<div id="wrap">
  <div id="header">
    <div class="container"></div>
  </div>
  <div id="nav">
    <div class="container"></div>
  </div>
  <div id="section">
    <div class="container"></div>
  </div>
  <div id="footer">
    <div class="container"></div>
  </div>
</div>

* {
  margin: 0;
  padding: 0;
}
#header {
  height: 100px;
  background-color: #E0F2F1;
}
#nav {
  height: 300px;
  background-color: #80CBC4;
}
#section {
  height: 580px;
  background-color: #26A69A;
}
#footer {
  height: 100px;
  background-color: #00897B;
}

/* 아이디/클래스 차이점 
#   /   .
한번/두개이상(중복) 사용가능
전체적인 틀, 스크립트 -->id
세부적인 영역, 반복 -->class
*/
.container {
  width: 1200px;
  height: inherit;
  margin: 0 auto;
  background-color: rgba(0,0,0,0.3);;
}
@media (max-width: 1220px){
  .container {
    width: 96%;

  }
}
@media (max-width: 768px){
  .container {
    width: 100%;

  }
}