mdBook/data/assets/_html-template/_stylus/menu.styl

.menu-bar {
    position: relative
    height: 50px

    i {
        position: relative
        margin: 0 10px
        z-index: 10
        line-height: 50px

        transition: color 0.5s

        &:hover { cursor: pointer }
    }

    .left-buttons { float: left }
    .right-buttons { float: right }
}

h1.menu-title {
    float: left
    margin: 0 0 0 2em
    padding: 0
    font-weight: 200
    font-size: 20px
    line-height: 50px

    opacity: 0
    transition: opacity 0.5s ease-in-out
}

.menu-bar:hover .menu-title {
    opacity: 1
}