issue {
  background: var(--sand);
  color: var(--ink);
}

/* ---- 图 ---- */
.page-about .about-figure {
  margin: 18px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border: 2px solid var(--line);
}

.page-about .about-card--teal .about-figure img,
.page-about .about-card--indigo .about-figure img,
.page-about .about-card--ink .about-figure img {
  border-color: rgba(255, 255, 255, 0.22);
}

/* ---- 阶段列表 ---- */
.page-about .about-phases {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-phases__item {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 12px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
}

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

.page-about .about-phases__idx {
  font-size: 20px;
  font-weight: 900;
  line-height: 1.1;
  color: var(--tiger);
  letter-spacing: -0.02em;
}

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

.page-about .about-phases__title {
  margin: 0 0 4px;
  font-size: 16px;
  font-weight: 900;
  line-height: 1.4;
}

.page-about .about-phases__body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
}

/* ---- 三步法 ---- */
.page-about .about-steps {
  margin: 16px 0 4px;
}

.page-about .about-step {
  margin-bottom: 10px;
  background: rgba(0, 0, 0, 0.16);
  border: 2px solid rgba(255, 255, 255, 0.16);
  transition: border-color 0.18s ease, background 0.18s ease;
}

.page-about .about-step[open] {
  border-color: var(--cyan);
  background: rgba(0, 0, 0, 0.26);
}

.page-about .about-step__summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  cursor: pointer;
  list-style: none;
  font-weight: 900;
  color: #ffffff;
}

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

.page-about .about-step__summary::after {
  content: "+";
  margin-left: auto;
  font-size: 18px;
  color: var(--cyan);
  line-height: 1;
}

.page-about .about-step[open] .about-step__summary::after {
  content: "−";
}

.page-about .about-step__idx {
  flex: none;
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  background: var(--tiger);
  color: #ffffff;
  font-size: 13px;
  font-weight: 900;
  transform: rotate(-4deg);
}

.page-about .about-step[open] .about-step__idx {
  background: var(--sand);
  color: var(--ink);
}

.page-about .about-step__title {
  font-size: 15px;
  letter-spacing: 0.01em;
}

.page-about .about-step__body {
  padding: 0 14px 14px 56px;
}

.page-about .about-step__body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: #cfe0db;
}

/* ---- 团队 ---- */
.page-about .about-crew {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-crew__item {
  border-left: 5px solid var(--sand);
  background: var(--paper);
  padding: 12px 14px;
}

.page-about .about-crew__num {
  display: inline-block;
  font-size: 30px;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.page-about .about-crew__role {
  display: inline-block;
  margin-left: 8px;
  padding: 3px 8px;
  background: var(--ink);
  color: var(--sand);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.1em;
  vertical-align: 6px;
}

.page-about .about-crew__text {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.75;
}

/* ---- 标签切换 ---- */
.page-about .about-tabs {
  position: relative;
  margin: 14px 0 0;
}

.page-about .about-tabs__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.page-about .about-tabs__bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.page-about .about-tabs__chip {
  padding: 7px 14px;
  border: 2px solid var(--line);
  background: var(--paper);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-tabs__chip:hover {
  border-color: var(--tiger);
}

.page-about .about-tabs__input:focus-visible ~ .about-tabs__bar {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
}

.page-about #about-tag-device:checked ~ .about-tabs__bar .about-tabs__chip[for="about-tag-device"],
.page-about #about-tag-version:checked ~ .about-tabs__bar .about-tabs__chip[for="about-tag-version"],
.page-about #about-tag-time:checked ~ .about-tabs__bar .about-tabs__chip[for="about-tag-time"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

.page-about .about-tabs__panel {
  display: none;
  border-left: 5px solid var(--cyan);
  background: var(--paper);
  padding: 12px 14px;
}

.page-about #about-tag-device:checked ~ #about-panel-device,
.page-about #about-tag-version:checked ~ #about-panel-version,
.page-about #about-tag-time:checked ~ #about-panel-time {
  display: block;
}

.page-about .about-tabs__panel p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
}

/* ---- 接下来一年 ---- */
.page-about .about-next {
  list-style: none;
  margin: 14px 0 16px;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-next__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 11px 12px;
  border-left: 5px solid var(--tiger);
  background: var(--charcoal);
}

.page-about .about-next__key {
  font-size: 15px;
  font-weight: 900;
  letter-spacing: 0.04em;
  color: var(--sand);
}

.page-about .about-next__text {
  font-size: 14.5px;
  line-height: 1.75;
  color: #cfc4b8;
}

/* ---- 断点 ---- */
@media (min-width: 700px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-card {
    padding: 26px 44px 28px 24px;
  }

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

  .page-about .about-next__item {
    grid-template-columns: 7.5em minmax(0, 1fr);
    align-items: start;
    gap: 14px;
  }
}

@media (min-width: 1000px) {
  .page-about .crumbs {
    padding: 22px 28px 0;
  }

  .page-about .about-hero {
    padding: 34px 28px 48px;
  }

  .page-about .about-body {
    grid-template-columns: 226px minmax(0, 1fr);
    gap: 44px;
    padding: 0 28px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 28px;
    align-self: start;
  }

  .page-about .about-card {
    padding: 30px 48px 32px 28px;
    margin-bottom: 44px;
  }

  .page-about .about-card:nth-child(1) {
    margin-right: 8%;
  }

  .page-about .about-card:nth-child(2) {
    margin-left: 7%;
    margin-bottom: 38px;
  }

  .page-about .about-card:nth-child(3) {
    margin-right: 3%;
    margin-bottom: 32px;
  }

  .page-about .about-card:nth-child(4) {
    margin-left: 10%;
    margin-bottom: 28px;
  }

  .page-about .about-card:nth-child(5) {
    margin-right: 6%;
    margin-bottom: 24px;
  }

  .page-about .about-card:nth-child(6) {
    margin-left: 4%;
    margin-bottom: 20px;
  }

  .page-about .about-card:nth-child(7) {
    margin-right: 12%;
    margin-bottom: 0;
  }

  .page-about .about-card__title {
    max-width: 20em;
  }

  .page-about .about-phases__item {
    grid-template-columns: 46px minmax(0, 1fr);
    gap: 16px;
  }

  .page-about .about-phases__idx {
    font-size: 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-card,
  .page-about .about-rail__dot,
  .page-about .about-link,
  .page-about .about-tabs__chip,
  .page-about .about-step {
    transition: none;
  }

  .page-about .about-card:hover {
    transform: none;
  }
}