/* Sonograph interface. The plot and its painters draw on a light surface. */
:root{
  --bg:#f6f7f9;--surface:#fff;--subtle:#f9fafb;--hover:#f2f3f6;
  --line:#e6e8ec;--line-strong:#d6d9e0;
  --text:#111827;--text-2:#4b5563;--muted:#6b7280;--faint:#9ca3af;
  --accent:#4f46e5;--accent-hover:#4338ca;--accent-soft:#eef2ff;--accent-text:#4338ca;
  --radius:14px;--radius-sm:8px;--sidebar:288px;
  --shadow:0 1px 2px rgb(16 24 40 / 4%),0 1px 3px rgb(16 24 40 / 3%);
  --ring:0 0 0 3px rgb(79 70 229 / 22%);
  --font:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  --mono:ui-monospace,"SFMono-Regular","Cascadia Mono",Consolas,monospace;
  --math:"Cambria Math","STIX Two Math",Cambria,Georgia,serif;
  color-scheme:light;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:14px/1.5 var(--font);font-feature-settings:"cv11","ss01";-webkit-font-smoothing:antialiased}
button,input,select{font:inherit;color:inherit}
button{cursor:pointer}
a{color:inherit}
svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.75;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}
:focus-visible{outline:none;box-shadow:var(--ring)}
[hidden]{display:none!important}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
kbd{font:500 11px/1 var(--font);color:var(--muted);background:var(--surface);border:1px solid var(--line);border-bottom-width:2px;border-radius:5px;padding:3px 5px;min-width:20px;text-align:center}

/* Buttons */
.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:36px;padding:0 14px;border-radius:var(--radius-sm);border:1px solid transparent;font-weight:500;white-space:nowrap;transition:background .15s,border-color .15s,color .15s}
.button.secondary{background:var(--surface);border-color:var(--line-strong);color:var(--text);box-shadow:var(--shadow)}
.button.secondary:hover{background:var(--hover)}
.button kbd{margin-left:2px}
.icon-button{display:inline-flex;align-items:center;justify-content:center;width:36px;height:36px;padding:0;border:0;border-radius:var(--radius-sm);background:transparent;color:var(--muted);transition:background .15s,color .15s}
.icon-button:hover{background:var(--hover);color:var(--text)}

/* Brand */
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;font-weight:650;font-size:16px;letter-spacing:-.2px}
.brand-mark{display:grid;place-items:center;width:28px;height:28px;border-radius:8px;background:var(--accent);color:#fff}
.brand-mark svg{width:20px;height:20px;stroke-width:2.4}

/* Shell */
.shell{display:grid;grid-template-columns:var(--sidebar) minmax(0,1fr);min-height:100vh}
.main{width:100%;max-width:1320px;height:100vh;height:100dvh;margin:0 auto;padding:24px 32px;display:flex;flex-direction:column;gap:16px;min-width:0;overflow:hidden}
.workspace{flex:1;min-height:0;display:grid;grid-template-columns:minmax(0,1fr) 320px;grid-template-rows:minmax(0,1fr);gap:20px}
.topbar{display:none}

