.main-menu-btn {
    position: relative;
    display: inline-block;
    width: 28px;
    height: 28px;
    text-indent: 28px;
    white-space: nowrap;
    overflow: hidden;
    cursor: pointer;
    -webkit-tap-highlight-color: rgba(0,0,0,0);
}
/* hamburger icon */
.main-menu-btn-icon, .main-menu-btn-icon:before, .main-menu-btn-icon:after {
    position: absolute;
    top: 50%;
    left: 2px;
    height: 2px;
    width: 24px;
    background: #bbb;
    -webkit-transition: all 0.25s;
    transition: all 0.25s;
}
.main-menu-btn-icon:before {
    content: '';
    top: -7px;
    left: 0;
}
.main-menu-btn-icon:after {
    content: '';
    top: 7px;
    left: 0;
}
/* x icon */
#main-menu-state:checked ~ .main-menu-btn .main-menu-btn-icon {
    height: 0;
    background: transparent;
}
#main-menu-state:checked ~ .main-menu-btn .main-menu-btn-icon:before {
    top: 0;
    -webkit-transform: rotate(-45deg);
    transform: rotate(-45deg);
}
#main-menu-state:checked ~ .main-menu-btn .main-menu-btn-icon:after {
    top: 0;
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}
/* hide menu state checkbox (keep it visible to screen readers) */
#main-menu-state {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    border: 0;
    padding: 0;
    overflow: hidden;
    clip: rect(1px,1px,1px,1px);
}
/* hide the menu in mobile view */
#main-menu-state:not(:checked) ~ #main-menu {
    display: none;
}
#main-menu-state:checked ~ #main-menu {
    display: block;
}
@media (min-width: 768px) {
    /*hide the button in desktop view*/ 
    .main-menu-btn {
        position: absolute;
        top: -99999px;
    }
    /*     always show the menu in desktop view */
    #main-menu-state:not(:checked) ~ #main-menu {
        display: flex;
        justify-content:space-around;
    }
    #main-nav {
        line-height: 0;
        text-align: left;
    }
    #main-menu {
        display: inline-block;
    }
}

@media(max-width: 768px){
    #main-nav {
        height: 100%;
    }

    #main-menu {
        height: 100%;
        overflow-y: scroll;
    }

    #clock {            
        text-align: left;
        line-height: 15pt;
        bottom: 8px;
        left: 8px;
    }

    #clocklabel {
        font-size: 30px;
    }

    #clocklabeldate {
        font-size: 12px;
    }
}
@media(max-width: 320px){
    #main-nav {
        height: 100%;
    }
.main-menu-btn {
        position: absolute;
       
    }
    #main-menu {
        height: 100%;
        overflow-y: scroll;
    }

    #clock {            
        text-align: left;
        line-height: 15pt;
        bottom: 8px;
        left: 8px;
    }

    #clocklabel {
        font-size: 30px;
    }

    #clocklabeldate {
        font-size: 12px;
    }
}