html {
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}
body {
  font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  background-color: white;
  color: #131313;
  text-align: center;
  margin: 0;
  padding: 0;
}

/* top */
#topNav {
  position: -webkit-sticky;
  position: sticky;
  top: 0;
  height: 5rem;
  font-size: 3rem;
  text-align: center;
  color: #1C3966;
  background-color: #fff;
  box-shadow: 0 1px 0 rgb(0 0 0 / 5%), 0 1px 3px rgb(0 0 0 / 10%), inset 0 1px 1px rgb(255 255 255 / 50%);
  z-index: 4;
}
#logo {
  display: inline-block;
  margin: 1rem;
}
#logo img {
  display: block;
  height: 3rem;
}
/* main */
main {
  text-align: center;
  color: #131313;
}
.sectionWrapper {
  position: relative;
  display: block;
  float: left;
  box-sizing: border-box;
  height: calc((100vh - 5rem - 6px) / 2);
  width: calc(50% - 1px);
  background-color: #131313;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  overflow: hidden;
  /* height: calc((100vh - 5rem - 6px) / 2); */
  /* width: 100%; */
  margin: 0 0 2px;
}

.sectionWrapper:first-child {
  width: 100%;
  margin: 0 0 2px 0;
}
.sectionWrapper:nth-child(2) {
  margin-right: 1px;
}
.sectionWrapper:nth-child(3) {
  margin-left: 1px;
}

/* .sectionWrapper {
  width: 100%;
  margin: 0 0 2px 0;
} */

.sectionWrapper .sectionLink {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 3;
}
.sectionWrapper .sectionLink:hover+.sectionInfo header .headline {
  color: #c7abe5;
}
.sectionWrapper .sectionLink:hover~.sectionBackground {
  -webkit-transform: scale(1.1);
  -moz-transform: scale(1.1);
  -ms-transform: scale(1.1);
  -o-transform: scale(1.1);
  transform: scale(1.1);
}
.sectionWrapper .sectionBackground {
  position: absolute;
  background-position: center center;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  opacity: 0.4;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  -webkit-transition: 0.3s;
  -moz-transition: 0.3s;
  -ms-transition: 0.3s;
  -o-transition: 0.3s;
  transition: 0.3s;
  z-index: 1;
}
.sectionWrapper .sectionInfo {
  display: inline-block;
  margin: 0 auto;
  max-width: 90%;
  position: relative;
  text-align: center;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
  top: 50%;
  color: #fbf7fe;
  pointer-events: none;
  z-index: 2;
}
.sectionWrapper .sectionInfo header .headline {
  display: inline-block;
  margin: 1rem auto;
  font-size: 3rem;
  pointer-events: auto;
  cursor: pointer;
  -webkit-transition: 0.3s;
  -moz-transition: 0.3s;
  -ms-transition: 0.3s;
  -o-transition: 0.3s;
  transition: 0.3s;
}
.sectionWrapper .sectionInfo .subhead {
  margin: 0 auto;
  font-size: 1.5rem;
  color: #efefef;
}
.sectionWrapper .sectionInfo .sectionDate {
  margin: 0.2rem 0 0 0;
  font-size: 0.8rem;
  color: #7BB8F9;
}
.sectionWrapper:first-child .sectionBackground {
  background-image: url(/image/readme.jpg);
}
.sectionWrapper:nth-child(2) .sectionBackground {
  background-image: url(/image/black.svg);
}
.sectionWrapper:nth-child(3) .sectionBackground {
  background-image: url(/image/blue.svg);
}
/* .sectionWrapper:nth-child(3) .sectionBackground {
  background-image: url(/image/blue.svg);
} */
*::selection {
  background-color: #7BB8F9;
  color: #1C3966;
}

/* article */
article {
  position: relative;
}
article #articleInfo {
  position: relative;
  overflow: hidden;
  height: 35rem;
  width: 100%;
  margin-bottom: 4rem;
}
article #articleInfo header {
  display: inline-block;
  margin: 0 auto;
  max-width: 90%;
  position: relative;
  text-align: center;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
  top: 50%;
  font-size: 3rem;
  color: #fbf7fe;
  z-index: 1;
}
article #articleInfo header #headline {
  word-break: keep-all;
  font-size: 4.5rem;
}
article #articleMainImage, article #AboutImage {
  position: absolute;
  background-position: center;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  background-repeat: no-repeat;
  bottom: 0;
  left: 0;
  height: 100%;
  width: 100%;
}
article a {
  color: #5C95C5;
}
article a:visited {
  color: #3377A9;
}
article section, article #bottomFooter {
  width: 900px;
  max-width: 85%;
  margin: 0 auto;
  text-align: justify;
  color: #131313;
  margin-bottom: 4rem;
}
article img {
  width: 900px;
  max-width: 85vw;
}
article h2 {
  color: #007ACC;
  font-size: 2.5rem;
}
article h3 {
  font-size: 1.3rem;
}
article h4 {
  display: inline-block;
  font-size: 1.2rem;
  margin: 0;
}
article p {
  margin-bottom: 5rem;
}
article .date {
  display: inline-block;
  font-size: 1.1rem;
  margin: 0.5rem 0.5rem 0.5rem 0;
  color: #007ACC;
}
article #link {
  display: inline-block;
  font-size: 1.5rem;
  border-radius: 1.5rem;
  color: #efefef;
  margin-bottom: 2rem;
}
article .download {
  padding: 2rem;
  border-radius: 1.5rem;
  background-color: #1c3966;
}
article #bottomFooter {
  margin-top: 10rem;
  margin-bottom: 2rem;
  color: #7BB8F9;
}
article #bottomFooter p {
  display: inline-block;
  margin-top: 0;
  font-size: 0.7rem;
}
article #bottomFooter p a:link {
  color: #7BB8F9;
}
article #bottomFooter p a:visited {
  color: #7BB8F9;
}
article #bottomFooter h5 {
  display: inline-block;
  vertical-align: top;
  margin-top: 0;
  font-size: 0.7rem;
}

@media only screen and (max-width: 800px) {
  /* top */
  #topNav {
    height: 4rem;
    font-size: 3rem;
  }
  #logo {
    width: 5.92rem;
    height: 2.4rem;
    margin: 0.8rem;
  }
  /* main */
  .sectionWrapper {
    height: calc((100vh - 4rem - 6px) / 3);
    width: 100%;
    margin: 0 0 1px !important;
  }

  /* article */
  article #articleInfo {
    height: 25rem;
    margin-bottom: 4rem;
  }
  article #articleInfo header {
    font-size: 3rem;
  }
  article #articleInfo header #headline {
    font-size: 3rem;
  }
  article section, article #bottomFooter {
    width: 900px;
    max-width: 85%;
    margin: 0 auto;
    margin-bottom: 4rem;
  }
  article img {
    width: 900px;
    max-width: 85vw;
  }
  article h2 {
    font-size: 2.5rem;
  }
  article h3 {
    font-size: 1.3rem;
  }
  article h4 {
    font-size: 1.2rem;
    margin: 0;
  }
  article h5 {
    font-size: 1.1rem;
    margin: 0.5rem 0.5rem 0.5rem 0;
  }
  article p {
    margin-bottom: 5rem;
  }
  article #bottomFooter {
    margin-top: 10rem;
    margin-bottom: 2rem;
  }
  article #bottomFooter p {
    font-size: 0.7rem;
  }
  article #bottomFooter h5 {
    font-size: 0.7rem;
  }

}