index.css

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans',
    'Droid Sans', 'Helvetica Neue', sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New', monospace;
}
#root {
  display: flex;
  justify-content: center;
  align-items: center;
}
@font-face {
  font-family: 'Pretendard-Black';
  font-display: fallback;

  /* 
  src: 사용할 폰트의 위치 및 형식 
     Safari, Android, iOS => ttf
     Modern Browsers => woff
*/

  src: url('./font/Pretendard-Black.otf') format('opentype'), url('./font/Pretendard-Black.woff') format('woff');
  /*사용할 폰트 기본 스타일 */
  font-weight: 900;
  font-style: normal;
}
@font-face {
  font-family: 'Pretendard-Bold';
  font-display: fallback;

  /* 
  src: 사용할 폰트의 위치 및 형식 
     Safari, Android, iOS => ttf
     Modern Browsers => woff
     IE6-IE8 => eot
*/

  src: url('./font/Pretendard-Bold.otf') format('opentype'), url('./font/Pretendard-Bold.woff') format('woff'),
    url('./font/Pretendard-Bold.eot?iefix') format('embedded-opentype');

  /*사용할 폰트 기본 스타일 */
  font-weight: 700;
  font-style: normal;
}

@font-face {
  font-family: 'Pretendard-Regular';
  font-display: fallback;

  /* 
  src: 사용할 폰트의 위치 및 형식 
     Safari, Android, iOS => ttf
     Modern Browsers => woff
     IE6-IE8 => eot
*/

  src: url('./font/Pretendard-Regular.otf') format('opentype'), url('./font/Pretendard-Regular.woff') format('woff'),
    url('./font/Pretendard-Regular.eot?iefix') format('embedded-opentype');

  /*사용할 폰트 기본 스타일 */
  font-weight: 400;
  font-style: normal;
}

@font-face {
  font-family: 'Pretendard-ExtraBold';
  font-display: fallback;

  /* 
  src: 사용할 폰트의 위치 및 형식 
     Safari, Android, iOS => ttf
     Modern Browsers => woff
     IE6-IE8 => eot
*/

  src: url('./font/Pretendard-ExtraBold.otf') format('opentype'), url('./font/Pretendard-ExtraBold.woff') format('woff'),
    url('./font/Pretendard-ExtraBold.eot?iefix') format('embedded-opentype');

  /*사용할 폰트 기본 스타일 */
  font-weight: 800;
  font-style: normal;
}

@font-face {
  font-family: 'Pretendard-Medium';
  font-display: fallback;

  /* 
  src: 사용할 폰트의 위치 및 형식 
     Safari, Android, iOS => ttf
     Modern Browsers => woff
     IE6-IE8 => eot
*/

  src: url('./font/Pretendard-Medium.otf') format('opentype'), url('./font/Pretendard-Medium.woff') format('woff'),
    url('./font/Pretendard-Medium.eot?iefix') format('embedded-opentype');

  /*사용할 폰트 기본 스타일 */
  font-weight: 500;
  font-style: normal;
}

@font-face {
  font-family: 'GmarketSansMedium';
  font-display: fallback;
  src: url('./font/GmarketSansMedium.otf') format('opentype');
}