/* ===== 页面作用域：.page-about ===== */
.page-about {
  --about-clip-angle: 4deg;
  --about-header-padding: 3.5rem 0 4.5rem;
  --about-card-min-height: 180px;
  display: block;
  width: 100%;
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-top: 1.5rem;
  padding-bottom: 1rem;
  font-size: 0.875rem;
  color: var(--clr-text-secondary, #555);
}
.page-about .breadcrumb a {
  color: var(--clr-primary-orange, #FF6F00);
  text-decoration: none;
}
.page-about .breadcrumb a:hover {
  text-decoration: underline;
}
.page-about .breadcrumb .sep {
  margin: 0 0.5rem;
  color: var(--clr-border-light, rgba(0,61,107,0.15));
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--clr-text-primary, #1A1A2E);
  font-weight: 600;
}

/* ===== 首屏分屏 ===== */
.page-about .about-hero {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  padding-top: 1rem;
  padding-bottom: var(--section-gap, 4rem);
  align-items: center;
}
.page-about .about-hero-text {
  flex: 1 1 50%;
}
.page-about .about-hero-text h1 {
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: clamp(2.2rem, 6vw, 4rem);
  line-height: 1.1;
  color: var(--clr-primary-blue, #003D6B);
  margin: 0 0 1.25rem;
  letter-spacing: -0.02em;
}
.page-about .about-hero-text p {
  font-family: var(--font-body, sans-serif);
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--clr-text-secondary, #555);
  max-width: 36em;
}
.page-about .about-hero-visual {
  flex: 1 1 45%;
  display: flex;
  justify-content: center;
  align-items: center;
}
.page-about .about-hero-visual img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md, 16px);
  box-shadow: var(--shadow-lg, 0 20px 60px rgba(0,0,0,0.12));
  object-fit: cover;
}

/* ===== 章节通用 ===== */
.page-about .chapter-header {
  position: relative;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: var(--about-header-padding);
  margin-bottom: 2.5rem;
  background: var(--gradient-hero, linear-gradient(135deg,rgba(255,111,0,0.08) 0%,rgba(199,215,0,0.05) 100%));
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-clip-angle) * 1.2), 0 100%);
  border-radius: 0;
}
@media (min-width: 768px) {
  .page-about .chapter-header {
    padding: 4rem 0 5rem;
    margin-bottom: 3rem;
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 3vw), 0 100%);
  }
}
.page-about .chapter-header .section-number {
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: clamp(4rem, 12vw, 8rem);
  line-height: 1;
  color: var(--clr-primary-orange, #FF6F00);
  opacity: 0.35;
  transition: transform 0.3s ease, opacity 0.3s ease;
  cursor: default;
  user-select: none;
}
.page-about .chapter-header .section-number:hover,
.page-about .chapter-header .section-number:focus-visible {
  transform: scale(1.08);
  opacity: 0.55;
}
.page-about .chapter-header h2 {
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: clamp(1.8rem, 4vw, 3rem);
  line-height: 1.15;
  color: var(--clr-primary-blue, #003D6B);
  margin: 0;
  letter-spacing: -0.01em;
}

/* ===== 章节01：故事 ===== */
.page-about .story-chapter {
  background-color: var(--clr-bg-light, #F5F5F5);
}
.page-about .story-chapter .chapter-body {
  max-width: 48em;
  font-family: var(--font-body, sans-serif);
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--clr-text-primary, #1A1A2E);
}
.page-about .story-chapter .chapter-body p {
  margin: 0 0 1.25em;
}
.page-about .story-chapter .chapter-body .text-small {
  font-size: 0.9375rem;
  color: var(--clr-text-secondary, #555);
  margin-top: 1.5rem;
}
.page-about .story-chapter .chapter-body a {
  color: var(--clr-primary-orange, #FF6F00);
  text-decoration: underline;
  text-underline-offset: 0.15em;
}

