* {
    margin: 0;
    padding: 0;
}
body{
    background-color: #050303;
}
.flex{
    display: flex;
    align-items: center;
}
.flex-column {
    flex-direction: column;
}
.flex-center {
    justify-content: center;
}
.flex-between {
    justify-content: space-between;
}
.flex-around {
    justify-content: space-around;
}
.flex-start {
    justify-content: flex-start;
}
.content-full-screen {
    width: 100vw;
    height: calc(100vh - 90px);
}
.bottom-img {
    width: 100%;
    height: 100vh;
    position: fixed;
    bottom: 0;
    left: 0;
    z-index: -1;
}
.top-img {
    width: 100%;
    height: 100vh;
    position: fixed;
    top: 0;
    left: 0;
    z-index: -1;
    transform: rotate(180deg);
}
.nav {
    width: 100%;
    height: 90px;
    color: #eee;
    background-color: #050303;
}
.nav-img {
    width: 90px;
    height: 90px;
}
.nav-login {
    font-size: 16px;
    padding-right: 20px;
    cursor: pointer;
}
.nav-item {
    margin-left: 25px;
    position: relative;
    cursor: pointer;
}
.nav-mobile {
    display: none;
}
.nav-mobile-open {
    display: none;
}
.nav-item-active::after {
    position: absolute;
    bottom: -10px;
    left: 50%;
    width: 90%;
    transform: translateX(-50%);
    height: 4px;
    background-color: #00FFFF;
    border-radius: 40px;
    content: '';
}
.certificate {
    width: 100vw;
    padding: 0 0 6px;
    position: absolute;
    bottom: 50px;
    text-align: center;
    color: #fff;
}
.bottom-certificate{
    color: #aaa;
    background-image: linear-gradient(to right, rgba(0, 0, 0, 0), rgba(0, 0, 0, .7), rgba(0, 0, 0, 0));
}
.top-certificate {
    background-image: linear-gradient(to right, rgba(0, 255, 255, 0), rgba(0, 255, 255, .5), rgba(0, 255, 255, 0));
}
.line {
    width: 100%;
    height: 1px;
    background-color: rgba(0, 255, 255, 1);
}


@media (max-width: 1600px) {
    
}
@media (max-width: 800px) {
    .nav {
        width: 100%;
        height: 50px;
        color: #eee;
        background-color: #050303;
    }
    .nav-img {
        width: 50px;
        height: 50px;
    }
    .nav-pc {
        display: none;
    }
    .nav-mobile-open {
        display: block;
    }
    .nav-mobile {
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99;
        width: 100vw;
        height: 100vh;
        background-color: rgba(0, 0, 0, .5);
    }
    .nav-mobile-list {
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99;
        width: 50vw;
        height: 100vh;
        background-color: #000;
        transition: all .5s;
    }
    .nav-mobile .nav-item {
        margin: 1em 1em 2em;
    }
    .nav-mobile .nav-item-active::after {
        position: absolute;
        bottom: -10px;
        left: 50%;
        width: 100%;
        transform: translateX(-50%);
        height: 4px;
        background-color: #00FFFF;
        border-radius: 40px;
        content: '';
    }
}