/* Ditherer DTH-08. Instrument Sheet chassis, accent #3F5F7F (steel blue). The slab is a printer's
   screen; a comparison frame sits on it with a paper divider you drag. Paper on steel blue is 5.4:1,
   so paper type is fine at every size on the slab. */
:root{
  --paper:#EDE9E2;
  --ink:#1E1D1B;
  --panel:#DEDACF;
  --line:#B7B0A2;
  --chassis:#2A2924;
  --accent:#3F5F7F;
  --on-accent:#EDE9E2;          /* paper type on the slab */
  --on-accent-ink:#1E1D1B;      /* ink on the slab: the primary button, chip text */
  --sheet-paper:#EDE9E2;        /* chips on the slab are real paper in both schemes */
  --sheet-ink:#1E1D1B;
  --font-ui:"Familjen Grotesk",system-ui,sans-serif;
  --font-spec:"Martian Mono",ui-monospace,monospace;
  --ease:cubic-bezier(.2,.8,.2,1);
}
@media (prefers-color-scheme:dark){
  :root{--paper:#1E1D1B;--ink:#EDE9E2;--panel:#2A2924;--line:#4A473F;--chassis:#111}
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font-ui);font-size:1rem;line-height:1.55;overflow-x:hidden}
a{color:inherit}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
button{font:inherit;color:inherit}
h1,h2,h3,p,dl,dd,ol,ul,figure,pre,fieldset{margin:0}
fieldset{padding:0;border:0;min-width:0}
legend{padding:0}
[hidden]{display:none!important}
code{font-family:var(--font-spec);font-size:.8em}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* label strip */
.strip{max-width:1120px;margin:0 auto;padding:18px 32px 0;display:flex;justify-content:space-between;align-items:baseline;font-family:var(--font-spec);font-size:.75rem;font-weight:500;letter-spacing:.02em;border-bottom:1px solid var(--line)}
.strip-maker{text-decoration:none;padding-bottom:12px}
.strip-maker:hover{text-decoration:underline;text-underline-offset:3px}
.strip-code{padding-bottom:12px}

/* page */
.wrap{max-width:1120px;margin:0 auto;padding:40px 32px 0}
.title{font-size:4.5rem;font-weight:600;line-height:1;letter-spacing:-.01em;margin-bottom:16px}
.lede{font-size:1.125rem;max-width:60ch;margin-bottom:24px}
.lede strong{font-weight:600}
.section-head{font-size:2rem;font-weight:600;line-height:1.1;margin:40px 0 14px}

/* the steel-blue slab: the screen. The one accent shape */
.hero{position:relative;background:var(--accent);color:var(--on-accent);padding:28px 32px 28px;transition:outline-color .15s var(--ease)}
.hero::before,.hero::after,.hero>.ticks::before,.hero>.ticks::after{content:"";position:absolute;width:14px;height:14px;border:0 solid var(--on-accent);pointer-events:none;z-index:2}
.hero::before{top:0;left:0;border-top-width:1px;border-left-width:1px}
.hero::after{top:0;right:0;border-top-width:1px;border-right-width:1px}
.hero>.ticks::before{bottom:0;left:0;border-bottom-width:1px;border-left-width:1px}
.hero>.ticks::after{bottom:0;right:0;border-bottom-width:1px;border-right-width:1px}
.hero.is-over{outline:2px dashed var(--on-accent);outline-offset:-10px}

/* the feed row on the slab */
.feed{display:flex;flex-wrap:wrap;align-items:center;gap:12px 18px;margin-bottom:18px}
.feed-say{font-size:1.5rem;font-weight:500;line-height:1.2;margin:0}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.samples{margin-left:auto}
.btn:has(input:focus-visible){outline:2px solid var(--on-accent);outline-offset:3px}

/* the comparison frame: original under, dithered over, clipped at the divider */
.frame{position:relative;width:min(100%,calc(var(--maxh,720px) * (var(--ar))));aspect-ratio:var(--ar);background:var(--sheet-paper);border:1px solid var(--sheet-paper);overflow:hidden;touch-action:none;user-select:none;-webkit-user-select:none;cursor:ew-resize;
  --pos:50%}
.frame canvas{position:absolute;inset:0;width:100%;height:100%;display:block}
.frame .result{image-rendering:pixelated;image-rendering:crisp-edges;clip-path:inset(0 0 0 var(--pos))}
.frame.is-busy .result{opacity:.6}
.tag{position:absolute;bottom:10px;font-size:.875rem;font-weight:500;line-height:1;padding:6px 8px;background:var(--sheet-paper);color:var(--sheet-ink);border:1px solid var(--sheet-ink);pointer-events:none;z-index:2}
.tag-left{left:10px}
.tag-right{right:10px}
.divider{position:absolute;top:0;bottom:0;left:var(--pos);width:0;z-index:3;pointer-events:none}
.divider::before{content:"";position:absolute;top:0;bottom:0;left:-1px;width:2px;background:var(--sheet-paper)}
.divider::after{content:"";position:absolute;top:0;bottom:0;left:-2px;width:4px;background:var(--sheet-ink);opacity:.25}
.handle{position:absolute;top:50%;left:clamp(17px,var(--pos),calc(100% - 17px));z-index:4;width:32px;height:52px;margin:-26px 0 0 -16px;background:var(--sheet-paper);color:var(--sheet-ink);border:1px solid var(--sheet-ink);display:flex;align-items:center;justify-content:center;pointer-events:auto;cursor:ew-resize}
.handle:focus-visible{outline:2px solid var(--sheet-ink);outline-offset:3px}
.frame.is-drag .handle{background:var(--sheet-ink);color:var(--sheet-paper)}
.frame.is-anim{cursor:default}