/* ===== 章节02：核心价值 ===== */
.page-about .value-chapter {
  background-color: var(--clr-card-bg, #FFFFFF);
}
.page-about .value-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}
@media (min-width: 640px) {
  .page-about .value-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }
}
.page-about .value-grid .exhibit-card {
  min-height: var(--about-card-min-height);
  padding: 1.75rem 1.5rem;
  border: 1px solid var(--clr-border-light, rgba(0,61,107,0.15));
  border-radius: var(--radius-sm, 8px);
  background: var(--clr-card-bg, #FFFFFF);
  box-shadow: var(--shadow-sm, 0 2px 12px rgba(0,0,0,0.06));
  transition: box-shadow 0.25s ease, transform 0.25s ease;
}
.page-about .value-grid .exhibit-card:hover {
  box-shadow: var(--shadow-md, 0 8px 40px rgba(0,0,0,0.08));
  transform: translateY(-3px);
}
.page-about .value-grid .exhibit-card h3 {
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: 1.5rem;
  color: var(--clr-primary-blue, #003D6B);
  margin: 0 0 0.75rem;
  letter-spacing: 0.01em;
}
.page-about .value-grid .exhibit-card p {
  font-family: var(--font-body, sans-serif);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--clr-text-secondary, #555);
  margin: 0;
}
.page-about .value-visual {
  display: flex;
  justify-content: center;
  margin-top: 1.5rem;
}
.page-about .value-visual img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md, 16px);
  box-shadow: var(--shadow-md, 0 8px 40px rgba(0,0,0,0.08));
  object-fit: cover;
}

/* ===== 章节03：版本历程 ===== */
.page-about .version-chapter {
  background-color: var(--clr-bg-light, #F5F5F5);
}
.page-about .version-timeline {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}
.page-about .version-item {
  border-left: 4px solid var(--clr-primary-orange, #FF6F00);
  padding-left: 1.25rem;
}
.page-about .version-item:first-child {
  border-left-color: var(--clr-primary-orange, #FF6F00);
}
.page-about .version-item:last-child {
  border-left-color: var(--clr-border-light, rgba(0,61,107,0.15));
}
.page-about .version-details {
  font-family: var(--font-body, sans-serif);
}
.page-about .version-summary {
  display: flex;
  align-items: center;
  gap: 1rem;
  cursor: pointer;
  list-style: none;
  padding: 0.5rem 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--clr-text-primary, #1A1A2E);
  transition: color 0.2s ease;
}
.page-about .version-summary::-webkit-details-marker {
  display: none;
}
.page-about .version-summary:hover {
  color: var(--clr-primary-orange, #FF6F00);
}
.page-about .version-badge {
  display: inline-block;
  padding: 0.2rem 1rem;
  border-radius: var(--radius-lg, 50px);
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: 0.875rem;
  letter-spacing: 0.05em;
  color: #fff;
  background: var(--gradient-cta, linear-gradient(135deg,#FF6F00 0%,#C7D700 100%));
}
.page-about .version-label {
  font-size: 0.875rem;
  color: var(--clr-text-secondary, #555);
  font-weight: 400;
}
.page-about .version-body {
  padding: 0.75rem 0 0.25rem;
}
.page-about .version-body ul {
  margin: 0;
  padding: 0 0 0 1.25rem;
  list-style: disc;
}
.page-about .version-body li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
  color: var(--clr-text-primary, #1A1A2E);
}
.page-about .version-details[open] .version-summary .version-badge {
  background: var(--clr-primary-blue, #003D6B);
}
.page-about .version-visual {
  display: flex;
  justify-content: center;
  margin-top: 1rem;
}
.page-about .version-visual img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md, 16px);
  box-shadow: var(--shadow-md, 0 8px 40px rgba(0,0,0,0.08));
  object-fit: cover;
}

