body {
  font-family: "Microsoft YaHei", sans-serif;
  background-color: #121212;
  color: #e1e1e1;
}

.mai-icon {
  background: #4a6ef5;
  color: #fff;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  text-align: center;
  line-height: 40px;
  margin-right: 20px;
}
/*导航*/
.navbar {
  margin-bottom: 0;
  border-bottom: 1px solid #2d2d2d;
}
.navbar-default {
  background-color: #1a1a1a;
  /* box-shadow: 0px 2px 8px 0px rgba(0,0,0,0.5); */
}
.navbar-default .navbar-brand {
  font-size: 30px;
  font-weight: bold;
  color: #4a6ef5;
  height: 70px;
  line-height: 35px;
  padding: 0;
}
.navbar-default .navbar-nav > li > a {
  font-size: 16px;
  color: #e1e1e1;
  height: 70px;
  line-height: 35px;
}
.navbar-default .navbar-nav > li > a:hover {
  color: #4a6ef5;
}
.navbar-toggle {
  margin-top: 17px;
  background-color: #2d2d2d;
}
.navbar-default .navbar-toggle .icon-bar {
  background-color: #e1e1e1;
}

.navbar-default .navbar-nav .navbar-right > li > a:visited {
  color: #e1e1e1;
}

.banner {
  text-align: center;
  color: #fff;
  background: url("../images/banner.png");
  background-size: cover;
  background-position: 0 45%;
}
.lvjing {
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  padding: 80px 0;
}
/*home*/
/* #home 样式注释保持不变 */
/*bbs*/
#bbs {
  padding: 80px 0;
  text-align: center;
  background-color: #121212;
}
#bbs .col-md-4 {
  padding: 15px;
}
#bbs .col-md-4:hover {
  background: #2d2d2d;
  box-shadow: 1px 1px 4px #000;
}
#bbs a {
  color: #e1e1e1;
  text-decoration: none;
}
#bbs img {
  margin: 0 auto;
}

#bbs .title {
  font-size: 3rem;
  font-weight: bold;
}

#bbs #element {
  display: inline;
  font-size: 4rem;
  margin-top: 20px;
}

.typed-cursor {
  font-size: 4rem;
}

/*HTML5 + bootstrap*/
#html5 {
  background: #1a1a1a;
}
#html5,
#bootstrap {
  padding: 80px 0;
}
#html5 h2,
#bootstrap h2 {
  font-weight: bold;
  color: #fff;
}
#html5 p,
#bootstrap p {
  line-height: 25px;
  color: #e1e1e1;
}

/*course*/
#course {
  background: #1a1a1a;
  padding: 80px 0;
  text-align: center;
}
#course h2 {
  font-weight: bold;
  padding-bottom: 60px;
  color: #fff;
}
#course .col-md-3 {
  margin-bottom: 20px;
}
.course {
  background: #2d2d2d;
  border: 1px solid #333;
  position: relative;
}

.course .course-title {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 10px;
  background-color: rgba(0, 0, 0, 0.5);
  color: #fff;
  box-sizing: border-box;
  /* 如果文字与图片之间需要间隔，可加上 margin-bottom 或其他定位设置 */
}

.course .course-title p {
  display: none;
  text-align: left;
}

#course .btn {
  background: transparent;
  border: 1px solid #4a6ef5;
  border-radius: 0px;
  color: #4a6ef5;
  margin-top: 20px;
  margin-bottom: 30px;
  padding: 8px 40px;
  transition: all 0.3s;
}
#course .btn:hover {
  background: #4a6ef5;
  color: #fff;
}
.course .case-img {
  width: 100%;
  height: auto;
}

/*app*/
#app {
  padding: 80px 0;
  background-color: #121212;
}
#app h2 {
  font-weight: bold;
  padding-bottom: 30px;
  color: #fff;
}
#app .btn {
  margin: 10px 0;
  background: #40d2b1;
  border-color: #40d2b1;
  border-radius: 0;
  padding: 6px 30px;
  transition: all 0.3s;
}
#app .btn:hover {
  background: rgb(44, 142, 120);
}

/*contact*/
#contact {
  background: url("../images/contact-bg.jpeg") no-repeat;
  background-size: cover;
  color: #ffffff;
}
#contact h2 {
  font-weight: bold;
  margin-top: 0;
  margin-bottom: 25px;
}
#contact p {
  line-height: 24px;
  margin-bottom: 2px;
}
#contact a {
  color: #e1e1e1;
  text-decoration: underline;
}

#contact .form-control {
  border: none;
  border-radius: 0;
  height: 50px;
  margin-bottom: 20px;
  background-color: rgba(45, 45, 45, 0.9);
  color: #e1e1e1;
}
#contact textarea.form-control {
  height: auto;
}
#contact input[type="submit"] {
  background: #40d2b1;
  color: #fff;
  font-weight: bold;
  transition: all 0.3s;
}
#contact input[type="submit"]:hover {
  background: rgb(44, 142, 120);
}

/*footer*/
footer {
  font-weight: 400;
  text-align: center;
  padding: 20px;
  color: #999;
  background-color: #0a0a0a;
}
footer a {
  color: #4a6ef5;
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  z-index: 9999;
}
.back-to-top a {
  opacity: 0.7;
  border-radius: 50%;
  padding: 15px 17px;
}
.back-to-top a:hover {
  opacity: 1;
}