/* ============================================================
   品牌档案 /brand/ —— 页面专属样式
   全部选择器限定在 .page-about 作用域内
   ============================================================ */

.page-about {
  padding-bottom: var(--sp-6);
}

.page-about .breadcrumb {
  margin-top: var(--sp-3);
  font-size: var(--fs-sm);
}

/* ---------------- 首屏框景 ---------------- */

.page-about .about-hero {
  margin-top: var(--sp-3);
  padding: clamp(24px, 4.5vw, 56px) clamp(18px, 3.6vw, 52px) clamp(26px, 4.5vw, 52px);
}

.page-about .hero-kicker {
  margin: 0 0 var(--sp-3);
  font-size: var(--fs-label);
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .hero-title {
  margin: 0;
  max-width: 22ch;
  font-size: clamp(1.9rem, 5vw, 4rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--paper);
}

.page-about .hero-lead {
  margin: var(--sp-3) 0 0;
  max-width: 64ch;
  font-size: var(--fs-base);
  line-height: 1.75;
  color: var(--paper-dim);
}

.page-about .hero-stats {
  list-style: none;
  margin: var(--sp-5) 0 0;
  padding: var(--sp-3) 0 0;
  border-top: 1px solid var(--line-soft);
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-3);
}

.page-about .hero-stat b {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 2.6vw, 2.125rem);
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--cyan);
  line-height: 1.1;
}

.page-about .hero-stat span {
  display: block;
  margin-top: 6px;
  font-size: var(--fs-sm);
  line-height: 1.6;
  color: var(--muted);
}

/* ---------------- 主体骨架 ---------------- */

.page-about .about-layout {
  margin-top: var(--sp-6);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-4);
}

.page-about .about-rail {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  overflow-x: auto;
  padding-bottom: var(--sp-2);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .rail-list {
  display: flex;
  gap: var(--sp-3);
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .rail-link {
  display: block;
  padding: 4px 0 4px 10px;
  border-left: 2px solid transparent;
  font-family: var(--font-mono);
  font-size: var(--fs-label);
  letter-spacing: 0.12em;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible,
.page-about .rail-link[aria-current] {
  color: var(--cyan);
  border-left-color: var(--cyan);
}

.page-about .rail-spine {
  display: none;
  margin: 0;
}

.page-about .about-stream {
  display: flex;
  flex-direction: column;
  gap: var(--sp-6);
  min-width: 0;
}

/* ---------------- 章节通用 ---------------- */

.page-about .about-sec {
  scroll-margin-top: calc(var(--header-h) + 28px);
  min-width: 0;
}

.page-about .sec-head {
  display: flex;
  align-items: baseline;
  gap: var(--sp-2);
  padding-bottom: var(--sp-2);
  margin-bottom: var(--sp-3);
  border-bottom: 1px solid var(--line);
}

.page-about .sec-no {
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .sec-title {
  margin: 0;
  font-size: clamp(1.3125rem, 2.5vw, 1.875rem);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-p {
  margin: 0 0 var(--sp-3);
  max-width: 68ch;
  font-size: var(--fs-base);
  line-height: 1.75;
  color: var(--paper-dim);
}

.page-about .about-sec .about-p:last-of-type {
  margin-bottom: 0;
}

.page-about .inline-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 242, 214, 0.35);
  transition: border-color 200ms var(--ease);
}

.page-about .inline-link:hover,
.page-about .inline-link:focus-visible {
  border-bottom-color: var(--cyan);
}

/* ---------------- 图片 ---------------- */

.page-about .about-figure {
  margin: 0 0 var(--sp-4);
}

.page-about .about-figure .media-frame img,
.page-about .about-band .media-frame img,
.page-about .ver-figure .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-figcap {
  margin-top: 10px;
  font-size: var(--fs-micro);
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .about-band {
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 10px;
}

.page-about .about-band .media-frame {
  width: 100%;
  max-width: 420px;
}

/* ---------------- 工序流程 ---------------- */

.page-about .flow-list {
  list-style: none;
  margin: 0 0 var(--sp-3);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .flow-step {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: var(--sp-3) var(--sp-3) var(--sp-3) var(--sp-4);
  background: var(--ink);
  transition: background 220ms var(--ease);
}

.page-about .flow-step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--line);
  transition: background 220ms var(--ease);
}

.page-about .flow-step:hover::before {
  background: var(--orange);
}

.page-about .flow-step:hover {
  background: var(--glass);
}

.page-about .flow-idx {
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .flow-name {
  margin: 0;
  font-size: var(--fs-lg);
  font-weight: 700;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .flow-desc {
  margin: 0;
  max-width: 62ch;
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--paper-dim);
}

