#sideMenu {
  position: fixed;
  left: 0;
  top: 0;
  width: 180px;
  height: 100vh;
  overflow-y: auto;
  padding: 20px 15px;
  box-sizing: border-box;
  background: #f0f5fa;
  z-index: 9999;
}

#sideMenu img {
  width: 140px;
  height: auto;
  display: block;
  margin: 0 auto 15px;
}

#sideMenu h3 {
  margin: 0 0 10px;
  font-size: 16px;
}

#sideMenu a {
  display: block;
  padding: 5px 0;
  font-size: 14px;
  text-decoration: none;
}

/* FLAGと技術紹介の間 */
.menu-gap {
  height: 15px;
}

/* PC：左サイドバー分だけ本文を右へ */
body {
  padding-left: 180px;
}

/* タブレット・スマホ：上部固定 */
@media screen and (max-width: 768px) {

  #sideMenu {
    left: 0;
    top: 0;
    width: 100%;
    height: auto;
    max-height: 100px;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 10px 15px;
    display: flex;
    align-items: center;
    gap: 15px;
  }

  #sideMenu img {
    width: 80px;
    flex-shrink: 0;
    margin: 0;
  }

  #sideMenu h3 {
    display: none;
  }

  #sideMenu a {
    white-space: nowrap;
    padding: 5px;
    flex-shrink: 0;
  }

  body {
    padding-left: 0;
    padding-top: 60px;
  }
}