.sg-zoom-btn {
    position: absolute;
    width: 30px; height: 30px;
    background: white;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 18px; font-weight: bold;
    cursor: pointer; z-index: 10;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 1px 4px rgba(0,0,0,0.15);
}
.sg-zoom-btn:hover { background: #f0f0f0; }
.sg-zoom-in  { top: 10px; right: 10px; }
.sg-zoom-out { top: 44px; right: 10px; }