pre[name="code"] {
    position: relative;
}
.ccb-btn {
    position: absolute;
    top: 8px;
    right: 8px;
    padding: 3px 10px;
    font-size: 12px;
    line-height: 1.6;
    color: #666;
    background: rgba(255, 255, 255, 0.92);
    border: 1px solid #ccc;
    border-radius: 4px;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.15s ease;
    z-index: 10;
    font-family: -apple-system, "Segoe UI", sans-serif;
}
pre[name="code"]:hover .ccb-btn,
.ccb-btn:focus {
    opacity: 1;
}
.ccb-btn:hover {
    background: #fff;
    color: #333;
    border-color: #999;
}
.ccb-btn.ccb-done {
    color: #1a7f37;
    border-color: #1a7f37;
    opacity: 1;
}