.page-about {
  --about-notch: 14px;
  --about-rule: rgba(255, 255, 255, 0.06);
  background-color: var(--ink-900);
  color: var(--mist);
  overflow-x: clip;
}

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

.page-about .about-crumb {
  padding-top: clamp(20px, 3vw, 32px);
}

/* ---------- 封面 ---------- */
.page-about .about-cover {
  position: relative;
  padding: clamp(26px, 5vw, 54px) 0 clamp(40px, 6vw, 76px);
  background-image:
    repeating-linear-gradient(to right, var(--about-rule) 0 1px, transparent 1px 76px),
    repeating-linear-gradient(to bottom, var(--about-rule) 0 1px, transparent 1px 76px);
}

.page-about .about-cover::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(115% 78% at 16% 0%, rgba(226, 58, 46, 0.16), transparent 62%);
  pointer-events: none;
}

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

.page-about .about-cover__grid {
  display: grid;
  gap: clamp(28px, 4vw, 44px);
  grid-template-columns: 1fr;
  align-items: start;
}

.page-about .about-cover__kicker {
  color: var(--amber);
  margin: 0 0 14px;
}

.page-about .about-cover__title {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 5.6vw, 3.9rem);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--mist);
}

.page-about .about-cover__intro {
  margin: 0;
  max-width: 34em;
  font-size: clamp(0.98rem, 1.2vw, 1.08rem);
  line-height: 1.88;
  color: var(--mist);
  opacity: 0.86;
}

.page-about .about-cover__index {
  border-left: 2px solid var(--maple);
  padding-left: 18px;
}

.page-about .about-cover__index-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--slate);
}

.page-about .about-cover__index ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-cover__index a {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 8px 0;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid var(--about-rule);
  font-size: 0.94rem;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.page-about .about-cover__index a .mono {
  color: var(--cyan);
  font-size: var(--step--1);
  flex: 0 0 auto;
}

.page-about .about-cover__index a:hover {
  color: var(--cyan);
  padding-left: 6px;
}

.page-about .about-cover__index a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

/* ---------- 概览数字 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: clamp(32px, 5vw, 56px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .about-stat {
  background: var(--ink-800);
  padding: 20px 18px 22px;
}

.page-about .about-stat__num {
  display: block;
  font-size: clamp(1.7rem, 3.4vw, 2.5rem);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--mist);
}

.page-about .about-stat:nth-child(1) .about-stat__num { color: var(--cyan); }
.page-about .about-stat:nth-child(2) .about-stat__num { color: var(--amber); }
.page-about .about-stat:nth-child(4) .about-stat__num { color: var(--maple); }

.page-about .about-stat__label {
  display: block;
  margin-top: 10px;
  font-size: var(--step--1);
  line-height: 1.5;
  color: var(--slate);
  letter-spacing: 0.02em;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  position: relative;
  padding: clamp(48px, 7vw, 96px) 0;
}

.page-about .about-chapter + .about-chapter {
  border-top: 1px solid var(--about-rule);
}

.page-about .about-chapter__grid {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
  grid-template-columns: 1fr;
}

.page-about .chapter-num {
  position: relative;
  display: inline-block;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 4.6vw, 3rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--maple);
}

.page-about .chapter-num::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -9px;
  width: 100%;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.4s var(--ease);
}

.page-about .chapter-num.is-visible::after {
  transform: scaleX(1);
}

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

.page-about .about-chapter__body > .section-title {
  margin: 0 0 16px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(1.35rem, 2.6vw, 1.9rem);
  line-height: 1.3;
  color: var(--mist);
}

.page-about .about-chapter__body > .lead {
  max-width: 34em;
  margin: 0 0 clamp(24px, 3.4vw, 36px);
  font-size: clamp(0.98rem, 1.25vw, 1.08rem);
  line-height: 1.88;
  color: var(--mist);
  opacity: 0.86;
}

.page-about .about-quote {
  margin: 0;
  padding: 18px 0 18px 18px;
  border-left: 2px solid var(--maple);
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.06), transparent 72%);
  backdrop-filter: blur(4px);
  font-family: var(--font-serif);
  font-size: clamp(1rem, 1.4vw, 1.18rem);
  line-height: 1.72;
  color: var(--mist);
}

