Pocket Synth

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247

<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
<title>Pocket Synth — sloprun.dev</title>
<style>
/* ── sloprun design tokens (verbatim from demos/tokens.css) ───────────────── */
:root {
  --bg: #F6F6F3;          /* neutral paper, not cream */
  --surface: #FFFFFF;
  --ink: #1A1D21;
  --muted: #5A6068;
  --line: #E3E2DC;
  --accent: #C05600;      /* phosphor amber, darkened for light bg */
  --accent-soft: #FFF3E6;
  --run: #1A7F37;         /* earned green */
  --run-soft: #E7F4EA;
  --danger: #C93C37;
  --radius: 10px;
  --font-sans: system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #14161A; --surface: #1C1F26; --ink: #E8E6E1; --muted: #9AA0A8;
    --line: #2A2E36; --accent: #FFB454; --accent-soft: #2A2118;
    --run: #3FB950; --run-soft: #16281B; --danger: #F47067;
  }
}
:root[data-theme="dark"] {
  --bg: #14161A; --surface: #1C1F26; --ink: #E8E6E1; --muted: #9AA0A8;
  --line: #2A2E36; --accent: #FFB454; --accent-soft: #2A2118;
  --run: #3FB950; --run-soft: #16281B; --danger: #F47067;
}
body { background: var(--bg); color: var(--ink); font-family: var(--font-sans); }
/* ── end tokens ───────────────────────────────────────────────────────────── */

/* demo-local values the shared tokens don't carry */
:root {
  --shadow: 0 1px 2px rgba(26,29,33,.05);
  --well: #F1F0EC;         /* recessed panel the keys sit in */
  --wkey: #FFFFFF;         /* long key face */
  --wkey-lo: #EFEDE6;      /* long key shading toward the front lip */
  --wkey-edge: #D5D3CB;
  --bkey: #23262C;         /* short key face */
  --bkey-lo: #14161A;
  --bkey-ink: #C9C6BE;
  --wkey-ink: #4A4F57;     /* legend on the long keys, readable on both faces */
  --glow: rgba(192,86,0,.30);
  --rail: #B0ACA2;         /* the strip the keys hinge on */
  --btn-ink: #FFFFFF;
  --kbh: clamp(140px, 34vw, 178px);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --shadow: 0 1px 2px rgba(0,0,0,.35);
    --well: #16181D;
    --wkey: #DAD7D0; --wkey-lo: #B4B0A8; --wkey-edge: #4A4E56;
    --bkey: #23262C; --bkey-lo: #0C0E11; --bkey-ink: #9AA0A8;
    --wkey-ink: #3E434B;
    --glow: rgba(255,180,84,.34);
    --rail: #0C0E11;
    --btn-ink: #14161A;
  }
}
:root[data-theme="dark"] {
  --shadow: 0 1px 2px rgba(0,0,0,.35);
  --well: #16181D;
  --wkey: #DAD7D0; --wkey-lo: #B4B0A8; --wkey-edge: #4A4E56;
  --bkey: #23262C; --bkey-lo: #0C0E11; --bkey-ink: #9AA0A8;
  --wkey-ink: #3E434B;
  --glow: rgba(255,180,84,.34);
  --rail: #0C0E11;
  --btn-ink: #14161A;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body { min-height: 100%; overflow-x: hidden; }

.wrap {
  max-width: 940px; margin: 0 auto;
  padding: 22px 16px 26px;
  display: flex; flex-direction: column; gap: 14px;
}
@media (max-width: 460px) { .wrap { padding: 16px 8px 20px; gap: 11px; } }

h1 { margin: 0 0 6px; font-size: clamp(21px, 3.6vw, 29px); letter-spacing: -.021em; line-height: 1.15; }
.lede { margin: 0; max-width: 66ch; color: var(--muted); font-size: 14.5px; line-height: 1.55; }
.lede b { color: var(--ink); font-weight: 600; }

.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 14px;
}
@media (max-width: 460px) { .card { padding: 10px 9px; } }

/* ── transport ────────────────────────────────────────────────────────────── */
.transport {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px;
  padding-bottom: 12px; margin-bottom: 12px;
  border-bottom: 1px dashed var(--line);
}
.btn {
  font: inherit; font-size: 13.5px; font-weight: 600;
  color: var(--ink); background: var(--surface);
  border: 1px solid var(--line); border-radius: 8px;
  padding: 8px 13px; cursor: pointer;
  display: inline-flex; align-items: center; gap: 7px;
  transition: background .12s ease, border-color .12s ease, transform .06s ease;
  -webkit-tap-highlight-color: transparent;
}
.btn:hover { background: var(--accent-soft); border-color: var(--accent); }
.btn:active { transform: translateY(1px); }
.btn.primary {
  background: var(--accent); border-color: var(--accent); color: var(--btn-ink);
  min-width: 122px; justify-content: center; padding: 9px 15px;
  position: relative;
}
.btn.primary:hover { filter: brightness(1.07); background: var(--accent); }
.btn.primary.on { background: var(--surface); color: var(--ink); border-color: var(--ink); }
.btn.primary.nudge::after {
  content: ""; position: absolute; inset: -4px; border-radius: 11px;
  border: 2px solid var(--accent); opacity: 0;
  animation: ring 2.6s ease-out infinite; pointer-events: none;
}
@keyframes ring { 0% { opacity: .55; transform: scale(1) } 45%,100% { opacity: 0; transform: scale(1.12) } }
.btn .gl { font-size: 11px; line-height: 1; }

.btn:focus-visible, .chip:focus-visible, .tog:focus-visible, .oct:focus-visible,
.k:focus-visible, input[type=range]:focus-visible, .wave input:focus-visible + label {
  outline: 2px solid var(--ink); outline-offset: 2px;
}
/* the ring sits inside the key face, so --ink is wrong on half of them: it
   vanishes on a white key in dark theme and on a black key in light theme.
   currentColor is already the one colour picked to read on that key. */
.k:focus-visible { outline-color: currentColor; outline-offset: -3px; z-index: 5; }

.status {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .07em;
  padding: 5px 9px; border-radius: 99px; white-space: nowrap;
  background: var(--well); color: var(--muted); border: 1px solid var(--line);
}
.status .led { width: 7px; height: 7px; border-radius: 50%; background: var(--muted); opacity: .45; }
.status.live { background: var(--run-soft); color: var(--run); border-color: transparent; }
.status.live .led { background: var(--run); opacity: 1; }
.status.live.blink .led { animation: blink 1.05s steps(1) infinite; }
@keyframes blink { 0%,55% { opacity: 1 } 56%,100% { opacity: .28 } }

.readout {
  font-family: var(--font-mono); font-size: 12.5px; color: var(--muted);
  display: flex; gap: 5px; align-items: baseline; white-space: nowrap;
}
.readout b { color: var(--ink); font-weight: 600; font-variant-numeric: tabular-nums; }
.readout .sep { opacity: .4; }

