footer {
  width: 100%;
}

footer ul {
  display: flex;
  flex-wrap: wrap;
}

footer li a,
footer li.copy {
  color: #fff;
  padding: 0.5em;
  display: block;
}

/*----------------------
スマホ以下
----------------------*/
@media screen and (max-width: 767px) {

  footer li,
  .footer .copy {
    flex-basis: 100%;
    min-width: 100%;
    text-align: center;
  }

  footer li:nth-child(1) {
    background-color: #676767;
  }

  footer li:nth-child(2) {
    background-color: #494949;
  }

  footer li:nth-child(3) {
    background-color: #2c2c2c;
  }
}

/*----------------------
タブレット以上
----------------------*/
@media screen and (min-width: 768px) {
  .footer .ul {
    justify-content: center;
  }

  .footer .copy {
    text-align: center;
  }

  footer li a, footer .copy {
    color: #fff;
  }

}

/*----------------------
PC以上
----------------------*/
@media screen and (min-width: 1600px) {
  .footer {
    position: relative;
  }

  .footer .copy {
    position: absolute;
    right: 5%;
    bottom: 0;
    padding: 0.5em;
  }
}