:root{--bg-color: #1e1e24;--panel-bg: rgba(30, 30, 36, .9);--text-color: #ffffff;--accent-blue: #3498db;--accent-red: #e74c3c;--font-math: "Courier New", Courier, monospace}body,html{margin:0;padding:0;width:100%;height:100%;background-color:var(--bg-color);font-family:Segoe UI,sans-serif;overflow:hidden}#scene-container{position:absolute;top:0;left:0;width:100%;height:100%;z-index:0}#ui-layer{position:relative;z-index:10;width:100%;height:100%;pointer-events:none}header,button,#settings-panel,#solver-bar{pointer-events:auto}header{position:absolute;top:20px;left:50%;transform:translate(-50%);text-align:center;background:var(--panel-bg);padding:10px 30px;border-radius:12px;border:1px solid #444;box-shadow:0 4px 15px #0000004d}#equation-display{font-family:var(--font-math);font-size:1.8rem;font-weight:700;color:var(--text-color)}#balance-state{margin-top:5px;font-size:.8rem;color:#888;text-transform:uppercase;letter-spacing:1px}button{background:#333;border:1px solid #555;color:#fff;padding:10px;border-radius:6px;cursor:pointer;transition:all .2s}button:hover{background:#444;transform:translateY(-2px)}button:active{transform:translateY(0)}#settings-panel{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);background:#1e1e24f2;padding:25px;border:1px solid #555;border-radius:12px;z-index:100;min-width:320px;box-shadow:0 10px 25px #00000080;-webkit-backdrop-filter:blur(5px);backdrop-filter:blur(5px)}#settings-panel h2{margin-top:0;color:#e5e7eb;border-bottom:1px solid #444;padding-bottom:10px;margin-bottom:20px}.setting-group{margin-bottom:20px}.setting-group label{display:block;margin-bottom:8px;color:#9ca3af;font-size:.9rem}.setting-group select{width:100%;padding:8px;background:#111;color:#fff;border:1px solid #4b5563;border-radius:6px;font-size:1rem}#close-settings{width:100%;padding:10px;background:#e74c3c;border:none;font-weight:700}#close-settings:hover{background:#c0392b}#btn-settings{position:fixed;bottom:20px;right:20px;width:45px;height:45px;border-radius:50%;background:#374151;font-size:22px;z-index:50}.hidden{display:none!important}input[type=range]{width:100%;margin-top:5px;background:transparent;cursor:pointer}#solver-bar{position:fixed;bottom:20px;left:50%;transform:translate(-50%);background:#1e1e24f2;border:1px solid #555;border-radius:16px;padding:10px 20px;display:flex;align-items:center;gap:20px;z-index:90;box-shadow:0 10px 30px #00000080;-webkit-backdrop-filter:blur(5px);backdrop-filter:blur(5px)}.solver-group{display:flex;align-items:center;gap:10px}.solver-label{color:#bbb;font-size:.9rem;font-weight:700;text-transform:uppercase}#solver-input{background:#111;border:1px solid #444;color:#fff;padding:8px;border-radius:8px;width:60px;text-align:center;font-size:1.1rem;font-weight:700}.solver-actions{display:flex;align-items:center;gap:10px}.action-pair{display:flex;gap:5px}.separator{width:1px;height:30px;background:#555;margin:0 5px}.btn-solve{width:50px;height:40px;border:none;border-radius:8px;font-size:1rem;font-weight:700;color:#fff}.btn-solve.plus{background:#27ae60}.btn-solve.minus{background:#c0392b}@media(max-width:600px){#solver-bar{width:90%;flex-direction:column;gap:10px}}.switch-label{position:relative;display:inline-block;width:34px;height:20px}.switch-label input{opacity:0;width:0;height:0}.slider-round{position:absolute;cursor:pointer;inset:0;background-color:#ccc;transition:.4s;border-radius:34px}.slider-round:before{position:absolute;content:"";height:14px;width:14px;left:3px;bottom:3px;background-color:#fff;transition:.4s;border-radius:50%}input:checked+.slider-round{background-color:#2196f3}input:checked+.slider-round:before{transform:translate(14px)}