/* Library sidebar */
.library{position:sticky;top:0;height:100vh;height:100dvh;display:flex;flex-direction:column;background:var(--surface);border-right:1px solid var(--line);min-width:0}
.library-head{display:flex;align-items:center;justify-content:space-between;padding:20px 20px 16px}
.library-close{display:none}
.search{position:relative;display:flex;align-items:center;margin:0 16px 8px}
.search svg{position:absolute;left:10px;width:16px;height:16px;color:var(--faint);pointer-events:none}
.search input{width:100%;height:36px;padding:0 36px 0 34px;border:1px solid var(--line-strong);border-radius:var(--radius-sm);background:var(--subtle);transition:border-color .15s,background .15s}
.search input::placeholder{color:var(--faint)}
.search input:focus{background:var(--surface);border-color:var(--accent);box-shadow:var(--ring)}
.search input::-webkit-search-cancel-button{display:none}
.search kbd{position:absolute;right:8px;pointer-events:none}
.search input:focus~kbd,.search input:not(:placeholder-shown)~kbd{display:none}
.library-list{flex:1;overflow-y:auto;padding:4px 10px 16px;overscroll-behavior:contain;scrollbar-width:thin;scrollbar-color:var(--line-strong) transparent}
.library-group+.library-group{margin-top:6px}
.library-group h3{position:sticky;top:0;z-index:1;display:flex;justify-content:space-between;margin:0;padding:12px 10px 6px;background:var(--surface);font-size:11px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--faint)}
.library-group ul{list-style:none;margin:0;padding:0}
.library-item{display:block;width:100%;padding:6px 10px;border:0;border-radius:6px;background:transparent;text-align:left;color:var(--text-2);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.library-item:hover{background:var(--hover);color:var(--text)}
.library-item[aria-current="true"]{background:var(--accent-soft);color:var(--accent-text);font-weight:550}
.library-empty{margin:0;padding:24px 20px;color:var(--muted);text-align:center}
.library-foot{display:flex;justify-content:space-between;padding:12px 20px;border-top:1px solid var(--line);font-size:12px;color:var(--faint)}
.library-foot a{text-decoration:none}
.library-foot a:hover{color:var(--text)}
.scrim{display:none}

/* Title */
.title-row{display:flex;align-items:flex-end;justify-content:space-between;gap:16px}
.title-text{min-width:0}
.eyebrow{margin:0 0 4px;font-size:12px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
h1{margin:0;font-size:28px;line-height:1.2;font-weight:650;letter-spacing:-.6px;overflow-wrap:anywhere}

/* Stage */
.stage{display:flex;flex-direction:column;min-height:0;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}
.plot-shell{position:relative;flex:1;min-height:180px;padding:6px 6px 0}
canvas{display:block;width:100%;height:100%}
.domain-label{position:absolute;right:16px;bottom:10px;font:12px var(--mono);color:var(--faint);pointer-events:none}
.machine-controls{display:flex;flex-wrap:wrap;align-items:center;gap:10px 20px;padding:12px 20px;border-top:1px solid var(--line);font-size:13px;color:var(--text-2)}
.machine-controls label{display:flex;align-items:center;gap:8px}
.machine-controls select,.machine-controls button{height:32px;padding:0 10px;border:1px solid var(--line-strong);border-radius:var(--radius-sm);background:var(--surface);color:var(--text)}
.machine-controls button:hover{background:var(--hover)}
.machine-controls input[type=range]{width:110px;accent-color:var(--accent)}
.machine-controls output{min-width:28px;font-variant-numeric:tabular-nums;color:var(--muted)}

/* Transport */
.transport{display:flex;align-items:center;gap:12px;padding:14px 20px;border-top:1px solid var(--line);background:var(--subtle)}
.play-button{display:grid;place-items:center;width:44px;height:44px;flex-shrink:0;border:0;border-radius:50%;background:var(--accent);color:#fff;box-shadow:0 2px 6px rgb(79 70 229 / 30%);transition:background .15s,transform .1s}
.play-button:hover{background:var(--accent-hover)}
.play-button:active{transform:scale(.96)}
.play-button svg{width:18px;height:18px;fill:currentColor;stroke:none}
.time{font:500 12px var(--mono);font-variant-numeric:tabular-nums;color:var(--text-2);white-space:nowrap}
.time span{color:var(--faint)}
.progress-track{position:relative;flex:1;height:20px;cursor:pointer;border-radius:10px;min-width:60px}
.progress-track::before{content:"";position:absolute;left:0;right:0;top:8px;height:4px;border-radius:2px;background:var(--line)}
#progress{position:absolute;left:0;top:8px;height:4px;width:0;border-radius:2px;background:var(--accent)}
#progress::after{content:"";position:absolute;right:-6px;top:-4px;width:12px;height:12px;border-radius:50%;background:var(--surface);border:2px solid var(--accent);opacity:0;transition:opacity .15s}
.progress-track:hover #progress::after,.progress-track:focus-visible #progress::after{opacity:1}
.volume{display:flex;align-items:center;gap:8px;color:var(--muted)}
.volume input{-webkit-appearance:none;appearance:none;width:88px;height:4px;margin:0;border-radius:2px;background:linear-gradient(var(--text-2),var(--text-2)) 0/var(--fill,35%) 100% no-repeat,var(--line);cursor:pointer}
.volume input::-webkit-slider-thumb{-webkit-appearance:none;appearance:none;width:12px;height:12px;border-radius:50%;background:var(--surface);border:2px solid var(--text-2)}
.volume input::-moz-range-thumb{width:8px;height:8px;border-radius:50%;background:var(--surface);border:2px solid var(--text-2)}

