button {
    border: 0;
    width: 100px;
    height: 40px;
    line-height: 40px;
}

li {
    list-style: none;
}

.nav {
    margin: 0 auto;
    text-align: center;

}

.cover {
    width: 100%;
    display: block;
}

.tch {
    margin: 0 auto;
    padding: 50px 0 30px;
    width: 100%;
    text-align: center;
}

.tch1,
.pro1,
.fre1,
.hh1 {
    position: relative;
    font-size: 32px;
    color: #287F58;
    margin-bottom: 18px;
    text-shadow: #12411c 2px 1px 3px;
    font-weight: bold;
    letter-spacing: 10px;
}

.tch2 {
    position: relative;
    font-size: 20px;
    color: #000000;
    margin-bottom: 50px;
    text-shadow: #666d68 1px 1px 1px;
    font-weight: lighter;
}

.tch1::after {
    font-size: 16px;
    position: absolute;
    top: 36px;
    left: 520px;
    color: black;
}

.tch>img {
    width: 200px;
    margin: 20px 30px 0 30px;
}

.pro {
    width: 100%;
    text-align: center;
}

.pro1::after {
    font-size: 16px;
    position: absolute;
    top: 36px;
    left: 570px;
    color: black;
}

.ppro2 {
    width: 60%;
    margin: 50px auto;
    display: flex;
    flex-wrap: nowrap;
    justify-content: space-between;
}

.pro2 {

    text-align: left;
}

.pro2>p {
    font-size: 24px;
    width: 600px;
    position: relative;
    margin-bottom: 40px;
}

.pro2>p::after {
    content: 'Electronic universal testing machine';
    font-size: 16px;
    position: absolute;
    top: 36px;
    left: 0;
    color: #31A05E;
}

.pro2>span {
    display: block;
    margin: 60px 0;
    text-indent: 2em;
}

.pro>img {
    display: block;
    text-align: right;
}

.bu1 {
    background-color: black;
    border-radius: 13px 0 0 13px;
}

.bu2 {
    background-color: #E6E6E6;
    border-radius: 0 13px 13px 0;
}

.pro-more {
    position: relative;
    margin-top: 30px;
    line-height: 0.95;
}

.pro-more-icon {
    position: absolute;
    left: 64px;
}

.back {
    position: relative;
    width: 100%;
}

.back>img {
    width: 100%;
}

.about {
    background-color: white;
    position: absolute;
    box-sizing: border-box;
    top: 60%;
    left: 20%;
    width: 60%;
    padding: 50px;
    display: flex;
    justify-content: center;
    box-shadow: 0 5px 10px 0 #c4c4c4;
}

.about>li:first-child {
    margin-right: 5%;
    width: 30%;
}

.about>li:last-child {
    text-align: left;
    width: 60%;
}

.about img {
    width: 100%;
}

.about>li:last-child>p {
    font-size: 24px;
}

.about>li:last-child>span {
    display: block;
    text-indent: 32px;
    margin: 20px 0 20px;
    font-size: 15px;
}

.ffre1 {
    width: 70%;
    margin: 280px auto 40px;
    text-align: center;
}

.fre {

    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.fre>p::after {
    font-size: 16px;
    position: absolute;
    top: 36px;
    left: 470px;
    color: black;
}

.fre>li {
    width: 300px;
    height: 300px;
}

.fre2 {
    margin: 10px 0 10px;
    font-size: 60px;
}

.fre3 {
    margin: 20px 0;
    color: #287E3A;
    font-size: 28px;
    text-shadow: #12411c 1px 2px 3px;
}

.fre4 {
    padding: 0 16px;
}

.honor {
    width: 70%;
    margin: 0 auto 40px;
    text-align: center;
}

.hh1::after {
    font-size: 16px;
    position: absolute;
    top: 36px;
    left: 520px;
    color: black;
}

.home_honor {
    width: 1280px;
}

.home_honor>img {
    width: 300px;
    margin: 0px 59px;
}

.home_honor>img:hover {
    transform: scale(1.2);
    transition: all .4s;
}