.page-about {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
}

.page-about .about-shell {
  position: relative;
  max-width: 1180px;
  margin-inline: auto;
  padding: clamp(1.6rem, 5vw, 3.4rem) clamp(1.1rem, 4vw, 2.6rem) clamp(3rem, 8vw, 6rem);
}

/* 纵向刻度轨道：移动端隐藏，桌面端作为全页视觉锚点 */
.page-about .about-spine {
  display: none;
}

@media (min-width: 960px) {
  .page-about .about-shell {
    padding-left: clamp(3.4rem, 6.5vw, 5.6rem);
  }

  .page-about .about-spine {
    display: block;
    position: absolute;
    top: clamp(2rem, 5vw, 3.4rem);
    bottom: clamp(3rem, 8vw, 6rem);
    left: clamp(1.4rem, 2.4vw, 2rem);
    width: 1px;
    background-image: repeating-linear-gradient(
      to bottom,
      var(--hair-strong) 0,
      var(--hair-strong) 1px,
      transparent 1px,
      transparent 12px
    );
  }

  .page-about .about-spine::before {
    content: "";
    position: absolute;
    top: 0;
    left: -1px;
    width: 3px;
    height: clamp(90px, 14vh, 150px);
    background: linear-gradient(to bottom, var(--cyan), rgba(53, 232, 210, 0));
  }
}

/* 面包屑 */
.page-about .breadcrumb {
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--grey);
  margin-bottom: clamp(1.6rem, 4vw, 2.6rem);
}

.page-about .breadcrumb a {
  color: var(--grey);
  text-decoration: none;
  padding-bottom: 1px;
  background-image: linear-gradient(var(--cyan), var(--cyan));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: color var(--dur) var(--ease), background-size var(--dur) var(--ease);
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan);
  background-size: 100% 1px;
}

/* 首屏 */
.page-about .about-hero {
  padding-bottom: clamp(2rem, 6vw, 3.6rem);
  border-bottom: 1px solid var(--hair);
}

.page-about .idx {
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--grey);
  margin: 0 0 1.1rem;
}

.page-about .about-hero__label {
  color: var(--violet);
}

.page-about .about-hero__title {
  margin: 0 0 clamp(1.3rem, 3.5vw, 2rem);
  font-family: var(--font-display);
  font-size: clamp(2.15rem, 8.4vw, 4.8rem);
  line-height: 0.97;
  letter-spacing: -0.02em;
}

.page-about .about-hero__line1,
.page-about .about-hero__line2 {
  display: block;
}

.page-about .about-hero__line1 {
  font-weight: 300;
  color: var(--paper);
}

.page-about .about-hero__line2 {
  font-weight: 850;
  color: var(--cyan);
}

.page-about .about-hero__lead {
  max-width: 62ch;
  margin: 0 0 clamp(2rem, 5vw, 3rem);
  font-size: clamp(1rem, 1.6vw, 1.1rem);
  line-height: 1.85;
  color: var(--dim);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: var(--hair);
  border: 1px solid var(--hair);
}

@media (min-width: 760px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-fact {
  background: var(--ink);
  padding: 0.95rem 1.05rem 1.05rem;
}

.page-about .about-fact__k {
  margin: 0 0 0.45rem;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  color: var(--grey);
}

.page-about .about-fact__v {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-fact__v.mono {
  color: var(--cyan);
  font-size: 0.86rem;
  letter-spacing: 0.06em;
}

/* 区块通用 */
.page-about .about-section {
  padding-block: clamp(2.4rem, 7vw, 4.6rem);
  border-bottom: 1px solid var(--hair);
}

.page-about .about-panel {
  position: relative;
  margin-block: clamp(2rem, 6vw, 3.6rem);
  padding: clamp(1.7rem, 5vw, 3rem) clamp(1.3rem, 4vw, 2.8rem);
  border-bottom: none;
}

.page-about .about-panel--paper {
  background: var(--paper);
  color: var(--text);
  border-left: 3px solid var(--violet);
}

.page-about .about-panel--paper::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  width: 34%;
  height: 5px;
  background: linear-gradient(to left, var(--violet), rgba(123, 91, 255, 0));
}

