.page-about {
  --snow-line: rgba(184, 216, 232, 0.14);
  --gold-soft: rgba(212, 175, 55, 0.2);
  --night-deep: #0B1C36;
  --card-bg: #23180F;
  background: var(--night-blue);
  color: var(--glacier-blue);
  overflow-x: hidden;
}

/* ===== 顶部经幡与英雄区 ===== */
.page-about .about-hero {
  position: relative;
  padding: 36px 0 72px;
  background:
    radial-gradient(ellipse at 78% 18%, rgba(212, 175, 55, 0.16) 0%, transparent 52%),
    linear-gradient(120deg, var(--night-deep) 0%, var(--night-blue) 62%);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 18px;
  background: repeating-linear-gradient(90deg,
      var(--gold) 0 48px,
      var(--football-green) 48px 96px,
      var(--stadium-red) 96px 144px,
      var(--glacier-blue) 144px 192px,
      var(--ember-orange) 192px 240px);
  opacity: 0.5;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 0 100%);
  z-index: 2;
}

.page-about .about-hero::after {
  content: '';
  position: absolute;
  right: -8%;
  bottom: 0;
  width: 58%;
  height: 76%;
  background: linear-gradient(135deg, transparent 30%, var(--gold-soft) 100%);
  clip-path: polygon(18% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
}

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

.page-about .about-hero-grid {
  display: grid;
  gap: 44px;
  margin-top: 36px;
  align-items: center;
}

.page-about .about-hero-content {
  max-width: 620px;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(40px, 7.5vw, 72px);
  line-height: 1.05;
  color: var(--cream);
  margin: 18px 0 10px;
  text-shadow: 0 4px 28px rgba(0, 0, 0, 0.45);
}

.page-about .about-hero-sub {
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 0 0 18px;
}

.page-about .about-hero-lead {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  color: var(--glacier-blue);
  max-width: 470px;
  margin: 0;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 28px;
}

.page-about .about-hero-visual {
  position: relative;
  text-align: center;
}

.page-about .about-hero-frame {
  display: inline-block;
  padding: 12px;
  border: 1px solid rgba(212, 175, 55, 0.55);
  background: linear-gradient(145deg, rgba(212, 175, 55, 0.08), rgba(10, 22, 40, 0.5));
  transform: rotate(2deg);
  transition: transform 0.3s ease;
}

.page-about .about-hero-frame:hover {
  transform: rotate(0deg);
}

.page-about .about-hero-img {
  display: block;
  width: 100%;
  max-width: 360px;
  height: auto;
  object-fit: cover;
}

.page-about .about-hero-caption {
  font-family: var(--font-body);
  font-size: 13px;
  color: rgba(184, 216, 232, 0.7);
  margin-top: 14px;
  letter-spacing: 0.06em;
}

/* ===== 第一部分：从雪原到数据高原 ===== */
.page-about .about-origin {
  padding: 72px 0;
  border-top: 1px solid rgba(212, 175, 55, 0.22);
  background: linear-gradient(180deg, var(--night-blue) 0%, rgba(13, 30, 60, 0.55) 100%);
}

.page-about .about-origin-grid {
  display: grid;
  gap: 32px;
}

.page-about .about-origin-aside {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .about-index {
  font-family: var(--font-display);
  font-size: 64px;
  line-height: 1;
  color: var(--gold);
  opacity: 0.7;
  letter-spacing: 2px;
}

.page-about .about-origin-main .section-title,
.page-about .about-evolution-main .section-title {
  color: var(--cream);
}

.page-about .about-origin-main .section-title {
  font-size: clamp(30px, 4.8vw, 48px);
  margin-bottom: 22px;
}

.page-about .about-origin-prose p {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.9;
  color: var(--glacier-blue);
  margin: 0 0 16px;
  max-width: 660px;
}

.page-about .about-origin-stats {
  list-style: none;
  margin: 36px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.page-about .about-origin-stats li {
  background: rgba(255, 255, 255, 0.04);
  border-left: 3px solid var(--gold);
  padding: 16px 18px;
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: 30px;
  color: var(--gold);
  line-height: 1.15;
}

.page-about .about-stat-label {
  display: block;
  font-family: var(--font-body);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--glacier-blue);
  margin-top: 5px;
}

/* ===== 第二部分：版本演进 ===== */
.page-about .about-evolution {
  position: relative;
  padding: 80px 0 72px;
  background: var(--night-blue);
}