/* Panels */
.side{display:flex;flex-direction:column;gap:16px;min-height:0;overflow-y:auto;overscroll-behavior:contain;scrollbar-width:thin;scrollbar-color:var(--line-strong) transparent;border-radius:var(--radius)}
.sheet-head,.equation-mini{display:none}
.panel{flex-shrink:0;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:18px 20px;min-width:0}
.panel-title{margin:0 0 14px;font-size:12px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--faint)}
.equation{display:flex;align-items:center;flex-wrap:wrap;gap:8px;font:20px/1.55 var(--math);color:var(--text);overflow-wrap:anywhere}
.equation.long-equation{font-size:17px}
.equation sup{font-size:.65em;vertical-align:super;line-height:0}
.equation sub{font-size:.65em;line-height:0}
.equation .variable{font-style:italic}
.equation .brace{font-size:2.3em;line-height:1;font-weight:300;color:var(--text-2)}
.equation .cases{font-size:.86em;line-height:1.75}
.pattern-notes{margin-top:14px;padding-top:14px;border-top:1px solid var(--line)}
.pattern-notes p{margin:0;color:var(--text-2);line-height:1.65}
.pattern-meta{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:6px 16px;margin-top:12px;font-size:13px}
.voice-tag{color:var(--muted)}
.pattern-meta a{display:inline-flex;align-items:center;gap:4px;color:var(--accent-text);text-decoration:none;font-weight:500}
.pattern-meta a:hover{text-decoration:underline;text-underline-offset:3px}
.pattern-meta a svg{width:14px;height:14px}

.field{display:flex;flex-direction:column;gap:6px}
.field+.field{margin-top:16px}
.field>label{font-size:13px;font-weight:500;color:var(--text-2)}
.segmented{display:grid;grid-auto-flow:column;grid-auto-columns:1fr;padding:3px;border-radius:var(--radius-sm);background:var(--hover);border:1px solid var(--line)}
.segmented button{height:30px;border:0;border-radius:6px;background:transparent;color:var(--muted);font-weight:500;transition:background .15s,color .15s}
.segmented button:hover{color:var(--text)}
.segmented button[aria-pressed="true"]{background:var(--surface);color:var(--text);box-shadow:0 1px 2px rgb(16 24 40 / 10%)}
select[data-segmented].enhanced{display:none}
.field select{height:36px;padding:0 10px;border:1px solid var(--line-strong);border-radius:var(--radius-sm);background:var(--surface)}
.seed-input{display:flex;align-items:center;border:1px solid var(--line-strong);border-radius:var(--radius-sm);background:var(--subtle);transition:border-color .15s,box-shadow .15s}
.seed-input:focus-within{border-color:var(--accent);box-shadow:var(--ring);background:var(--surface)}
.seed-input input{flex:1;min-width:0;height:34px;padding:0 0 0 10px;border:0;background:transparent;font:12.5px var(--mono);color:var(--text-2)}
.seed-input input:focus{outline:none;box-shadow:none}
.seed-input .icon-button{width:34px;height:34px}
.seed-input .icon-button svg{width:16px;height:16px}
.seed-row{display:flex;gap:8px}
.seed-row .seed-input{flex:1;min-width:0}
.load-seed{height:36px;padding:0 12px}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.field-row+.field{margin-top:16px}
.field-row .field+.field{margin-top:0}
.field-row .segmented button{padding:0 4px}
.disclosure{display:inline-flex;align-items:center;gap:4px;margin:0;padding:0;border:0;background:none;color:var(--text-2);font-size:13px;font-weight:500}
.disclosure:hover{color:var(--text)}
.disclosure svg{width:16px;height:16px;transition:transform .2s}
.disclosure[aria-expanded="true"] svg{transform:rotate(180deg)}
.pattern-notes p{margin-top:10px}
.pattern-notes:not(.expanded) #pattern-definitions{display:none}


