/* ===== 品牌档案页 – 页面专属样式 ===== */
.page-about {
  /* ---- 页面级设计变量 ---- */
  --page-primary: #7B8A6F;       /* 岩灰绿 */
  --page-primary-dark: #5A6B4F;
  --page-secondary: #C4A97D;     /* 陶土金 */
  --page-secondary-light: #D9C5A0;
  --page-accent: #A06B5A;        /* 陶土红 */
  --page-bg: #F5F1EB;            /* 米白 */
  --page-surface: #FFFFFF;
  --page-text: #2C2C2C;
  --page-text-muted: #5C5C5C;
  --page-border: #D1C7B8;
  --page-radius: 16px;
  --page-radius-sm: 8px;
  --page-gap: 32px;
  --page-timeline-dot-size: 20px;
  --page-timeline-line-width: 3px;

  background-color: var(--page-bg);
  color: var(--page-text);
  font-family: var(--font-body, 'Inter Variable', sans-serif);
  line-height: 1.6;
  padding-top: 24px;
  padding-bottom: 64px;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  max-width: var(--max-width, 1200px);
  margin: 0 auto 40px;
  padding: 0 24px;
  font-size: 0.875rem;
  color: var(--page-text-muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}
.page-about .breadcrumb a {
  color: var(--page-primary);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-fast, 0.2s ease);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  border-bottom-color: var(--page-primary);
}
.page-about .breadcrumb .separator {
  color: var(--page-border);
  font-size: 0.75rem;
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--page-text);
  font-weight: 500;
}

/* ---------- 容器 ---------- */
.page-about .container {
  max-width: var(--max-width, 1200px);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* ---------- 章节标题 ---------- */
.page-about .section-title {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 700;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  color: var(--page-text);
  margin: 0 0 16px;
  padding-bottom: 12px;
  position: relative;
  letter-spacing: -0.02em;
}
.page-about .section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 64px;
  height: 4px;
  background: linear-gradient(90deg, var(--page-primary), var(--page-secondary));
  border-radius: 4px;
}
.page-about .section-title-center {
  text-align: center;
}
.page-about .section-title-center::after {
  left: 50%;
  transform: translateX(-50%);
}

/* ---------- 卡片 ---------- */
.page-about .card {
  background-color: var(--page-surface);
  border-radius: var(--page-radius);
  padding: 28px 24px;
  border: 1px solid var(--page-border);
  box-shadow: var(--shadow-card, 0 4px 16px rgba(0,0,0,0.04));
  transition: transform var(--transition-fast, 0.2s ease),
              box-shadow var(--transition-fast, 0.2s ease),
              border-color var(--transition-fast, 0.2s ease);
}
.page-about .card:hover,
.page-about .card:focus-within {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover, 0 8px 32px rgba(0,0,0,0.08));
  border-color: var(--page-secondary);
}
.page-about .card-title {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 600;
  font-size: 1.15rem;
  margin: 0 0 8px;
  color: var(--page-text);
}
.page-about .card-text {
  font-size: 0.95rem;
  color: var(--page-text-muted);
  margin: 0;
  line-height: 1.65;
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  padding: 24px 0 48px;
}
.page-about .about-hero__inner {
  display: flex;
  flex-direction: column;
  gap: 40px;
  align-items: center;
}
.page-about .about-hero__content {
  flex: 1 1 50%;
}
.page-about .about-hero__title {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 800;
  font-size: clamp(2.2rem, 5.5vw, 3.6rem);
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin: 0 0 16px;
  background: linear-gradient(135deg, var(--page-primary) 0%, var(--page-secondary) 60%, var(--page-primary-dark) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.page-about .about-hero__subtitle {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 500;
  font-size: clamp(1.05rem, 2.2vw, 1.3rem);
  color: var(--page-text);
  margin: 0 0 12px;
  line-height: 1.4;
}
.page-about .about-hero__desc {
  font-size: 1rem;
  color: var(--page-text-muted);
  max-width: 480px;
  line-height: 1.7;
  margin: 0;
}
.page-about .about-hero__visual {
  flex: 0 0 auto;
  max-width: 340px;
  width: 100%;
}
.page-about .about-hero__img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--page-radius);
  background-color: var(--page-surface);
  box-shadow: var(--shadow-card, 0 4px 16px rgba(0,0,0,0.06));
}

