body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #f9f9f9;
    color: #333;
    margin: 0;
    padding: 20px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    color: #1a1a1a;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

p {
    line-height: 1.6;
    font-size: 1.1rem;
}

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

ul li::before {
    content: "• ";
    color: #0055cc;
    font-weight: bold;
}

a.button {
    display: inline-block;
    background-color: #0055cc;
    color: white;
    padding: 0.6em 1.2em;
    margin-top: 1.5rem;
    text-decoration: none;
    border-radius: 4px;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

a.button:hover {
    background-color: #003d99;
}

footer {
    margin-top: 3rem;
    font-size: 0.9rem;
    text-align: center;
    color: #777;
}

.screenshots {
    display: flex;
    gap: 10px;
    /* 画像間の隙間 */
    justify-content: center;
    /* 中央寄せ */
    flex-wrap: wrap;
    /* 画面が狭いときは折り返す */
    margin-top: 1rem;
}

.screenshots img {
    max-width: 30%;
    /* 親幅の30%までに縮小 */
    height: auto;
    border: 1px solid #ccc;
    border-radius: 6px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    object-fit: contain;
}

/* 横並びナビゲーション */
.nav {
  display: flex;
  gap: 1rem; /* 各項目の間隔 */
  padding: 0;
  list-style: none;
  justify-content: center; /* 中央寄せ（必要なら） */
}

.nav li a {
  text-decoration: none;
  color: #0055cc;
  font-weight: bold;
  padding: 0.5em;
  transition: color 0.3s ease;
}

.nav li a:hover {
  color: #003d99;
}

@media (max-width: 600px) {
  .nav {
    flex-direction: column;
    align-items: center;
  }
}

/* 本文中のリンク */
a:not(.button):not(.nav a) {
  color: #0055cc;
  text-decoration: underline;
  font-weight: bold;
}

a:not(.button):not(.nav a):hover {
  color: #003d99;
  text-decoration: none;
}