header{
    width: 100%;
    height: 100%;
    position: relative;
    overflow: hidden;
}

.headerTitle{
    font-size: 100px;
    color: rgb(15, 153, 123);
    width: 100%;
    top: 30%;
    font-weight: bold;
    position: absolute;
    text-align: center;
}

.headerUnderLine{
    position: absolute;
    width: 50%;
    height: 3px;
    background-color: rgb(0, 0, 0);
    left: 25%;
}

.bigTitle{
    position: absolute;
    z-index: 30;
    line-height: 4rem;
    top: calc(50% - 10rem);
    width: 100%;
    height: 100%;
    text-align: center;
    font-size: 5rem;
    font-weight: 600;
    color: #fff;
}

.downBtn{
    position: absolute;
    font-size: 50%;
    color: rgb(0, 225, 255);
    z-index: 30;
    width: 100%;
    bottom: 50%;
    text-align: center;
    font-size: 5rem;
    font-weight: 600;
}

.downBtn a{
    color: white;
    text-decoration: none;
}

.downBtn a:hover{
    color: thistle;
}

.shadow{
    position: absolute;
    top: 0;
    height: 100%;
    width: 100%;
    left: 0;
    z-index: 10;
    background: linear-gradient(to top, #151515, transparent);
}

.TWbackgroundImg{
    background-image: url(images/tw_page.jpeg);
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.vaccineBgImg{
    background-image: url(images/vaccine_page.jpeg);
}

.videoBgImg{
    background-image: url(images/video_page.jpeg);
}

.titleBgImg{
    background-image: url(images/world.jpg);
}

@media(max-width: 600px){
    .bigTitle{
        font-size: 50px;
    }
}

@media(max-width: 400px){
    .bigTitle{
        font-size: 35px;
    }
}