* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  background: #3398db;
  padding: 40px;
}
.slider_wrap {
  margin: 0 auto;
  width: 1200px;
}
.slider img {
  height: auto;
  width: 100%;
}

/*ad*/
.ad{
  margin: 100px auto;
  max-width: 1000px;
}