.banner-box {
  height: 455px;
  position: relative;
  color: #fff;
}

.course-detail-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 30px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  font-size: 14px;
}

.breadcrumb a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: #fff;
}

.breadcrumb span {
  margin: 0 8px;
  color: rgba(255, 255, 255, 0.6);
}

.header-actions {
  display: flex;
  gap: 20px;
}

.header-actions a {
  display: flex;
  align-items: center;
  color: #fff;
  text-decoration: none;
  font-size: 14px;
}

.header-actions a:hover {
  opacity: 0.8;
}

.course-title-section {
  text-align: center;
  padding: 40px 0;
}

.course-title {
  height: 60px;
  max-width: 1200px;
  margin-top: 62px;
  color: #ffffff;
  text-align: center;
  font-size: 34px;
  letter-spacing: 4px;
  line-height: 50px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.course-info {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
  font-size: 14px;
  color: white;
  margin-top: 15px;
}

.info-divider {
  color: rgba(255, 255, 255, 0.4);
}

.action-section {
  text-align: center;
  margin-top: 20px;
}

.watch-btn {
  display: inline-block;

  background: linear-gradient(90deg, #f38d1f 0%, #ffae58 100%) !important;
  color: #fff;
  font-size: 20px;
  text-decoration: none;
  border-radius: 30px;
  width: 200px;
  height: 43px;
  line-height: 43px;
}

/* Tab 样式 */
.tab {
  background: #fff;
  border-bottom: 1px solid #e5e5e5;
  position: sticky;
  top: 0;
  z-index: 100;
}

.tab .wrap {
  display: flex;
  align-items: center;
}

.tab .box {
  position: relative;
  padding: 20px 30px;
  cursor: pointer;
  margin-right: 50px;
}

.tab .box a {
  font-size: 16px;
  color: #333;
  text-decoration: none;
  transition: color 0.3s;
}

.tab .box:hover a {
  color: #ff5400;
}

.tab .box .choose {
  color: #ff5400;
}

.tab .box span {
  font-size: 12px;
  color: #999;
  margin-left: 5px;
}

.tab .box .line {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 3px;
  background: #ff5400;
  transition: width 0.3s;
}

.tab .box .line.active {
  width: 40px;
}

.tab .consult {
  margin-left: auto;
}

.tab #consultQQ {
  height: 30px;
  width: 110px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #ffa545;
  color: #fff;
  font-size: 14px;
  border-radius: 5px;
  cursor: pointer;
  margin-left: 20px;
}

.tab #consultQQ:hover {
  opacity: 0.9;
}

#consultQQ .icon-xiada-pc-zixun {
  font-size: 14px;
  margin-right: 5px;
}

/* Tab Content 样式 */
.tab-content {
  min-height: 400px;
}

.tab-content .content {
  display: none;
}

.tab-content .content.active {
  display: block;
}

/*content-box样式开始处*/
.section0 {
  width: 100%;
  background: #f8fafc;
}
.section0 .wrap {
  height: 495px;
  box-sizing: border-box;
  text-align: center;
}
.section0 .wrap .content-box {
  margin: 0 auto;
  text-align: center;
}
.section0 .wrap .content-box .class-info {
  width: 1152px;
  height: 450px;
  box-sizing: border-box;
  margin: 36px auto 48px auto;
  text-align: left;
  padding: 95px 0 72px 0;
  box-shadow: 0 4px 8px 0 rgba(7, 17, 27, 0.1);
  border-radius: 16px;
  display: block;
  background: #4d4d4d;
  background-size: cover;
  background-position: center;
  -webkit-background-size: inherit;
  background-image: url(https://static-xiaodaa-com.oss-cn-shanghai.aliyuncs.com/image/PC/course-teacher-info-bk435413.png);
}
.content-box .class-info .dark-box {
  width: 862px;
  height: 312px;
  box-sizing: border-box;
}
.content-box .class-info .dark-box .video-btn {
  width: 96px;
  margin: 40px 100px 86px 100px;
}
.content-box .class-info .dark-box .video-btn .play img {
  width: 100px;
  height: 100px;
  cursor: pointer;
}
.content-box .class-info .dark-box .video-btn .play img:hover {
  /* for IE */
  filter: alpha(opacity=60);
  /* CSS3 standard */
  opacity: 0.6;
  cursor: pointer;
}
.content-box .class-info .dark-box .video-btn p {
  font-size: 16px;
  color: #ffffff;
  line-height: 24px;
  text-align: center;
  margin-top: 23px;
}
.content-box .class-info .dark-box .banji-info {
  width: 564px;
  height: 260px;
  float: left;
  position: relative;
  box-sizing: border-box;
  padding-right: 34px;
}
.content-box .class-info .dark-box .banji-info .title {
  font-weight: bold;
  font-size: 24px;
  color: #ffffff;
  line-height: 36px;
  margin-bottom: 30px;
}
.content-box .class-info .dark-box .banji-info .desc {
  width: 470px;
  font-size: 14px;
  color: #ffffff;
  line-height: 28px;
}
.content-box .class-info .dark-box .banji-info .line {
  position: absolute;
  top: 0;
  right: 3px;
  width: 2px;
  height: 100%;
  background: rgba(255, 255, 255, 0.4);
}
.class-info .white-box {
  position: relative;
  margin-top: -95px;
  left: 0;
  width: 880px;
  box-sizing: border-box;
  height: 450px;
  background: #ffffff;
  box-shadow: 0 8px 16px 0 rgba(7, 17, 27, 0.1);
  border-radius: 16px 0 0 16px;
  padding: 48px 60px 60px 64px;
  overflow: hidden;
}
.class-info .white-box .nickname {
  font-weight: bold;
  font-size: 30px;
  color: #f20d0d;
  line-height: 48px;
}
.class-info .white-box .job {
  font-weight: bold;
  font-size: 18px;
  color: #07111b;
  line-height: 30px;
  letter-spacing: 1px;
  margin-bottom: 24px;
}
.class-info .white-box .introduce {
  padding-right: 60px;
  font-size: 16px;
  line-height: 30px;
  letter-spacing: 1px;
}
.class-info .tutor-box {
  width: 272px;
  /*margin-top: -260px;*/
  height: 267px;
  padding-top: 10px;
  position: relative;
}
.tutor {
  width: 160px;
  margin: 0 auto;
  position: relative;
  text-align: center;
}
.class-info .tutor-box .avator {
  width: 132px;
  height: 132px;
  border-radius: 50%;
  overflow: hidden;
  display: block;
  margin-left: 12px;
}
.class-info .tutor-box .nickname {
  font-weight: bold;
  font-size: 20px;
  color: #ffffff;
  line-height: 60px;
  height: 60px;
}
.class-info .tutor-box p {
  font-size: 14px;
  color: #ffffff;
  line-height: 22px;
}
.class-info .tutor-box .jiao {
  position: absolute;
  top: 57px;
  height: 0;
  width: 0;
  border-top: 20px solid transparent;
  border-left: 25px solid #fff;
  border-bottom: 20px solid transparent;
}