/* ---------- 小组分工 ---------- */
.page-about .role-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: 1fr;
  margin-bottom: clamp(24px, 3.4vw, 40px);
}

.page-about .role-card {
  position: relative;
  padding: 22px 20px 24px;
  background: var(--glass);
  border: 1px solid var(--about-rule);
  clip-path: polygon(
    var(--about-notch) 0,
    100% 0,
    100% calc(100% - var(--about-notch)),
    calc(100% - var(--about-notch)) 100%,
    0 100%,
    0 var(--about-notch)
  );
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .role-card:hover,
.page-about .role-card:focus-within {
  transform: translateY(-4px);
  border-color: var(--cyan);
  background: var(--glass-strong);
}

.page-about .role-card__head {
  display: flex;
  align-items: baseline;
  gap: 5px;
  margin: 0 0 10px;
}

.page-about .role-card__num {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .role-card__unit {
  font-size: var(--step--1);
  color: var(--slate);
  letter-spacing: 0.1em;
}

.page-about .role-card__name {
  margin: 0 0 10px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-1);
  color: var(--mist);
}

.page-about .role-card__desc {
  margin: 0 0 14px;
  font-size: 0.94rem;
  line-height: 1.82;
  color: var(--mist);
  opacity: 0.82;
}

.page-about .role-card__out {
  margin: 0;
  padding-top: 12px;
  border-top: 1px dashed var(--about-rule);
  font-family: var(--font-mono);
  font-size: var(--step--1);
  line-height: 1.6;
  color: var(--amber);
  letter-spacing: 0.02em;
}

/* ---------- 作业流程 ---------- */
.page-about .flow {
  list-style: none;
  margin: 0 0 clamp(24px, 3.4vw, 40px);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .flow-step {
  display: grid;
  gap: 6px 18px;
  grid-template-columns: 44px minmax(0, 1fr);
  padding: 20px 20px 22px;
  background: var(--ink-800);
  transition: background-color var(--dur) var(--ease);
}

.page-about .flow-step:hover {
  background: #16223c;
}

.page-about .flow-step__num {
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: var(--cyan);
  padding-top: 3px;
}

.page-about .flow-step__title {
  margin: 0 0 6px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-1);
  color: var(--mist);
}

.page-about .flow-step__text {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.82;
  color: var(--slate);
}

/* ---------- 版本时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  position: relative;
  margin: 0;
  padding: 6px 0 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 14px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(39, 224, 208, 0.06));
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 26px 36px;
  outline: none;
}

.page-about .timeline__item:last-child {
  padding-bottom: 4px;
}

.page-about .timeline__item:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
}

.page-about .timeline__dot {
  position: absolute;
  left: 1px;
  top: 7px;
  width: 15px;
  height: 15px;
  border: 1px solid var(--cyan);
  background: var(--ink-900);
  transform: rotate(45deg);
  transition: background-color var(--dur) var(--ease);
}

.page-about .timeline__item:hover .timeline__dot,
.page-about .timeline__item:focus-within .timeline__dot {
  background: var(--cyan);
}

.page-about .timeline__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  margin: 0;
}

.page-about .timeline__ver {
  font-size: var(--step--1);
  letter-spacing: 0.06em;
  color: var(--amber);
  padding: 2px 8px;
  border: 1px solid rgba(242, 179, 61, 0.35);
}

.page-about .timeline__title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-1);
  color: var(--mist);
}

.page-about .timeline__notes-wrap {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--dur-slow) var(--ease);
}

.page-about .timeline__item:hover .timeline__notes-wrap,
.page-about .timeline__item:focus-within .timeline__notes-wrap {
  grid-template-rows: 1fr;
}

.page-about .timeline__notes {
  list-style: none;
  margin: 0;
  padding: 0;
  min-height: 0;
  overflow: hidden;
}

.page-about .timeline__notes li {
  position: relative;
  padding: 0 0 0 16px;
  margin-top: 8px;
  font-size: 0.92rem;
  line-height: 1.78;
  color: var(--slate);
}

.page-about .timeline__notes li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 6px;
  height: 1px;
  background: var(--cyan);
}

