/* 基本設定 */
* {
  box-sizing: border-box;
}

body {
  font-family: 'Helvetica Neue', sans-serif;
  margin: 0;
  padding: 0;
  background: #f9fafa;
  color: #333;
  line-height: 1.6;
}

/* ヘッダー */
header {
  background: linear-gradient(to right, #2c3e50, #34495e);
  color: white;
  padding: 2em 1em;
  text-align: center;
  border-bottom: 5px solid #1abc9c;
}

header h1 {
  font-size: 2em;
  margin: 0.2em 0;
}

header p {
  font-size: 1.1em;
  margin: 0.2em 0 1em;
}

nav ul {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1em;
}

nav li a {
  color: #ecf0f1;
  text-decoration: none;
  background-color: #1abc9c;
  padding: 0.5em 1em;
  border-radius: 6px;
  transition: background 0.3s;
}

nav li a:hover {
  background-color: #16a085;
}

/* メインコンテンツ */
main {
  max-width: 1000px;
  margin: 2em auto;
  padding: 1em;
}

section {
  margin-bottom: 3em;
  padding: 1.5em;
  background-color: #ffffff;
  border-left: 6px solid #1abc9c;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

section h2 {
  margin-top: 0;
  color: #1abc9c;
  font-size: 1.6em;
}

section ul {
  list-style: none;
  padding: 0;
}

section li {
  margin: 0.5em 0;
}

section li a {
  text-decoration: none;
  color: #2c3e50;
  font-weight: bold;
  padding: 0.3em 0.5em;
  border-bottom: 2px solid transparent;
  transition: all 0.3s ease;
}

section li a:hover {
  border-bottom: 2px solid #1abc9c;
  color: #16a085;
}

/* フッター */
footer {
  background: #ecf0f1;
  text-align: center;
  padding: 1em;
  color: #555;
  font-size: 0.9em;
  border-top: 1px solid #ddd;
}

pre {
    background: linear-gradient(to right, #2c3e50, #34495e);
    color: white;
    padding: 1em;
    border-radius: 8px;
    overflow: auto;
}



/* ========== 左側の目次 ========== */
aside#toc {
  position: fixed;
  top: 0;
  left: 0;
  height: calc(100%);
  overflow-y: auto;
  width: 250px;
  background: rgba(243, 248, 250, 0.9);
  border-right: 1px solid #ddd;
  padding: 1em;
  font-size: 0.9em;
  line-height: 1.5;
  box-shadow: 2px 0 5px rgba(0, 0, 0, 0.03);
}

aside#toc h2 {
  font-size: 1.1em;
  margin-bottom: 0.8em;
  color: #006064;
  border-bottom: 1px solid #b2ebf2;
  padding-bottom: 0.3em;
}

aside#toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

aside#toc ul li {
  margin: 0.3em 0;
}

aside#toc ul li a {
  text-decoration: none;
  color: #444;
  transition: 0.2s;
}

aside#toc ul li a:hover {
  color: #00796b;
  text-decoration: underline;
}