:root {
  --font-sans: ui-sans-serif, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --ink: #2b2f36;
  --muted: #6a717c;
  --paper: #fafafa;      /* diagram-viewer.js background */
  --panel: #ffffff;
  --line: #dde1e6;
  --accent: #2f6fb3;
  --ok: #1e7a46;
  --bad: #c0392b;
  --event: #227744;      /* RenderDOT event-link green */
  --side-w: 380px;
  --focus: #0b57d0;      /* the focus ring: 3px, with a white halo, on any background */
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body { font: 13px/1.45 var(--font-sans); color: var(--ink); background: #eef0f3; }
code, pre { font-family: var(--font-mono); font-size: 11.5px; }
a { color: var(--accent); }
.muted { color: var(--muted); }
.small { font-size: 11.5px; }
.ok { color: var(--ok); }
.warn { color: var(--bad); }

/* header */
.top { display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: center; padding: 8px 14px; background: var(--panel); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 5; }
.brand { display: flex; flex-direction: column; min-width: 260px; }
.brand b { font-size: 15px; }
.brand h1 { margin: 0; font-size: inherit; font-weight: inherit; }
.brand .muted { font-size: 11px; }
.examples { display: flex; }
.seg { border: 1px solid var(--line); background: #f6f7f9; padding: 6px 10px; cursor: pointer; font: inherit; }
.seg:first-child { border-radius: 6px 0 0 6px; }
.seg:last-child { border-radius: 0 6px 6px 0; border-left: 0; }
.seg.active { background: var(--ink); color: #fff; border-color: var(--ink); }
.tabs { display: flex; flex-wrap: wrap; gap: 4px; max-height: 30vh; overflow-y: auto; padding: 2px; margin: -2px; } /* many views scroll here, not over the diagram */
.tab { border: 1px solid var(--line); background: #fff; border-radius: 6px; padding: 5px 9px; cursor: pointer; font: inherit; }
.tab.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.tab.broken { text-decoration: line-through; color: var(--bad); }

/* layout */
.layout { display: grid; grid-template-columns: minmax(0, 1fr) var(--side-w); gap: 10px; padding: 10px; height: calc(100vh - 64px); }
.stage-wrap { display: flex; flex-direction: column; min-width: 0; min-height: 0; position: relative; }
.view-bar { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; padding: 4px 8px; margin-bottom: 6px; background: var(--panel); border: 1px solid var(--line); border-radius: 8px; }
.view-link { flex: 1 1 14em; min-width: 0; font: 12px ui-monospace, monospace; color: var(--muted); padding: 2px 6px; border: 1px solid var(--line); border-radius: 4px; background: #fff; }
.view-bar .warn { flex-basis: 100%; margin: 0; }
.stored { display: block; max-width: 100%; }
iframe.stored { width: 100%; height: 70vh; border: 1px solid var(--line); }
.stored-text { white-space: pre-wrap; overflow-wrap: anywhere; }
.view-index table { border-collapse: collapse; width: 100%; font-size: 12px; }
.view-index th, .view-index td { text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); padding: 6px 8px; }
.view-index tbody th { font-weight: 600; min-width: 14em; }
.view-index tbody th p { margin: 2px 0 0; font-weight: 400; }
.view-index .num kbd { display: block; margin-top: 2px; }
.view-index .links div { white-space: nowrap; margin-bottom: 3px; }
.view-index ul { margin: 2px 0; padding-left: 16px; }
.view-index .reads ul { list-style: none; padding: 0; }
.view-index tr.broken th { color: var(--bad); }
.toolbar[hidden] { display: none; }
.toolbar { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; padding: 6px 8px; background: var(--panel); border: 1px solid var(--line); border-radius: 8px 8px 0 0; }
.tb-label { color: var(--muted); }
.tb-sep { width: 1px; height: 18px; background: var(--line); margin: 0 4px; }
.chip, .btn { font: inherit; border: 1px solid var(--line); background: #fff; border-radius: 999px; padding: 3px 9px; cursor: pointer; }
.btn { border-radius: 6px; }
.chip.active { background: var(--chip, var(--ink)); color: #fff; border-color: var(--chip, var(--ink)); }
.stage { flex: 1; overflow: auto; background: var(--paper); border: 1px solid var(--line); border-top: 0; border-radius: 0 0 8px 8px; padding: 10px; }
.view-svg { display: block; max-width: 100%; height: auto; user-select: none; }
.stage-note { margin: 0 0 8px; padding: 6px 10px; border-radius: 6px; font-size: 12px; border-left: 4px solid; }
.stage-note.honesty { background: #f3f6fb; border-color: var(--accent); }
.stage-note.na { background: #fbf4e6; border-color: #c47a12; }
.stage-note.warn { background: #fbecea; border-color: var(--bad); }
/* fixed to the viewport, not the stage: the stage can be taller than the screen, and the reason a target is refused is read here (the keyboard path never shows the pointer's tip) */
.snap-status { position: fixed; bottom: 10px; left: 14px; max-width: min(760px, calc(100vw - 28px)); z-index: 30; font-size: 11.5px; color: var(--ink); pointer-events: none; }
.snap-status:not(:empty) { background: rgba(255, 255, 255, 0.94); border: 1px solid var(--line); border-radius: 6px; padding: 3px 8px; }

