/* ===== 基本設定・ヘッダー・フッダー ===== */
body {
    margin: 0;
    font-family: sans-serif;
    background: #f6f8fb;
    color: #0b1220;
}
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
    background: white;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
}
nav ul {
    list-style: none;
    display: flex;
    gap: 12px;
    margin: 0;
    padding: 0;
}
nav a {
    text-decoration: none;
    padding: 8px 12px;
    color: #333;
    padding: 6px 10px;
    border-radius: 6px;
    display: inline-block;
}
nav a:hover {
    background: #e6f2fb;
    text-decoration: underline;
}
.btn {
    display: inline-block;
    background: #0b78d1;
    color: white;
    padding: 8px 12px;
    border-radius: 6px;
    text-decoration: none;
    z-index: 2;
}
.school-logo {
    height: 12px;
    vertical-align: middle;
    margin-top: -3px;
    margin-right: 3px;
}
main {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}
.main-logo {
    height: 50px;
    vertical-align: middle;
    margin-top: -3px;
    margin-right: 3px;
}
footer {
    text-align: center;
    margin: 30px 0;
    color: #555;
    font-size: 14px;
}
.menu-toggle {
  display: none; /* デフォルトは非表示 */
  background: none;
  border: none;
  font-size: 26px;
  cursor: pointer;
}

/* ===== スマホ対応 ===== */
@media (max-width: 700px) {
  .menu-toggle {
    display: block; /* スマホでのみ☰を表示 */
  }

  nav {
    display: none; /* デフォルトは非表示 */
    position: fixed;
    top: 78px;
    left: 0;
    width: 100%;
    background: white;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
    border-top: 1px solid #eee;
    z-index: 100;
    padding: 0;
  }

  nav.open {
    display: block; /* JSで開いたときだけ表示 */
  }

  nav ul {
    flex-direction: column;
    margin: 0;
    padding: 0;
    gap: 0;
  }

  nav li {
    border-bottom: 1px solid #eee;
  }

  .btn-group-separator {
    margin-bottom: 6px;
    border-bottom: none;
  }

   nav li a.btn {
    width: 100%;
    display: block;
    box-sizing: border-box;
    text-align: center;
    padding: 8px 16px;
   }

  nav a {
    display: block;
    text-decoration: none;
    padding: 8px 16px;
    width: 100%;
  }
}