.page-about {
  --cut: 18px;
  --about-blue: var(--bg-deep-blue);
  --about-green: var(--bg-deep-green);
  background: var(--bg);
  color: var(--text-main);
  font-family: var(--font-body);
}

.page-about .container {
  width: 100%;
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: 1rem;
}

.page-about .breadcrumb {
  padding: 1rem 0 0.25rem;
  font-size: 0.8rem;
  color: var(--text-sub);
}

.page-about .breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0;
  padding: 0;
}

.page-about .breadcrumb li + li::before {
  content: '/';
  margin-right: 0.5rem;
  color: var(--text-sub);
}

.page-about .breadcrumb a {
  color: var(--text-sub);
  text-decoration: none;
}

.page-about .breadcrumb a[aria-current="page"] {
  color: var(--accent);
}

.page-about .about-hero {
  padding: 1.5rem 0 2.5rem;
  position: relative;
}

.page-about .about-hero::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 120px;
  height: 120px;
  background: linear-gradient(135deg, transparent 50%, var(--card-orange) 50%, var(--card-orange) 56%, transparent 56%);
  opacity: 0.55;
}

.page-about .hero-kicker {
  margin: 0 0 0.6rem;
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--text-sub);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  font-family: var(--font-head);
  font-size: clamp(1.9rem, 5vw, 3.5rem);
  line-height: 1.1;
  margin: 0;
  padding-left: 0.8rem;
  border-left: 6px solid var(--accent);
}

.page-about .page-lead {
  margin: 1rem 0 0;
  max-width: 44rem;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-sub);
}

.page-about .about-layout {
  display: block;
  gap: 2rem;
}

.page-about .about-toc {
  background: var(--about-blue);
  border-left: 4px solid var(--accent);
  padding: 1rem;
  margin-bottom: 1.5rem;
}

.page-about .toc-label {
  margin: 0 0 0.5rem;
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--accent);
  text-transform: uppercase;
}

.page-about .toc-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1rem;
}

.page-about .toc-nav a {
  display: inline-block;
  padding: 0.35rem 0;
  font-size: 0.86rem;
  color: var(--text-main);
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.page-about .toc-nav a:hover,
.page-about .toc-nav a[aria-current="true"] {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.page-about .about-toc-btn {
  margin-top: 1rem;
}

.page-about .about-main {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.page-about .about-section {
  position: relative;
  padding: 1.5rem;
  background: var(--about-blue);
  border-top: 4px solid var(--card-teal);
}

.page-about .about-section::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, transparent 50%, rgba(0, 0, 0, 0.18) 50%);
}

.page-about .about-section--scope {
  background: var(--about-blue);
  border-top-color: var(--card-teal);
}

.page-about .about-section--dimensions {
  background: var(--about-green);
  border-top-color: var(--card-yellow);
}

.page-about .about-section--updates {
  background: var(--about-blue);
  border-top-color: var(--card-orange);
}

.page-about .about-section--search {
  background: var(--about-green);
  border-top-color: var(--accent);
}

.page-about .about-section--versions {
  background: var(--about-blue);
  border-top-color: var(--card-teal);
}

.page-about .about-section--feedback {
  background: var(--about-green);
  border-top-color: var(--card-yellow);
}

.page-about .section-head {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: 1.25rem;
}

.page-about .section-head h2 {
  font-family: var(--font-head);
  font-size: clamp(1.3rem, 3vw, 2rem);
  margin: 0;
}

.page-about .section-meta {
  font-size: 0.78rem;
  color: var(--text-sub);
}

.page-about .scope-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.page-about .scope-lead {
  margin: 0 0 1rem;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text-main);
}

.page-about .scope-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.page-about .scope-stats li {
  background: rgba(255, 255, 255, 0.05);
  padding: 0.8rem;
  border-left: 4px solid var(--card-yellow);
}

.page-about .scope-stats li:nth-child(2) {
  border-left-color: var(--card-orange);
}

.page-about .scope-stats li:nth-child(3) {
  border-left-color: var(--card-teal);
}

.page-about .scope-stats li:nth-child(4) {
  border-left-color: var(--accent);
}

.page-about .stat-num {
  display: block;
  font-size: 1.7rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--card-yellow);
}

.page-about .stat-label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-sub);
  margin-top: 0.2rem;
}

.page-about .scope-chart,
.page-about .dimension-figure,
.page-about .device-figure {
  margin-top: 0.5rem;
}

.page-about .scope-chart img,
.page-about .dimension-figure img,
.page-about .device-figure img {
  display: block;
  width: 100%;
  height: auto;
  background: var(--bg);
  border: 1px solid var(--border);
}

.page-about .dimension-stack {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

.page-about .dim-col {
  padding: 1.25rem;
  background: rgba(255, 255, 255, 0.05);
  border-bottom: 4px solid var(--card-teal);
}

