pico.chat/pico.css

body {
    margin: 0;
    padding: 0;
}
.chat {
    display: grid;
    grid-template-areas:
        'posts online'
        'actions actions'
    ;
    grid-template-columns: 1fr auto;
    grid-template-rows: 140px auto;

    position: fixed;
    top: 0;

    --pad: 3px;
    padding: var(--pad);
    width: calc(100vw - 2 * var(--pad));
}
.ts {
    color: rgba(0, 0, 0, 0.4);
    font-family: monospace;
}
.source {
    font-weight: bold;
}
.online {
    grid-area: online;
}
.posts {
    grid-area: posts;
    overflow-y: scroll;
}
.post .text p {
    margin: 0;
}
.post .text p:first-child {
    display: inline;
}
.actions {
    grid-area: actions;
    display: grid;
    grid-template-columns: 1fr auto;
}
#textbox {
    resize: vertical;
}
.post > div {
    display: inline;
    padding-left: var(--pad);
}
.videos {
    overflow: hidden;
    resize: vertical;
    height: 150px;
    display: grid;
    grid-auto-flow: column;
    grid-template-rows: 1fr;
}
video {
    background-color: black;
    object-fit: cover;
    height: 100%;
    width: 100%;
}
video.mirrored {
    transform: scaleX(-1);
}