@media (hover: none) {
  .page-about .timeline__notes-wrap {
    grid-template-rows: 1fr;
  }
}

/* ---------- 内容栏目 ---------- */
.page-about .column-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .column-item {
  display: grid;
  gap: 8px;
  grid-template-columns: 1fr;
  padding: 20px 0;
  border-bottom: 1px solid var(--about-rule);
  transition: padding-left var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .column-item:hover {
  padding-left: 10px;
  background: linear-gradient(90deg, rgba(39, 224, 208, 0.07), transparent 62%);
}

.page-about .column-item__head {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}

.page-about .column-item__name {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-1);
  color: var(--mist);
}

.page-about .column-item__desc {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.82;
  color: var(--slate);
}

/* ---------- 外部参照 ---------- */
.page-about .trust-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: 1fr;
  margin-bottom: 22px;
}

.page-about .trust-card {
  padding: 24px 22px 26px;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--about-rule);
  clip-path: polygon(
    0 0,
    100% 0,
    100% calc(100% - var(--about-notch)),
    calc(100% - var(--about-notch)) 100%,
    0 100%
  );
}

.page-about .trust-card__score {
  display: block;
  margin: 0 0 14px;
  font-size: clamp(2.1rem, 4.4vw, 3.1rem);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .trust-card__score span {
  margin-left: 6px;
  font-size: 0.9rem;
  color: var(--slate);
}

.page-about .trust-card__name {
  margin: 0 0 8px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-0);
  color: var(--mist);
}

.page-about .trust-card__desc {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--slate);
}

.page-about .trust-note {
  margin: 0;
  padding-left: 16px;
  border-left: 2px solid var(--amber);
  font-size: 0.94rem;
  line-height: 1.82;
  color: var(--mist);
  opacity: 0.84;
}

/* ---------- 联系与反馈 ---------- */
.page-about .reach-list {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}

.page-about .reach-item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 10px;
  padding: 20px;
  background: var(--glass);
  border: 1px solid var(--about-rule);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .reach-item:hover {
  transform: translateY(-4px);
  border-color: var(--cyan);
}

.page-about .reach-item h3 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--step-0);
  color: var(--mist);
}

.page-about .reach-item p {
  margin: 0;
  flex: 1 1 auto;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--slate);
}

.page-about .reach-contact {
  display: grid;
  gap: 12px;
  padding: 20px 22px;
  background: var(--ink-800);
  border: 1px solid var(--about-rule);
}

.page-about .reach-contact__item {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .reach-contact__key {
  display: block;
  margin-bottom: 4px;
  font-size: var(--step--1);
  letter-spacing: 0.12em;
  color: var(--slate);
}

.page-about .reach-contact__item .mono {
  color: var(--cyan);
  word-break: break-all;
}

.page-about .reach-note {
  margin: 12px 0 0;
  font-size: 0.86rem;
  line-height: 1.78;
  color: var(--slate);
}

.page-about .about-cta {
  display: grid;
  gap: 18px;
  margin-top: clamp(30px, 4vw, 44px);
  padding: clamp(22px, 3.4vw, 34px);
  background: var(--ink-800);
  border: 1px solid var(--about-rule);
  border-left: 3px solid var(--maple);
}

.page-about .about-cta p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(1.02rem, 1.5vw, 1.22rem);
  line-height: 1.7;
  color: var(--mist);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .role-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .reach-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .flow-step {
    grid-template-columns: 62px minmax(0, 1fr);
  }

  .page-about .column-item {
    grid-template-columns: 200px minmax(0, 1fr);
    column-gap: 30px;
    align-items: start;
  }

  .page-about .trust-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .reach-contact {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }
}

@media (min-width: 768px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 76px minmax(0, 1fr);
  }

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

  .page-about .about-chapter__body {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-chapter__side {
    grid-column: 2;
    grid-row: 2;
  }
}

@media (min-width: 860px) {
  .page-about .reach-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .page-about .about-cover__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(240px, 0.85fr);
  }

  .page-about .role-card:nth-child(even) {
    margin-top: 34px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 88px minmax(0, 1fr) 258px;
  }

  .page-about .about-chapter__side {
    grid-column: 3;
    grid-row: 1;
  }
}