#header {
    width: 100%;
    height: 100px;
}
#logo {
    position: absolute;
    top: 4%;
    left: 4%;
    width: 300px;
}
#txt {
    position: relative;
    top: 100%;
    left: 4%;

    font-size: 12px;
    font-weight: bold;
    line-height: 20px;
    color: #114756;
    width: calc(100% - 4%);

 }
 
.block-menu {
    position: absolute;
    top: 5%;
    right: 5%;
    display: block;
}

.block-menu li {
    display: inline-block;
}

.block-menu li a {
    color: #fff;
    display: block;
    text-decoration: none;
    text-transform: uppercase;
    overflow: visible;
    line-height: 20px;
    font-size: 12px;
    padding: 15px 10px;
}

.three-d {
    perspective: 200px;
    transition: all .07s linear;
    position: relative;
    cursor: pointer;
}

    .three-d:hover .three-d-box, 
    .three-d:focus .three-d-box {
        transform: translateZ(-25px) rotateX(90deg);
    }

.three-d-box {
    transition: all 0.3s ease-out;
    transform: translatez(-25px);
    transform-style: preserve-3d;
    pointer-events: none;
    position: absolute;
    top: 0;
    left: 0;
    display: block;
    width: 100%;
    height: 100%;
}

.front {
    transform: rotatex(0deg) translatez(25px);
}

.back {
    transform: rotatex(-90deg) translatez(25px);
}

.front, .back {
    display: block;
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    background: #114756;
    padding: 15px 10px;
    color: white;
    pointer-events: none;
    box-sizing: border-box;
}