/* --- Research Tree Window --- */
#research-window-backdrop {
    position: fixed; top: 0; left: 0; width: 100vw; height: 100vh;
    background-color: rgba(0, 0, 0, 0.7); 
    z-index: 2000;
    display: flex; 
    justify-content: center; 
    align-items: center;
}

#research-window {
    width: 90%; 
    max-width: 1600px; 
    height: 90%;
    background-color: var(--pico-card-background-color);
    border: 1px solid var(--pico-contrast);
    border-radius: var(--pico-border-radius);
    display: flex; 
    flex-direction: column;
    box-shadow: var(--pico-box-shadow);
    overflow: hidden; /* Prevent content from spilling out */
}

#research-window-content {
    display: grid;
    grid-template-columns: 1fr 3fr; /* Main tree area and a sidebar for info */
    gap: 1rem;
    padding: 1rem;
    flex-grow: 1;
    min-height: 0; /* Important for flexbox children to scroll properly */
}

#research-tree-container {
    background-color: var(--pico-background-color);
    border-radius: var(--pico-border-radius);
    padding: 0.5rem;
    overflow: hidden; /* The D3 zoom will handle scrolling/panning */
    position: relative; /* Needed for positioning SVG */
}

#research-info-panel {
    background-color: var(--pico-background-color);
    border-radius: var(--pico-border-radius);
    padding: 1rem;
    overflow-y: auto; /* Allow scrolling for detailed info */
}

/* D3 Tree text styling */
.node text {
    paint-order: stroke;
    stroke: var(--pico-background-color);
    stroke-width: 3px;
    stroke-linecap: butt;
    stroke-linejoin: miter;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    pointer-events: none;
}