.header {
  overflow: hidden;
  background-color: #f1f1f1;
  padding: 20px 10px;
}

.header a {
  float: left;
  color: black;
  text-align: center;
  padding: 12px;
  text-decoration: none;
  font-size: 18px; 
  line-height: 25px;
  border-radius: 4px;
}

.header a.logo {
  font-family: arial, sans-serif;
  font-weight: bold;
  color: #000000;
  font-size:2.7vw;"
}

.header a:hover {
  background-color: #ddd;
  color: black;
}

.header a.active {
  background-color: #3f84f2;
  color: white;
}

.header-right {
  float: right;
}

.image-jcc {
  width: 100%;
  max-width: 1000px;
  height: auto;

}


@media screen and (max-width: 1470px) {
 .image-jcc {
  width: 100%;
  max-width: 750px;
  height: auto;
  }
 
}

@media screen and (max-width: 1380px) {
 .image-jcc {
  width: 100%;
  max-width: 750px;
  height: auto;
 
 }
 
}

@media screen and (max-width: 1280px) {
 .image-jcc {
  width: 100%;
  max-width: 750px;
  height: auto;

}

}

@media screen and (max-width: 1139px) {
 .image-jcc {
  width: 100%;
  max-width: 750px;
  height: auto;

}

}

@media screen and (max-width: 950px) {
 .image-jcc {
  width: 100%;
  max-width: 750px;
  height: auto;

}

}

@media screen and (max-width: 800px) {
  .header a {
    float: none;
    display: block;
    text-align: left;
  }

  .header-right {
    float: none;
  }

 .image-jcc {
  width: 100%;
  height: auto;

}

}

@media screen and (max-width: 500px) {
  .header a {
    float: none;
    display: block;
    text-align: left;
  }

  .header-right {
    float: none;
  }

}