.scopebox {
  flex: 1 1 190px; min-width: 150px; margin-left: auto;
  height: 46px; border-radius: 7px; overflow: hidden;
  background: var(--well); border: 1px solid var(--line);
}
@media (max-width: 620px) { .scopebox { margin-left: 0; flex-basis: 100%; } }
#scope { display: block; width: 100%; height: 100%; }

/* ── control rack ─────────────────────────────────────────────────────────── */
.rack { display: flex; flex-direction: column; gap: 13px; }
.row1 {
  display: flex; flex-wrap: wrap; align-items: center;
  gap: 10px 22px; justify-content: space-between;
}
.row2 { display: flex; flex-wrap: wrap; align-items: flex-end; gap: 13px 18px; }
.grp { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; min-width: 0; }
.rl {
  font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .1em;
  color: var(--muted); flex: none;
}

.wave { display: flex; gap: 5px; flex-wrap: wrap; position: relative; }
.wave input { position: absolute; opacity: 0; width: 1px; height: 1px; pointer-events: none; }
.wave label {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 12.5px; color: var(--muted);
  background: var(--surface); border: 1px solid var(--line);
  border-radius: 99px; padding: 5px 11px 5px 9px; cursor: pointer;
  transition: background .12s ease, color .12s ease, border-color .12s ease;
  -webkit-tap-highlight-color: transparent;
}
.wave label:hover { color: var(--ink); border-color: var(--accent); background: var(--accent-soft); }
.wave label svg { display: block; overflow: visible; }
.wave label svg polyline, .wave label svg path { stroke: currentColor; stroke-width: 1.6; fill: none; stroke-linejoin: round; stroke-linecap: round; }
.wave input:checked + label {
  color: var(--ink); border-color: var(--accent); background: var(--accent-soft); font-weight: 600;
}

.chip {
  font: inherit; font-size: 12.5px; color: var(--muted);
  background: var(--surface); border: 1px solid var(--line);
  border-radius: 99px; padding: 5px 11px; cursor: pointer;
  transition: background .12s ease, color .12s ease, border-color .12s ease;
  -webkit-tap-highlight-color: transparent;
}
.chip:hover { color: var(--ink); border-color: var(--accent); background: var(--accent-soft); }
.chip[aria-pressed="true"] { color: var(--ink); border-color: var(--accent); background: var(--accent-soft); font-weight: 600; }

.knob { flex: 1 1 148px; min-width: 118px; max-width: 250px; }
.dgrp {
  display: flex; flex-wrap: wrap; align-items: flex-end; gap: 13px 14px;
  flex: 1 1 336px; min-width: 250px;
}
.dgrp .knob { flex: 1 1 116px; min-width: 104px; max-width: none; }
.knob .kl {
  display: flex; justify-content: space-between; align-items: baseline; gap: 8px;
  font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .1em;
  color: var(--muted); margin-bottom: 3px;
}
.knob .kv { color: var(--ink); font-weight: 600; font-variant-numeric: tabular-nums; letter-spacing: .02em; }
.knob.off { opacity: .42; }
.knob.off .kv { color: var(--muted); font-weight: 500; }

input[type=range] {
  -webkit-appearance: none; appearance: none;
  width: 100%; background: transparent; margin: 0; height: 20px; cursor: pointer;
  touch-action: pan-y;
}
input[type=range]:disabled { cursor: default; }
input[type=range]::-webkit-slider-runnable-track { height: 5px; border-radius: 99px; background: var(--line); }
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 17px; height: 17px; margin-top: -6px;
  border-radius: 50%; background: var(--accent);
  border: 2px solid var(--surface); box-shadow: 0 1px 3px rgba(0,0,0,.25);
}
input[type=range]::-moz-range-track { height: 5px; border-radius: 99px; background: var(--line); }
input[type=range]::-moz-range-thumb {
  width: 13px; height: 13px; border-radius: 50%; background: var(--accent);
  border: 2px solid var(--surface); box-shadow: 0 1px 3px rgba(0,0,0,.25);
}
input[type=range]:disabled::-webkit-slider-thumb { background: var(--muted); }
input[type=range]:disabled::-moz-range-thumb { background: var(--muted); }

.tog {
  font: inherit; font-family: var(--font-mono); font-size: 11px; letter-spacing: .1em;
  color: var(--muted); background: var(--surface);
  border: 1px solid var(--line); border-radius: 8px;
  padding: 8px 12px; cursor: pointer; flex: none; align-self: flex-end;
  display: inline-flex; align-items: center; gap: 7px;
  transition: background .12s ease, color .12s ease, border-color .12s ease;
  -webkit-tap-highlight-color: transparent;
}
.tog .led2 { width: 7px; height: 7px; border-radius: 50%; background: var(--muted); opacity: .35; }
.tog:hover { color: var(--ink); border-color: var(--accent); }
.tog[aria-pressed="true"] { color: var(--ink); border-color: var(--accent); background: var(--accent-soft); }
.tog[aria-pressed="true"] .led2 { background: var(--accent); opacity: 1; }

/* ── keyboard ─────────────────────────────────────────────────────────────── */
.kbwrap {
  background: var(--well); border: 1px solid var(--line);
  border-radius: 9px; padding: 9px;
  margin-top: 13px;
}
@media (max-width: 460px) { .kbwrap { padding: 6px; } }
.kb {
  position: relative; display: flex; height: var(--kbh);
  touch-action: none; user-select: none; -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  border-top: 3px solid var(--rail);
  border-radius: 5px 5px 8px 8px;
  isolation: isolate;
}
.k {
  font: inherit; padding: 0; margin: 0; cursor: pointer;
  display: flex; flex-direction: column; justify-content: flex-end; align-items: center;
  gap: 3px; overflow: hidden; -webkit-tap-highlight-color: transparent;
}
.wk {
  flex: 1 1 0; min-width: 0; position: relative;
  background: linear-gradient(180deg, var(--wkey) 0%, var(--wkey) 72%, var(--wkey-lo) 100%);
  border: 1px solid var(--wkey-edge); border-top: none;
  border-radius: 2px 2px 6px 6px;
  margin-right: -1px; padding-bottom: 8px;
  color: var(--wkey-ink);
  box-shadow: inset 0 -3px 0 rgba(0,0,0,.05);
}
.wk.lastw { margin-right: 0; }
.bk {
  position: absolute; top: 0; z-index: 3;
  height: 62%; padding-bottom: 7px;
  background: linear-gradient(180deg, var(--bkey) 0%, var(--bkey) 68%, var(--bkey-lo) 100%);
  border: 1px solid var(--bkey-lo); border-top: none;
  border-radius: 2px 2px 5px 5px;
  color: var(--bkey-ink);
  box-shadow: 0 3px 5px rgba(0,0,0,.28), inset 0 -3px 0 rgba(255,255,255,.06);
}
.k .nm, .k .ltr {
  font-family: var(--font-mono); line-height: 1;
  pointer-events: none; max-width: 100%;
}
/* the note name has to clear 4.5:1 against the key face in BOTH themes — the
   dark-theme key is a light beige, so anything fainter than this fails there */
.k .nm { font-size: 9.5px; letter-spacing: .02em; opacity: .9; }
.wk .ltr {
  font-size: 10px; font-weight: 600;
  border: 1px solid var(--wkey-edge); border-radius: 4px;
  padding: 2px 0; width: 15px; text-align: center;
  background: rgba(0,0,0,.03);
}
.bk .ltr {
  font-size: 10px; font-weight: 600;
  border: 1px solid rgba(255,255,255,.22); border-radius: 4px;
  padding: 2px 0; width: 15px; text-align: center;
}
/* the strike glows from the rail down; the legend end of the key stays on
   --accent-soft so the letter never lands accent-on-accent */
.wk.lit {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent) 24%, var(--accent-soft) 58%, var(--accent-soft) 100%);
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent), 0 0 12px var(--glow);
  color: var(--ink);
}
.wk.lit .ltr { border-color: var(--accent); background: transparent; }
.bk.lit {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent) 70%, var(--accent) 100%);
  border-color: var(--accent);
  box-shadow: 0 0 12px var(--glow), inset 0 -3px 0 rgba(0,0,0,.18);
  color: var(--btn-ink);
}
.bk.lit .ltr { border-color: rgba(0,0,0,.28); }
/* the key press itself must feel instant; only the fade-out is eased */
.k { transition: background .16s ease, box-shadow .16s ease, color .16s ease, border-color .16s ease; }
.k.lit { transition: none; }

