books/theme/myplugin/pagetoc/style.css

@media only screen and (max-width:1439px) {
    .sidetoc {
        display: none;
    }
}

@media only screen and (min-width:1440px) {
    main {
        position: relative;
    }
    .sidetoc {
        margin-left: auto;
        margin-right: auto;
        left: calc(100% + (var(--content-max-width))/4 - 290px);
        position: absolute;
    }
    .pagetoc {
        position: fixed;
		z-index:9999;
		background: var(--sidebar-bg);
        width: 200px;
        height: calc(100vh - var(--menu-bar-height) - 0.67em * 4);
        overflow-x:hidden;
		word-wrap:break-word;
		overflow-y:auto;
    }
    .pagetoc a {
        border-left: 1px solid var(--sidebar-bg);
        color: var(--fg) !important;
        display: block;
        padding-bottom: 5px;
        padding-top: 5px;
        padding-left: 10px;
        text-align: left;
        text-decoration: none;
    }
    .pagetoc a:hover,
    .pagetoc a.active {
        background: white;
        color: var(--sidebar-fg) !important;
    }
    .pagetoc .active {
        background: var(--sidebar-bg);
        color: var(--sidebar-fg);
    }
}
#pop-sidebar {
	margin:1rem;
	max-height:80vh;
	display:none;
	overflow-y:auto;
}
#pop-sidebar a{
	display:block;
	margin-top:5px;
}

#btn-showsidebar {
	position:fixed;
	right:0px;
	top:50%;
	margin-top:-90px;
	padding:1rem 1rem 1rem 1rem;
	writing-mode:tb-rl;
	box-shadow:0px 0px 20px rgba(0,0,0,.3);
	z-index:999;
}

#btn-showsidebar a{
	display:block;
	text-decoration:none;
}