CSS Navigation Menu

menu.less

@charset "UTF-8";
ul.navigation-menu { // Level 1
    .transition() {
        -webkit-transition: all 300ms ease;
        -moz-transition: all 300ms ease;
        -ms-transition: all 300ms ease;
        -o-transition: all 300ms ease;
        transition: all 300ms ease;
    }
    @text-color: #ffffff;
    @top-height: 50px;
    @top-width: 975px;
    @no-first-level: 5;
    @bg-color: rgb(54,169,225);
    @border-color: rgb(43,135,180);
    @infinity: 9999999px;
    @sub-width: @top-width/@no-first-level - 1;
    @radius: 5px;

    list-style-type: none;
    list-style-image: none;
    width: @top-width;
    height: @top-height;
    text-align: center;
    display: inline-block;
    margin: 0;
    padding: 0;
    position: relative;
    font-family: Helvetica, Arial, sans-serif;
    color: @text-color;
    cursor: pointer;

    ul {
        list-style-type: none;
        list-style-image: none;
        opacity: 0;
        position: relative;
        z-index: -999;
    }

    /* CSS3 Gradient */
    background: @bg-color;

    a:link, a:visited {
        text-decoration: none;
        color: @text-color;
        display: inline-block;
        width: 100%;
        height: 100%;
    }

    > li { // level 1
        display: block;
        float: left;
        line-height: @top-height;
        height: @top-height;
        text-align: center;
        width: (@top-width/@no-first-level)-1px;
        padding: 0;
        margin: 0;
        border-right: 1px solid @border-color;
        box-shadow: 1px 0 0 rgba(255, 255, 255, 0.5) inset;
        .transition;

        > ul { // Level 2 - unshown
            .transition;
            list-style-type: none;
            list-style-image: none;
            text-align: center;
            padding: 0;
            margin: 0;
            height: 0;

            > li { // Level 2 - unshown
                display: block;
                opacity: 0;
                padding: 0;
                margin: 0;
                height: 0;
                .transition;
            }
        }

        &:hover {
            background-color: #a3c4e9;
            > ul { // Level 2 shown
                .transition;
                position: relative;
                z-index: 9999;
                height: auto;
                opacity: 1;
                border-bottom-left-radius: @radius;
                border-bottom-right-radius: @radius;
                box-shadow: 1px 2px @radius rgba(0, 0, 0, 0.5);
                background: @bg-color;

                > li { // Level 2 shown
                    opacity: 1;
                    border-bottom: 1px solid @border-color;
                    box-shadow: 0 1px 0 rgba(255, 255, 255, 0.5) inset;
                    height: @top-height;
                    line-height: @top-height;

                    &:first-child {
                        box-shadow: none;
                    }

                    &:last-child {
                        border-bottom: none;
                    }
                    &:hover {
                        background-color: #a3c4e9;
                    }

                    &:active {
                        background-color: #93b4d9;
                    }

                    &.maple {
                        background-image: url('http://2013.igem.org/wiki/images/8/82/MapleLogo.png');
                        background-size: 65% auto;
                        background-repeat: no-repeat;
                        background-position: 40% 40%;
                        background-color: #ffce32;

                        a {
                            text-indent: -@infinity;
                        }

                        &:hover {
                            background-color: #fff;
                        }

                        &:active {
                            background-color: #ffce32;
                        }
                    }
                    > ul { // Level 3 unshown
                        .transition;
                        list-style-type: none;
                        list-style-image: none;
                        text-align: center;
                        padding: 0;
                        margin: 0;
                        position: relative;
                        left: @sub-width;
                        top: -@top-height;
                        opacity: 1;

                        &:before {
                            content: "»";
                            display: block;
                            position: absolute;
                            left: -20px;
                            text-align: right;
                            line-height: @top-height;
                        }

                        > li { // Level 3 unshown
                            .transition;
                            width: 0;
                            width: 0;
                            opacity: 0;
                            padding: 0;
                            margin: 0;
                        }

                        &.left {
                            left: 0;
                            right: @sub-width;
                        }
                    }
                    &:hover {
                        > ul { // Level 3 shown
                            height: auto;
                            width: @sub-width;
                            opacity: 1;
                            border-top-right-radius: @radius;
                            border-bottom-left-radius: @radius;
                            border-bottom-right-radius: @radius;
                            box-shadow: 1px 2px @radius rgba(0, 0, 0, 0.5);
                            background: @bg-color;
                            z-index: 9999999;

                            > li {
                                width: @sub-width;
                                height: @top-height;
                                line-height: @top-height;
                                opacity: 1;
                                border-bottom: 1px solid @border-color;
                                box-shadow: 0 1px 0 rgba(255, 255, 255, 0.5) inset;

                                &:first-child {
                                    box-shadow: none;
                                    border-top-right-radius: @radius;
                                }

                                &:last-child {
                                    border-bottom: none;
                                    border-bottom-left-radius: @radius;
                                    border-bottom-right-radius: @radius;
                                }
                                &:hover {
                                    background-color: #a3c4e9;
                                }
                            }
                        }
                    }
                }
            }
        }

        &:active {
            background-color: #93b4d9;
        }
    }
}