@media (max-width: 560px) {
  .wk .nm.opt { display: none; }
}
@media (max-width: 440px) {
  .wk .ltr { width: 13px; font-size: 9px; padding: 1px 0; }
  .bk .ltr { width: auto; border: none; padding: 0; font-size: 9.5px; }
  .k .nm { font-size: 8.5px; }
  .wk { padding-bottom: 6px; }
  .bk { padding-bottom: 5px; }
}

/* ── keyboard bar ─────────────────────────────────────────────────────────── */
.kbbar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px;
  margin-top: 11px;
}
.oct {
  font: inherit; font-size: 15px; line-height: 1;
  color: var(--ink); background: var(--surface);
  border: 1px solid var(--line); border-radius: 7px;
  width: 30px; height: 28px; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: background .12s ease, border-color .12s ease;
  -webkit-tap-highlight-color: transparent;
}
.oct:hover:not(:disabled) { background: var(--accent-soft); border-color: var(--accent); }
.oct:disabled { color: var(--muted); opacity: .45; cursor: default; }
.octv {
  font-family: var(--font-mono); font-size: 12.5px; font-weight: 600;
  color: var(--ink); min-width: 74px; text-align: center; letter-spacing: .03em;
}
.tip { font-size: 12.5px; color: var(--muted); margin-left: auto; }
@media (max-width: 620px) { .tip { margin-left: 0; flex-basis: 100%; } }

.hint { margin: 0; color: var(--muted); font-size: 12.5px; line-height: 1.85; }
.hint b { color: var(--ink); font-weight: 600; }
kbd {
  font-family: var(--font-mono); font-size: 11px;
  border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 5px;
  padding: 1px 5px; background: var(--surface); color: var(--ink);
  margin-right: 1px; white-space: nowrap;
}
.note { font-family: var(--font-mono); font-size: 12px; color: var(--danger); margin: 0; }
footer {
  font-family: var(--font-mono); font-size: 11.5px; color: var(--muted);
  letter-spacing: .04em; padding-top: 2px;
}
.sr {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important; animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}
</style>
</head>
<body>
<div class="wrap">

  <header>
    <h1>Pocket Synth</h1>
    <p class="lede">Two octaves of playable synthesiser, built from raw oscillators — <b>no sound files anywhere in this page</b>. Every note is generated the moment you press a key.</p>
  </header>

  <main class="card">

    <div class="transport">
      <button class="btn primary nudge" id="riffBtn"><span class="gl" id="riffGl">&#9654;</span><span id="riffTxt">Play riff</span></button>
      <span class="status" id="status"><span class="led"></span><span id="statusTxt">TAP TO START</span></span>
      <div class="readout">
        <span>NOTE</span><b id="roNote">&mdash;</b>
        <span class="sep">&middot;</span><b id="roHz">&mdash;</b><span>Hz</span>
        <span class="sep">&middot;</span><span>VOICES</span><b id="roV">0</b>
      </div>
      <div class="scopebox"><canvas id="scope" aria-hidden="true"></canvas></div>
    </div>

    <div class="rack">
      <div class="row1">
        <div class="grp">
          <span class="rl">WAVE</span>
          <div class="wave" id="waveGrp" role="radiogroup" aria-label="Waveform"></div>
        </div>
        <div class="grp">
          <span class="rl">PATCH</span>
          <div class="grp" id="presets"></div>
        </div>
      </div>

      <div class="row2">
        <div class="knob">
          <div class="kl"><span>ATTACK</span><span class="kv" id="atkV">8 ms</span></div>
          <input type="range" id="atk" min="0" max="1000" step="1" value="207" aria-label="Attack time">
        </div>
        <div class="knob">
          <div class="kl"><span>RELEASE</span><span class="kv" id="relV">420 ms</span></div>
          <input type="range" id="rel" min="0" max="1000" step="1" value="536" aria-label="Release time">
        </div>
        <div class="knob">
          <div class="kl"><span>TONE</span><span class="kv" id="cutV">3.2 kHz</span></div>
          <input type="range" id="cut" min="0" max="1000" step="1" value="677" aria-label="Tone, filter cutoff">
        </div>
        <div class="dgrp">
          <button class="tog" id="dlyBtn" aria-pressed="true"><span class="led2"></span>DELAY</button>
          <div class="knob" id="dtKnob">
            <div class="kl"><span>TIME</span><span class="kv" id="dtV">260 ms</span></div>
            <input type="range" id="dt" min="0" max="1000" step="1" value="654" aria-label="Delay time">
          </div>
          <div class="knob" id="dfKnob">
            <div class="kl"><span>FEEDBACK</span><span class="kv" id="dfV">28 %</span></div>
            <input type="range" id="df" min="0" max="75" step="1" value="28" aria-label="Delay feedback">
          </div>
        </div>
      </div>
    </div>

    <div class="kbwrap">
      <div class="kb" id="kb" role="group" aria-label="Two octave keyboard. Use left and right arrows to move between keys, space to play."></div>
    </div>

    <div class="kbbar">
      <span class="rl">OCTAVE</span>
      <button class="oct" id="octDn" aria-label="Shift down an octave">&minus;</button>
      <span class="octv" id="octV">C3&ndash;B4</span>
      <button class="oct" id="octUp" aria-label="Shift up an octave">+</button>
      <span class="tip">Drag across the keys to slide &middot; hold several at once for a chord</span>
    </div>

