#controls {
    margin-top: 20px;
    display: flex;
    gap: 12px;
}
button {
    padding: 12px 24px;
    font-size: 16px;
    font-weight: bold;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
}
#startBtn {
    background: #2ecc71;
    color: white;
}
#startBtn:hover { background: #27ae60; }
#stepBtn {
    background: #c3cc2a;
    color: white;
}
#stepBtn:hover { background: #adae26; }
#resetBtn {
    background: #e74c3c;
    color: white;
}
#resetBtn:hover { background: #c0392b; }