미디어쿼리는 브라우저의 화면 크기에 따라 사이트의 레이아웃이 바뀌도록 CSS를 작성하는 방법을 미디어쿼리라고 한다.
@media [only | not] 미디어유형 [and 조건] * [and 조건]
@media screen and (min-width: 500px) and (max-width: 1000px) {
} @media (min-width: 600px) {
    .column {
      flex: 50%;
      padding: 0 4px;
      max-width: 50%;
    }
  }
  @media (min-width: 960px) {
    .column {
      flex: 25%;
      max-width: 25%;
    }
@media print and (min-width: 600px) {}
@media screen and (max-width: 1024px) {
	body {
    	background-color: yellow;
        }
}
<!DOCTYPE html>
<html lang="ko">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/reset-css@5.0.1/reset.min.css" />
  <link rel="stylesheet" href="./mediaquery.css" />
</head>
<body>
  <header>
    <div class="header">
      <h1>My Website</h1>
      <p>With a flexible layout</p>
    </div>
  </header>
  <nav>
    <div class="nav">
      <a href="javascript:void(0)">Profile</a>
      <a href="javascript:void(0)">My favorite</a>
      <a href="javascript:void(0)">Photo</a>
      <a href="javascript:void(0)">Video</a>
    </div>
  </nav>
  <main>
    <div class="main">
      <div class="left-content">
        <p class="title">About Me</p>
        <p>Photo of me: </p>
        <div class="image">
          image
        </div>
        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Molestiae, fuga!</p>
        <p class="sub-title">More Text</p>
        <div class="image">
          image
        </div>
        <div class="image">
          image
        </div>
        <div class="image">
          image
        </div>
      </div>
      <div class="right-content">
        <p class="title">TITLE HEADING</p>
        <p>Title description, Dec 7, 2022</p>
        <div class="image">
          image
        </div>
        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Nam exercitationem praesentium recusandae, est explicabo molestiae iure eius minus reprehenderit sequi!</p>
        <p class="title">TITLE HEADING</p>
        <p>Title description, Dec 7, 2022</p>
        <div class="image">
          image
        </div>
        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Nam exercitationem praesentium recusandae, est explicabo molestiae iure eius minus reprehenderit sequi!</p>
      </div>
    </div>
  </main>
  <footer>
    <div class="footer"></div>
  </footer>
  
</body>
</html>
$white: #fff;
$gray: #ccc;
$titleSize: 30px;
$blue-color : powderblue;
$black: #000;
$w: 100%;
$n : none;
$img-margin: 8px;
$line-h : 1.5;
.header {
  background-color: $blue-color;
  width: $w;
  height: 150px;
  h1 {
    font: {
      size: $titleSize;
      weight: 700;
    };
    color: $white;
    line-height: $line-h;
  }
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  p {
    color: $white;
  }
}
.nav {
  background-color: yellowgreen;
  display: flex;
  a {
    text-decoration: $n;
    color: $white;
    padding: 16px;
    display: block;
  }
}
.main {
  display: flex;
  width: $w;
  box-sizing: border-box;
  flex-wrap: wrap;
  .left-content {
    background-color: beige;
    flex: 30%;
    line-height: $line-h;
    padding: {
      top: 16px;
      left: 10px;
      right: 10px;
      bottom: 16px;
    }
    .title {
      font: {
        size: $titleSize;
        weight: 700;
      };
    }
    .image {
      background-color: $gray;
      width: $w;
      height: 150px;
      margin: {
        top: $img-margin;
        bottom: $img-margin;
      }
    }
    .sub-title {
      font: {
        weight: 700;
        size: 20px;
      }
    }
  }
  .right-content {
    flex: 70%;
    background-color: yellow;
    line-height: $line-h;
    box-sizing: border-box;
    padding: {
      top: 16px;
      left: 10px;
      right: 10px;
      bottom: 16px;
    }
    .title {
      font: {
        size: $titleSize;
        weight: 700;
      }
    }
    .image {
      background-color: $gray;
      width: $w;
      height: 250px;
    }
  }
}
.footer {
  background-color: $gray;
  width: $w;
  height: 100px;
}
@media (max-width: 720px) {
  .header {
    flex: 100%;
  }
  .nav {
    justify-content: space-between;
  }
  .main {
    flex-wrap: wrap;
    .left-content{
      flex: 100%;
    }
    .right-content{
      flex: 100%;
    }
  }
}
scss를 손에 익힐 겸 scss 문법을 사용해서 미디어 쿼리를 적용해보았다.