    <p class="sr" id="live" role="status" aria-live="polite"></p>
  </main>

  <p class="hint"><b>Type to play:</b>
    <kbd>A</kbd><kbd>W</kbd><kbd>S</kbd><kbd>E</kbd><kbd>D</kbd><kbd>F</kbd><kbd>T</kbd><kbd>G</kbd><kbd>Y</kbd><kbd>H</kbd><kbd>U</kbd><kbd>J</kbd><kbd>K</kbd>
    runs C up to C across the lower octave &mdash; the same letters are printed on the keys.
    <kbd>Z</kbd> and <kbd>X</kbd> shift the whole keyboard down or up an octave.</p>

  <p class="note" id="audioNote" hidden>This browser has no Web Audio support, so the keys light up but stay silent.</p>

  <footer>demo &middot; sloprun.dev</footer>
</div>

<script>
(function () {
  "use strict";

  var root = document.documentElement;

  /* ── theme plumbing ─────────────────────────────────────────────────────── */
  window.addEventListener("message", function (e) {
    var d = e.data;
    if (d && d.type === "sloprun:theme" && (d.theme === "light" || d.theme === "dark")) {
      root.setAttribute("data-theme", d.theme);
      themeDirty = true;
      drawScope();
    }
  });

  var mqReduce = window.matchMedia ? window.matchMedia("(prefers-reduced-motion: reduce)") : null;
  var reduce = !!(mqReduce && mqReduce.matches);
  if (mqReduce && mqReduce.addEventListener) {
    mqReduce.addEventListener("change", function (e) { reduce = e.matches; });
  }
  var mqDark = window.matchMedia ? window.matchMedia("(prefers-color-scheme: dark)") : null;
  if (mqDark && mqDark.addEventListener) {
    /* the scope caches its colours, so an idle canvas keeps the old palette
       unless we repaint it right here */
    mqDark.addEventListener("change", function () { themeDirty = true; drawScope(); });
  }

  /* ── notes ──────────────────────────────────────────────────────────────── */
  var NAMES = ["C", "C♯", "D", "D♯", "E", "F", "F♯", "G", "G♯", "A", "A♯", "B"];
  var PLAIN = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"];
  var BLACK = [0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0];
  var SPAN = 24;                                    /* two octaves on screen */
  var LETTERS = ["A", "W", "S", "E", "D", "F", "T", "G", "Y", "H", "U", "J", "K"];
  var KEYMAP = {};
  LETTERS.forEach(function (l, i) { KEYMAP[l] = i; });

  function nameOf(m) { return NAMES[m % 12] + (Math.floor(m / 12) - 1); }
  function plainOf(m) { return PLAIN[m % 12] + (Math.floor(m / 12) - 1); }
  function hzOf(m) { return 440 * Math.pow(2, (m - 69) / 12); }

  var oct = 3;                                      /* C3 is the low key */
  function baseMidi() { return 12 * (oct + 1); }

  /* ── audio graph ────────────────────────────────────────────────────────── */
  var AC = window.AudioContext || window.webkitAudioContext;
  var ctx = null, bus = null, filt = null, dry = null, dl = null, fb = null, fbLp = null,
      wet = null, master = null, comp = null, analyser = null, scopeBuf = null;
  var audioDead = !AC;

  var PEAK = { sine: 0.30, triangle: 0.25, sawtooth: 0.15, square: 0.13 };

  function expo(v, lo, hi) { return lo * Math.pow(hi / lo, v / 1000); }

  var P = {                                          /* the live patch */
    wave: "triangle",
    atk: 0.008, rel: 0.42, cut: 3200,
    delay: true, dtime: 0.26, dfb: 0.28
  };

  function buildGraph() {
    ctx = new AC();
    bus = ctx.createGain();      bus.gain.value = 0.9;
    filt = ctx.createBiquadFilter(); filt.type = "lowpass"; filt.frequency.value = P.cut; filt.Q.value = 0.8;
    dry = ctx.createGain();      dry.gain.value = 1;
    dl = ctx.createDelay(1.2);   dl.delayTime.value = P.dtime;
    fb = ctx.createGain();       fb.gain.value = P.dfb;
    fbLp = ctx.createBiquadFilter(); fbLp.type = "lowpass"; fbLp.frequency.value = 2600;
    wet = ctx.createGain();      wet.gain.value = P.delay ? 0.42 : 0;
    master = ctx.createGain();   master.gain.value = 0.85;
    comp = ctx.createDynamicsCompressor();
    comp.threshold.value = -14; comp.knee.value = 24; comp.ratio.value = 5;
    comp.attack.value = 0.004; comp.release.value = 0.2;
    analyser = ctx.createAnalyser();
    analyser.fftSize = 2048; analyser.smoothingTimeConstant = 0.2;
    scopeBuf = new Uint8Array(analyser.fftSize);

    bus.connect(filt);
    filt.connect(dry); dry.connect(master);
    filt.connect(dl);
    dl.connect(fb); fb.connect(fbLp); fbLp.connect(dl);   /* feedback loop */
    dl.connect(wet); wet.connect(master);
    master.connect(comp);
    comp.connect(analyser);
    comp.connect(ctx.destination);
  }

  function ensureAudio() {
    if (audioDead) return false;
    if (!ctx) {
      try { buildGraph(); }
      catch (err) { audioDead = true; document.getElementById("audioNote").hidden = false; return false; }
      riffBtn.classList.remove("nudge");
      setStatus();
    }
    if (ctx.state === "suspended" && ctx.resume) { ctx.resume().then(setStatus, function () {}); }
    return true;
  }

  /* ── voices ─────────────────────────────────────────────────────────────── */
  var voiceCount = 0;

  function bump(v, on) {
    if (on === !!v.counted) return;
    v.counted = on; voiceCount += on ? 1 : -1;
    if (voiceCount < 0) voiceCount = 0;
    paintVoices();
  }

  function startVoice(midi, when) {
    if (!ctx) return null;
    var peak = PEAK[P.wave] || 0.2;
    var atk = P.atk, dec = 0.35 + atk * 0.6, sus = peak * 0.7;

    var env = ctx.createGain();
    var relG = ctx.createGain();
    env.gain.setValueAtTime(0, when);
    env.gain.linearRampToValueAtTime(peak, when + atk);
    env.gain.linearRampToValueAtTime(sus, when + atk + dec);
    relG.gain.setValueAtTime(1, when);

    var f = hzOf(midi);
    var o1 = ctx.createOscillator(); o1.type = P.wave; o1.frequency.value = f; o1.detune.value = -6;
    var o2 = ctx.createOscillator(); o2.type = P.wave; o2.frequency.value = f; o2.detune.value = 7;
    var g2 = ctx.createGain(); g2.gain.value = 0.55;

    o1.connect(env); o2.connect(g2); g2.connect(env);
    env.connect(relG); relG.connect(bus);
    o1.start(when); o2.start(when);

    var v = { o1: o1, o2: o2, env: env, relG: relG, g2: g2, t0: when, dead: false, counted: false, tin: 0 };
    /* a note the riff booked for four seconds from now is not sounding yet, so
       count it when it actually starts rather than when it is scheduled */
    var lead = (when - ctx.currentTime) * 1000;
    if (lead <= 12) bump(v, true);
    else v.tin = window.setTimeout(function () { v.tin = 0; if (!v.dead) bump(v, true); }, lead);

    o1.onended = function () {
      if (v.dead) return;
      v.dead = true;
      if (v.tin) { clearTimeout(v.tin); v.tin = 0; }
      bump(v, false); setStatus();
      try { o1.disconnect(); o2.disconnect(); g2.disconnect(); env.disconnect(); relG.disconnect(); } catch (e) {}
    };
    return v;
  }

  function stopVoice(v, when) {
    if (!v || v.stopped) return;
    v.stopped = true;
    var rel = P.rel;
    /* release rides its own gain node, so the attack curve is never cancelled
       mid-flight — that is what stops the click on short notes with slow attacks */
    v.relG.gain.setValueAtTime(1, when);
    v.relG.gain.linearRampToValueAtTime(0.0001, when + rel);
    try { v.o1.stop(when + rel + 0.03); v.o2.stop(when + rel + 0.03); } catch (e) {}
  }

