.page-about {
  --about-col: 62ch;
  --about-wide: 46rem;
}

/* ---------- 页面头 ---------- */

.page-about .about-mast {
  padding-top: clamp(2rem, 5vw, 3.5rem);
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
  border-bottom: 1px solid var(--line);
}

.page-about .crumb a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .18s ease, border-color .18s ease;
}

.page-about .crumb a:hover,
.page-about .crumb a:focus-visible {
  color: var(--mint);
  border-bottom-color: var(--mint);
}

.page-about .about-mast__kicker {
  margin: 1.6rem 0 0;
  font-family: var(--font-label);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--green);
}

.page-about .about-mast__title {
  margin: 1rem 0 0;
  max-width: 16ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 7.4vw, 4.4rem);
  line-height: 1.06;
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .about-mast__lede {
  margin: 1.5rem 0 0;
  max-width: var(--about-col);
  color: var(--mist);
  font-size: 1.0625rem;
  line-height: 1.85;
}

.page-about .about-mast__meta {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

/* ---------- 阶段轴 ---------- */

.page-about .about-axis {
  margin: 0;
  padding: clamp(2.25rem, 6vw, 4.5rem) 0 0;
  list-style: none;
}

.page-about .about-axis__item {
  position: relative;
  padding: 0 0 3.25rem 2.6rem;
}

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

.page-about .about-axis__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: .5rem;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 2px solid var(--green);
  background: var(--deep);
  box-shadow: 0 0 0 4px rgba(53, 224, 138, .09);
}

.page-about .about-axis__item::after {
  content: "";
  position: absolute;
  left: 4.5px;
  top: 1.6rem;
  bottom: .6rem;
  width: 1px;
  background: linear-gradient(180deg, var(--line-strong), var(--line-soft));
}

.page-about .about-axis__item:last-child::after {
  display: none;
}

.page-about .about-axis__idx {
  display: block;
  margin-bottom: .5rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: .8rem;
  letter-spacing: .26em;
  color: var(--cyan);
}

.page-about .about-block__title {
  margin: 0 0 1.1rem;
  max-width: 22ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.45rem, 4.2vw, 2.25rem);
  line-height: 1.18;
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .about-block p {
  max-width: var(--about-col);
  margin: 0 0 1.05rem;
  color: var(--mist);
  font-size: 1rem;
  line-height: 1.85;
}

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

.page-about .about-block strong {
  color: var(--paper);
  font-weight: 700;
}

/* ---------- 四步闭环 ---------- */

.page-about .loop {
  display: grid;
  gap: .7rem;
  margin: 1.9rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .loop__card {
  height: 100%;
  padding: 1rem 1.1rem;
  border: 2px solid var(--line-strong);
  border-left: 4px solid var(--green);
  background: var(--night);
  box-shadow: 4px 4px 0 rgba(6, 16, 31, .85);
}

.page-about .loop__card[open] {
  border-left-color: var(--mint);
}

.page-about .loop__sum {
  display: flex;
  align-items: baseline;
  gap: .6rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .loop__sum:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 3px;
}

.page-about .loop__num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.3rem;
  letter-spacing: .05em;
  color: var(--green);
}

.page-about .loop__name {
  font-family: var(--font-label);
  font-weight: 600;
  font-size: .95rem;
  letter-spacing: .05em;
  color: var(--paper);
}

.page-about .loop__body {
  margin-top: .85rem;
  padding-top: .85rem;
  border-top: 1px dashed var(--line);
}

.page-about .loop__body p {
  margin: 0 0 .6rem;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--mist);
}

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

.page-about .loop__body b {
  color: var(--mint);
  font-weight: 600;
}

/* ---------- 图片 ---------- */

.page-about .figure {
  max-width: var(--about-wide);
  margin: 2rem 0 0;
}

.page-about .figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 终端窗口 ---------- */

.page-about .term-window {
  max-width: var(--about-wide);
  margin: 2rem 0 0;
  border: 2px solid var(--line-strong);
  background: linear-gradient(180deg, var(--ink), var(--night));
  box-shadow: inset 0 1px 0 rgba(168, 245, 200, .09), 6px 6px 0 rgba(6, 16, 31, .85);
}

.page-about .term-window__bar {
  display: flex;
  gap: .4rem;
  padding: .6rem .9rem;
  border-bottom: 1px solid var(--line);
  background: rgba(6, 16, 31, .62);
}

.page-about .term-window__dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--line-strong);
}

.page-about .term-window__dot:first-child {
  background: var(--red);
}

.page-about .term-window__dot:nth-child(2) {
  background: var(--amber);
}

.page-about .term-window__dot:nth-child(3) {
  background: var(--green);
}

.page-about .term-window__body {
  margin: 0;
  padding: 1.1rem 1.3rem;
}

.page-about .term-window__body p {
  margin: 0 0 .55rem;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--mist);
}

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

.page-about .term-window__body span {
  color: var(--green);
  font-weight: 600;
}

/* ---------- 规模数据 ---------- */

.page-about .scale {
  margin-top: 1.6rem;
  border-top: 2px solid var(--line-strong);
}

