@import url("https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;700&display=swap");

body {
  font-family: "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  line-height: 1.8;
  color: #333;
  margin: 0;
  padding: 0;
  background-color: #fff;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  letter-spacing: 0.03em;
  font-weight: 300;
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

img {
  max-width: 300px;
  height: auto;
  display: block;
  margin: 20px auto 60px;
}

h1 {
  font-size: 28px;
  font-weight: 300;
  margin-top: 30px;
  margin-bottom: 30px;
  color: #333;
  line-height: 1.4;
  text-align: center;
}

h2 {
  font-size: 22px;
  font-weight: 300;
  margin-top: 40px;
  margin-bottom: 20px;
  color: #333;
  border-bottom: none;
  padding-bottom: 10px;
  line-height: 1.4;
}

h3 {
  font-size: 18px;
  font-weight: 400;
  margin-top: 25px;
  margin-bottom: 15px;
  color: #333;
  line-height: 1.4;
}

p {
  margin-bottom: 16px;
  line-height: 1.8;
}

.text {
  display: block;
  margin-bottom: 16px;
  font-size: 16px;
  line-height: 1.8;
  color: #333;
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.text-left {
  text-align: left;
}

span.text {
  display: block;
  margin-bottom: 12px;
  padding-left: 20px;
  position: relative;
  line-height: 1.8;
}

span.text:before {
  content: "・";
  position: absolute;
  left: 0;
  top: 0;
}

a {
  color: #3498db;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #2980b9;
  text-decoration: underline;
}

.footer {
  margin-top: 60px;
  padding-top: 25px;
  border-top: 1px solid #eee;
  text-align: center;
  font-size: 14px;
  color: #777;
}

footer {
  text-align: center;
}

.version-info {
  margin-top: 50px;
  text-align: left;
  font-size: 14px;
  color: #777;
}

.previous-versions {
  margin-top: 50px;
  padding-top: 25px;
  border-top: 1px solid #eee;
}

.previous-versions h3 {
  font-size: 16px;
  color: #555;
  margin-bottom: 15px;
}

.previous-versions ul {
  list-style-type: none;
  padding-left: 0;
}

.previous-versions li {
  margin-bottom: 8px;
}

.previous-versions a {
  color: #3498db;
  text-decoration: none;
}

.previous-versions a:hover {
  text-decoration: underline;
}

/* ユーティリティクラス */
.mb-0 {
  margin-bottom: 0 !important;
}

.pt-30 {
  padding-top: 30px;
}

.ml-5 {
  margin-left: 5px;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
  main {
    padding: 20px 15px;
  }

  img {
    max-width: 240px;
    margin-bottom: 30px;
  }

  h1 {
    font-size: 24px;
    margin-top: 20px;
    margin-bottom: 20px;
  }

  h2 {
    font-size: 20px;
    margin-top: 30px;
    margin-bottom: 15px;
  }

  h3 {
    font-size: 16px;
    margin-top: 20px;
    margin-bottom: 10px;
  }
}

@media (max-width: 480px) {
  main {
    padding: 15px 10px;
  }

  img {
    max-width: 200px;
    margin-bottom: 20px;
  }

  h1 {
    font-size: 22px;
  }
}