  /* cancel a voice outright: stopVoice() has already run on every riff note at
     schedule time, so "Stop" has to override that automation, not re-request it */
  function killVoice(v, when) {
    if (!v || v.killed) return;
    v.killed = true;
    if (v.tin) { clearTimeout(v.tin); v.tin = 0; }
    var g = v.relG.gain;
    try {
      if (g.cancelAndHoldAtTime) g.cancelAndHoldAtTime(when);
      else { g.cancelScheduledValues(when); g.setValueAtTime(g.value, when); }
      g.linearRampToValueAtTime(0.0001, when + 0.06);
    } catch (e) {}
    /* a note booked for later has not started yet — stopping before its own
       start time would leave it dangling, so stop it just after instead */
    var end = Math.max(when + 0.09, v.t0 + 0.005);
    try { v.o1.stop(end); v.o2.stop(end); } catch (e) {}
  }

  /* ── key lighting ───────────────────────────────────────────────────────── */
  var keyEls = [], litN = new Array(SPAN).fill(0);
  function light(off, d) {
    if (off < 0 || off >= SPAN) return;
    litN[off] += d;
    var el = keyEls[off];
    if (!el) return;
    if (litN[off] > 0) el.classList.add("lit");
    else { litN[off] = 0; el.classList.remove("lit"); }
  }

  /* ── held notes (pointer + typing share one map) ─────────────────────────── */
  var held = new Map();      /* offset -> { v, srcs:Set } */

  function press(off, src) {
    if (off < 0 || off >= SPAN) return;
    var h = held.get(off);
    if (h) { h.srcs.add(src); return; }
    var ok = ensureAudio();
    var midi = baseMidi() + off;
    var v = ok && ctx ? startVoice(midi, ctx.currentTime) : null;
    held.set(off, { v: v, srcs: new Set([src]) });
    light(off, 1);
    showNote(midi);
    startScope();
    setStatus();
  }

  function release(off, src) {
    var h = held.get(off);
    if (!h) return;
    h.srcs.delete(src);
    if (h.srcs.size) return;
    held.delete(off);
    if (h.v && ctx) stopVoice(h.v, ctx.currentTime);
    light(off, -1);
    setStatus();
  }

  function releaseAll() {
    Array.from(held.keys()).forEach(function (off) {
      var h = held.get(off);
      held.delete(off);
      if (h.v && ctx) stopVoice(h.v, ctx.currentTime);
      light(off, -1);
    });
    setStatus();
  }

  /* a one-shot note, for Enter/Space on a focused key */
  function blip(off) {
    var ok = ensureAudio();
    var midi = baseMidi() + off;
    if (ok && ctx) {
      var v = startVoice(midi, ctx.currentTime);
      stopVoice(v, ctx.currentTime + 0.3);
    }
    light(off, 1);
    window.setTimeout(function () { light(off, -1); setStatus(); }, 300);
    showNote(midi);
    startScope();
    setStatus();
  }

  /* ── readouts ───────────────────────────────────────────────────────────── */
  var roNote = document.getElementById("roNote"),
      roHz = document.getElementById("roHz"),
      roV = document.getElementById("roV"),
      statusEl = document.getElementById("status"),
      statusTxt = document.getElementById("statusTxt"),
      live = document.getElementById("live");

  function showNote(midi) {
    roNote.textContent = plainOf(midi);
    roHz.textContent = hzOf(midi).toFixed(2);
  }
  function paintVoices() { roV.textContent = String(Math.max(0, voiceCount)); }

  function setStatus() {
    var on = !!ctx && ctx.state === "running";
    var sounding = held.size > 0 || voiceCount > 0 || riffOn;
    statusEl.classList.toggle("live", on);
    statusEl.classList.toggle("blink", on && sounding);
    statusTxt.textContent = !on ? (audioDead ? "NO AUDIO" : "TAP TO START")
      : (sounding ? "SOUNDING" : "AUDIO ON");
  }

  /* ── build the keyboard ─────────────────────────────────────────────────── */
  var kb = document.getElementById("kb");

  function buildKeys() {
    kb.textContent = "";
    keyEls = [];
    var whites = 0, plan = [];
    for (var i = 0; i < SPAN; i++) {
      if (BLACK[i % 12]) plan.push({ i: i, black: true, after: whites - 1 });
      else { plan.push({ i: i, black: false, w: whites }); whites++; }
    }
    var u = 100 / whites, bw = u * 0.62;

    /* appended in pitch order, not layout order: the short keys are absolutely
       positioned so they are out of the flex flow anyway, which means the DOM
       can read C, C♯, D … the way a reader expects */
    plan.forEach(function (p) {
      var el = makeKey(p);
      if (p.black) {
        el.style.width = bw + "%";
        el.style.left = ((p.after + 1) * u - bw / 2) + "%";
      } else if (p.w === whites - 1) {
        el.classList.add("lastw");
      }
      kb.appendChild(el);
    });
    keyEls.forEach(function (el, i) { el.tabIndex = i === 0 ? 0 : -1; });
    relabel();
  }

  function makeKey(p) {
    var el = document.createElement("button");
    el.type = "button";
    el.className = "k " + (p.black ? "bk" : "wk");
    el.dataset.off = String(p.i);
    var nm = document.createElement("span"); nm.className = "nm";
    var lt = document.createElement("span"); lt.className = "ltr";
    if (!p.black) el.appendChild(nm);
    el.appendChild(lt);
    el._nm = nm; el._lt = lt;
    keyEls[p.i] = el;
    return el;
  }

  function relabel() {
    var b = baseMidi();
    keyEls.forEach(function (el, i) {
      var midi = b + i, black = !!BLACK[i % 12];
      var letter = i < LETTERS.length ? LETTERS[i] : "";
      el._lt.textContent = letter;
      el._lt.style.display = letter ? "" : "none";
      if (!black) {
        el._nm.textContent = nameOf(midi);
        el._nm.className = "nm" + (midi % 12 === 0 ? "" : " opt");
      }
      el.setAttribute("aria-label", plainOf(midi) + (letter ? ", key " + letter : ""));
    });
    document.getElementById("octV").textContent = nameOf(b) + "–" + nameOf(b + SPAN - 1);
    document.getElementById("octDn").disabled = oct <= 1;
    document.getElementById("octUp").disabled = oct >= 6;
  }

  function setOct(n) {
    n = Math.max(1, Math.min(6, n));
    if (n === oct) return;
    stopRiff();
    releaseAll();
    oct = n;
    relabel();
    if (!held.size) showNote(baseMidi());
    live.textContent = "Octave " + nameOf(baseMidi()) + " to " + nameOf(baseMidi() + SPAN - 1);
  }

  buildKeys();
  document.getElementById("octDn").addEventListener("click", function () { setOct(oct - 1); });
  document.getElementById("octUp").addEventListener("click", function () { setOct(oct + 1); });

