.page-about {
  --about-line: rgba(242, 243, 247, 0.12);
  --about-line-strong: rgba(242, 243, 247, 0.26);
  --about-section-space: clamp(56px, 7vw, 104px);
  --about-serif: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --about-mono: 'Roboto Mono', 'SFMono-Regular', Consolas, monospace;
  position: relative;
  color: var(--ink);
  overflow-x: clip;
}

/* ===== Hero ===== */
.page-about .about-hero {
  position: relative;
  padding: 32px 0 72px;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(circle at 82% 20%, rgba(109, 90, 240, 0.16) 0%, transparent 42%),
    linear-gradient(135deg, var(--deep) 0%, var(--canvas) 68%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(-12deg, rgba(255, 255, 255, 0.015) 0px, rgba(255, 255, 255, 0.015) 1px, transparent 1px, transparent 14px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -2%;
  bottom: -1px;
  width: 48%;
  height: 100%;
  background: linear-gradient(200deg, var(--violet) 0%, transparent 70%);
  opacity: 0.12;
  clip-path: polygon(12% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumb {
  margin-bottom: 40px;
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
}

.page-about .about-hero-copy {
  min-width: 0;
}

.page-about .hero-kicker {
  margin: 0 0 16px;
  font-size: 13px;
  font-family: var(--about-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mint);
}

.page-about .about-hero h1 {
  margin: 0 0 24px;
  font-size: clamp(54px, 9vw, 120px);
  font-weight: 300;
  line-height: 1.02;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.page-about .hero-lead {
  max-width: 64ch;
  margin: 0 0 36px;
  font-size: clamp(17px, 1.8vw, 22px);
  line-height: 1.7;
  color: var(--ink-soft);
}

.page-about .hero-lead strong {
  color: var(--ink);
  font-weight: 600;
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.page-about .hero-actions .btn,
.page-about .text-actions .btn,
.page-about .contact-cta .btn {
  min-height: 48px;
  padding: 12px 22px;
  border-radius: 2px;
  font-size: 15px;
}

/* Hero index */
.page-about .about-hero-index {
  min-width: 0;
  border-top: 3px solid var(--orange);
  background: rgba(18, 22, 42, 0.72);
  padding: 22px 20px 18px;
  box-shadow: var(--shadow-hard);
  backdrop-filter: blur(4px);
}

.page-about .index-caption {
  display: block;
  margin-bottom: 10px;
  font-size: 12px;
  font-family: var(--about-mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

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

.page-about .index-list li {
  border-bottom: 1px solid var(--about-line);
}

.page-about .index-list li:last-child {
  border-bottom: 0;
}

.page-about .index-list a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 12px 0;
  text-decoration: none;
  color: var(--ink);
  transition: color 0.2s ease;
}

.page-about .index-list a:hover {
  color: var(--mint);
}

.page-about .index-num {
  font-family: var(--about-mono);
  font-size: 14px;
  color: var(--orange);
  min-width: 2ch;
}

.page-about .index-name {
  font-size: 15px;
  font-weight: 500;
}

/* ===== Layout ===== */
.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  padding-top: 0;
  padding-bottom: 96px;
  align-items: start;
}

.page-about .about-sidebar {
  min-width: 0;
  margin: 0 -16px 8px;
  padding: 12px 16px 0;
  display: flex;
  align-items: stretch;
  gap: 12px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-sidebar::-webkit-scrollbar {
  display: none;
}

.page-about .about-side-nav {
  display: flex;
  gap: 8px;
  white-space: nowrap;
  flex: 0 0 auto;
}

.page-about .side-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  background: var(--surface);
  font-size: 13px;
  line-height: 1;
  color: var(--ink-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.page-about .side-link span {
  font-family: var(--about-mono);
  color: var(--orange);
}

.page-about .side-link:hover {
  border-color: var(--violet);
  color: var(--ink);
}

.page-about .side-link.is-active {
  border-color: var(--violet);
  background: var(--deep);
  color: var(--ink);
  box-shadow: 3px 3px 0 rgba(109, 90, 240, 0.35);
}

.page-about .side-note {
  display: none;
}

/* ===== Content sections ===== */
.page-about .about-content {
  min-width: 0;
}

.page-about .about-section {
  position: relative;
  padding: var(--about-section-space) 0;
  border-bottom: 1px solid var(--border);
}

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

.page-about .about-section-head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .about-section-head .section-index {
  font-family: var(--about-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--orange);
  line-height: 1;
}

.page-about .about-section-head .section-label {
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.page-about .about-section .section-title {
  margin: 6px 0 18px;
  font-size: clamp(30px, 4vw, 54px);
  font-weight: 800;
  line-height: 1.12;
  color: var(--ink);
}