/* ---------------- 三级口径对照 ---------------- */

.page-about .grade-table {
  border: 1px solid var(--line-soft);
  background: var(--ink-2);
  margin-bottom: var(--sp-3);
}

.page-about .grade-head {
  display: none;
}

.page-about .grade-row {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: var(--sp-3) var(--sp-3) var(--sp-3) var(--sp-4);
  border-bottom: 1px solid var(--line-soft);
  transition: background 220ms var(--ease);
}

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

.page-about .grade-row::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
}

.page-about .grade-row.is-live::before {
  background: var(--amber);
}

.page-about .grade-row.is-first::before {
  background: var(--muted);
}

.page-about .grade-row.is-calibrated::before {
  background: var(--cyan);
}

.page-about .grade-row:hover {
  background: var(--glass);
}

.page-about .grade-name {
  font-size: var(--fs-lg);
  line-height: 1.3;
  color: var(--paper);
}

.page-about .grade-row.is-live .grade-name {
  color: var(--amber);
}

.page-about .grade-row.is-first .grade-name {
  color: var(--paper-dim);
}

.page-about .grade-row.is-calibrated .grade-name {
  color: var(--cyan);
}

.page-about .grade-def,
.page-about .grade-use {
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--paper-dim);
}

.page-about .grade-time {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-sm);
  color: var(--muted);
}

/* ---------------- 团队构成 ---------------- */

.page-about .team-compose {
  margin-bottom: var(--sp-3);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-4);
}

.page-about .team-dots {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 8px;
  align-content: start;
}

.page-about .dot {
  display: block;
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: 2px;
}

.page-about .dot--record {
  background: var(--grass);
}

.page-about .dot--check {
  background: var(--cyan);
}

.page-about .dot--tech {
  background: var(--muted);
}

.page-about .dot--ops {
  background: var(--amber);
}

.page-about .team-legend {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .team-item {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 12px var(--sp-2);
  background: var(--ink);
}

.page-about .team-key {
  display: block;
  width: 12px;
  height: 12px;
  border-radius: 2px;
}

.page-about .team-role {
  font-size: var(--fs-base);
  color: var(--paper);
}

.page-about .team-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-lg);
  font-weight: 500;
  color: var(--cyan);
}

.page-about .team-desc {
  grid-column: 2 / -1;
  font-size: var(--fs-micro);
  line-height: 1.6;
  color: var(--muted);
}

/* ---------------- 版本演进 ---------------- */

.page-about .ver-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-4);
  margin-bottom: var(--sp-3);
}

.page-about .ver-jump {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-1);
  margin-bottom: var(--sp-3);
}

.page-about .ver-jump a {
  padding: 4px 12px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: var(--fs-label);
  letter-spacing: 0.1em;
  color: var(--muted);
  text-decoration: none;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .ver-jump a:hover,
.page-about .ver-jump a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .ver-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-3);
}

.page-about .ver-node {
  position: relative;
  padding-left: var(--sp-3);
  border-left: 2px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 28px);
}

.page-about .ver-no {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-xl);
  font-weight: 500;
  line-height: 1.1;
  color: var(--paper-dim);
}

.page-about .ver-node.is-current .ver-no {
  color: var(--cyan);
}

.page-about .ver-node.is-current {
  border-left-color: var(--cyan);
}

.page-about .ver-title {
  margin: 6px 0 6px;
  font-size: var(--fs-base);
  font-weight: 600;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .ver-text {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--paper-dim);
}

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

/* ---------------- 赛季专题结构 ---------------- */

.page-about .season-parts {
  list-style: none;
  margin: 0 0 var(--sp-3);
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-3);
}

.page-about .season-part {
  padding: var(--sp-3);
  border: 1px solid var(--line-soft);
  border-top: 2px solid var(--grass);
  background: var(--ink-2);
}

.page-about .season-part:nth-child(2) {
  border-top-color: var(--cyan);
}

.page-about .season-part:nth-child(3) {
  border-top-color: var(--orange);
}

.page-about .season-part:nth-child(4) {
  border-top-color: var(--amber);
}

.page-about .part-idx {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .part-name {
  margin: 8px 0 8px;
  font-size: var(--fs-lg);
  font-weight: 700;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .part-text {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--paper-dim);
}

/* ---------------- 内容边界 ---------------- */

.page-about .about-sec--short .sec-head {
  margin-bottom: var(--sp-3);
}

.page-about .boundary-list {
  list-style: none;
  margin: 0 0 var(--sp-3);
  padding: 0;
}