  /* ── pointer play ───────────────────────────────────────────────────────── */
  var pointers = new Map();   /* pointerId -> offset */

  function offAt(x, y) {
    var el = document.elementFromPoint(x, y);
    if (!el) return -1;
    var k = el.closest ? el.closest(".k") : null;
    if (!k || !kb.contains(k)) return -1;
    return +k.dataset.off;
  }

  kb.addEventListener("pointerdown", function (e) {
    var k = e.target.closest ? e.target.closest(".k") : null;
    if (!k) return;
    e.preventDefault();                       /* no focus ring on a mouse press, no page scroll on touch */
    var off = +k.dataset.off, id = "p" + e.pointerId;
    /* capture on the whole keyboard, not the key: without this a drag that ends
       outside the page never delivers pointerup and the note sustains forever */
    try { if (kb.setPointerCapture) kb.setPointerCapture(e.pointerId); } catch (err) {}
    pointers.set(e.pointerId, off);
    keyEls.forEach(function (el, i) { el.tabIndex = i === off ? 0 : -1; });
    press(off, id);
  });

  window.addEventListener("pointermove", function (e) {
    if (!pointers.has(e.pointerId)) return;
    var prev = pointers.get(e.pointerId);
    var next = offAt(e.clientX, e.clientY);
    if (next === prev) return;
    var id = "p" + e.pointerId;
    if (prev >= 0) release(prev, id);
    if (next >= 0) press(next, id);
    pointers.set(e.pointerId, next);
  }, { passive: true });

  function endPointer(e) {
    if (!pointers.has(e.pointerId)) return;
    var prev = pointers.get(e.pointerId);
    pointers.delete(e.pointerId);
    if (prev >= 0) release(prev, "p" + e.pointerId);
  }
  window.addEventListener("pointerup", endPointer);
  window.addEventListener("pointercancel", endPointer);

  /* arrow-key travel across the keys — the whole row is one tab stop.
     Space/Enter are handled here rather than via click, so a touch tap can
     never be mistaken for a keyboard activation and fire the note twice. */
  kb.addEventListener("keydown", function (e) {
    var k = e.target.closest ? e.target.closest(".k") : null;
    if (!k) return;
    var off = +k.dataset.off, next = null;
    if (e.key === " " || e.key === "Spacebar" || e.key === "Enter") {
      e.preventDefault();
      if (!e.repeat) blip(off);
      return;
    }
    if (e.key === "ArrowRight") next = Math.min(SPAN - 1, off + 1);
    else if (e.key === "ArrowLeft") next = Math.max(0, off - 1);
    else if (e.key === "Home") next = 0;
    else if (e.key === "End") next = SPAN - 1;
    if (next === null) return;
    e.preventDefault();
    keyEls.forEach(function (el, i) { el.tabIndex = i === next ? 0 : -1; });
    keyEls[next].focus();
  });

  /* ── typing ─────────────────────────────────────────────────────────────── */
  function typedOff(e) {
    var k = (e.key || "").toUpperCase();
    return Object.prototype.hasOwnProperty.call(KEYMAP, k) ? KEYMAP[k] : -1;
  }

  window.addEventListener("keydown", function (e) {
    if (e.metaKey || e.ctrlKey || e.altKey) return;
    var t = e.target;
    if (t && (t.tagName === "TEXTAREA" || (t.tagName === "INPUT" && t.type !== "range" && t.type !== "radio"))) return;
    var k = (e.key || "").toUpperCase();
    if (k === "Z" || k === "X") { e.preventDefault(); setOct(oct + (k === "X" ? 1 : -1)); return; }
    var off = typedOff(e);
    if (off < 0) return;
    e.preventDefault();
    if (e.repeat) return;
    press(off, "kbd");
  });

  window.addEventListener("keyup", function (e) {
    var off = typedOff(e);
    if (off >= 0) release(off, "kbd");
  });

  /* losing focus (or the tab going away) swallows the keyup AND the pointerup,
     so drop every held note rather than only the typed ones */
  function panic() {
    pointers.clear();
    releaseAll();
  }
  window.addEventListener("blur", panic);
  document.addEventListener("visibilitychange", function () {
    if (document.hidden) panic();
  });

  /* ── controls ───────────────────────────────────────────────────────────── */
  var WAVES = [
    { v: "sine",     label: "sine",   d: "M1 7 C 3.6 0.4, 6.4 0.4, 9 7 S 14.4 13.6, 17 7" },
    { v: "triangle", label: "tri",    poly: "1,12 5,2 9,12 13,2 17,12" },
    { v: "sawtooth", label: "saw",    poly: "1,12 6,2 6,12 11,2 11,12 16,2 16,12" },
    { v: "square",   label: "square", poly: "1,12 1,2 5,2 5,12 9,12 9,2 13,2 13,12 17,12 17,2" }
  ];
  var waveGrp = document.getElementById("waveGrp");
  WAVES.forEach(function (w) {
    var inp = document.createElement("input");
    inp.type = "radio"; inp.name = "wave"; inp.id = "w-" + w.v; inp.value = w.v;
    var lab = document.createElement("label");
    lab.htmlFor = inp.id;
    var svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
    svg.setAttribute("width", "18"); svg.setAttribute("height", "14");
    svg.setAttribute("viewBox", "0 0 18 14"); svg.setAttribute("aria-hidden", "true");
    var sh;
    if (w.poly) { sh = document.createElementNS("http://www.w3.org/2000/svg", "polyline"); sh.setAttribute("points", w.poly); }
    else { sh = document.createElementNS("http://www.w3.org/2000/svg", "path"); sh.setAttribute("d", w.d); }
    svg.appendChild(sh);
    lab.appendChild(svg);
    lab.appendChild(document.createTextNode(w.label));
    inp.addEventListener("change", function () {
      if (!inp.checked) return;
      P.wave = w.v;
      held.forEach(function (h) { if (h.v) { h.v.o1.type = w.v; h.v.o2.type = w.v; } });
      markPreset(null);
      drawScope();
    });
    waveGrp.appendChild(inp); waveGrp.appendChild(lab);
  });

