.content.main {
    background-image: url(../img/bg_main.png);
    background-size: 100% auto;
    background-position: center top;
    background-repeat: no-repeat;
    padding-bottom: 60px;
}
.cnt-top-txt {
    font-size: 30px;
    color: #fff;
    line-height: 52px;
    text-align: center;
    padding-top: 40px;
    height: 250px;
}
.book-category {
    padding: 0 43px;
}
.book-category li a {
    display: block;
    height: 231px;
    background-color: #fff;
    border-radius: 20px;
    box-shadow: 0px 2px 11.28px 0.72px rgba(0, 0, 0, 0.23);
    padding-left: 100px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
}
.book-category li+li {
    margin-top: 24px;
}
.book-category .eng {
    font-size: 48px;
    color: #393939;
}
.book-category .chn {
    font-size: 44px;
    color: #654ebc;
}
.book-category li a::before {
    content: '';
    width: 157px;
    height: 157px;
    position: absolute;
    right: 56px;
    top: 50%;
    transform: translateY(-50%);
    background-size: 100% 100%;
}
.book-category li.writing a::before {
    background: url(../img/ico_writing.png);
    background-size: 100% 100%;
}
.book-category li.speaking a::before {
    background: url(../img/ico_speaking.png);
    background-size: 100% 100%;
}
.book-category li.listening a::before {
    background: url(../img/ico_listening.png);
    background-size: 100% 100%;
}
.book-category li.reading a::before {
    background: url(../img/ico_reading.png);
    background-size: 100% 100%;
}
.book-category li.grammar a::before {
    background: url(../img/ico_grammar.png);
    background-size: 100% 100%;
}


@media all and (max-width: 960px) {
    .content.main {
        padding-bottom: 6.25vw;
    }
    .cnt-top-txt {
        font-size: 3.125vw;
        line-height: 5.416vw;
        padding-top: 4.1666vw;
        height: 26.041vw;
    }
    .book-category {
        padding: 0 4.479vw;
    }
    .book-category li a {
        height: 24.0625vw;
        border-radius: 2.083vw;
        box-shadow: 0px 0.208vw 1.145vw 0.104vw rgba(0, 0, 0, 0.23);
        padding-left: 10.416vw;
    }
    .book-category li+li {
        margin-top: 2.5vw;
    }
    .book-category .eng {
        font-size: 5vw;
    }
    .book-category .chn {
        font-size: 4.583vw;
    }
    .book-category li a::before {
        width: 16.354vw;
        height: 16.354vw;
        right: 5.833vw;
    }
}