.page-about .scale__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .scale__item {
  display: grid;
  grid-template-columns: 5.25rem 1fr;
  gap: .4rem 1rem;
  align-items: baseline;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .scale__num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.8rem, 5.5vw, 2.6rem);
  line-height: 1;
  letter-spacing: .01em;
  color: var(--green);
  white-space: nowrap;
}

.page-about .scale__num small {
  margin-left: .15rem;
  font-size: .42em;
  font-weight: 600;
  letter-spacing: .08em;
  color: var(--mist);
}

.page-about .scale__label {
  color: var(--mist);
  font-size: .9375rem;
  line-height: 1.78;
}

.page-about .scale__label b {
  display: block;
  margin-bottom: .2rem;
  color: var(--paper);
  font-weight: 700;
}

/* ---------- 兼容性对照 ---------- */

.page-about .compat {
  max-width: var(--about-wide);
  margin-top: 1.7rem;
  border: 2px solid var(--line-strong);
  background: var(--night);
}

.page-about .compat__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .compat__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: .2rem;
  padding: .85rem 1.1rem;
  border-bottom: 1px solid var(--line-soft);
}

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

.page-about .compat__key {
  font-family: var(--font-label);
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .17em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .compat__val {
  color: var(--paper);
  font-size: .9375rem;
  line-height: 1.72;
}

/* ---------- 联系方式条 ---------- */

.page-about .contact-band {
  display: grid;
  gap: 1px;
  margin-top: 1.7rem;
  border: 2px solid var(--line-strong);
  background: var(--line-soft);
}

.page-about .contact-band__cell {
  padding: 1.05rem 1.15rem;
  background: var(--night);
}

.page-about .contact-band__k {
  display: block;
  margin-bottom: .4rem;
  font-family: var(--font-label);
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .17em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .contact-band__v {
  display: block;
  color: var(--paper);
  font-size: .9875rem;
  line-height: 1.6;
  overflow-wrap: anywhere;
}

/* ---------- 现象入口 ---------- */

.page-about .phenom {
  margin-top: clamp(2rem, 5vw, 3.5rem);
  border: 2px solid var(--line-strong);
  background: var(--line-soft);
}

.page-about .phenom__list {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .phenom__item {
  background: var(--night);
}

.page-about .phenom__item a {
  display: block;
  height: 100%;
  padding: 1.2rem 1.25rem;
  text-decoration: none;
  color: inherit;
  border-left: 3px solid var(--green);
  transition: background .18s ease;
}

.page-about .phenom__item a:hover,
.page-about .phenom__item a:focus-visible {
  background: var(--deep);
}

.page-about .phenom__item b {
  display: block;
  margin-bottom: .35rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.0625rem;
  letter-spacing: .05em;
  color: var(--paper);
}

.page-about .phenom__item span {
  color: var(--mist);
  font-size: .875rem;
  line-height: 1.7;
}

/* ---------- 收尾 ---------- */

.page-about .about-next {
  padding: clamp(2.25rem, 5vw, 3.5rem) 0 clamp(2.5rem, 6vw, 4rem);
}

.page-about .nextlist {
  display: grid;
  gap: 1px;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
  background: var(--line-soft);
  border: 2px solid var(--line-strong);
}

.page-about .nextlist li {
  background: var(--deep);
}

.page-about .nextlist a {
  display: block;
  height: 100%;
  padding: 1.2rem 1.25rem;
  text-decoration: none;
  color: inherit;
  border-left: 3px solid var(--green);
  transition: background .18s ease;
}

.page-about .nextlist a:hover,
.page-about .nextlist a:focus-visible {
  background: var(--night);
}

.page-about .nextlist b {
  display: block;
  margin-bottom: .35rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: .06em;
  color: var(--paper);
}

.page-about .nextlist span {
  color: var(--mist);
  font-size: .875rem;
  line-height: 1.7;
}

/* ---------- 响应式 ---------- */

@media (min-width: 40rem) {
  .page-about .scale__item {
    grid-template-columns: 8rem 1fr;
    gap: 1.6rem;
    padding: 1.35rem 0;
  }

  .page-about .compat__row {
    grid-template-columns: 8.5rem 1fr;
    gap: 1.6rem;
    align-items: baseline;
  }

  .page-about .contact-band {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (min-width: 60rem) {
  .page-about .loop {
    grid-template-columns: repeat(4, 1fr);
    gap: .85rem;
  }

  .page-about .about-axis__item {
    padding-left: 6.5rem;
    padding-bottom: 4.25rem;
  }

  .page-about .about-axis__item::before {
    left: 2rem;
    top: .75rem;
  }

  .page-about .about-axis__item::after {
    left: 36.5px;
    top: 1.85rem;
  }

  .page-about .contact-band {
    grid-template-columns: repeat(3, 1fr);
  }

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

@media (min-width: 76rem) {
  .page-about .about-mast__title {
    max-width: 18ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .phenom__item a,
  .page-about .nextlist a,
  .page-about .crumb a {
    transition: none;
  }
}