YouTube full-height theater

YouTube full-height theater.css

:root {
    --bar-height: 23px;
    --bar-height-orig: 56px;
}
ytd-app[is-watch-page=""] #player-theater-container {
    min-height: calc(100vh - var(--bar-height)) !important;
}
ytd-app[is-watch-page=""]:not([masthead-hidden_=""]) #page-manager {
    margin-top: var(--bar-height) !important;
}
/* title bar */
ytd-app[is-watch-page=""] #masthead {
    height: var(--bar-height);
    overflow: hidden;
    transition: all 500ms ease-in-out !important;
    background-color: #000;
}
ytd-app[is-watch-page=""] #masthead:hover, ytd-app[is-watch-page=""]  #masthead:focus-within {
    height: var(--bar-height-orig);
}

ytd-app[is-watch-page=""] #masthead > #container {
    margin-top: calc(0px - var(--bar-height));
    transition: all 500ms ease-in-out !important;
    opacity: 1;
}
ytd-app[is-watch-page=""] #masthead:hover > #container, ytd-app[is-watch-page=""] #masthead:focus-within > #container {
    margin-top: 0px;
    opacity: 1;
}

/* hide buttons */
ytd-app[is-watch-page=""] #masthead > #container > * {
    opacity: 0;
    transition: all 500ms ease-in-out !important;
}
ytd-app[is-watch-page=""] #masthead:hover > #container > *, ytd-app[is-watch-page=""] #masthead:focus-within > #container > * {
    opacity: 1;
}