*
{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  /*font-family: "Poppins", sans-serif;*/
}

.material-symbols-outlined {
  user-select: none;
  cursor: pointer;
}

a {
  text-decoration: none;
}


header {
  margin: 0 auto;
  max-width: 720px;
}

header .site-title {
  width: 120px;
  line-height: 1px;
}

header .site-title img {
  width: 100%;
}

section {
  display: flex;
  justify-content: center;
  align-items: start;
  width: 100%;
  padding: 0;
  background-color: #2b2b2b;
}

.container {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  user-select: none;
}


.container #video_player {
  position: relative;
  width: 780px;
  height: 100%;
  overflow: hidden;
  box-shadow: 0 0 5px rgba(255, 255, 255, 0);
}

.container #video_player #main-video {
  position: relative;
  width: 100%;
  height: 100%;
  outline: none;
  vertical-align: bottom;
}


.youtube-area {
  width: 100%;
  background-color: rgb(255, 201, 201);
}

.youtube-area.hidden {
  display: none;
}

.youtube {
  max-width: 780px;
  height: 440px;
  margin: 0 auto;
}


iframe {
  width: 100%;
  height: 100%;
}





.video-container-color {
  background: #e9e9e9;
  padding: 18px 0;
}

.video-container {
  max-width: 780px;
  align-items: center;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
}

.video-container .title-area {
  width: 60%;
}

.video-container .title-area .video-title {
  text-align: center;
}


.video-container .menu-area {
  width: 40%;
}


.video-container .menu-area ul {
  display: flex;
  justify-content: end;
}

.video-container .menu-area li {
  user-select: none;
  list-style: none;
}

.video-container .menu-area li:nth-of-type(n + 2) {
  margin-left: 10px;
}

.video-container .menu-area li a {
  display: block;
  height: 38px;
  text-decoration: none;
  padding: 5px 10px;
  background: #fff;
  color: #000;
  border: 2px solid #3a3a3a;
  border-radius: 5px;
  box-shadow: 2px 2px 10px rgba(0,0,0,0.3);  
}

.video-container .menu-area li a:hover {
  background: #dfdfdf;;
  transition: .5s;
}

.video-container .menu-area .next-video,
.video-container .menu-area .previous-video {


  max-width: 50px;
  height: 100%;
}

.video-container .menu-area .next-video.active {
  pointer-events: none;
  background: #dfdfdf;
}

.video-container .menu-area .previous-video.active {
  pointer-events: none;
  background: #dfdfdf;
}



.video-container .menu-area .video-list {
  text-align: center;
  max-width: 100px;
}


.overview-area {
  /* border: 1px solid red; */
  max-width: 780px;
  padding: 0 20px;
  margin:10px auto 0 auto;
}

.group {
  padding: 14px 5px;
  margin-bottom: 10px;
  border-top: 1px solid #000000;
}



p {
  padding: 5px 5px 0;
  color: #6a6a6a;
}

#change-button {
  display: block;
  background-color: rgb(255, 201, 201);
  margin-top: 10px;
  width: 200px;
  text-align: center;
  border-radius: 10px;
  padding: 10px 20px;
  cursor: pointer;
  user-select: none;
}

#return-button {
    display: block;
  margin-top: 10px;
  width: 200px;
  text-align: center;
  background-color: rgb(59, 59, 59);
  color: #fff;
  border-radius: 10px;
  padding: 10px 20px;
  cursor: pointer;
  user-select: none;
}

@media(max-width: 630px) {
    
    .youtube {
        height: 355px;
    }
}


@media(max-width: 560px) {
    
    .youtube {
      height: 310px;
    }    


  .video-container {
    display: block;
  }


  .video-container .title-area {
    width: 100%;
    text-align: center;
  }
  
  .video-container .menu-area {
    margin-top: 5px;
    margin-left: 0px;
    width: 100%;
  }

  .video-container .menu-area ul {
    justify-content: center;
  }

  .video-container .menu-area li:nth-of-type(n + 2) {
    margin-left: 15px;
  }
 

  
}

@media(max-width: 450px) {
    body {
        line-height: 1.5;
    }
    
    .youtube {
        height: 255px;
    }
}


@media(max-width: 400px) {
    
     .youtube {
      height: 225px;
    }  
    
  .video-container .title-area .video-title {
    font-size: 20px;
  }
}