/* ===== 章节04：用户承诺 ===== */
.page-about .promise-chapter {
  background-color: var(--clr-card-bg, #FFFFFF);
}
.page-about .promise-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-bottom: 2rem;
}
@media (min-width: 640px) {
  .page-about .promise-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.75rem;
  }
}
.page-about .promise-grid .label-card {
  border-left: 4px solid var(--clr-accent-yellow, #C7D700);
  padding: 1.25rem 1.25rem;
  background: var(--clr-bg-light, #F5F5F5);
  border-radius: 0 var(--radius-sm, 8px) var(--radius-sm, 8px) 0;
}
.page-about .promise-grid .label-card .label-title {
  display: block;
  font-family: var(--font-headings, 'Impact','Arial Black',sans-serif);
  font-size: 1.25rem;
  color: var(--clr-primary-blue, #003D6B);
  margin-bottom: 0.4rem;
}
.page-about .promise-grid .label-card .label-value {
  display: block;
  font-family: var(--font-body, sans-serif);
  font-size: 0.95rem;
  color: var(--clr-text-secondary, #555);
  line-height: 1.5;
}
.page-about .promise-cta {
  text-align: center;
  padding: 1.5rem 0 0.5rem;
  font-family: var(--font-body, sans-serif);
  font-size: 1.0625rem;
  color: var(--clr-text-primary, #1A1A2E);
}
.page-about .promise-cta a {
  color: var(--clr-primary-orange, #FF6F00);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 0.15em;
}

/* ===== 底部内链区域 ===== */
.page-about .about-connect {
  background-color: var(--clr-bg-light, #F5F5F5);
  padding-top: 2rem;
  padding-bottom: 2rem;
}
.page-about .connect-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem 1.5rem;
}
.page-about .connect-links .btn-ghost,
.page-about .connect-links .btn-primary {
  text-decoration: none;
  padding: 0.7rem 2rem;
  border-radius: var(--radius-lg, 50px);
  font-family: var(--font-body, sans-serif);
  font-weight: 600;
  font-size: 1rem;
  transition: background 0.25s ease, color 0.25s ease, box-shadow 0.25s ease;
}
.page-about .connect-links .btn-ghost {
  border: 2px solid var(--clr-primary-orange, #FF6F00);
  color: var(--clr-primary-orange, #FF6F00);
  background: transparent;
}
.page-about .connect-links .btn-ghost:hover {
  background: var(--clr-primary-orange, #FF6F00);
  color: #fff;
}
.page-about .connect-links .btn-primary {
  background: var(--gradient-cta, linear-gradient(135deg,#FF6F00 0%,#C7D700 100%));
  color: #fff;
  border: none;
}
.page-about .connect-links .btn-primary:hover {
  box-shadow: var(--shadow-md, 0 8px 40px rgba(0,0,0,0.08));
  transform: translateY(-2px);
}

/* ===== 响应式增强 ===== */
@media (min-width: 768px) {
  .page-about .about-hero {
    flex-direction: row;
    gap: 3rem;
    padding-top: 2rem;
  }
  .page-about .about-hero-text h1 {
    margin-bottom: 1.5rem;
  }
  .page-about .about-hero-text p {
    font-size: 1.25rem;
  }
  .page-about .version-timeline {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
  .page-about .version-item {
    padding-left: 1.5rem;
  }
  .page-about .value-visual img,
  .page-about .version-visual img {
    max-width: 90%;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    gap: 4rem;
  }
  .page-about .chapter-header {
    padding: 5rem 0 6rem;
  }
  .page-about .chapter-header .section-number {
    font-size: 10rem;
  }
}

/* ===== 窄屏安全 ===== */
@media (max-width: 480px) {
  .page-about .chapter-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
    padding: 2rem 0 3rem;
  }
  .page-about .chapter-header h2 {
    font-size: 1.6rem;
  }
  .page-about .connect-links {
    flex-direction: column;
    align-items: center;
  }
  .page-about .connect-links .btn-ghost,
  .page-about .connect-links .btn-primary {
    width: 100%;
    max-width: 280px;
    text-align: center;
  }
}

/* ===== 焦点与可访问性 ===== */
.page-about a:focus-visible,
.page-about button:focus-visible,
.page-about summary:focus-visible {
  outline: 3px solid var(--clr-primary-orange, #FF6F00);
  outline-offset: 3px;
}
.page-about .section-number:focus-visible {
  outline: 3px solid var(--clr-primary-blue, #003D6B);
  outline-offset: 4px;
}