nav {
    background-color: #253746;
}

.carouesl {
    max-height: your size;
    max-width: your width;
    overflow: hidden;
}

.carousel-inner > .item > img {
    margin: 0 auto;
}

.img_body {
    height: 260px;
}

.btn_prop {
    border: 2px solid yellow;
    color: white;
    background-color: transparent;
}

.btn_prop:hover {
    background-color: yellow;
    color: black;
}

.mission_img {
    background: url(../image/missionwordcloud.png) no-repeat center center;
    -webkit-background-size: cover;
    background-size: cover;
}

.yellow_btn {
    border: 2px solid yellow;
    background-color: transparent;
    color: white;
}