/* palette (connect-4) */
.palette { display: flex; flex-wrap: wrap; gap: 4px 12px; width: 100%; }
.pal-group { display: flex; flex-wrap: wrap; gap: 4px; align-items: center; }
.pal-label { color: var(--muted); font-size: 11px; }
.pal-piece { border: 1.5px solid var(--kc); color: var(--kc); background: #fff; border-radius: 4px; padding: 2px 7px; cursor: grab; font-family: var(--font-mono); font-size: 11.5px; }
.pal-piece.reserved { border-style: dashed; }
.pal-piece.proposed { border-style: dotted; opacity: 0.75; }
.pal-piece sup { font-size: 8px; margin-left: 2px; }

/* side */
.side { overflow: auto; display: flex; flex-direction: column; gap: 8px; min-height: 0; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; }
.card h3 { margin: 0 0 6px; font-size: 13px; }
.card p { margin: 4px 0; }
.honesty { margin: 4px 0; padding-left: 18px; font-size: 12px; }
.honesty li { margin: 2px 0; }
.bib, .insp-cites, .insp-bib { margin: 4px 0; padding-left: 16px; font-size: 11px; }
.content-entry { margin: 2px 0; font-size: 12px; }
.content-entry summary { cursor: pointer; }
.content-entry p { margin: 4px 0; }
.content-kind { font-size: 10px; text-transform: uppercase; letter-spacing: .03em; padding: 0 4px; border-radius: 3px; background: #eceef1; }
.content-judgment .content-kind { background: #fdf0d8; }
.content-caveat .content-kind { background: #fbe9e7; }
.content-finding .content-kind { background: #e7f3ec; }
.content-kind-h { margin: 8px 0 2px; font-size: 12px; }
.content-pass { color: #1e7a3c; font-weight: 600; }
.content-fail { color: #b3261e; font-weight: 600; }
.conv-ex { font-size: 12px; background: #f6f7f9; padding: 4px 6px; border-radius: 4px; }
.rule-row { border-left: 4px solid var(--rc); padding: 3px 6px; margin: 3px 0; font-size: 11.5px; border-radius: 3px; }
.rule-row b { color: var(--rc); }
.rule-glyph { color: var(--rc); font-weight: bold; margin-right: 4px; }
.rule-row.flash { animation: rule-flash 1.6s ease-out 2; }
@keyframes rule-flash { 0% { background: color-mix(in srgb, var(--rc) 35%, white); } 100% { background: transparent; } }
.links { list-style: none; padding: 0; margin: 0; }
.links li { position: relative; padding: 3px 18px 3px 4px; border-bottom: 1px dashed var(--line); font-family: var(--font-mono); font-size: 11px; }
.links li.leak { background: #fdf0ee; }
.links .idiom { color: var(--muted); }
.links .leak-note { color: var(--bad); font-family: var(--font-sans); }
.links .x { position: absolute; right: 0; top: 2px; border: 0; background: none; cursor: pointer; color: var(--bad); font-size: 14px; }
.plan-json { background: #f6f7f9; padding: 6px; border-radius: 4px; white-space: pre-wrap; margin: 0; }

/* inspector */
.insp-title { font-weight: 600; }
.insp-concept code { background: #f0f2f5; padding: 1px 4px; border-radius: 3px; }
.insp-types { color: var(--muted); font-size: 11.5px; }
.insp-unserved { color: var(--muted); font-size: 10.5px; }
.insp-def { font-style: italic; }
.insp-facts { display: grid; grid-template-columns: max-content 1fr; gap: 1px 8px; margin: 4px 0; font-size: 11.5px; }
.insp-facts dt { color: var(--muted); }
.insp-facts dd { margin: 0; }
.insp-note { background: #fbf4e6; padding: 3px 6px; border-radius: 4px; font-size: 11.5px; }
.insp-caveats { font-size: 11.5px; }
.insp-cite-note { color: var(--muted); }
.insp.pinned { outline: 2px solid var(--accent); outline-offset: 4px; border-radius: 4px; }
.hover-tip { position: fixed; z-index: 30; pointer-events: none; background: rgba(30, 33, 38, 0.92); color: #fff; padding: 4px 8px; border-radius: 4px; font-size: 11.5px; opacity: 0; transition: opacity 0.1s; max-width: 320px; overflow-wrap: anywhere; }
.snap-tip { overflow-wrap: anywhere; }
.hover-tip.show { opacity: 1; }
.hover-tip code { color: #cfe3ff; }
.inspectable { cursor: help; }

/* flash banner: the rule that allowed it */
.flash-banner { position: absolute; top: 48px; left: 50%; transform: translate(-50%, -8px); z-index: 10; background: #fff; border: 2px solid var(--fc, var(--event)); border-radius: 8px; padding: 6px 12px; box-shadow: 0 6px 20px rgba(0,0,0,0.15); max-width: 92%; font-size: 12px; opacity: 0; pointer-events: none; transition: opacity 0.25s, transform 0.25s; }
.flash-banner.show { opacity: 1; transform: translate(-50%, 0); }
.flash-banner .idiom { color: var(--muted); }

