/* ============================================================
   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;
}

.overlay.active {
    display: flex;
}

#interval-blackout {
    position: absolute;
    inset: 0;
    background: #000;
    z-index: 1;
    pointer-events: none;
    opacity: 1;
    transition: opacity 0.2s ease;
}

#interval-blackout.fade-out {
    opacity: 0;
}

#interval-overlay .overlay-content {
    position: relative;
    z-index: 2;
    animation: intervalContentFadeIn 0.3s ease both;
}

@keyframes intervalContentFadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

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

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