/* ===== 品牌理念 ===== */
.page-about .about-mission {
  padding: 56px 0 48px;
}
.page-about .about-mission__intro {
  font-size: 1.05rem;
  color: var(--page-text-muted);
  max-width: 680px;
  margin: 0 0 36px;
  line-height: 1.7;
}
.page-about .about-mission__grid {
  display: flex;
  flex-direction: column;
  gap: var(--page-gap);
}
.page-about .about-mission__card {
  flex: 1 1 100%;
}
.page-about .about-mission__icon {
  display: inline-block;
  font-size: 2rem;
  line-height: 1;
  margin-bottom: 12px;
  color: var(--page-primary);
}
.page-about .about-mission__card .card-title {
  color: var(--page-primary-dark);
}

/* ===== 技术演进（时间轴） ===== */
.page-about .about-evolution {
  padding: 48px 0 56px;
}
.page-about .about-evolution__intro {
  font-size: 1.05rem;
  color: var(--page-text-muted);
  max-width: 640px;
  margin: 0 0 40px;
  line-height: 1.7;
}

/* 时间轴容器 – 背景固定产生视差 */
.page-about .timeline-container {
  position: relative;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(123,138,111,0.06) 0%, transparent 50%),
    radial-gradient(circle at 80% 50%, rgba(196,169,125,0.05) 0%, transparent 50%),
    linear-gradient(0deg, transparent 0%, var(--page-bg) 100%);
  background-attachment: fixed;
  background-size: cover;
  padding: 32px 0 40px;
}
.page-about .timeline__inner {
  display: flex;
  flex-direction: column;
  gap: 40px;
  align-items: flex-start;
}
.page-about .timeline__list {
  position: relative;
  flex: 1 1 auto;
  width: 100%;
  padding-left: calc(var(--page-timeline-dot-size) + 20px);
}
/* 垂直线 – 使用伪元素 */
.page-about .timeline__list::before {
  content: '';
  position: absolute;
  left: calc(var(--page-timeline-dot-size) / 2);
  top: 12px;
  bottom: 12px;
  width: var(--page-timeline-line-width);
  background: linear-gradient(180deg, var(--page-primary) 0%, var(--page-secondary) 100%);
  border-radius: 4px;
}
.page-about .timeline__item {
  position: relative;
  margin-bottom: 36px;
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.page-about .timeline__item:last-child {
  margin-bottom: 0;
}
/* 圆点 – sticky 实现滚动时停留 */
.page-about .timeline__dot {
  position: absolute;
  left: calc(-1 * var(--page-timeline-dot-size) - 20px);
  top: 20px;
  width: var(--page-timeline-dot-size);
  height: var(--page-timeline-dot-size);
  border-radius: 50%;
  background-color: var(--page-primary);
  border: 4px solid var(--page-bg);
  box-shadow: 0 0 0 2px var(--page-primary), 0 4px 12px rgba(123,138,111,0.25);
  z-index: 2;
  position: sticky;
  top: calc(var(--header-height, 72px) + 24px);
}
/* 脉冲动画增强交互感 */
@keyframes about-timeline-pulse {
  0%, 100% { box-shadow: 0 0 0 2px var(--page-primary), 0 4px 12px rgba(123,138,111,0.25); }
  50% { box-shadow: 0 0 0 6px rgba(123,138,111,0.15), 0 4px 20px rgba(123,138,111,0.2); }
}
.page-about .timeline__dot {
  animation: about-timeline-pulse 3s ease-in-out infinite;
}
.page-about .timeline__content {
  padding: 20px 24px;
}
.page-about .timeline__phase {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--page-primary-dark);
  margin: 0 0 6px;
}
.page-about .timeline__desc {
  font-size: 0.92rem;
  color: var(--page-text-muted);
  margin: 0;
  line-height: 1.65;
}
.page-about .timeline__figure {
  flex: 0 0 auto;
  width: 100%;
  max-width: 600px;
  margin-top: 8px;
}
.page-about .timeline__img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--page-radius);
  background-color: var(--page-surface);
  box-shadow: var(--shadow-card, 0 4px 16px rgba(0,0,0,0.05));
}

