ytfv.css

/* ==UserStyle==
@name           youtube - fill view
@namespace      github.com/openstyles/stylus
@version        1.0.0
@description    A new userstyle
@author         Me
==/UserStyle== */
@-moz-document domain("youtube.com") {
    ytd-watch-flexy[flexy_][js-panel-height_]:not([is-two-columns_])
        #chat.ytd-watch-flexy:not([collapsed]).ytd-watch-flexy,
    ytd-watch-flexy[flexy_][js-panel-height_]
        #chat-container.ytd-watch-flexy:not([chat-collapsed]).ytd-watch-flexy {
        height: 380px;
        min-height: unset;
    }

    html:not(.style-scope) {
        --ytd-toolbar-height: 38px;
        --ytd-margin-2x: 2px;
        --ytd-margin-3x: var(--ytd-margin-2x);
        --ytd-margin-4x: var(--ytd-margin-2x);
        --ytd-margin-5x: var(--ytd-margin-2x);
        --ytd-margin-6x: 12px;
        --ytd-margin-7x: var(--ytd-margin-6x);
        --ytd-margin-8x: var(--ytd-margin-6x);
        --ytd-margin-9x: var(--ytd-margin-6x);
        --ytd-margin-10x: var(--ytd-margin-6x);
        --ytd-margin-11x: var(--ytd-margin-6x);
        --ytd-margin-12x: var(--ytd-margin-6x);
        --ytd-margin-14x: var(--ytd-margin-6x);
        --ytd-margin-16x: var(--ytd-margin-6x);
        --ytd-margin-17x: var(--ytd-margin-6x);
        --ytd-margin-24x: var(--ytd-margin-6x);
        --ytd-margin-25x: var(--ytd-margin-6x);
        --ytd-margin-35x: var(--ytd-margin-6x);
    }

    #container.ytd-masthead {
        height: var(--ytd-toolbar-height);
    }

    ytd-watch-flexy:not([theater]):not([fullscreen]) #primary.ytd-watch-flexy,
    ytd-watch-flexy:not([theater]):not([fullscreen])
        #secondary.ytd-watch-flexy {
        padding-top: var(--ytd-margin-6x);
    }

    .html5-video-player .video-click-tracking,
    .html5-video-player .video-stream {
        height: 100% !important;
        height: -moz-available !important;
        height: -webkit-fill-available !important;
        width: 100% !important;
    }

    ytd-watch-flexy #primary.ytd-watch-flexy {
        max-width: unset;
        min-width: var(--ytd-watch-flexy-min-player-width);
    }

    ytd-watch-flexy[flexy_] {
        --ytd-watch-flexy-space-below-player: 20px;
    }

    ytd-watch-flexy[flexy_] #columns.ytd-watch-flexy {
        max-width: unset;
    }

    ytd-guide-section-renderer {
        --paper-item-min-height: 30px;
    }
}