.page-about .boundary-item {
  position: relative;
  padding: var(--sp-2) 0 var(--sp-2) var(--sp-4);
  border-bottom: 1px solid var(--line-soft);
  font-size: var(--fs-base);
  line-height: 1.7;
  color: var(--paper);
}

.page-about .boundary-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: calc(var(--sp-2) + 0.72em);
  width: 14px;
  height: 2px;
  background: var(--orange);
}

/* ---------------- 章节小结数据点 ---------------- */

.page-about .digest {
  position: relative;
  display: inline-block;
  margin: var(--sp-4) 0 0;
  padding: 10px 14px;
  border: 1px solid var(--line);
  background: var(--glass);
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--paper-dim);
  cursor: help;
}

.page-about .digest::before {
  content: "";
  position: absolute;
  left: -1px;
  top: -1px;
  bottom: -1px;
  width: 3px;
  background: var(--cyan);
}

.page-about .digest::after {
  content: attr(data-note);
  position: absolute;
  left: 0;
  bottom: calc(100% + 8px);
  width: max-content;
  max-width: 260px;
  padding: 8px 10px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  font-size: var(--fs-micro);
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: var(--muted);
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  pointer-events: none;
  z-index: 3;
  transition: opacity 200ms var(--ease), transform 200ms var(--ease), visibility 200ms;
}

.page-about .digest:hover::after,
.page-about .digest:focus-visible::after {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

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

/* ============================================================
   断点：平板
   ============================================================ */

@media (min-width: 720px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
  }

  .page-about .hero-stat + .hero-stat {
    padding-left: var(--sp-3);
    border-left: 1px solid var(--line-soft);
  }

  .page-about .flow-step {
    grid-template-columns: 64px 180px minmax(0, 1fr);
    align-items: baseline;
    gap: var(--sp-3);
  }

  .page-about .flow-idx {
    padding-top: 4px;
  }

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

/* ============================================================
   断点：桌面
   ============================================================ */

@media (min-width: 900px) {
  .page-about .grade-head {
    display: grid;
    grid-template-columns: 130px minmax(0, 1.4fr) 170px minmax(0, 1fr);
    gap: var(--sp-3);
    padding: var(--sp-2) var(--sp-3) var(--sp-2) var(--sp-4);
    border-bottom: 1px solid var(--line);
    font-size: var(--fs-micro);
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--muted);
  }

  .page-about .grade-row {
    grid-template-columns: 130px minmax(0, 1.4fr) 170px minmax(0, 1fr);
    gap: var(--sp-3);
    align-items: baseline;
  }

  .page-about .team-compose {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: var(--sp-4);
    align-items: start;
  }

  .page-about .team-dots {
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
  }

  .page-about .ver-body {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: var(--sp-5);
    align-items: start;
  }

  .page-about .ver-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--sp-4);
    position: relative;
  }

  .page-about .ver-track::before {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    top: 8px;
    height: 2px;
    background: linear-gradient(90deg, var(--muted) 0%, var(--cyan) 58%, var(--orange) 100%);
    opacity: 0.85;
  }

  .page-about .ver-node {
    padding-left: 0;
    padding-top: var(--sp-4);
    border-left: 0;
  }

  .page-about .ver-node::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--ink);
    border: 2px solid var(--muted);
  }

  .page-about .ver-node:last-child::before {
    border-color: var(--orange);
  }

  .page-about .ver-node.is-current::before {
    border-color: var(--cyan);
    box-shadow: 0 0 0 5px rgba(53, 242, 214, 0.14);
    animation: aboutPulse 3.2s var(--ease) infinite;
  }
}

/* ============================================================
   断点：宽屏纵读版式
   ============================================================ */

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 64px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    display: block;
    overflow: visible;
    padding-bottom: 0;
    border-bottom: 0;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: var(--sp-2);
  }

  .page-about .rail-link {
    font-size: var(--fs-sm);
  }

  .page-about .rail-spine {
    display: block;
    margin-top: var(--sp-4);
    writing-mode: vertical-rl;
    max-height: 320px;
    font-size: var(--fs-micro);
    letter-spacing: 0.4em;
    text-transform: uppercase;
    color: var(--muted);
    opacity: 0.75;
  }

  .page-about .about-stream {
    gap: var(--sp-7);
  }
}

@keyframes aboutPulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.75;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ver-node.is-current::before {
    animation: none;
  }

  .page-about .flow-step,
  .page-about .grade-row,
  .page-about .digest::after,
  .page-about .rail-link,
  .page-about .ver-jump a {
    transition: none;
  }
}