/* ===== 用户承诺 ===== */
.page-about .about-promise {
  padding: 48px 0 40px;
}
.page-about .about-promise__content {
  display: flex;
  flex-direction: column;
  gap: 32px;
  margin-top: 28px;
}
.page-about .about-promise__cards {
  display: flex;
  flex-direction: column;
  gap: 20px;
  flex: 1 1 60%;
}
.page-about .about-promise__card {
  padding: 24px 22px;
  border-left: 4px solid var(--page-primary);
  border-radius: var(--page-radius-sm) var(--page-radius) var(--page-radius) var(--page-radius-sm);
}
.page-about .about-promise__card .card-title {
  color: var(--page-primary-dark);
}
.page-about .about-promise__card:hover {
  border-left-color: var(--page-secondary);
}
.page-about .about-promise__figure {
  flex: 0 0 auto;
  width: 100%;
  max-width: 400px;
}
.page-about .about-promise__img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--page-radius);
  background-color: var(--page-surface);
  box-shadow: var(--shadow-card, 0 4px 16px rgba(0,0,0,0.05));
}
.page-about .about-promise__note {
  margin-top: 32px;
  font-size: 0.95rem;
  color: var(--page-text-muted);
  font-style: italic;
  text-align: center;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== 内链区域 ===== */
.page-about .about-links {
  padding: 48px 0 0;
}
.page-about .about-links__grid {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 28px;
}
.page-about .about-links__card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  text-decoration: none;
  padding: 20px 24px;
  transition: transform var(--transition-fast, 0.2s ease),
              border-color var(--transition-fast, 0.2s ease),
              box-shadow var(--transition-fast, 0.2s ease);
}
.page-about .about-links__card:hover,
.page-about .about-links__card:focus-visible {
  border-color: var(--page-secondary);
  transform: translateY(-3px);
}
.page-about .about-links__label {
  font-family: var(--font-heading, 'Inter Variable', sans-serif);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--page-primary-dark);
}
.page-about .about-links__arrow {
  font-size: 1.3rem;
  color: var(--page-secondary);
  transition: transform var(--transition-fast, 0.2s ease);
}
.page-about .about-links__card:hover .about-links__arrow,
.page-about .about-links__card:focus-visible .about-links__arrow {
  transform: translateX(4px);
}

/* ========== 桌面端（≥768px） ========== */
@media (min-width: 768px) {
  .page-about {
    padding-top: 32px;
    padding-bottom: 80px;
  }
  .page-about .breadcrumb {
    margin-bottom: 56px;
  }

  /* 首屏 – 分屏 */
  .page-about .about-hero__inner {
    flex-direction: row;
    gap: 48px;
    align-items: center;
  }
  .page-about .about-hero__visual {
    max-width: 420px;
  }

  /* 品牌理念 – 三列网格 */
  .page-about .about-mission__grid {
    flex-direction: row;
  }
  .page-about .about-mission__card {
    flex: 1 1 33.33%;
  }

  /* 时间轴 – 双栏 */
  .page-about .timeline__inner {
    flex-direction: row;
    align-items: flex-start;
    gap: 48px;
  }
  .page-about .timeline__list {
    width: auto;
    flex: 1 1 55%;
  }
  .page-about .timeline__figure {
    flex: 0 0 40%;
    max-width: 460px;
    margin-top: 40px;
  }

  /* 用户承诺 – 双栏 */
  .page-about .about-promise__content {
    flex-direction: row;
    align-items: flex-start;
    gap: 40px;
  }
  .page-about .about-promise__figure {
    width: auto;
    flex: 0 0 35%;
    max-width: 360px;
  }
  .page-about .about-promise__cards {
    flex: 1 1 60%;
  }

  /* 内链 – 三列 */
  .page-about .about-links__grid {
    flex-direction: row;
    gap: 24px;
  }
  .page-about .about-links__card {
    flex: 1 1 33.33%;
  }
}

/* ========== 大桌面（≥1024px） ========== */
@media (min-width: 1024px) {
  .page-about .about-hero__visual {
    max-width: 500px;
  }
  .page-about .about-hero__title {
    font-size: 3.6rem;
  }
  .page-about .about-mission {
    padding: 64px 0 56px;
  }
  .page-about .about-evolution {
    padding: 56px 0 64px;
  }
  .page-about .about-promise {
    padding: 56px 0 48px;
  }
  .page-about .timeline__list {
    padding-left: calc(var(--page-timeline-dot-size) + 32px);
  }
  .page-about .timeline__dot {
    left: calc(-1 * var(--page-timeline-dot-size) - 32px);
  }
}