:root{color-scheme:dark}*{box-sizing:border-box}body{margin:0;font-family:Segoe UI,sans-serif;background:radial-gradient(circle at 20% 20%,#1b2a4b,#06070c 60%);color:#e9edf8}.app-shell{min-height:100vh;display:grid;grid-template-columns:240px minmax(0,1fr) 240px;gap:12px;padding:12px}main{display:grid;gap:12px}#sim-canvas{width:100%;height:auto;border:1px solid #2d3f6b;border-radius:10px}@media(max-width:900px){.app-shell{grid-template-columns:1fr}}.panel{background:#0f1420d9;border:1px solid #29385f;border-radius:10px;padding:12px}.panel-title{margin:0 0 8px;font-size:1rem}.panel-copy{margin:0 0 8px;font-size:.9rem;color:#c7d4f3}.edu-controls summary{cursor:pointer;font-weight:600;margin-bottom:8px}.panel-tabs{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-bottom:10px}.panel-tab{border-radius:8px;border:1px solid #3b4f84;background:#10192d;color:#b8c9f0;padding:8px;cursor:pointer;font-size:.84rem}.panel-tab.is-active{background:#182848;color:#f2f6ff;border-color:#5a76bf}.tab-pane{display:none}.tab-pane.is-active{display:block}.field-row{display:grid;grid-template-columns:1fr;gap:6px;margin-bottom:12px}.field-row span{font-size:.86rem}.field-row strong{font-size:.82rem;color:#9ec1ff}.panel-button,.field-row input[type=range]{width:100%}.panel-button{border-radius:8px;border:1px solid #3b4f84;background:#121b30;color:#ecf1ff;padding:8px;margin-top:6px;cursor:pointer}.panel-button:hover{background:#18233f}