.coursecontent {
    display: flex;
    justify-content: space-evenly;
    margin: 40px 0 0 0;
}
.coursecontent li {
    width: 16%;
}
.coursebox {
    position: relative;
    background: #fff;
    margin: 100px auto 30px auto;
    padding: 20px;
}
.coursebox:last-of-type {
    margin: 100px auto 0 auto;
}
.boxttl {
    position: absolute;
    left: 16%;
    transform: translate(-50%, -90%);
    -webkit-transform: translate(-50%, -90%);
    -ms-transform: translate(-50%, -90%);
    display: block;
    width: 35%;
    margin: 0 auto;
    padding: 10px 0 0 0;
} 
.coursebox ul li {
    margin: 20px 0 0 0;
    text-align: left;
    font-size: 14px;
}
.coursebox ul li h3 {
    height: 50px;
    padding: 10px 0 0 60px;
    font-size: 18px;
    background-image: url(../images/course/icon_word.png);
    background-repeat: no-repeat;
    background-size: 50px;
}
.coursebox ul li h3.excel {
    background-image: url(../images/course/icon_ecxel.png);
}
.coursebox ul li h3.powerpoint {
    background-image: url(../images/course/icon_powerpoint.png);
}
.coursebox ul li h3.access {
    background-image: url(../images/course/icon_access.png);
}
.coursebox ul li h3.icon_internet {
    background-image: url(../images/course/icon_internet.png);
}
.coursebox ul li h3.icon_sousa {
    background-image: url(../images/course/icon_sousa.png);
}
.coursebox ul li h3.icon_mail {
    background-image: url(../images/course/icon_mail.png);
}
.coursebox ul li h3.icon_type {
    background-image: url(../images/course/icon_type.png);
}
.coursebox ul li h3.icon_photo {
    background-image: url(../images/course/icon_photo.png);
}
.coursebox ul li h3.icon_album {
    background-image: url(../images/course/icon_album.png);
}
.coursebox ul li h3.icon_nenga {
    background-image: url(../images/course/icon_nenga.png);
}
.coursebox ul li h3.icon_phone {
    background-image: url(../images/course/icon_phone.png);
}
.coursebox ul li h3.icon_shuri {
    background-image: url(../images/course/icon_shuri.png);
}
.coursebox ul li h3.icon_home {
    background-image: url(../images/course/icon_home.png);
}
.coursebox ul li h3.icon_zoom {
    background-image: url(../images/course/icon_zoom.png);
}
.coursebox ul li h3.icon_program {
    background-image: url(../images/course/icon_program.png);
}
.coursebox ul li h3.icon_henshu {
    background-image: url(../images/course/icon_henshu.png);
}

.coursebox ul li .recommend{
    margin: 10px 0;
    padding: 10px 16px;
    background: #c3e1cd;
}
.coursebox ul li .recommend p {
    font-size: 14px;
}
.coursebox ul li strong {
    display: inline-block;
    margin: 0 10px 0 0;
}
.aboutonline {
    margin: 30px 0 0 0;
}
/******** course_phone *********/
.course_summary {
    text-align: left;
}
.course_summary .detail {
    display: flex;
    flex-wrap: wrap;
    margin: 0 0 30px 0;
}
.course_summary .detail li {
    width: 33%;
}
.course_summary p {
    font-size: 16px;
}
.course_summary li i {
    display: inline-block;
    margin: 0 0 10px 0;
    padding: 0 0 0 10px;
    font-size: 14px;
    font-style: normal;
    color: rgb(80, 72, 72);
}
.course_summary strong {
    color: #eb3b00;
    font-weight: bold;
} 
@media screen and (max-width: 800px) {
.boxttl {
    width: 50%;
    left: 25%;
}

.coursecontent li {
    width: 26%;
}
.course_summary .detail li {
    width: 50%;
}
}
@media screen and (max-width: 500px) {
.coursebox {
    margin: 50px auto 30px auto;
    padding: 20px 10px;
}
.boxttl {
    width: 60%;
    left: 29%;
    padding: 10px 0 0px 0;
}
.course_summary .detail li {
    width: 100%;
}
.coursecontent {
    margin: 20px 0 0 0;
}
.coursebox ul li h3 {
    height: auto;
    padding: 10px 0 0 40px;
    font-size: 16px;
    background-size: 30px;
    background-position: left center;
}
}

.youtube-box{
    width: 100%;
    max-width: 700px;
    aspect-ratio: 16 / 9;
}
.youtube-box iframe{
    width: 100%;height: 100%;
}