.extra {
  width: 110px;
  height: 32px;
  border-radius: 2px;
  font-family: MicrosoftYaHei;
  font-weight: bold;
  font-size: 16px;
  color: #ffffff;
  box-shadow: 0px 1px 2px 0px #000000;
  opacity: 0.97;
  cursor: pointer;
  border: none;
  background-image: linear-gradient(-90deg, #1d7ce1 0%, #29b8f4 100%),
    linear-gradient(#1d7ce1, #1d7ce1);
}

#about-container {
  width: 100%;
}
#about-container .about-content {
  max-width: 1440px;
  height: 210px;
  margin: 0 auto 40px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  background: url(../image/about.jpg) no-repeat center/cover;
}
#about-container .about-content span {
  font-size: 24px;
  color: white;
  font-weight: bold;
  font-family: MicrosoftYaHei;
  margin: 20px 0;
  text-shadow: 0px 1px 2px #000000;
}

/* media */
@media screen and (max-width: 1439px) {
  #about-container .about-content span {
    font-size: 22px;
  }
  .extra {
    font-size: 14px;
  }
}
@media screen and (max-width: 959px) {
  #about-container .about-content span {
    font-size: 20px;
  }

  .extra {
    font-size: 12px;
  }
  #about-container .about-content {
    padding: 0 8%;
  }
}
@media screen and (max-width: 480px) {
  #about-container .about-content span {
    font-size: 18px;
  }
  .extra {
    font-size: 10px;
  }
}