* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.8;
  color: #1a1a1a;
  background: #f8f8f5;
  padding: 80px 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

h1 {
  font-size: 48px;
  font-weight: 400;
  text-align: center;
  margin-bottom: 8px;
  color: #000;
  letter-spacing: -0.5px;
}

h1::after {
  content: '';
  display: block;
  width: 260px;
  height: 2px;
  background: #000;
  margin: 20px auto 60px;
}

.intro {
  font-size: 17px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 40px;
}

.content-section {
  margin-bottom: 40px;
}

.content-section h2 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 16px;
  color: #000;
}

.content-section h3 {
  font-size: 16px;
  font-weight: 600;
  margin: 20px 0 10px;
  color: #000;
}

.content-section p {
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 12px;
}

.content-section ul {
  margin-left: 40px;
  margin-bottom: 16px;
}

.content-section li {
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 8px;
}

a {
  color: #000;
  text-decoration: underline;
  transition: opacity 0.2s;
}

a:hover {
  opacity: 0.7;
}

.note-box {
  background: #fff;
  border: 1px solid #e0e0e0;
  border-radius: 6px;
  padding: 24px;
  margin: 40px 0;
}

.note-box p {
  font-size: 14px;
  color: #666;
  line-height: 1.7;
}

footer {
  margin-top: 80px;
  text-align: center;
  color: #999;
  font-size: 14px;
}

@media (max-width: 768px) {
  body {
    padding: 40px 20px;
  }

  h1 {
    font-size: 36px;
  }

  h1::after {
    width: 200px;
  }

  .intro {
    font-size: 16px;
  }

  .content-section p,
  .content-section li {
    font-size: 15px;
  }
}