/*lesson-chapter样式开始处*/
.lesson-chapter {
  padding: 50px 0 30px;
  background-color: #ffffff;
  padding-left: 20px;
}
.lesson-chapter .chapter-box {
}
.lesson-chapter .chapter-box .chapter-name {
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0.16px;
  line-height: 14px;
  text-align: center;
  color: #4d4d4d;
}
.lesson-chapter .chapter-box p {
  padding-left: 20px;
  margin-top: 15px;
  font-size: 14px;
  color: #6c7a7a;
}
.lesson-chapter .chapter-box ul {
  margin-top: 10px;
  padding: 20px;
}
.lesson-chapter .chapter-box ul li {
  margin-bottom: 20px;
  height: 25px;
  cursor: pointer;
  font-size: 14px;
}
.lesson-chapter .chapter-box ul li em {
  float: left;
  color: #647070;
}
.lesson-chapter .chapter-box ul li .dot {
  margin-top: -3px;
  margin-right: 15px;
  font-size: 20px;
  color: #e3e3e3;
}
.lesson-chapter .chapter-box ul li .sec-tit {
  margin-left: 15px;
}
.lesson-chapter .chapter-box ul li span {
  float: right;
  margin-right: 24px;
}
.lesson-chapter .chapter-box ul li span i {
  margin-right: 9px;
  float: left;
  margin-top: 1px;
  font-size: 20px;
}
.lesson-chapter .active {
  color: #ff5400 !important;
}
.lesson-chapter .tit img {
  float: left;
  margin-right: 10px;
  height: 14px;
  width: 7px;
}
.main .none {
  height: 700px;
}

.free .active {
  color: #0fd491 !important;
}

/*main样式开始处*/
.main {
  margin-top: 10px;
}

/*left-box样式开始处*/
.main .left-box {
  width: 835px;
}

/*sideBar样式开始处*/
.main .sideBar {
  margin-left: 10px;
  width: 355px;
}

/*teacher-info样式开始处*/
.teacher-info {
  padding: 30px;
  background-color: #ffffff;
}
.teacher-info img {
  margin-left: 85px;
  width: 120px;
  height: 120px;
  border-radius: 50%;
}
.teacher-info .name {
  margin-top: 15px;
  margin-bottom: 20px;
  text-align: center;
  font-size: 20px;
}
.teacher-info .info {
  text-align: center;
  color: #858585;
  font-size: 14px;
}

/*QQ-group样式开始处*/
.QQ-group {
  margin-top: 10px;
  padding: 15px 20px;
  background-color: #ffffff;
}
.QQ-group .circle {
  margin-right: 20px;
  margin-top: 4px;
  float: left;
  width: 60px;
  height: 60px;
  line-height: 45px;
  text-align: center;
  background-color: #d7e8f5;
}

/*常见问题problem样式开始处*/
.problem {
  margin-top: 20px;
}
.problem .wrap {
  background-color: #ffffff;
  padding: 40px 120px;
  box-sizing: border-box;
}
.problem .list {
  font-size: 16px;
}
.problem .item {
  padding: 24px 0;
  border-bottom: 1px solid #f0f0f0;
  transition: all 0.3s ease;
}
.problem .item:last-child {
  border-bottom: none;
}
.problem .item:hover {
  background-color: #fafafa;
  padding-left: 10px;
}
.problem .question {
  color: #343434;
  font-weight: 600;
  font-size: 16px;
  margin-bottom: 16px;
  line-height: 1.6;
}
.problem .question::before {
  content: 'Q';
  display: inline-block;
  width: 24px;
  height: 24px;
  background: linear-gradient(135deg, #ff6b35 0%, #ff9a3c 100%);
  color: #fff;
  font-size: 14px;
  font-weight: bold;
  text-align: center;
  line-height: 24px;
  border-radius: 50%;
  margin-right: 12px;
}
.problem .answer {
  color: #666666;
  font-size: 15px;
  line-height: 1.8;
  padding-left: 36px;
  margin-bottom: 40px;
}