.year-calendar-tooltip {
    position: absolute;
    background: #222;
    color: #fff;
    padding: 10px 12px;
    border-radius: 6px;
    font-size: 13px;
    max-width: 220px;
    z-index: 9999;
    box-shadow: 0 4px 12px rgba(0,0,0,0.25);
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.15s ease;
}

.year-calendar-tooltip.visible {
    opacity: 1;
}