:root {
  color: #1a1a1a;
  background: #ffffff;
  font-family: Arial, Helvetica, sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #ffffff;
  color: #1a1a1a;
  line-height: 1.6;
}

main {
  width: min(920px, calc(100% - 40px));
  margin: 0 auto;
}

.paper-header {
  padding: 72px 0 64px;
  text-align: center;
  border-bottom: 1px solid #d9d9d9;
}

.supplement-label,
.case-label {
  margin: 0;
  color: #666666;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  max-width: 900px;
  margin: 16px auto 22px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 600;
  line-height: 1.18;
}

.introduction {
  max-width: 780px;
  margin: 0 auto;
  color: #444444;
  font-size: 16px;
  text-align: left;
}

.playback-note {
  max-width: 780px;
  margin: 18px auto 0;
  padding-top: 14px;
  color: #555555;
  border-top: 1px solid #e5e5e5;
  font-size: 13px;
  text-align: left;
}

section {
  padding-top: 64px;
}

.group-title {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 30px;
  text-align: center;
}

.group-description {
  margin: 8px 0 0;
  color: #555555;
  text-align: center;
}

.experiment {
  padding: 72px 0 0;
  text-align: center;
}

.experiment + .experiment {
  margin-top: 72px;
  border-top: 1px solid #e3e3e3;
}

.experiment h3 {
  margin: 7px 0 8px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 28px;
  line-height: 1.25;
}

.task-description {
  max-width: 760px;
  margin: 0 auto 24px;
  color: #4d4d4d;
}

video {
  display: block;
  width: 100%;
  height: auto;
  margin: 0 auto;
  background: #000000;
  border: 1px solid #d4d4d4;
}

video:focus-visible {
  outline: 3px solid #555555;
  outline-offset: 3px;
}

.caption {
  max-width: 820px;
  margin: 18px auto 0;
  color: #333333;
  font-size: 15px;
  text-align: left;
}

.ablation-section,
.group-section {
  margin-top: 96px;
  padding-top: 64px;
  border-top: 2px solid #222222;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 56px 32px;
  padding-top: 56px;
}

.grid-item {
  margin: 0;
  text-align: center;
}

.grid-item h3 {
  margin: 6px 0 14px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 20px;
  line-height: 1.3;
}

.grid-item .caption {
  margin-top: 12px;
  font-size: 14px;
}

footer {
  width: min(920px, calc(100% - 40px));
  margin: 120px auto 0;
  padding: 28px 0 42px;
  color: #666666;
  border-top: 1px solid #d9d9d9;
  font-size: 13px;
  text-align: center;
}

@media (max-width: 640px) {
  main,
  footer {
    width: min(100% - 28px, 920px);
  }

  .paper-header {
    padding: 48px 0 44px;
  }

  h1 {
    font-size: 31px;
  }

  .introduction,
  .playback-note,
  .task-description,
  .caption {
    font-size: 14px;
  }

  section {
    padding-top: 48px;
  }

  .group-title {
    font-size: 27px;
  }

  .experiment {
    padding-top: 52px;
  }

  .experiment + .experiment {
    margin-top: 52px;
  }

  .experiment h3 {
    font-size: 24px;
  }

  .ablation-section,
  .group-section {
    margin-top: 72px;
    padding-top: 48px;
  }

  .video-grid {
    grid-template-columns: 1fr;
    gap: 44px;
    padding-top: 44px;
  }

  .grid-item h3 {
    font-size: 19px;
  }
}