.site-footer {
  background-color: #000;
  padding: 0 40px;
  color: #fff;
  height: 200px;
  display: flex;
  align-items: center;              /* 上下中央揃え */
  justify-content: space-between;  /* 左右に分ける */
}

.footer-logo img {
  height: 70px;
}

.footer-social {
  display: flex;
  align-items: center;
}

.footer-social a {
  margin-left: 20px;
}

.footer-social img {
  height: 50px;
  width: auto;
  transition: opacity 0.3s ease;
}

.footer-social img:hover {
  opacity: 0.7;
}

@media (max-width: 768px) {
  .site-footer {
    height:  130px;
    justify-items: center;
  }
  .footer-logo img {
    height: 35px;
  }
}