:root{--bg: #121212;--surface: #1e1e1e;--surface2: #2a2a2a;--text: #ffffff;--text-dim: #888888;--red: #ef5350;--blue: #42a5f5;--green: #66bb6a}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,system-ui,sans-serif;background:var(--bg);color:var(--text);min-height:100dvh;overflow-x:hidden;user-select:none;-webkit-user-select:none}#app{display:flex;flex-direction:column;min-height:100dvh}nav{display:flex;border-bottom:1px solid var(--surface2)}nav a{flex:1;text-align:center;padding:12px;color:var(--text-dim);text-decoration:none;font-size:14px;font-weight:600;text-transform:uppercase;letter-spacing:1px}nav a.active{color:var(--text);border-bottom:2px solid var(--blue)}.screen{display:none;flex:1;flex-direction:column;padding:16px}.screen.visible{display:flex}.workout-stats{flex:1;display:flex;flex-direction:column;align-items:center;gap:0}.stat{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;width:100%}.stat-value{font-size:96px;font-weight:700;font-variant-numeric:tabular-nums;line-height:1}.stat-label{font-size:18px;color:var(--text-dim);text-transform:uppercase;letter-spacing:1px;margin-top:6px;font-weight:300}.stat-value.bpm{color:var(--red)}.stat-value.jumps{color:var(--blue)}.stat-value.countdown{color:var(--green)}.ble-status{font-size:12px;color:var(--text-dim);text-align:center;padding:8px}.ble-status.connected{color:var(--green)}.controls{display:flex;gap:12px;padding:16px 0}.btn{flex:1;padding:18px;border:none;border-radius:12px;font-size:18px;font-weight:600;cursor:pointer;text-transform:uppercase;letter-spacing:1px}.btn-start{background:var(--green);color:#000}.btn-pause{background:var(--blue);color:#000}.btn-stop{background:var(--red);color:#fff}.btn-secondary{background:var(--surface2);color:var(--text)}.btn:disabled{opacity:.4;cursor:not-allowed}.history-list{display:flex;flex-direction:column;gap:8px}.history-item{background:var(--surface);border-radius:12px;padding:16px;display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center}.history-info h3{font-size:16px;font-weight:600;margin-bottom:4px}.history-info p{font-size:13px;color:var(--text-dim)}.history-actions{display:flex;gap:8px}.btn-icon{background:var(--surface2);border:none;border-radius:8px;color:var(--text);padding:8px 12px;font-size:13px;cursor:pointer}.btn-export{background:var(--blue);color:#000;border:none;border-radius:8px;padding:10px 16px;font-size:14px;font-weight:600;cursor:pointer}.btn-delete{font-size:18px;padding:6px 10px}.confirm-delete{display:flex;align-items:center;gap:8px;width:100%;margin-top:12px;padding-top:12px;border-top:1px solid var(--surface2);font-size:14px;color:var(--red)}.confirm-delete span{flex:1}.btn-confirm-yes{background:var(--red)!important;color:#fff!important}.history-empty{text-align:center;color:var(--text-dim);padding:48px 16px}.dialog-overlay{display:none;position:fixed;inset:0;background:#000000b3;z-index:100;align-items:center;justify-content:center;padding:24px}.dialog-overlay.open{display:flex}.dialog{background:var(--surface);border-radius:16px;padding:24px;width:100%;max-width:400px}.dialog h2{font-size:20px;margin-bottom:16px}.dialog-row{display:flex;justify-content:space-between;padding:8px 0;font-size:15px}.dialog-row .label{color:var(--text-dim)}.dialog-row .value{font-weight:600}.dialog .btn{margin-top:16px}.btn-centered{display:block;margin-left:auto;margin-right:auto;flex:none;width:60%}.summary-buttons{display:flex;flex-wrap:wrap;gap:12px;margin-top:16px}.summary-buttons .btn{margin-top:0}.confirm-text{font-size:14px;color:var(--red);text-align:center;width:100%;margin-bottom:12px}.setting-group{margin-bottom:16px}.setting-group label{display:block;font-size:14px;color:var(--text-dim);margin-bottom:8px}.setting-group input[type=range]{width:100%;accent-color:var(--blue)}.setting-value{text-align:center;font-size:18px;font-weight:600;margin-top:4px}.toolbar{display:flex;justify-content:flex-end;gap:8px;padding:8px 0}