.upgrade-card {
    transition: all 0.15s ease;
    cursor: pointer;
}
.upgrade-card:hover {
    transform: translateY(-2px);
    background: #1e293b;
    border-color: #60a5fa;
}
#joystick-container {
    position: absolute;
    bottom: 40px;
    left: 40px;
    width: 120px;
    height: 120px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: none;
}
#joystick-knob {
    position: absolute;
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    top: 35px;
    left: 35px;
}