.page-about .about-evolution-head {
  display: grid;
  gap: 24px;
  margin-bottom: 48px;
}

.page-about .about-evolution-title {
  display: flex;
  align-items: flex-start;
  gap: 18px;
}

.page-about .about-index-invert {
  font-size: 68px;
  color: var(--ember-orange);
}

.page-about .about-evolution-title .section-title {
  font-size: clamp(30px, 4.6vw, 46px);
  color: var(--cream);
  margin: 8px 0 0;
}

.page-about .about-evolution-lead {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  color: var(--glacier-blue);
  max-width: 440px;
  margin: 0;
}

.page-about .about-timeline {
  position: relative;
  display: grid;
  gap: 28px;
  padding: 8px 0;
}

.page-about .about-timeline-line {
  position: absolute;
  top: 10px;
  bottom: 10px;
  left: 13px;
  width: 2px;
  transform: translateX(-50%);
  background: linear-gradient(180deg, var(--gold), var(--football-green), var(--glacier-blue));
}

.page-about .about-timeline-item {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding-left: 40px;
}

.page-about .about-timeline-item::before {
  content: '';
  position: absolute;
  left: 13px;
  top: 22px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--gold);
  border: 2px solid var(--night-blue);
  transform: translateX(-50%);
  box-shadow: 0 0 14px rgba(212, 175, 55, 0.5);
}

.page-about .about-tl-tag {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 13px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gold);
  background: rgba(212, 175, 55, 0.12);
  border: 1px solid rgba(212, 175, 55, 0.35);
  padding: 4px 10px;
  margin-bottom: 8px;
}

.page-about .about-tl-card {
  background: var(--card-bg);
  border: 1px solid rgba(212, 175, 55, 0.18);
  border-left: 3px solid var(--gold);
  padding: 20px;
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-tl-card:hover {
  transform: translateX(6px);
  border-color: var(--gold);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.35);
}

.page-about .about-tl-card h3 {
  font-family: var(--font-display);
  font-size: 20px;
  color: var(--cream);
  margin: 8px 0 6px;
}

.page-about .about-tl-card p {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  color: var(--glacier-blue);
  margin: 0;
}

.page-about .about-evolution-media {
  margin-top: 48px;
  position: relative;
}

.page-about .about-evolution-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 1200px;
  margin: 0 auto;
  clip-path: polygon(2% 0, 100% 0, 98% 100%, 0 100%);
  opacity: 0.92;
}

/* ===== 第三部分：数据从哪里来 ===== */
.page-about .about-source {
  position: relative;
  background: var(--cream);
  color: var(--deep-brown);
  padding: 80px 0;
  border-top: 4px solid var(--gold);
}

.page-about .about-source-grid {
  display: grid;
  gap: 40px;
}

.page-about .about-source-copy {
  position: relative;
}

.page-about .about-source-copy .section-label {
  color: var(--stadium-red);
}

.page-about .about-source-copy .section-title {
  color: var(--deep-brown);
  font-size: clamp(30px, 4.6vw, 46px);
  margin-bottom: 18px;
}

.page-about .about-source-lead {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  color: rgba(44, 30, 22, 0.85);
  margin-bottom: 28px;
}

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

.page-about .about-source-steps li {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 14px 0;
  border-bottom: 1px solid rgba(44, 30, 22, 0.14);
}

.page-about .about-step-num {
  font-family: var(--font-display);
  font-size: 22px;
  color: var(--gold);
  letter-spacing: 1px;
  min-width: 34px;
  line-height: 1;
  padding-top: 4px;
}

.page-about .about-source-steps h3 {
  font-family: var(--font-display);
  font-size: 18px;
  color: var(--deep-brown);
  margin: 0 0 4px;
}

.page-about .about-source-steps p {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  margin: 0;
  color: rgba(44, 30, 22, 0.78);
}

.page-about .about-source-visual img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 800px;
  border: 6px solid var(--night-blue);
  box-shadow: 16px 16px 0 0 rgba(212, 175, 55, 0.75);
}

.page-about .about-source-note {
  margin-top: 24px;
  padding: 16px 20px;
  background: var(--night-blue);
  color: var(--glacier-blue);
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
}

.page-about .about-source-note p {
  margin: 0;
}

/* ===== 第四部分：做数据对照的人进入指引 ===== */
.page-about .about-guide {
  position: relative;
  padding: 80px 0;
  background:
    linear-gradient(180deg, rgba(212, 175, 55, 0.05) 0%, transparent 30%),
    var(--night-blue);
}

