.panel-section.left { width: 30%; padding: 8px; border-right: 1px solid #333; display: flex; flex-direction: column; background: #151515; }
.brand-area { text-align: center; margin-bottom: 8px; font-family: 'Segoe UI', sans-serif; font-weight: 900; font-size: 1.1em; text-transform: uppercase; letter-spacing: 1px; padding-bottom: 5px; border-bottom: 1px solid rgba(255,255,255,0.05); }
.brand-piano { color: #ff3366; text-shadow: 0 0 8px rgba(255, 51, 102, 0.6); }
.brand-mitra { color: #00bfff; text-shadow: 0 0 8px rgba(0, 191, 255, 0.6); margin-left: 3px; }
.controls-container.grid-2x2 { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; width: 100%; height: 100%; align-content: center; }
.control-btn { background: #2a2a2a; color: #ccc; border: 1px solid #444; border-radius: 4px; padding: 0; font-size: 0.7em; font-weight: bold; cursor: pointer; width: 100%; height: 40px; display: flex; align-items: center; justify-content: center; transition: background 0.1s; }
.control-btn:active { background: #444; color: white; transform: translateY(1px); }
#custom-tone-btn { border-color: #00bfff; color: #00bfff; }