.page-about .about-head {
  margin-bottom: clamp(1.4rem, 4vw, 2.3rem);
}

.page-about .about-head h2 {
  margin: 0 0 0.7rem;
  font-family: var(--font-display);
  font-weight: 850;
  font-size: clamp(1.5rem, 4.2vw, 2.4rem);
  line-height: 1.14;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .about-head__note {
  max-width: 58ch;
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--dim);
}

.page-about .about-panel--paper .about-head h2 {
  color: var(--text);
}

.page-about .about-panel--paper .about-head__note {
  color: rgba(17, 23, 37, 0.68);
}

.page-about .about-panel--paper .idx {
  color: rgba(17, 23, 37, 0.5);
}

/* 运营与备案 */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.4rem, 4vw, 2.6rem);
}

@media (min-width: 860px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr);
    align-items: start;
  }
}

.page-about .prose {
  max-width: 44em;
}

.page-about .prose--narrow {
  max-width: 32em;
}

.page-about .about-panel--paper .prose p {
  margin: 0 0 1.15em;
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(17, 23, 37, 0.86);
}

.page-about .about-panel--paper .prose p:last-child {
  margin-bottom: 0;
}

.page-about .about-note {
  padding: 1.1rem 1.2rem 1.3rem;
  border-top: 2px solid var(--violet);
  background: rgba(123, 91, 255, 0.06);
}

.page-about .about-note__k {
  margin: 0 0 0.8rem;
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: rgba(17, 23, 37, 0.55);
}

.page-about .about-note__list {
  margin: 0 0 1.2rem;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
}

.page-about .about-note__list li {
  position: relative;
  padding-left: 1.05rem;
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--text);
}

.page-about .about-note__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 7px;
  height: 1px;
  background: var(--violet);
}

.page-about .about-panel--paper .btn--ghost {
  color: var(--text);
  border-color: rgba(17, 23, 37, 0.28);
}

.page-about .about-panel--paper .btn--ghost:hover,
.page-about .about-panel--paper .btn--ghost:focus-visible {
  color: var(--violet);
  border-color: var(--violet);
}

/* 三个方向 */
.page-about .dir-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

@media (min-width: 880px) {
  .page-about .dir-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .dir-card {
  background: var(--ink);
  padding: clamp(1.1rem, 3vw, 1.6rem) clamp(1rem, 2.6vw, 1.5rem) clamp(1.2rem, 3vw, 1.7rem);
  border-left: 3px solid transparent;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .dir-card:hover,
.page-about .dir-card:focus-within,
.page-about .dir-card[open] {
  border-left-color: var(--cyan);
}

.page-about .dir-card[open] {
  background: var(--deep);
}

.page-about .dir-card > summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  grid-template-areas:
    "num title"
    "num toggle";
  align-items: baseline;
  gap: 0.25rem 0.85rem;
}

.page-about .dir-card > summary::-webkit-details-marker {
  display: none;
}

.page-about .dir-card > summary:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 4px;
}

.page-about .dir-card__num {
  grid-area: num;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--violet);
}

.page-about .dir-card__title {
  grid-area: title;
  font-family: var(--font-display);
  font-size: 1.18rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .dir-card__toggle {
  grid-area: toggle;
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  color: var(--grey);
}

.page-about .dir-card__panel {
  padding-top: 1.05rem;
}

.page-about .dir-card__desc {
  margin: 0 0 0.95rem;
  font-size: 0.9rem;
  line-height: 1.78;
  color: var(--dim);
}

.page-about .dir-card__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
}

.page-about .dir-card__list li {
  position: relative;
  padding-left: 1.1rem;
  font-size: 0.86rem;
  line-height: 1.65;
  color: var(--paper);
}

.page-about .dir-card__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.66em;
  width: 6px;
  height: 1px;
  background: var(--cyan);
}

/* 语义配图 */
.page-about .about-figure {
  margin: clamp(1.8rem, 5vw, 2.8rem) 0 0;
}

.page-about .about-figure--slim {
  margin-bottom: clamp(1.6rem, 4vw, 2.4rem);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--hair);
  background: var(--deep);
}

.page-about .about-figure--wide img {
  aspect-ratio: 3 / 2;
}

.page-about .about-figure--slim img {
  aspect-ratio: 8 / 3;
}

.page-about .about-figure__cap {
  margin: 0.7rem 0 0;
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--grey);
}

