body {
  /* font-family: 'Helvetica', sans-serif; */
  font-family: 'Roboto', sans-serif;

  background-color: #f5f8ff;
  color: #333;
  margin: 0;
  padding: 0;
}
h1, h2, h3 {
  font-family: 'Roboto', sans-serif;
}
h1 {
  font-size: 4rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  margin-bottom: 1rem;
}
h3 {
  margin-left: 1rem;
}
h4 {
  margin-left: 2rem;
}

header {
  background-color: #003366;
  color: white;
  padding: 2rem;
  text-align: left;
}

nav {
  background-color: #e0e0e0;
  padding: 0.5rem;
  text-align: center;
}

nav ul {
  list-style-type: none;
  padding: 0;
}

nav ul li {
  display: inline-block;
  margin: 0 1rem;
}

nav ul li a {
  text-decoration: none;
  color: #003366;
  font-weight: bold;
}

section {
  padding: 2rem;
  max-width: 800px;
  margin: auto;
}

footer {
  background-color: #003366;
  color: white;
  text-align: center;
  padding: 1rem;
}

.hero {
  display: flex;
  justify-content: center;    /* 横方向中央に配置 */
  align-items: center;        /* 縦方向中央に配置 */
  height: 300px;              /* お好みで調整 */
  background: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)),
url('images/oist.jpg') no-repeat center/cover;
  padding: 1rem 1rem 3rem 1rem;
}

.hero-text {
  text-align: left;           /* テキストは左揃え */
  max-width: 700px;           /* 横幅制限で読みやすく */
}

.image-container {
  position: relative;
  width: 100%;
}

.image-container img {
  width: 100%;
  height: auto;
  display: block;
}

.image-container .overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background-color: rgba(0, 0, 0, 0.4); /* 黒く、でも透け感あり */
}

ul li, ol li {
  line-height: 1.8; /* 文字の上下スペースを広げる */
}

p {
margin-left: 2em;

}

.hyphen-list {
  list-style-type: none;
}

.hyphen-list li::before {
  content: "-";
  margin-right: 5px; /* ハイフンとテキストの間隔 */
}