/* actions on the slab */
.actions{display:flex;flex-wrap:wrap;align-items:center;gap:10px}
.hero-actions{margin-top:18px}
.btn{position:relative;display:inline-block;padding:12px 18px;border:1px solid var(--ink);background:var(--paper);color:var(--ink);font-weight:500;line-height:1.2;cursor:pointer;border-radius:0;text-decoration:none}
.btn:hover{background:var(--panel)}
.btn:disabled{opacity:.45;cursor:default}
.btn-primary{background:var(--on-accent-ink);border-color:var(--on-accent-ink);color:var(--on-accent)}
.btn-primary:hover{background:var(--on-accent-ink)}
.btn-primary .ticks{position:absolute;inset:0;pointer-events:none}
.btn-primary::before,.btn-primary::after,.btn-primary .ticks::before,.btn-primary .ticks::after{content:"";position:absolute;width:14px;height:14px;border:0 solid var(--on-accent);opacity:0;pointer-events:none}
.btn-primary::before{top:-6px;left:-6px;border-top-width:1px;border-left-width:1px}
.btn-primary::after{top:-6px;right:-6px;border-top-width:1px;border-right-width:1px}
.btn-primary .ticks::before{bottom:-6px;left:-6px;border-bottom-width:1px;border-left-width:1px}
.btn-primary .ticks::after{bottom:-6px;right:-6px;border-bottom-width:1px;border-right-width:1px}
.btn-primary:hover::before,.btn-primary:hover::after,.btn-primary:hover .ticks::before,.btn-primary:hover .ticks::after,
.btn-primary:focus-visible::before,.btn-primary:focus-visible::after,.btn-primary:focus-visible .ticks::before,.btn-primary:focus-visible .ticks::after{opacity:1}
.btn-primary:focus-visible{outline-color:var(--on-accent);outline-offset:4px}
.btn-paper{background:var(--sheet-paper);border-color:var(--sheet-paper);color:var(--on-accent-ink)}
.btn-paper:hover{background:#DEDACF}
.btn-paper:focus-visible{outline-color:var(--on-accent)}
.btn-paper.is-done{background:var(--on-accent-ink);border-color:var(--on-accent-ink);color:var(--on-accent)}
.modes{display:flex;border:1px solid var(--sheet-paper)}
.mode{padding:12px 14px;border:0;border-right:1px solid var(--sheet-paper);background:var(--accent);color:var(--on-accent);font-weight:500;line-height:1.2;cursor:pointer;border-radius:0}
.mode:last-child{border-right:0}
.mode:hover{background:var(--sheet-paper);color:var(--on-accent-ink)}
.mode[aria-pressed="true"]{background:var(--sheet-paper);color:var(--on-accent-ink)}
.mode:focus-visible{outline-offset:-3px;outline-color:var(--on-accent-ink)}
.hint{font-size:1.25rem;font-weight:500;line-height:1.2;margin-left:6px}
.hint:empty{display:none}

/* reading line */
.reading{font-family:var(--font-spec);font-size:.75rem;font-weight:500;letter-spacing:.02em;white-space:pre;margin:12px 0 0;overflow-x:auto}

