<div id="wrap">
  <div id="header"></div>
  <div id="nav"></div>
  <div id="main" class="clearfix">
    <div id="aside"></div>
    <div id="article1"></div>
    <div id="article2"></div>
    <div id="article3"></div>
  </div>
  <div id="footer"></div>
</div>

* {
  margin: 0;
}
body {
  background-color: #e1f5fe;
}
#wrap {
  width: 1200px;
  margin: 0 auto;
}
#header {
  height: 100px;
  background-color: #b3e5fc;
}
#nav {
  height: 100px;
  background-color: #81d4fa;
}
#main {

}
#aside {
  width: 30%;
  height: 780px;
  background-color: #4fc3f7;
  float: left;
}
#article1 {
  width: 70%;
  height: 260px;
  background-color: #29b6f6;
  float: left;
}
#article2 {
  width: 70%;
  height: 260px;
  background-color: #03a9f4;
  float: left;
}
#article3 {
  width: 70%;
  height: 260px;
  background-color: #039be5;
  float: left;
}
#footer {
  height: 100px;
  background-color: #0288d1;
}

/* clearfix */
.clearfix::before,
.clearfix::after {
  content: '';
  display: block;
  line-height: 0;
}
.clearfix::after {
  clear: both;
}
@media (max-width: 1300px) {
  #wrap {
    width: 96%;
  }
  #article2 {
    width: 35%;
    height: 520px;
  }
  #article3 {
    width: 35%;
    height: 520px;
  }
}
@media (max-width: 768px) {
  #wrap {
    width: 100%;
  }
  #article1 {
    width: 70%;
    height: 390px;
  }
  #article2 {
    width: 70%;
    height: 390px;
  }
  #article3 {
    display: none;
  }
}
@media (max-width: 480px) {
  #aside {
    width: 100%;
    height: 200px;
  }
  #article1 {
    width: 100%;
    height: 430px;
  }
  #article2 {
    width: 100%;
    height: 150px;
  }
  #article3 {
    display: none;
  }
}