html {
  height: 100%;
}
body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}
#top_image {
  width: 960px;
  height: 400px;
  display: table;
}
#top_image .textbox {
  width: 100%;
  display: table-cell;
  background-image: url(../img/f2.png);
  background-repeat: repeat-x;
  background-position: right bottom;
  border: 3px solid #000;
}
.catch {
  width: 960px;
}

#down_btn {
  position: absolute;
  text-align: center;
  width: 100%;
}
@media screen and (max-width: 639px) {
  #top_image {
    width: 100%;
    height: auto;
    display: table;
  }
}