  var atk = document.getElementById("atk"), atkV = document.getElementById("atkV"),
      rel = document.getElementById("rel"), relV = document.getElementById("relV"),
      cut = document.getElementById("cut"), cutV = document.getElementById("cutV"),
      dt = document.getElementById("dt"), dtV = document.getElementById("dtV"),
      df = document.getElementById("df"), dfV = document.getElementById("dfV"),
      dlyBtn = document.getElementById("dlyBtn"),
      dtKnob = document.getElementById("dtKnob"), dfKnob = document.getElementById("dfKnob");

  function fmtMs(s) {
    var ms = s * 1000;
    return ms >= 1000 ? (ms / 1000).toFixed(2) + " s" : Math.round(ms) + " ms";
  }
  function fmtHz(h) { return h >= 1000 ? (h / 1000).toFixed(1) + " kHz" : Math.round(h) + " Hz"; }

  function setAtk(v, fromUser) { P.atk = v; atkV.textContent = fmtMs(v); if (fromUser) markPreset(null); }
  function setRel(v, fromUser) { P.rel = v; relV.textContent = fmtMs(v); if (fromUser) markPreset(null); }
  function setCut(v, fromUser) {
    P.cut = v; cutV.textContent = fmtHz(v);
    if (filt) filt.frequency.setTargetAtTime(v, ctx.currentTime, 0.01);
    if (fromUser) markPreset(null);
  }
  function setDt(v, fromUser) {
    P.dtime = v; dtV.textContent = fmtMs(v);
    if (dl) dl.delayTime.setTargetAtTime(v, ctx.currentTime, 0.05);
    if (fromUser) markPreset(null);
  }
  function setDf(v, fromUser) {
    P.dfb = v; dfV.textContent = Math.round(v * 100) + " %";
    if (fb) fb.gain.setTargetAtTime(v, ctx.currentTime, 0.02);
    if (fromUser) markPreset(null);
  }
  function readAtk(u) { setAtk(expo(+atk.value, 0.002, 1.6), u); }
  function readRel(u) { setRel(expo(+rel.value, 0.04, 3.2), u); }
  function readCut(u) { setCut(expo(+cut.value, 200, 12000), u); }
  function readDt(u) { setDt(expo(+dt.value, 0.04, 0.7), u); }
  function readDf(u) { setDf((+df.value) / 100, u); }
  function paintDelay() {
    dlyBtn.setAttribute("aria-pressed", P.delay ? "true" : "false");
    dtKnob.classList.toggle("off", !P.delay);
    dfKnob.classList.toggle("off", !P.delay);
    dt.disabled = !P.delay; df.disabled = !P.delay;
    if (wet) wet.gain.setTargetAtTime(P.delay ? 0.42 : 0, ctx.currentTime, 0.03);
  }

  atk.addEventListener("input", function () { readAtk(true); });
  rel.addEventListener("input", function () { readRel(true); });
  cut.addEventListener("input", function () { readCut(true); });
  dt.addEventListener("input", function () { readDt(true); });
  df.addEventListener("input", function () { readDf(true); });
  dlyBtn.addEventListener("click", function () { P.delay = !P.delay; paintDelay(); markPreset(null); });

  /* ── patches ────────────────────────────────────────────────────────────── */
  var PATCHES = {
    "warm keys": { wave: "triangle", atk: 0.008, rel: 0.42, cut: 3200, delay: true,  dtime: 0.26, dfb: 0.28 },
    "bell":      { wave: "sine",     atk: 0.003, rel: 1.60, cut: 9000, delay: true,  dtime: 0.34, dfb: 0.44 },
    "slow pad":  { wave: "sawtooth", atk: 0.62,  rel: 1.50, cut: 1400, delay: true,  dtime: 0.45, dfb: 0.50 },
    "buzzy":     { wave: "square",   atk: 0.004, rel: 0.16, cut: 2400, delay: false, dtime: 0.16, dfb: 0.18 }
  };
  var presetsEl = document.getElementById("presets"), presetBtns = {};
  Object.keys(PATCHES).forEach(function (name) {
    var b = document.createElement("button");
    b.type = "button"; b.className = "chip"; b.textContent = name;
    b.setAttribute("aria-pressed", "false");
    b.addEventListener("click", function () { applyPatch(name); });
    presetsEl.appendChild(b);
    presetBtns[name] = b;
  });

  function inv(x, lo, hi) { return Math.round(1000 * Math.log(x / lo) / Math.log(hi / lo)); }

  function applyPatch(name) {
    var p = PATCHES[name];
    if (!p) return;
    var w = document.getElementById("w-" + p.wave); if (w) w.checked = true;
    P.wave = p.wave;
    held.forEach(function (h) { if (h.v) { h.v.o1.type = p.wave; h.v.o2.type = p.wave; } });
    atk.value = inv(p.atk, 0.002, 1.6);   setAtk(p.atk, false);
    rel.value = inv(p.rel, 0.04, 3.2);    setRel(p.rel, false);
    cut.value = inv(p.cut, 200, 12000);   setCut(p.cut, false);
    dt.value = inv(p.dtime, 0.04, 0.7);   setDt(p.dtime, false);
    df.value = Math.round(p.dfb * 100);   setDf(p.dfb, false);
    P.delay = p.delay; paintDelay();
    markPreset(name);
    drawScope();
    live.textContent = "Patch " + name;
  }
  function markPreset(name) {
    Object.keys(presetBtns).forEach(function (n) {
      presetBtns[n].setAttribute("aria-pressed", n === name ? "true" : "false");
    });
  }

  /* ── the riff ───────────────────────────────────────────────────────────── */
  var BARS = [
    [0, 7, 12, 16, 19, 16, 12, 7],
    [9, 12, 16, 21, 16, 12, 9, 4],
    [5, 9, 12, 17, 21, 17, 12, 9],
    [7, 11, 14, 19, 23, 19, 14, 11]
  ];
  var STEP = 0.215;
  var RIFF = [];
  BARS.forEach(function (bar, bi) {
    bar.forEach(function (o, si) {
      RIFF.push({ o: o, t: (bi * 8 + si) * STEP, d: STEP * 1.65 });
    });
  });
  [0, 7, 12, 16].forEach(function (o) { RIFF.push({ o: o, t: 32 * STEP, d: 2.1 }); });
  var RIFF_END = 32 * STEP + 2.1;

  var riffBtn = document.getElementById("riffBtn"),
      riffTxt = document.getElementById("riffTxt"),
      riffGl = document.getElementById("riffGl");
  var riffOn = false, riffVoices = [], riffTimers = [];
  var riffLit = new Array(SPAN).fill(0);   /* lights this riff owns, so stopping
                                              it never darkens a key you are holding */

  function stopRiff() {
    if (!riffOn) return;
    riffOn = false;
    riffTimers.forEach(clearTimeout); riffTimers = [];
    if (ctx) riffVoices.forEach(function (v) { killVoice(v, ctx.currentTime); });
    riffVoices = [];
    for (var i = 0; i < SPAN; i++) {
      while (riffLit[i] > 0) { riffLit[i]--; light(i, -1); }
    }
    riffBtn.classList.remove("on");
    riffTxt.textContent = "Play riff";
    riffGl.innerHTML = "&#9654;";
    setStatus();
  }