.page-about .section-intro {
  max-width: 70ch;
  margin: 0 0 28px;
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-soft);
}

/* ===== I. Brand ===== */
.page-about .about-brand-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  align-items: start;
}

.page-about .about-brand-text {
  min-width: 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .about-brand-text p {
  margin: 0 0 18px;
}

.page-about .about-quote {
  position: relative;
  margin: 28px 0;
  padding: 18px 22px 18px 26px;
  border-left: 4px solid var(--orange);
  background: var(--surface);
  box-shadow: var(--shadow-hard);
  font-size: 17px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .quote-mark {
  color: var(--orange);
  font-size: 28px;
  line-height: 0;
  margin-right: 4px;
  vertical-align: -6px;
}

.page-about .text-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-brand-visual {
  position: relative;
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--border-strong);
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.38);
}

.page-about .about-brand-visual::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(145deg, transparent 60%, rgba(109, 90, 240, 0.24) 100%);
  pointer-events: none;
}

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

.page-about .visual-caption {
  display: block;
  padding: 10px 14px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

/* ===== II. Timeline ===== */
.page-about .about-timeline {
  list-style: none;
  margin: 32px 0 24px;
  padding: 0;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 16px;
  bottom: 16px;
  width: 2px;
  background: linear-gradient(180deg, var(--violet) 0%, var(--mint) 55%, var(--orange) 100%);
}

.page-about .timeline-item {
  position: relative;
  padding: 0 0 32px 52px;
}

.page-about .timeline-item:last-child {
  padding-bottom: 8px;
}

.page-about .timeline-badge {
  position: absolute;
  left: 0;
  top: 2px;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.page-about .timeline-badge svg {
  display: block;
}

.page-about .timeline-card {
  background: var(--surface);
  border: 1px solid var(--about-line);
  box-shadow: var(--shadow-hard);
  padding: 20px 20px 18px;
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.page-about .timeline-card:hover {
  border-color: var(--violet);
  transform: translateY(-3px);
}

.page-about .timeline-topline {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .timeline-phase {
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
}

.page-about .timeline-card h3 {
  margin: 0 0 8px;
  font-size: 20px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .timeline-card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-soft);
}

.page-about .timeline-footnote {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding: 16px 20px;
  border: 1px dashed var(--border-strong);
  font-size: 14px;
  color: var(--ink-soft);
}

.page-about .timeline-footnote a {
  color: var(--mint);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.page-about .timeline-footnote a:hover {
  border-color: var(--mint);
}

/* ===== III. Ecosystem ===== */
.page-about .channel-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 0 0 28px;
  padding: 0;
}

.page-about .channel-item {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--about-line);
  border-top: 3px solid transparent;
  padding: 18px 16px 16px;
  min-width: 0;
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.page-about .channel-item:hover {
  border-top-color: var(--orange);
  border-color: var(--violet);
  transform: translateY(-4px);
}

.page-about .channel-idx {
  display: block;
  margin-bottom: 12px;
  font-family: var(--about-mono);
  font-size: 13px;
  color: var(--orange);
}

.page-about .channel-item h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .channel-item p {
  margin: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink-soft);
}

.page-about .about-eco-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin: 28px 0;
  align-items: center;
}

.page-about .eco-note {
  border: 2px solid var(--border-strong);
  background: var(--deep);
  padding: 24px 22px;
  position: relative;
}

.page-about .eco-note::after {
  content: "";
  position: absolute;
  right: 0;
  top: 0;
  width: 36px;
  height: 6px;
  background: var(--orange);
}

.page-about .eco-note .tag {
  margin-bottom: 14px;
}

.page-about .eco-note h3 {
  margin: 0 0 12px;
  font-size: 21px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .eco-note p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .eco-visual {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--border-strong);
  filter: saturate(1.08);
}

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

.page-about .about-team-strip {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px 14px;
  padding: 16px 18px;
  background: linear-gradient(120deg, var(--raised), var(--surface));
  border-left: 4px solid var(--violet);
  font-size: 14px;
}

.page-about .team-label {
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.page-about .team-num {
  font-size: 24px;
  font-weight: 800;
  color: var(--gold);
  font-family: var(--about-mono);
}

.page-about .team-sep {
  color: var(--border-strong);
}

.page-about .team-desc {
  color: var(--ink-soft);
  line-height: 1.6;
}

/* ===== IV. Promise ===== */
.page-about .promise-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 0 0 28px;
}

.page-about .stat-item {
  background: var(--surface);
  border: 2px solid var(--about-line);
  border-top: 3px solid var(--gold);
  padding: 20px 14px 16px;
  box-shadow: var(--shadow-hard);
  min-width: 0;
}