.page-about .about-guide::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 10px;
  background: repeating-linear-gradient(90deg,
      var(--gold) 0 40px,
      var(--football-green) 40px 80px,
      var(--stadium-red) 80px 120px,
      var(--glacier-blue) 120px 160px,
      var(--ember-orange) 160px 200px);
  opacity: 0.35;
}

.page-about .about-guide-head {
  display: grid;
  gap: 24px;
  margin-bottom: 44px;
}

.page-about .about-guide-head .section-title {
  color: var(--cream);
  font-size: clamp(30px, 4.6vw, 46px);
  margin-bottom: 10px;
}

.page-about .about-guide-lead {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  color: var(--glacier-blue);
  max-width: 520px;
  margin: 0;
}

.page-about .about-guide-cards {
  display: grid;
  gap: 20px;
}

.page-about .about-guide-card {
  position: relative;
  background: var(--card-bg);
  border: 1px solid rgba(212, 175, 55, 0.22);
  border-top: 3px solid var(--gold);
  padding: 28px 22px 22px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-guide-card:hover {
  transform: translateY(-6px) rotate(-0.5deg);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.4);
}

.page-about .about-guide-index {
  font-family: var(--font-display);
  font-size: 48px;
  line-height: 1;
  color: var(--gold);
  opacity: 0.8;
}

.page-about .about-guide-card h3 {
  font-family: var(--font-display);
  font-size: 21px;
  color: var(--cream);
  margin: 14px 0 10px;
}

.page-about .about-guide-card p {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.8;
  color: var(--glacier-blue);
  margin-bottom: 16px;
}

.page-about .about-guide-link {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--gold);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: border-color 0.2s ease;
}

.page-about .about-guide-link:hover {
  border-bottom-color: var(--gold);
}

.page-about .about-guide-note {
  margin-top: 36px;
  padding: 14px 18px;
  border-left: 3px solid var(--ember-orange);
  background: rgba(212, 175, 55, 0.06);
  font-family: var(--font-body);
  font-size: 13px;
  color: rgba(184, 216, 232, 0.8);
}

.page-about .about-guide-note p {
  margin: 0;
}

/* ===== 平板断点 ===== */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 48px 0 88px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
  }

  .page-about .about-origin-stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
  }

  .page-about .about-source-grid {
    grid-template-columns: 1.1fr 0.9fr;
    gap: 48px;
    align-items: center;
  }

  .page-about .about-guide-cards {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }
}

/* ===== 桌面断点 ===== */
@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 56px 0 104px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: 1.3fr 0.8fr;
    gap: 64px;
  }

  .page-about .about-origin,
  .page-about .about-evolution,
  .page-about .about-source,
  .page-about .about-guide {
    padding: 96px 0;
  }

  .page-about .about-origin-grid {
    grid-template-columns: 0.65fr 1.35fr;
    gap: 64px;
  }

  .page-about .about-origin-aside {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .page-about .about-index {
    font-size: 88px;
  }

  .page-about .about-index-invert {
    font-size: 92px;
  }

  .page-about .about-evolution-head {
    grid-template-columns: 1fr 0.75fr;
    gap: 60px;
    align-items: end;
    margin-bottom: 56px;
  }

  .page-about .about-evolution-lead {
    margin-bottom: 8px;
  }

  /* 桌面时间线：左右交替 */
  .page-about .about-timeline {
    gap: 0;
  }

  .page-about .about-timeline-line {
    left: 50%;
    transform: translateX(-50%);
  }

  .page-about .about-timeline-item {
    padding-left: 0;
    margin-bottom: 44px;
  }

  .page-about .about-timeline-item::before {
    left: 50%;
    transform: translateX(-50%);
    top: 26px;
  }

  .page-about .about-tl-item-2,
  .page-about .about-tl-item-4 {
    align-items: flex-end;
  }

  .page-about .about-tl-card {
    width: 46%;
  }

  .page-about .about-tl-tag {
    margin-bottom: 10px;
  }

  .page-about .about-evolution-media {
    margin-top: 56px;
  }

  .page-about .about-guide-head {
    grid-template-columns: 0.55fr 1.45fr;
    gap: 48px;
    align-items: start;
  }

  .page-about .about-guide-cards {
    gap: 28px;
  }

  .page-about .about-guide-card:nth-child(2) {
    transform: translateY(32px);
  }

  .page-about .about-guide-card:nth-child(3) {
    transform: translateY(8px);
  }
}