.mmbr-tool-panel {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    overflow: hidden;
    min-height: 520px;
}

.mmbr-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 16px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-muted, #f9fafb);
}

.mmbr-toolbar-left { display: flex; align-items: center; gap: 8px; }

.mmbr-title {
    font-size: 0.9rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 6px;
}

.mmbr-title i { color: #6366f1; }

.mmbr-badge {
    font-size: 0.68rem;
    font-weight: 600;
    padding: 2px 7px;
    border-radius: 10px;
    background: rgba(99, 102, 241, 0.1);
    color: #6366f1;
}

.mmbr-toolbar-right { display: flex; gap: 6px; }

.mmbr-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 5px 10px;
    font-size: 0.78rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-card);
    cursor: pointer;
}

.mmbr-btn-primary {
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    border-color: transparent;
    color: #fff !important;
}

.mmbr-canvas-wrap {
    padding: 28px 32px;
    overflow: auto;
    background: #fafbff;
}

.mmbr-board {
    max-width: 820px;
    margin: 0 auto;
    display: flex;
    gap: 24px;
    align-items: stretch;
}

.mmbr-topic {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    flex-shrink: 0;
    width: 56px;
    padding: 16px 12px;
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    color: #fff;
    background: linear-gradient(180deg, #6366f1, #8b5cf6);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.25);
}

.mmbr-topic:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

.mmbr-groups {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.mmbr-group {
    display: flex;
    align-items: stretch;
    gap: 8px;
}

.mmbr-brace {
    flex-shrink: 0;
    width: 28px;
    font-size: 4.5rem;
    line-height: 1;
    font-weight: 200;
    color: #6366f1;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0.55;
    user-select: none;
}

.mmbr-group-body {
    flex: 1;
    background: #fff;
    border: 1px solid #e0e7ff;
    border-radius: var(--radius-lg);
    padding: 14px 16px;
}

.mmbr-group-title {
    font-size: 0.88rem;
    font-weight: 700;
    color: #4338ca;
    margin-bottom: 10px;
    padding-bottom: 8px;
    border-bottom: 1px dashed #c7d2fe;
}

.mmbr-items { display: flex; flex-direction: column; gap: 6px; }

.mmbr-item {
    padding: 8px 10px;
    font-size: 0.82rem;
    line-height: 1.45;
    color: var(--text-secondary);
    background: #f8fafc;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
}

.mmbr-item:focus {
    outline: none;
    background: #fff;
    border-color: #6366f1;
}

.mmbr-btn-add {
    margin-top: 8px;
    padding: 4px 10px;
    font-size: 0.75rem;
    border: 1px dashed #c7d2fe;
    border-radius: var(--radius-md);
    background: transparent;
    color: #6366f1;
    cursor: pointer;
}
@media (max-width: 640px) {
    .mmbr-board { flex-direction: column; }
    .mmbr-topic { writing-mode: horizontal-tb; width: auto; letter-spacing: normal; }
}