.page-about .stat-num {
  display: block;
  font-size: clamp(26px, 3.4vw, 46px);
  font-weight: 300;
  line-height: 1.1;
  color: var(--gold);
  font-family: var(--about-mono);
  letter-spacing: -0.02em;
  word-break: break-word;
}

.page-about .stat-label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.5;
}

.page-about .promise-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 28px 0;
}

.page-about .promise-card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--about-line);
  padding: 20px 18px 18px 18px;
  overflow: hidden;
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.page-about .promise-card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--violet);
  opacity: 0.7;
}

.page-about .promise-card:hover {
  border-color: var(--violet);
  transform: translateY(-3px);
}

.page-about .promise-idx {
  font-family: var(--about-mono);
  font-size: 13px;
  color: var(--orange);
}

.page-about .promise-card h3 {
  margin: 8px 0 8px;
  font-size: 19px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .promise-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-soft);
}

.page-about .promise-bottom {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  align-items: center;
  margin-top: 20px;
}

.page-about .promise-visual {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--border-strong);
}

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

.page-about .promise-note {
  border: 2px solid var(--border-strong);
  background: linear-gradient(145deg, var(--deep) 0%, var(--raised) 100%);
  padding: 28px 24px;
}

.page-about .promise-note .tag {
  margin-bottom: 14px;
}

.page-about .promise-note h3 {
  margin: 0 0 12px;
  font-size: 22px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .promise-note p {
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-soft);
}

/* ===== V. Contact ===== */
.page-about .about-contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 0 0 20px;
}

.page-about .contact-card {
  background: var(--surface);
  border: 1px solid var(--about-line);
  padding: 20px 18px;
  min-width: 0;
  transition: border-color 0.25s ease;
}

.page-about .contact-card:hover {
  border-color: var(--mint);
}

.page-about .contact-type {
  display: block;
  margin-bottom: 8px;
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.page-about .contact-card a {
  font-size: 19px;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
  word-break: break-word;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.page-about .contact-card a:hover {
  color: var(--mint);
  border-color: var(--mint);
}

.page-about .contact-card span:not(.contact-type) {
  font-size: 17px;
  color: var(--ink);
  word-break: break-word;
}

.page-about .contact-service-time {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  padding: 14px 18px;
  border: 1px dashed var(--border-strong);
  margin-bottom: 24px;
}

.page-about .contact-service-time p {
  margin: 0;
  font-size: 15px;
  color: var(--ink-soft);
}

.page-about .contact-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  padding-top: 8px;
}

/* ===== Tablet (≥600px) ===== */
@media (min-width: 600px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 44px;
    align-items: end;
  }

  .page-about .channel-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
  }

  .page-about .promise-stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
  }

  .page-about .promise-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
  }

  .page-about .about-contact-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
  }
}

/* ===== Desktop (≥768px) ===== */
@media (min-width: 768px) {
  .page-about .about-sidebar {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin: 0;
    padding: 0;
    overflow: visible;
  }

  .page-about .about-side-nav {
    flex-direction: column;
    gap: 0;
    white-space: normal;
  }

  .page-about .side-link {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 14px 16px;
    border: 0;
    border-bottom: 1px solid var(--about-line);
    background: transparent;
    font-size: 14px;
    border-left: 3px solid transparent;
  }

  .page-about .side-link:hover {
    background: var(--surface);
    border-left-color: var(--mint);
  }

  .page-about .side-link.is-active {
    background: var(--surface);
    border-left-color: var(--orange);
    box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.28);
  }

  .page-about .side-note {
    display: block;
    border: 1px solid var(--border);
    border-top: 3px solid var(--violet);
    padding: 16px;
    background: var(--surface);
  }

  .page-about .side-note p {
    margin: 14px 0 0;
    font-size: 13px;
    line-height: 1.7;
    color: var(--ink-soft);
  }

  .page-about .about-layout {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: clamp(40px, 5vw, 88px);
    padding-top: 0;
  }

  .page-about .about-brand-grid {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: 44px;
  }

  .page-about .about-eco-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    gap: 24px;
  }

  .page-about .promise-bottom {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 24px;
  }
}

/* ===== Wide Desktop (≥1100px) ===== */
@media (min-width: 1100px) {
  .page-about .about-layout {
    grid-template-columns: 260px minmax(0, 1fr);
  }

  .page-about .about-brand-grid {
    grid-template-columns: minmax(0, 1.15fr) 420px;
  }

  .page-about .about-timeline::before {
    left: 17px;
  }

  .page-about .timeline-item {
    padding-left: 56px;
  }

  .page-about .timeline-card {
    padding: 24px 26px 22px;
  }

  .page-about .timeline-card h3 {
    font-size: 22px;
  }
}