.support-bgm-control {
    position: fixed;
    right: 24px;
    bottom: 24px;
    z-index: var(--layer-floating-control);
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 10px;
}

.support-bgm-volume-panel {
    width: 238px;
    padding: 14px 15px 13px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 16px;
    background: rgba(24, 26, 30, 0.94);
    box-shadow: 0 14px 38px rgba(0, 0, 0, 0.38);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    color: #f3f4f6;
}

.support-bgm-volume-panel[hidden] {
    display: none;
}

.support-bgm-volume-panel__label {
    display: block;
    margin-bottom: 10px;
    font-size: 12px;
    font-weight: 740;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.support-bgm-volume-panel__row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 42px;
    align-items: center;
    gap: 10px;
}

.support-bgm-volume-panel input[type="range"] {
    width: 100%;
    min-width: 0;
    accent-color: #ff8400;
    cursor: pointer;
}

.support-bgm-volume-panel output {
    color: rgba(243, 244, 246, 0.72);
    font: 700 12px/1 Consolas, "Courier New", monospace;
    text-align: right;
}

.support-bgm-volume-panel__permanent {
    display: none;
}

.support-bgm-toggle {
    width: 50px;
    height: 50px;
    display: grid;
    place-items: center;
    padding: 0;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 50%;
    background: rgba(24, 26, 30, 0.90);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.34);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: #f3f4f6;
    cursor: pointer;
    transition:
        background 160ms ease,
        border-color 160ms ease,
        transform 160ms ease,
        opacity 160ms ease;
}

.support-bgm-toggle:hover {
    background: rgba(38, 40, 45, 0.94);
    border-color: rgba(255, 255, 255, 0.22);
    transform: translateY(-1px);
}

.support-bgm-toggle[data-playing="true"] {
    border-color: rgba(255, 132, 0, 0.55);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.34), 0 0 0 1px rgba(255, 132, 0, 0.10);
}

.support-bgm-toggle[data-muted="true"] {
    border-color: rgba(255, 255, 255, 0.18);
}

.support-bgm-toggle:focus-visible,
.support-bgm-volume-panel input[type="range"]:focus-visible {
    outline: 2px solid rgba(255, 132, 0, 0.9);
    outline-offset: 3px;
}

.support-bgm-toggle__icon {
    width: 22px;
    height: 22px;
    overflow: visible;
}

.support-bgm-toggle__speaker {
    fill: currentColor;
}

.support-bgm-toggle__wave,
.support-bgm-toggle__slash {
    fill: none;
    stroke: currentColor;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.support-bgm-toggle__wave {
    display: none;
}

.support-bgm-toggle__slash {
    display: none;
}

.support-bgm-toggle[data-muted="false"] .support-bgm-toggle__wave {
    display: block;
}

.support-bgm-toggle[data-muted="true"] .support-bgm-toggle__slash {
    display: block;
}

.support-bgm-toggle[data-waiting="true"] .support-bgm-toggle__wave {
    opacity: .68;
}

@media (max-width: 700px) {
    .support-bgm-control {
        right: max(16px, env(safe-area-inset-right));
        bottom: calc(16px + env(safe-area-inset-bottom));
    }

    .support-bgm-volume-panel {
        width: min(224px, calc(100vw - 32px));
    }

    .support-bgm-volume-panel__permanent {
        display: flex;
        align-items: center;
        gap: 8px;
        margin-top: 12px;
        padding-top: 11px;
        border-top: 1px solid rgba(255, 255, 255, 0.08);
        color: rgba(243, 244, 246, 0.82);
        font-size: 12px;
        font-weight: 720;
        line-height: 1.2;
        cursor: pointer;
        user-select: none;
    }

    .support-bgm-volume-panel__permanent input {
        position: absolute;
        width: 1px;
        height: 1px;
        opacity: 0;
        pointer-events: none;
    }

    .support-bgm-volume-panel__check {
        width: 17px;
        height: 17px;
        flex: 0 0 17px;
        display: grid;
        place-items: center;
        border: 1px solid rgba(255, 255, 255, 0.28);
        border-radius: 5px;
        background: rgba(255, 255, 255, 0.035);
        transition: background 140ms ease, border-color 140ms ease;
    }

    .support-bgm-volume-panel__permanent input:checked + .support-bgm-volume-panel__check {
        border-color: rgba(255, 132, 0, 0.78);
        background: #ff8400;
    }

    .support-bgm-volume-panel__permanent input:checked + .support-bgm-volume-panel__check::after {
        content: "✓";
        color: #17120e;
        font-size: 12px;
        font-weight: 900;
        line-height: 1;
    }

    .support-bgm-volume-panel__permanent input:focus-visible + .support-bgm-volume-panel__check {
        outline: 2px solid rgba(255, 132, 0, 0.9);
        outline-offset: 2px;
    }

    .support-bgm-toggle {
        width: 42px;
        height: 42px;
    }

    .support-bgm-toggle__icon {
        width: 20px;
        height: 20px;
    }
}

@media (min-width: 901px) {
    body.is-support-work-open .support-bgm-control {
        right: calc(52% + 24px);
    }
}

@media (max-width: 900px) {
    body.is-support-work-open .support-bgm-control {
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
    }
}