.frame_main {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    background-color: #000;
    line-height: 1.5;
    background: url("/static/img/wave.svg") no-repeat,
                linear-gradient(110deg, #333 50%, #444 50%);
    overflow: hidden;
    background-size: cover;
}

/* Subpage menu */
.nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    list-style: none;
    position: relative;
    width: 250px;
    margin: 15px 5px;
    padding:0 10px;
}
.nav a {
    display: inline-block;
    position: relative;
    min-width: 200px;
    padding: 10px;
    z-index: 3;
    font-size: 20px;
    border: none;
    outline: none;
    color: #fff;
    margin: 1px 0;
    text-decoration: none;
    text-transform: uppercase;
    text-shadow: 1px 1px 0 #888;
    cursor: pointer;
}
.nav a:hover {
    background-color: transparent !important;
}
.nav .slide1,
.nav .slide2 {
    display: inline-block;
    position: absolute;
    height: 0.4em;
    bottom: 0px;
    box-shadow: 1px 1px 0 #666;
    transform: skew(-20deg);
    transition: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
}
.nav .slide1 {
    z-index: 3;
    background-color: rgba(238,238,238,0.3);
}
.nav .slide2 {
    opacity: 0;
    z-index: 2;
    background-color: transparent;
    border: 1px solid  rgba(238,238,238,0.7);
}

/* Subpage canvas */
.item-wrapper {
    display: block;
}
.item {
    display: none;
    justify-content: center;
    align-items: center;
    position: relative;
}
.item.active {
    display: flex;
}
.item-text-bg {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    position: relative;
    width: 500px;
    height: 500px;
    background-color: rgba(50,50,50,0.5);
    visibility: visible;
}
.item-text {
    display: inline-block;
    padding: 30px;
    color: #fff;
    word-wrap: break-word;
}
.item-pic-wrapper {
    display: inline-block;
    flex-wrap: wrap;
    width: 450px;
    height: auto;
    margin: 15px;
}
.item-pic {
    display: inline-block;
    position: relative;
    width: 200px;
    height: auto;
    margin: 5px auto;
    border: 6px solid #fff;
    background-color: #fff;
    box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.3);
}

.btn-top img{
    display: none;
}

/* RWD */
@media screen and (min-width: 1100px) and (max-height: 630px) {
    .item.active{
        overflow: auto;
        height: calc( 100vh - 120px );
        align-items: flex-start;
    }
    .item-pic-wrapper{
        margin: 0 15px;
    }
}
@media screen and (max-width: 1260px) {
    .nav {
        display: flex;
        width: 100%;
        min-width: auto;
        margin: 0;
        padding: 10px 0;
        text-align: center;
    }
    .item-text-bg {
        height: auto;
    }
}
@media screen and (max-width: 960px) {
    .item.active {
        display: flex;
        justify-content: center;
        flex-wrap: wrap;
        width: 100%;
        min-height: auto;
        max-height: auto;
        margin: 0 auto;
    }
    .item-text-bg {
        width: 550px;
        padding: 0;
    }
    .item-text {
        display: block;
        width: 500px;
        height: auto;
        padding: 20px 15px;
        margin: 0 auto;
    }
    .item-pic-wrapper {
        width: 646px;
        justify-content: center;
        padding: 10px 0;
    }
}
@media screen and (max-width: 646px) {
    .frame_main{
        display: block;
        overflow: auto;
    }
    .nav{
        height: auto;
        margin: 2px 0;
    }
    .item.active {
        display: block;
        width: 100%;
        padding: 0;
        overflow: unset;
    }
    .item-text-bg {
        width: calc(100% - 20px );
        margin: 0 auto;
    }
    .item-text {
        display: block;
        width: 100%;
        height: auto;
        margin: 0 auto;
        padding: 20px 15px;
    }
    .item-pic-wrapper {
        display: flex;
        width: calc( 100% - 10px );
        margin: 0 auto;
    }
}
@media screen and (max-width: 440px) {
    .item-pic {
        width: 300px;
        height: 220px;
        margin: 10px auto;
    }
}