html,
body {
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

#split-pane {
    display: flex;
    flex-direction: row;
    width: 100vw;
    flex: 1;
    overflow: hidden;
}

#left-pane {
    display: flex;
    flex-direction: column;
    min-width: 0;
    width: 20vw;
    height: 100%;
    background: var(--background-secondary);
    border-right: 5px solid var(--background-highlight);
    justify-content: flex-start;
    position: sticky;
    top: 0;
    overflow-y: auto;
    flex-shrink: 0;
    transition: width 0.3s ease, margin-left 0.3s ease;
}

.left-pane-collapsed #left-pane {
    width: 0;
    min-width: 0;
    margin-left: -5px; /* offset the border */
    overflow: hidden;
    border-right-width: 0;
}

#right-pane {
    flex: 1;
    overflow: auto;
    position: relative;
    min-height: 100%;
    display: flex;
    flex-direction: row;
    align-items: flex-start;
}

#main {
    order: 2;
    max-width: 1600px;
    flex: 1;
    min-width: 0;
    overflow-x: auto;
    margin: 0 auto;
    padding: 20px;
    box-sizing: border-box;
    width: 100%;
    transition: max-width 0.3s ease, margin 0.3s ease;
}

/* #main always has max-width: 1600px and margin: 0 auto for stability */

@media (min-width: 1200px) {
    #main {
        padding: 0 50px;
    }
}