/* Status toast */
.toast{position:fixed;left:50%;bottom:24px;z-index:30;transform:translateX(-50%);margin:0;max-width:calc(100% - 32px);padding:10px 16px;border-radius:10px;background:#111827;color:#fff;font-size:13px;box-shadow:0 10px 30px rgb(16 24 40 / 25%);animation:toast-in .2s ease-out}
.toast.error{background:#b42318}
@keyframes toast-in{from{opacity:0;transform:translate(-50%,8px)}}

/* Library becomes a drawer */
@media (max-width:1023px){
  .shell{grid-template-columns:minmax(0,1fr)}
  .library{position:fixed;inset:0 auto 0 0;z-index:20;width:min(320px,86vw);transform:translateX(-100%);transition:transform .22s ease;box-shadow:none;visibility:hidden}
  .library-open .library{transform:none;visibility:visible;box-shadow:0 20px 60px rgb(16 24 40 / 25%)}
  .library-close{display:inline-flex}
  .scrim{display:block;position:fixed;inset:0;z-index:15;background:rgb(17 24 39 / 40%);backdrop-filter:blur(2px);animation:fade .2s}
  .topbar{display:flex;align-items:center;justify-content:space-between}
  .topbar .brand{order:-1}
  .main{padding:16px 24px 20px;gap:14px}
  .workspace{grid-template-columns:minmax(0,1fr) 280px;gap:16px}
  h1{font-size:24px}
}
@keyframes fade{from{opacity:0}}

/* Phones: graph first, details in a bottom sheet */
@media (max-width:819px){
  .main{padding:12px 14px 14px;gap:12px}
  .title-row{align-items:center;gap:12px}
  h1{font-size:20px;line-height:1.25}
  .eyebrow{font-size:11px;margin-bottom:2px}
  #next{width:40px;padding:0;flex-shrink:0}
  #next .button-label,#next kbd,.search kbd{display:none}
  .workspace{display:flex;flex-direction:column;gap:10px}
  .stage{flex:1}
  .plot-shell{min-height:150px;padding:2px 0 0}
  .transport{flex-wrap:wrap;padding:10px 14px;gap:8px 10px}
  .progress-track{order:5;flex-basis:100%;height:16px}
  .progress-track::before,#progress{top:6px}
  .volume{margin-left:auto}
  .volume input{width:72px}
  .machine-controls{padding:10px 14px;gap:8px 14px}
  .equation-mini{display:flex;align-items:center;gap:12px;flex-shrink:0;max-height:26dvh;padding:12px 14px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
  .equation-mini .equation{flex:1;min-width:0;max-height:100%;overflow-y:auto;font-size:16px;gap:6px}
  .equation-mini .equation.long-equation{font-size:14px}
  .equation-mini .button{flex-shrink:0;align-self:flex-start}
  .side{position:fixed;left:0;right:0;bottom:0;z-index:25;max-height:86dvh;gap:12px;padding:0 14px 16px;background:var(--bg);border-radius:18px 18px 0 0;box-shadow:0 -10px 40px rgb(16 24 40 / 20%);transform:translateY(105%);visibility:hidden;transition:transform .25s ease,visibility .25s}
  .details-open .side{transform:none;visibility:visible}
  .sheet-head{display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:1;margin:0 -14px;padding:12px 14px 8px 18px;background:var(--bg);font-weight:600}
  .side .equation-panel .equation,.side #equation-title{display:none}
  .side .pattern-notes{margin-top:0;padding-top:0;border-top:0}
  .side .disclosure{display:none}
  .side .pattern-notes #pattern-definitions{display:block;margin-top:0}
  .side .pattern-notes #pattern-definitions[hidden]{display:none}
  .panel{padding:16px}
}

/* Very short screens fall back to a scrolling page. */
@media (max-height:540px){
  .main{height:auto;min-height:100dvh;overflow:visible}
  .workspace{flex:none}
  .plot-shell{flex:none;height:300px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}