@import url('https://fonts.font.im/css?family=Poppins:200,300,400,500,600,700,800,900&display=swap');

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

:root
{
    --black:#191a1f;
    --white:#fff;
}

.drak
{
    --black:#fff;
    --white:#191a1f;
}

header{
    position: absolute;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    padding: 15px 50px;
    z-index: 10000;
}

header .logo{
    position: relative;
    display: inline-flex;
    color: var(--black);
    font-size: 2em;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-decoration: none;
    text-transform: uppercase;
}

.rightSide{
    display: flex;
}

.btns{
    position: relative;
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    margin-left: 10px;
}

.btns ion-icon{
    font-size: 1.5em;
    color:var(--black);
}

.btns.menuToggle ion-icon{
    font-size: 3em;
}

.btns ion-icon:nth-child(2){
    display: none;
}

.btns.active ion-icon:nth-child(2){
    display: block;
}

.btns.active ion-icon:nth-child(1){
    display: none;
}

.main{
    position: relative;
    width: 100%;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    /* 添加垂直方向的布局 */
    flex-direction: column;
}

.main .bg-video{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height:100%;
    object-fit: cover;
}

.mask{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height:100%;
    z-index: 2;
    user-select: none;
    mix-blend-mode: screen;
}

.dark .mask{
    filter: invert(1);
    mix-blend-mode: multiply;
}

.main h2{
    position: relative;
    z-index: 3;
    color: #fff;
    font-size: 3vw;
    text-shadow: 0 20px 30px rgba(0, 0, 0, 0.5);
    letter-spacing: 10px;
}

.navigation{
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    background: var(--white);
    z-index: 999;
    transition: 0.5s;
}

.navigation.active{
    left: 0;
}

.navigation li{
    list-style: none;
}

.navigation li a{
    display: inline-flex;
    margin: 15px 0;
    font-size: 1.25em;
    text-decoration: none;
    color: var(--black);
    padding: 5px 20px;
    border-radius: 4px;
    letter-spacing: 1px;
}

.hover-ios-icon-white:hover ion-icon {
    color: white;
}

.navigation li a:hover{
    background: var(--black);
    color: var(--white);
}

.copyrightText{
    position: absolute;
    left: 50px;
    bottom: 20px;
    z-index: 4;
    font-size: 0.9em;
    color: var(--black);
}

.sci{
    position: absolute;
    right: 50px;
    bottom: 40px;
    z-index: 4;
    display: flex;
    flex-direction: column;
}

.sci li{
    list-style: none;
}

.sci li a{
    text-decoration: none;
    color: var(--black);
    font-size: 1.75em;
}

@media (max-width: 768px){
    header{
        padding: 20px ;
    }
    .copyrightText{
        left: 20px;
        bottom: 30px;
    }
    .sci{
        right: 20px;
        bottom: 20px;
    }
}