.page-about .dim-col--league {
  border-bottom-color: var(--card-orange);
}

.page-about .dim-col--date {
  border-bottom-color: var(--card-yellow);
}

.page-about .dim-col--replay {
  border-bottom-color: var(--accent);
}

.page-about .dim-step {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  text-transform: uppercase;
  background: rgba(0, 0, 0, 0.25);
  padding: 0.2rem 0.5rem;
}

.page-about .dim-col h3 {
  font-family: var(--font-head);
  font-size: 1.1rem;
  margin: 0.6rem 0 0.4rem;
}

.page-about .dim-desc {
  margin: 0 0 0.8rem;
  font-size: 0.86rem;
  line-height: 1.7;
  color: var(--text-sub);
}

.page-about .league-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-about .tag {
  font-size: 0.74rem;
  padding: 0.3rem 0.6rem;
  background: var(--card-teal);
  color: var(--bg);
  font-weight: 700;
  border-radius: 2px;
}

.page-about .tag--red {
  background: var(--tag-red);
  color: #fff;
}

.page-about .tag--blue {
  background: var(--tag-blue);
  color: #fff;
}

.page-about .tag--yellow {
  background: var(--tag-yellow);
  color: var(--bg);
}

.page-about .dim-arrow {
  text-align: center;
  font-size: 1.6rem;
  line-height: 1;
  color: var(--accent);
  font-weight: 700;
}

.page-about .date-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-about .date-block {
  background: var(--bg);
  color: var(--text-main);
  border: 1px solid var(--border);
  padding: 0.3rem 0.55rem;
  font-size: 0.75rem;
}

.page-about .replay-sample {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
}

.page-about .badge {
  font-size: 0.7rem;
  padding: 0.25rem 0.5rem;
  border-radius: 2px;
  font-weight: 700;
}

.page-about .badge--replay {
  background: var(--replay-green);
  color: var(--bg);
}

.page-about .badge--hd {
  background: var(--card-yellow);
  color: var(--bg);
}

.page-about .badge--new {
  background: var(--card-orange);
  color: #fff;
}

.page-about .batch-sample {
  display: block;
  width: 100%;
  margin-top: 0.4rem;
  font-size: 0.78rem;
  color: var(--text-sub);
}

.page-about .update-intro {
  margin-bottom: 1rem;
  font-size: 0.9rem;
  line-height: 1.8;
}

.page-about .update-intro .mono {
  background: rgba(0, 0, 0, 0.3);
  padding: 0.15rem 0.4rem;
  color: var(--accent);
  font-size: 0.82rem;
}

.page-about .batch-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.7rem;
}

.page-about .batch-cell {
  background: rgba(255, 255, 255, 0.05);
  padding: 0.75rem;
  border-left: 4px solid var(--card-orange);
  border-bottom: 1px solid var(--border);
}

.page-about .batch-grid .batch-cell:nth-child(4n+2) {
  border-left-color: var(--card-teal);
}

.page-about .batch-grid .batch-cell:nth-child(4n+3) {
  border-left-color: var(--card-yellow);
}

.page-about .batch-grid .batch-cell:nth-child(4n) {
  border-left-color: var(--accent);
}

.page-about .batch-time {
  display: block;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--card-yellow);
}

.page-about .batch-index {
  display: block;
  font-size: 0.74rem;
  color: var(--text-sub);
  margin-top: 0.1rem;
}

.page-about .batch-count {
  display: inline-block;
  margin-top: 0.3rem;
  font-size: 0.78rem;
  color: var(--text-main);
  background: rgba(0, 0, 0, 0.25);
  padding: 0.15rem 0.45rem;
}

.page-about .update-foot {
  margin-top: 1.25rem;
}

.page-about .btn {
  display: inline-block;
  font-family: var(--font-body);
  font-weight: 700;
  text-decoration: none;
  font-size: 0.86rem;
}

.page-about .btn--compact {
  padding: 0.5rem 0.8rem;
}

.page-about .btn--outline {
  border: 2px solid var(--accent);
  color: var(--accent);
  background: transparent;
}

.page-about .btn--yellow {
  background: var(--card-yellow);
  color: var(--bg);
}

.page-about .btn--teal {
  background: var(--card-teal);
  color: var(--bg);
}

.page-about .filter-board {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

.page-about .filter-row {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.page-about .filter-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--accent);
  text-transform: uppercase;
}

.page-about .filter-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-about .filter-dates,
.page-about .filter-batches {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-about .date-chip {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text-main);
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
}

.page-about .date-chip--active {
  background: var(--card-orange);
  border-color: var(--card-orange);
  color: #fff;
  font-weight: 700;
}

.page-about .batch-chip {
  background: rgba(0, 0, 0, 0.28);
  color: var(--text-main);
  border: 1px solid var(--border);
  padding: 0.35rem 0.7rem;
  font-size: 0.78rem;
}

.page-about .tag-cloud {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.45rem;
}

.page-about .cloud-tag {
  display: inline-block;
  background: rgba(255, 255, 255, 0.07);
  color: var(--text-main);
  border: 1px solid var(--border);
  padding: 0.3rem 0.7rem;
  border-radius: 3px;
  font-size: 0.76rem;
}