/* the bench: controls in a paper panel */
.bench{position:relative;margin-top:24px;border:1px solid var(--line);background:var(--panel);padding:24px 28px 28px;display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:24px 32px}
.px-field{grid-column:span 12;display:grid;grid-template-columns:auto minmax(0,1fr);gap:0 28px;align-items:center}
.px-field>label{grid-column:1 / span 2;font-weight:500;margin-bottom:6px}
.px-num{font-size:5rem;font-weight:600;line-height:.9;letter-spacing:-.02em;color:var(--accent);font-variant-numeric:tabular-nums;min-width:2ch}
.px-field.is-off .px-num{color:var(--line)}
.px-num small{display:block;font-size:1rem;font-weight:500;letter-spacing:0;color:var(--ink);margin-top:6px}
input[type=range]{-webkit-appearance:none;appearance:none;width:100%;height:32px;margin:0;background:transparent;cursor:pointer}
input[type=range]:focus{outline:none}
input[type=range]::-webkit-slider-runnable-track{height:2px;background:var(--ink)}
input[type=range]::-moz-range-track{height:2px;background:var(--ink)}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;appearance:none;width:22px;height:32px;margin-top:-15px;background:var(--accent);border:1px solid var(--ink);border-radius:0}
input[type=range]::-moz-range-thumb{width:20px;height:30px;background:var(--accent);border:1px solid var(--ink);border-radius:0}
input[type=range]:focus-visible::-webkit-slider-thumb{outline:2px solid var(--ink);outline-offset:2px}
input[type=range]:focus-visible::-moz-range-thumb{outline:2px solid var(--ink);outline-offset:2px}
.field{grid-column:span 4;min-width:0}
.field-algo{grid-column:span 6}
.field-pal{grid-column:span 3}
.field-tone{grid-column:span 3}
.field>label,.field legend{display:block;font-weight:500;margin-bottom:10px}
.field-note{font-size:.9375rem;margin-top:8px}
.kinds{display:grid;gap:6px}
.kinds-2{grid-template-columns:1fr 1fr}
.kind{position:relative;display:grid;grid-template-columns:auto 1fr;grid-template-rows:auto auto;column-gap:10px;align-items:center;padding:8px 10px;border:1px solid var(--line);background:var(--paper);cursor:pointer;line-height:1.25;min-width:0}
.kind input{grid-row:1 / span 2;width:18px;height:18px;margin:0;accent-color:var(--accent);cursor:pointer}
.kind span{font-weight:500}
.kind small{font-size:.8125rem;opacity:.75}
.kind:has(input:checked){border-color:var(--ink);background:var(--ink);color:var(--paper)}
.kind:has(input:focus-visible){outline:2px solid var(--accent);outline-offset:2px}
.kind-pal{grid-template-columns:auto 1fr auto}
.kind-pal input{grid-row:1 / span 2}
.sw{grid-column:3;grid-row:1 / span 2;width:28px;height:28px;display:grid;grid-template-columns:1fr 1fr;grid-template-rows:1fr 1fr;border:1px solid var(--line)}
.sw b{display:block}
.sw b:nth-child(1){background:var(--c1)}
.sw b:nth-child(2){background:var(--c2)}
.sw b:nth-child(3){background:var(--c3)}
.sw b:nth-child(4){background:var(--c4)}
.custom-row{display:flex;gap:10px;margin-top:8px}
.colour{display:flex;align-items:center;gap:8px;font-size:.9375rem;cursor:pointer}
.colour input{width:36px;height:28px;padding:0;border:1px solid var(--line);background:var(--paper);border-radius:0;cursor:pointer}
.colour input::-webkit-color-swatch-wrapper{padding:2px}
.colour input::-webkit-color-swatch{border:0;border-radius:0}
.colour input::-moz-color-swatch{border:0;border-radius:0}
.checks{display:flex;flex-direction:column;gap:8px}
.check{display:flex;align-items:center;gap:10px;margin:0;font-weight:400;cursor:pointer;line-height:1.3}
.check input{width:18px;height:18px;margin:0;flex:0 0 auto;accent-color:var(--accent);cursor:pointer}
.check input:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.check.is-off{opacity:.5}
.sub{margin-top:12px}
.slider-row{display:grid;grid-template-columns:minmax(0,1fr) 7ch;align-items:center;gap:12px;margin-bottom:6px}
.slider-row>label{font-weight:400}
.slider-row .val{font-family:var(--font-spec);font-size:.75rem;font-weight:500;text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
.slider-row input[type=range]{grid-column:1 / span 2;height:24px}
.slider-row input[type=range]::-webkit-slider-thumb{width:16px;height:22px;margin-top:-10px}
.slider-row input[type=range]::-moz-range-thumb{width:14px;height:20px}
.link-btn{background:none;border:0;padding:0;font:inherit;font-size:.9375rem;text-decoration:underline;text-underline-offset:3px;cursor:pointer;color:inherit}

/* notes */
.notes{display:grid;grid-template-columns:repeat(12,minmax(0,1fr))}
.notes>*{grid-column:span 8}
.notes p{max-width:68ch;margin-bottom:14px}

.foot{max-width:1120px;margin:0 auto;padding:20px 32px 40px;font-size:.875rem;opacity:.8}
.foot p{max-width:70ch}

/* narrow screens */
@media (max-width:960px){
  .notes>*{grid-column:span 12}
  .field-algo{grid-column:span 12}
  .field-pal,.field-tone{grid-column:span 6}
}
@media (max-width:640px){
  .strip{padding:14px 16px 0}
  .wrap{padding:28px 16px 0}
  .title{font-size:2.75rem}
  .lede{font-size:1rem}
  .hero{padding:18px 14px 18px}
  .feed{gap:10px 12px;margin-bottom:14px}
  .samples{margin-left:0}
  .feed-say{font-size:1.5rem}
  .frame{--maxh:70vh}
  .hint{display:none}
  .bench{padding:20px 16px 22px;gap:20px}
  .px-field{grid-template-columns:1fr;gap:10px}
  .px-num{font-size:4rem}
  .field,.field-algo,.field-pal,.field-tone{grid-column:span 12}
  .kinds-2{grid-template-columns:1fr}
  .section-head{font-size:1.625rem}
  .foot{padding:16px 16px 32px}
}

@media (prefers-reduced-motion:reduce){
  *{transition:none!important;animation:none!important}
}