.bk-interactive-test {
    margin: 1rem 0;
    padding: 1rem;
    border: 2px solid #8b1e1e;
    border-radius: 8px;
    background: #f7f3eb;
    font-weight: 700;
}
.bk-guitar-tool {
    width: 100%;
    margin: 1rem 0;
}

.bk-guitar-scroll {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 0.4rem;
    -webkit-overflow-scrolling: touch;
}

.bk-guitar-neck {
    display: grid;
    grid-template-columns: 42px repeat(13, minmax(48px, 1fr));
    min-width: calc(42px + (var(--bk-fret-count) * 48px));
    overflow: hidden;
    border: 1px solid #aaa;
    border-radius: 10px;
    background: #d1a46f;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.16);
}

.bk-guitar-cell {
    position: relative;
    min-height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-right: 1px solid rgba(70, 45, 25, 0.55);
    border-bottom: 1px solid rgba(70, 45, 25, 0.25);
}

.bk-guitar-fret-number,
.bk-guitar-corner {
    min-height: 34px;
    background: #f2eee7;
    color: #555;
    font-size: 0.78rem;
}

.bk-guitar-string-name {
    background: #f2eee7;
    color: #222;
    font-weight: 700;
}

.bk-guitar-fret {
    background:
        linear-gradient(
            90deg,
            rgba(255, 255, 255, 0.12),
            rgba(80, 45, 20, 0.08)
        );
}

.bk-guitar-string-line {
    position: absolute;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(
        to bottom,
        #fafafa,
        #777
    );
    box-shadow: 0 1px 1px rgba(0, 0, 0, 0.35);
}

.bk-guitar-string-name:nth-of-type(n + 67) {
    font-weight: 800;
}

.bk-guitar-caption {
    margin: 0.65rem 0 0;
    color: #666;
    font-size: 0.85rem;
}