/* ページ上部へ戻るボタン（全ページ共通） */
.back-to-top {
    position: fixed;
    right: clamp(16px, 3vw, 28px);
    bottom: clamp(16px, 3vw, 28px);
    z-index: 998;
    display: grid;
    place-items: center;
    width: 50px;
    height: 50px;
    padding: 0;
    border: 1px solid rgba(216, 102, 130, .28);
    border-radius: 50%;
    color: #d86682;
    background: rgba(255, 255, 255, .94);
    box-shadow: 0 4px 14px rgba(90, 145, 165, .2);
    font: 700 1.55rem/1 'M PLUS Rounded 1c', sans-serif;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: opacity .25s ease, visibility .25s ease, transform .25s ease,
        background-color .2s ease, color .2s ease;
    -webkit-tap-highlight-color: transparent;
}

.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    color: #fff;
    background: #ff9fb5;
}

.back-to-top:focus-visible {
    outline: 3px solid rgba(216, 102, 130, .35);
    outline-offset: 3px;
}

@media (max-width: 600px) {
    .back-to-top {
        width: 44px;
        height: 44px;
        font-size: 1.35rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    .back-to-top {
        transition: opacity .15s ease, visibility .15s ease;
    }
}