<style>
body {
  margin: 0;
  background: white; 
  font-family: 'メイリオ', 'Helvetica Neue', Arial, sans-serif;
}

.page-wrapper {
  text-align: center;
}

/* グラデーション背景 */
.gradient-bg {
  background: linear-gradient(to left,
    #b3e5fc 0%,
    #a5f2e5 30%,
    #d1c4e9 65%,
    #b39ddb 100%
  );
  width: min(90vw, 1000px);
  margin: 0 auto;
  padding: 20px;
  box-sizing: border-box;
  position: relative; 
}

/* ヘッダー画像 */
.header-img {
  width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
  transition: 0.3s;
}

/* 言語切替ボタン */
.lang-toggle {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #fff;
  color: #333;
  border: 1px solid #ccc;
  border-radius: 20px;
  padding: 5px 15px;
  cursor: pointer;
  font-size: 14px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  transition: 0.3s;
}
.lang-toggle:hover {
  background: #00B0F0;
  color: white;
  border-color: #00B0F0;
}

/* ナビメニュー */
nav {
  background: rgba(255,255,255,0.8);
  padding: 10px 0;
  margin-top: 10px;
}

nav ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  padding: 0;
  margin: 0;
}

nav li {
  list-style: none;
}

nav a {
  text-decoration: none;
  color: #333;
  font-weight: bold;
  padding: 5px 10px;
  transition: 0.3s;
}

nav a.current {
  color: #00B0F0;
  border-bottom: 2px solid #00B0F0;
}

nav a:hover {
  color: #F7CB4D;
  border-bottom: 2px solid #F7CB4D;
}

/* コンテンツ部分 */
.content {
  background: rgba(255,255,255,0.85);
  padding: 20px;
  margin-top: 15px;
  box-sizing: border-box;
  text-align: left;
  line-height: 1.6;
  color: #515254;
}

/* 右下固定ボタン */
.back-to-menu {
  position: fixed;
  right: 20px;
  bottom: 20px;
  background: #00B0F0;
  color: white;
  padding: 12px 18px;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  font-size: 14px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.2);
  transition: 0.3s;
  z-index: 999;
}
.back-to-menu:hover {
  background: #008ac1;
}

/* スマホ向け調整 */
@media (max-width: 600px) {
  .gradient-bg {
    width: 95vw;
    padding: 15px;
  }
  nav ul {
    flex-direction: column;
    gap: 5px;
  }
  .back-to-menu {
    font-size: 12px;
    padding: 10px 14px;
  }
}
</style>
