* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN";
}

a {
  text-decoration: none;
}

.text-contents {
  text-align: center;
  color: rgb(0, 0, 0);
}

.footer {
  width: 100%;
  color: rgb(255, 255, 255);
  padding-bottom: 40px;
}

.footer h1 {
  padding-left: 22px;
}

.footer h3 {
  width: 100%;
  padding: 0 0px;
  margin: 0 auto;
  color: rgb(0, 0, 0);
  font-size: 25px;
  letter-spacing: 7px;
  padding-top: 50px;
}

.footer h1 {
  font-size: 25px;
  padding-left: 0px;
}

.footer-text{
  font-size: 10px;
}

.top-wrapper {
  padding: 300px 0 150px 0;
  text-align: center;
  background: rgba(0, 0, 0, 0.5);
  background-image: url(a.mp4);
  background-size: cover;
  color: white;
  text-align: center;
}

.top-wrapper h1 {
  opacity: 0.9;
  font-size: 45px;
  letter-spacing: 5px;
}

.btn {
  padding: 8px 24px;
  color: white;
  display: inline-block;
  opacity: 0.8;
  border-radius: 4px;
  text-align: center;
}

.btn:hover {
  opacity: 1;
}

.fa {
  margin-right: 7px;
}

header {
  background: rgba(255, 255, 255, 0.25);
  box-shadow: 0 4px 200px 0 rgba(74, 74, 74, 0.37);
  backdrop-filter: blur( 6.5px );
  -webkit-backdrop-filter: blur( 6.5px );
  border: 1px solid rgba( 255, 255, 255, 0.18 );


  height: 90px;
  width: 100%;
  position: fixed;
  top: 0;
  z-index: 10;
  padding-left: 20px;
}

.logo {
  width: 124px;
  margin-top: 20px;
}

.header-left {
  font-weight: bold;
  color: #3f3f3f;
  float: left;
  padding: 10px 20px;
}

.header-right {
  padding: 10px 20px;
  float: right;
  letter-spacing: 2px;
  margin-right: -25px;
  padding-right: 40px;
}

.header-right a {
  line-height: 65px;
  padding: 0 25px;
  color: rgb(50, 50, 50);
  display: block;
  float: left;
  transition: all 0.5s;
}

.header-right a:hover {
  background-color: rgba(255, 255, 255, 0.3);
  font-family: "Hiragino Kaku Gothic ProN";
}

.lesson-wrapper {
  height: 580px;
  padding-bottom: 80px;
  padding-left: 5%;
  padding-right: 5%;
  background-color: #ffffff;
  color: black;
  text-align: center;
}

.heading {
  padding-left: 22px;
  padding-bottom: 70px;
  color: #ffffff;
}

.main {
  background: rgb(110, 180, 255);
  background: linear-gradient(90deg, rgb(86, 117, 255) 0%, rgb(136, 168, 255) 100%);
}

.sites h2 {
  font-weight: normal;
}

.lesson {
  float: left;
  width: 25%;
  color: black;
}

.lesson-icon {
  size: 20px;
  position: relative;
  display: inline-block;
  border-radius: 5%;
  cursor: pointer;
  transition: .3s;
}

.lesson-icon:hover {
  transform: scale(1.1, 1.1);
  /* 拡大 */
}

.lesson-icon p {
  position: absolute;
  top: 37%;
  width: 100%;
  color: white;
}

.text-contents {
  width: 80%;
  display: inline-block;
  margin-top: 15px;
  font-size: 20px;
  color: #000000;
}

.sites h3 {
  font-weight: normal;
}

.message-wrapper {
  border-bottom: 1px solid #eee;
  text-align: center;
}

.message {
  padding: 15px 40px;
  background-color: #5dca88;
  cursor: pointer;
  box-shadow: 0px 7px #1a7940;
}

.message:active {
  position: relative;
  top: 7px;
  box-shadow: none;
}

.sites {
  padding-right: 40px;
}

footer p {
  color: #ffffff;
  font-size: 12px;
  letter-spacing: 4px;
}

footer {
  padding-top: 30px;
  padding-left: 20px;
  padding-right: 20px;
}

.clear {
  clear: left;
}

@media all and (max-width: 1000px) {
  .lesson {
    width: 50%;
    margin-bottom: 50px;
  }
  .lesson-wrapper {
    height: 800px;
  }
  footer {
    text-align: center;
    background: rgb(110, 180, 255);
    background: linear-gradient(90deg, rgb(121, 186, 255) 0%, rgb(72, 77, 233) 100%);
  }
}

@media all and (max-width: 750px) {
  .top-wrapper h1 {
    font-size: 32px;
  }
  .sites h2 {
    font-size: 2px;
  }
}

@media all and (max-width: 670px) {
  .header-right {
    display: none;
  }
  .menu-icon {
    display: block;
  }
  .top-wrapper .btn {
    width: 100%;
  }
  .top-wrapper {
    text-align: center;
  }
  .top-wrapper p {
    font-size: 14px;
  }
  .lesson {
    width: 100%;
  }
  .lesson-wrapper {
    height: 1400px;
  }
  .message-wrapper .btn {
    width: 100%;
  }
}

.skill {
  background-color: #ffffff;
  padding: 20px 20px;
  color: #000000;
  font-weight: bold;
  text-align: center;
}

.skill-list {
  background: #ffffff;
  color: rgb(17, 11, 11);
  text-align: left;
  padding: 0px 50px;
  letter-spacing: 2px;
  padding-bottom: 20px;
  font-size: 17px;
}

footer {
  background: linear-gradient(90deg, rgb(121, 186, 255) 0%, rgb(72, 77, 233) 100%);
}

.shutter {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, rgb(209, 231, 255) 0%, rgb(255, 255, 255) 100%);
  z-index: 9999;
}

.shutter::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  margin: auto;
  background: linear-gradient(90deg, rgb(121, 186, 255) 0%, rgb(72, 77, 233) 100%);
  height: 1px;
}

.shutter {
  -webkit-animation: byeShutter 1.6s forwards;
  animation: byeShutter 1.6s forwards;
}

.shutter::before {
  -webkit-animation: shutterOpen 1.6s forwards;
  animation: shutterOpen 1.6s forwards;
}

.content {
  -webkit-animation: contentScale 1.6s forwards;
  animation: contentScale 1.6s forwards;
}

@keyframes byeShutter {
  70% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    display: none;
    z-index: -1;
  }
}

@keyframes shutterOpen {
  0% {
    width: 0;
    height: 1px;
  }
  50% {
    width: 100%;
    height: 1px;
  }
  90% {
    width: 100%;
    height: 100%;
  }
  100% {
    width: 100%;
    height: 100%;
  }
}