  function playRiff() {
    if (riffOn) { stopRiff(); return; }
    ensureAudio();   /* with no Web Audio at all the riff still runs as a light show */
    riffOn = true;
    riffBtn.classList.add("on");
    riffTxt.textContent = "Stop";
    riffGl.innerHTML = "&#9632;";
    setStatus();
    startScope();
    /* wait for the context to actually be running, or every note would be
       scheduled against a clock that has not started ticking yet */
    if (ctx && ctx.state !== "running" && ctx.resume) ctx.resume().then(schedRiff, schedRiff);
    else schedRiff();
  }

  function schedRiff() {
    if (!riffOn) return;
    var t0 = ctx ? ctx.currentTime + 0.09 : 0;
    var b = baseMidi();
    RIFF.forEach(function (n) {
      var v = ctx ? startVoice(b + n.o, t0 + n.t) : null;
      if (v) { stopVoice(v, t0 + n.t + n.d); riffVoices.push(v); }
      riffTimers.push(window.setTimeout(function () {
        riffLit[n.o]++; light(n.o, 1); showNote(b + n.o); setStatus();
      }, n.t * 1000 + 90));
      riffTimers.push(window.setTimeout(function () {
        if (riffLit[n.o] > 0) { riffLit[n.o]--; light(n.o, -1); }
        setStatus();
      }, (n.t + n.d) * 1000 + 90));
    });
    riffTimers.push(window.setTimeout(stopRiff, (RIFF_END + P.rel) * 1000 + 250));
  }
  riffBtn.addEventListener("click", playRiff);

  /* ── scope ──────────────────────────────────────────────────────────────── */
  var cv = document.getElementById("scope"), cx = cv.getContext("2d");
  var cw = 0, ch = 0, dpr = 1, themeDirty = true, colors = {};
  var rafId = 0, quietSince = 0;

  function readColors() {
    var cs = getComputedStyle(root);
    colors = {
      accent: cs.getPropertyValue("--accent").trim() || "#C05600",
      muted: cs.getPropertyValue("--muted").trim() || "#5A6068",
      line: cs.getPropertyValue("--line").trim() || "#E3E2DC"
    };
    themeDirty = false;
  }

  function sizeCanvas() {
    var r = cv.getBoundingClientRect();
    dpr = Math.min(2, window.devicePixelRatio || 1);
    cw = Math.max(1, Math.round(r.width)); ch = Math.max(1, Math.round(r.height));
    cv.width = Math.round(cw * dpr); cv.height = Math.round(ch * dpr);
    cx.setTransform(dpr, 0, 0, dpr, 0, 0);
    drawScope();
  }

  function shapeAt(x) {   /* one period of the selected wave, x in 0..1 */
    switch (P.wave) {
      case "square": return Math.sin(2 * Math.PI * x) >= 0 ? 1 : -1;
      case "sawtooth": return 2 * (x - Math.floor(x + 0.5));
      case "triangle": return 2 / Math.PI * Math.asin(Math.sin(2 * Math.PI * x));
      default: return Math.sin(2 * Math.PI * x);
    }
  }

  function drawScope() {
    if (themeDirty) readColors();
    if (!cw) return;
    cx.clearRect(0, 0, cw, ch);
    var mid = ch / 2;

    cx.strokeStyle = colors.line; cx.lineWidth = 1;
    cx.setLineDash([2, 4]);
    cx.beginPath(); cx.moveTo(0, mid + 0.5); cx.lineTo(cw, mid + 0.5); cx.stroke();
    cx.setLineDash([]);

    var amp = ch * 0.36, i, x, y, level = 0;

    if (analyser && scopeBuf) {
      analyser.getByteTimeDomainData(scopeBuf);
      var n = scopeBuf.length, sum = 0;
      for (i = 0; i < n; i++) { var d = (scopeBuf[i] - 128) / 128; sum += d * d; }
      level = Math.sqrt(sum / n);
    }

    cx.lineWidth = 1.7; cx.lineJoin = "round"; cx.lineCap = "round";

    if (level > 0.0025) {
      /* live output — trigger on a rising zero crossing so the trace holds still */
      var buf = scopeBuf, len = buf.length, start = 0;
      for (i = 1; i < len / 2; i++) {
        if (buf[i - 1] < 128 && buf[i] >= 128) { start = i; break; }
      }
      var take = Math.min(len - start, Math.max(256, Math.floor(len / 2)));
      var gain = Math.min(2.4, 0.5 / Math.max(0.04, level));
      cx.strokeStyle = colors.accent;
      cx.beginPath();
      for (i = 0; i < take; i++) {
        x = (i / (take - 1)) * cw;
        y = mid - ((buf[start + i] - 128) / 128) * amp * gain;
        y = Math.max(1, Math.min(ch - 1, y));
        i ? cx.lineTo(x, y) : cx.moveTo(x, y);
      }
      cx.stroke();
      quietSince = 0;
    } else {
      /* silent — show the shape of the wave that is armed, so the selector
         means something before a single key is pressed */
      cx.strokeStyle = colors.muted;
      cx.globalAlpha = 0.55;
      var cycles = 2.5, steps = Math.max(120, Math.round(cw));
      cx.beginPath();
      for (i = 0; i <= steps; i++) {
        x = (i / steps) * cw;
        y = mid - shapeAt((i / steps) * cycles) * amp * 0.8;
        i ? cx.lineTo(x, y) : cx.moveTo(x, y);
      }
      cx.stroke();
      cx.globalAlpha = 1;
    }
    return level;
  }

  function scopeFrame() {
    var level = drawScope();
    var sounding = held.size > 0 || riffOn || voiceCount > 0;
    if (!sounding && (level || 0) < 0.0025) {
      if (!quietSince) quietSince = Date.now();
      if (Date.now() - quietSince > 900) { rafId = 0; drawScope(); return; }
    } else quietSince = 0;
    if (reduce) rafId = window.setTimeout(scopeFrame, 100);
    else rafId = requestAnimationFrame(scopeFrame);
  }

  function startScope() {
    if (rafId) return;
    quietSince = 0;
    rafId = reduce ? window.setTimeout(scopeFrame, 100) : requestAnimationFrame(scopeFrame);
  }

  if (window.ResizeObserver) new ResizeObserver(sizeCanvas).observe(cv);
  window.addEventListener("resize", sizeCanvas);
  if (window.MutationObserver) {
    new MutationObserver(function () { themeDirty = true; drawScope(); })
      .observe(root, { attributes: true, attributeFilter: ["data-theme"] });
  }

  /* ── boot: arrive pre-loaded and ready to be pressed ─────────────────────── */
  if (audioDead) {
    document.getElementById("audioNote").hidden = false;
    riffBtn.classList.remove("nudge");   /* nothing to wake up, so stop nagging */
  }
  applyPatch("warm keys");
  showNote(baseMidi());
  paintVoices();
  setStatus();
  sizeCanvas();
})();
</script>
</body>
</html>