/* ============================================================
   各種オーバーレイ・モーダル (共通ベース)
   ============================================================ */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 100;
    backdrop-filter: blur(5px);
}

.overlay.active {
    display: flex;
}

.overlay-content {
    text-align: center;
}

#interval-overlay .overlay-content {
    display: flex;
    flex-direction: column;
    align-items: center;
}