.page-about .cloud-tag--xl {
  font-size: 1.05rem;
  font-weight: 800;
  background: var(--card-orange);
  color: var(--bg);
  border-color: var(--card-orange);
}

.page-about .cloud-tag--lg {
  font-size: 0.94rem;
  font-weight: 700;
}

.page-about .cloud-tag--md {
  font-size: 0.84rem;
}

.page-about .cloud-tag--teal {
  background: rgba(0, 194, 168, 0.16);
  color: var(--card-teal);
  border-color: rgba(0, 194, 168, 0.4);
}

.page-about .cloud-tag--rose {
  background: rgba(255, 59, 48, 0.14);
  color: #ff8a80;
  border-color: rgba(255, 59, 48, 0.35);
}

.page-about .cloud-tag--yellow {
  background: rgba(255, 209, 102, 0.18);
  color: var(--card-yellow);
  border-color: rgba(255, 209, 102, 0.4);
}

.page-about .cloud-tag--green {
  background: rgba(0, 200, 83, 0.15);
  color: #69f0ae;
  border-color: rgba(0, 200, 83, 0.35);
}

.page-about .keyword-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 0.55rem 0.75rem;
}

.page-about .keyword-prefix {
  color: var(--accent);
  font-size: 0.8rem;
  background: rgba(0, 0, 0, 0.35);
  padding: 0.2rem 0.4rem;
}

.page-about .keyword-text {
  flex: 1;
  font-size: 0.85rem;
  color: var(--text-sub);
}

.page-about .keyword-go {
  background: var(--card-yellow);
  color: var(--bg);
  font-weight: 700;
  font-size: 0.8rem;
  padding: 0.35rem 0.7rem;
}

.page-about .version-panels {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.page-about .version-panel {
  background: rgba(255, 255, 255, 0.05);
  padding: 1.25rem;
  border-top: 4px solid var(--card-orange);
}

.page-about .version-panel--devices {
  border-top-color: var(--card-teal);
}

.page-about .version-title {
  font-family: var(--font-head);
  font-size: 1.05rem;
  margin: 0 0 0.8rem;
}

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

.page-about .version-features li {
  padding: 0.45rem 0;
  border-bottom: 1px dashed var(--border);
  font-size: 0.88rem;
  line-height: 1.6;
}

.page-about .version-features li::before {
  content: '›';
  color: var(--accent);
  margin-right: 0.5rem;
  font-weight: 700;
}

.page-about .device-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.55rem;
}

.page-about .device-item {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  background: rgba(0, 0, 0, 0.25);
  padding: 0.7rem;
  border-left: 4px solid var(--card-teal);
}

.page-about .device-item--mobile {
  border-left-color: var(--card-orange);
}

.page-about .device-item--desktop {
  border-left-color: var(--card-teal);
}

.page-about .device-item--dlna {
  border-left-color: var(--card-yellow);
}

.page-about .device-item--airplay {
  border-left-color: var(--accent);
}

.page-about .device-name {
  font-size: 0.8rem;
  color: var(--text-main);
  font-weight: 700;
}

.page-about .device-desc {
  font-size: 0.74rem;
  color: var(--text-sub);
}

.page-about .feedback-intro {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--text-sub);
}

.page-about .contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.7rem;
}

.page-about .contact-card {
  background: rgba(255, 255, 255, 0.05);
  padding: 0.9rem 1rem;
  border-left: 4px solid var(--card-orange);
}

.page-about .contact-card:nth-child(2) {
  border-left-color: var(--card-teal);
}

.page-about .contact-card:nth-child(3) {
  border-left-color: var(--card-yellow);
}

.page-about .contact-card:nth-child(4) {
  border-left-color: var(--accent);
}

.page-about .contact-label {
  display: block;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-sub);
}

.page-about .contact-value {
  display: block;
  font-size: 0.95rem;
  font-weight: 700;
  margin-top: 0.25rem;
  word-break: break-all;
}

.page-about .feedback-btn {
  margin-top: 1.2rem;
}

@media (min-width: 720px) {
  .page-about .scope-stats {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

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

  .page-about .filter-row {
    flex-direction: row;
    align-items: baseline;
    gap: 1rem;
  }

  .page-about .filter-label {
    min-width: 5.5rem;
  }
}

@media (min-width: 920px) {
  .page-about .about-layout {
    display: grid;
    grid-template-columns: 230px minmax(0, 1fr);
    gap: 2.5rem;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 1.5rem;
    margin-bottom: 0;
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }

  .page-about .toc-nav {
    flex-direction: column;
    gap: 0.15rem;
  }

  .page-about .scope-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    align-items: center;
  }

  .page-about .dimension-stack {
    display: grid;
    grid-template-columns: 1fr auto 1fr auto 1fr;
    gap: 1rem 0.6rem;
    align-items: stretch;
  }

  .page-about .dim-arrow {
    align-self: center;
  }

  .page-about .batch-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .version-panels {
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
  }

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