input.menu-trigger {
    position: fixed;
    left: 0;
    top: 0;
    height: 53px;
    width: 52px;
    z-index: 1001;
    opacity: 0;
    cursor: pointer;
}

ul.menu {
    position: fixed;
    left: 0;
    top: 0;
    overflow: hidden;
    height: 52px;
    width: 52px;
    padding: 0;
    margin: 0;
    list-style-type: none;
    background: #B71C1C;
    transition: all 0.2s ease;
    z-index: 1000;
}
ul.menu li a {
    display: block;
    font-size: 18px;
    line-height: 18px;
    padding: 12px;
    color: #fff;
    text-decoration: none;
    transition: all 0.2s ease;
}
ul.menu li a:hover {
    background: #D32F2F;
    color: #fff;
}
ul.menu li ul {
    padding: 0;
    margin: 0;
    list-style-type: none;
    margin-left: 10px;
    transition: all 0.3s ease;
}
ul.menu > li {
    visibility: hidden;
    transition: all 0.5s ease;
}
ul.menu > li.start {
    position: fixed;
    visibility: visible;
    background: #B71C1C;
    text-align: center;
}
ul.menu > li.start a {
    width: 52px;
    height: 52px;
    text-align: center;
    padding: 0;
}
ul.menu > li.start + li {
    margin-top: 52px;
}
ul.menu:hover {
    height: 100%;
    width: 80%;
    overflow-y: scroll;
}
ul.menu:hover > li {
    visibility: visible;
}
ul.menu:hover + div.overlay {
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    opacity: 0.5;
    background: black;
    z-index: 999;
}

input.menu-trigger:checked + ul.menu {
    height: 100%;
    width: 80%;
    overflow-y: scroll;
}
input.menu-trigger:checked + ul.menu > li {
    visibility: visible;
}
input.menu-trigger:checked + ul.menu + div.overlay {
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    opacity: 0.5;
    background: black;
    z-index: 999;
}
input.menu-trigger:checked + ul.menu > li.start {
    background: #D32F2F;
}

div.overlay {
    opacity: 0;
    transition: all 0.2s ease;
}

@media screen and (min-width: 768px) {
    input.menu-trigger {
        left: 20%;
        margin-left: -52px;
    }

    ul.menu {
        left: 20%;
        margin-left: -52px;
        overflow: visible;
        transition-delay: 1s;
    }
    ul.menu:hover {
        left: 0;
        height: 52px;
        width: 100%;
        padding-left: 20%;
        overflow: visible;
        transition-delay: 0.15s;
    }
    ul.menu:hover > li {
        visibility: visible;
        opacity: 1;
        transition-delay: 0.15s;
    }
    ul.menu > li {
        position: relative;
        float: left;
        opacity: 0;
        visibility: hidden;
        transition: all 0.5s ease, visibility 0s linear;
        transition-delay: 0.5s;
    }
    ul.menu > li > ul {
        top: 100% !important;
        left: 0 !important;
    }
    ul.menu > li > ul li a {
        font-size: 22px;
        line-height: 24px;
    }
    ul.menu > li:hover > ul {
        top: 100% !important;
        left: 0 !important;
        opacity: 1;
    }
    ul.menu > li:hover > ul li {
        position: relative;
        width: 100%;
    }
    ul.menu > li:hover > ul li:hover > ul {
        opacity: 1;
    }
    ul.menu > li.start {
        position: relative;
        opacity: 1;
        visibility: visible;
    }
    ul.menu > li.start + li {
        margin-top: 0;
    }
    ul.menu li ul {
        position: absolute;
        opacity: 0;
        margin-left: 0;
        min-width: 200px;
        visibility: hidden;
        background: #B71C1C;
        transition: visibility 0s linear 0.5s, opacity 0.5s cubic-bezier(1, 0, 0.58, 1);
        top: 0;
        left: 100%;
    }
    ul.menu li ul li {
        position: relative;
        white-space: nowrap;
    }
    ul.menu li a {
        font-size: 26px;
        line-height: 28px;
    }
    ul.menu li:hover ul {
        z-index: 1001;
        transition: visibility 0s linear 0.2s, opacity 0.2s ease 0.2s;
    }
    ul.menu li:hover > ul {
        visibility: visible;
    }

    input.menu-trigger:checked + ul.menu {
        left: 0;
        height: 52px;
        width: 100%;
        padding-left: 20%;
        overflow: visible;
        transition-delay: 0.15s;
    }
    input.menu-trigger:checked + ul.menu > li {
        visibility: visible;
        opacity: 1;
        transition-delay: 0.15s;
    }

    div.overlay {
        display: none;
    }
}