/* 流程步骤 */
.page-about .pipe {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.75rem;
}

@media (min-width: 680px) {
  .page-about .pipe {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1040px) {
  .page-about .pipe {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .pipe__step {
  position: relative;
  padding: 1.1rem 1.15rem 1.2rem;
  background: var(--paper-2);
  border-left: 3px solid var(--paper-2);
  transition: border-color var(--dur) var(--ease);
}

.page-about .pipe__step:hover,
.page-about .pipe__step:focus-within {
  border-left-color: var(--cyan);
}

.page-about .pipe__num {
  display: block;
  margin-bottom: 0.55rem;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  color: var(--violet);
}

.page-about .pipe__name {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text);
}

.page-about .pipe__desc {
  margin: 0 0 0.85rem;
  font-size: 0.86rem;
  line-height: 1.72;
  color: rgba(17, 23, 37, 0.74);
}

.page-about .pipe__rec {
  margin: 0;
  padding-top: 0.6rem;
  border-top: 1px solid rgba(17, 23, 37, 0.18);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--text);
}

/* 编号与版本 */
.page-about .about-code {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.4rem, 4vw, 2.4rem);
  align-items: start;
}

@media (min-width: 900px) {
  .page-about .about-code {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  }
}

.page-about .about-code__media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border: 1px solid var(--hair);
  background: var(--deep);
}

.page-about .about-code__lead {
  margin: 0 0 1.4rem;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--dim);
}

.page-about .code-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hair);
  border-top: 1px solid var(--hair);
}

.page-about .code-list__item {
  background: var(--ink);
  padding: 0.95rem 0 1rem;
}

.page-about .code-list__k {
  display: block;
  margin-bottom: 0.45rem;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .code-list__v {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.78;
  color: var(--paper);
}

/* 形态演进 */
.page-about .evo {
  list-style: none;
  margin: 0;
  padding: 0 0 0 clamp(1.1rem, 4vw, 1.8rem);
  position: relative;
}

.page-about .evo::before {
  content: "";
  position: absolute;
  top: 0.4rem;
  bottom: 0.4rem;
  left: 3px;
  width: 1px;
  background-image: repeating-linear-gradient(
    to bottom,
    var(--hair-strong) 0,
    var(--hair-strong) 1px,
    transparent 1px,
    transparent 10px
  );
}

.page-about .evo-node {
  position: relative;
  padding-bottom: clamp(1.5rem, 4vw, 2.2rem);
}

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

.page-about .evo-node__dot {
  position: absolute;
  left: calc(-1 * clamp(1.1rem, 4vw, 1.8rem));
  top: 0.42rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  transition: background-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .evo-node:hover .evo-node__dot {
  background: var(--cyan);
}

.page-about .evo-node__year {
  display: block;
  margin-bottom: 0.4rem;
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .evo-node__body h3 {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
  font-size: 1.06rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .evo-node__body p {
  max-width: 56ch;
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--dim);
}

.page-about .evo-node:hover .evo-node__body h3 {
  color: var(--cyan);
  transition: color var(--dur) var(--ease);
}

/* 内容边界 */
.page-about .about-panel--closing {
  border-left-color: var(--cyan);
}

.page-about .about-panel--closing::after {
  background: linear-gradient(to left, var(--cyan), rgba(53, 232, 210, 0));
}

.page-about .about-closing__links {
  margin-top: 1.6rem;
  padding-top: 1.2rem;
  border-top: 1px solid rgba(17, 23, 37, 0.16);
  font-size: 0.94rem;
}

.page-about .about-panel--paper .about-closing__links a {
  color: var(--text);
  text-decoration: none;
  padding-bottom: 1px;
  background-image: linear-gradient(var(--violet), var(--violet));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 100% 1px;
  transition: color var(--dur) var(--ease), background-size var(--dur) var(--ease);
}

.page-about .about-panel--paper .about-closing__links a:hover,
.page-about .about-panel--paper .about-closing__links a:focus-visible {
  color: var(--violet);
  background-size: 0 1px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 1ms !important;
    transition-delay: 0ms !important;
  }
}