/* snap-together */
.snap-overlay { position: fixed; inset: 0; width: 100vw; height: 100vh; pointer-events: none; z-index: 20; overflow: visible; }
.snap-band { fill: none; stroke-width: 2.5; }
.snap-band-end { stroke-width: 2; }
.snap-port { cursor: crosshair; }
.snap-dragging .snap-port, .snap-dragging .snap-slot { transition: opacity 0.15s; }
.snap-dragging .snap-illegal { opacity: 0.15; }
.snap-legal { filter: drop-shadow(0 0 3px var(--snap-color)) drop-shadow(0 0 6px var(--snap-color)); animation: snap-pulse 0.8s ease-in-out infinite alternate; }
.snap-source { filter: drop-shadow(0 0 5px #000); }
@keyframes snap-pulse { from { filter: drop-shadow(0 0 2px var(--snap-color)) drop-shadow(0 0 4px var(--snap-color)); } to { filter: drop-shadow(0 0 5px var(--snap-color)) drop-shadow(0 0 12px var(--snap-color)); } }
.snap-tip { position: fixed; z-index: 31; pointer-events: none; background: #fff; border: 1.5px solid var(--line); border-radius: 6px; padding: 4px 8px; font-size: 11.5px; max-width: 380px; opacity: 0; }
.snap-tip.show { opacity: 1; }
.snap-tip.ok { border-color: var(--ok); }
.snap-tip.bad { border-color: var(--bad); color: var(--bad); }
.snap-piece { touch-action: none; }
.snap-port { touch-action: none; }

/* shared view classes (views may add their own in a <style> they inject) */
.just-added { animation: just-added 1.2s ease-out; }
@keyframes just-added { from { opacity: 0.2; } to { opacity: 1; } }

@media (max-width: 1000px) {
  .layout { grid-template-columns: 1fr; height: auto; }
  .stage { min-height: 60vh; }
}

/* accessibility (a11y.js, ACCESSIBILITY.md) */
.sr-only { position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap; border: 0; }
.skip { position: absolute; left: 8px; top: -48px; z-index: 60; background: var(--ink); color: #fff; padding: 8px 12px; border-radius: 6px; text-decoration: none; }
.skip:focus { top: 8px; }
.tabs-nav { display: block; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
/* SVG things get the page's own ring (a11y.js draws it: every browser, any shape, a white halo for contrast). */
svg *:focus, svg *:focus-visible { outline: none; }
.a11y-ring { position: fixed; z-index: 40; display: none; pointer-events: none; border: 3px solid var(--focus); border-radius: 7px; box-shadow: 0 0 0 2px #fff, inset 0 0 0 1px #fff; }
.a11y-ring.show { display: block; }
.a11y-badge { font-family: var(--font-sans); font-weight: 700; user-select: none; }
kbd { font-family: var(--font-mono); font-size: 10.5px; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 3px; padding: 0 4px; background: #fff; }
.keys-list { margin: 4px 0; padding-left: 16px; font-size: 11.5px; }
.keys-list li { margin: 3px 0; }
.card h4 { margin: 8px 0 2px; font-size: 12px; }
.lg-list { list-style: none; padding: 0; margin: 2px 0 6px; font-size: 11.5px; }
.lg-list li { display: flex; align-items: center; gap: 6px; margin: 3px 0; }
.lg-sample { flex: none; }
.lg-glyph { width: 1.2em; text-align: center; font-weight: 700; }
.lg-schemas { display: flex; flex-wrap: wrap; gap: 2px 14px; }
.lg-state { flex: none; width: 16px; height: 16px; border-radius: 50%; background: var(--accent); }
.lg-lit { box-shadow: 0 0 4px 2px var(--accent); }
.lg-dim { opacity: 0.2; }
.lg-ring { background: #fff; border: 3px solid var(--focus); box-shadow: 0 0 0 2px #fff; }
/* at least 24 x 24 px (WCAG 2.2 target size, 2.5.8), also on a narrow screen where the pinned inspector is a sheet */
.insp-close { float: right; margin: 0 0 4px 8px; font: inherit; font-size: 11.5px; border: 1px solid var(--line); background: #fff; border-radius: 6px; padding: 4px 10px; min-width: 28px; min-height: 28px; cursor: pointer; }
/* On a narrow screen the inspector is below the stage, out of sight from a tap: a pinned one is a sheet. */
@media (max-width: 1000px) {
  #inspector.has-pin { position: fixed; left: 8px; right: 8px; bottom: 8px; max-height: 45vh; overflow: auto; z-index: 25; border: 2px solid var(--accent); box-shadow: 0 -4px 24px rgba(0, 0, 0, 0.25); }
}
@media (forced-colors: active) {
  .a11y-ring { border-color: Highlight; box-shadow: none; }
  .lg-state { forced-color-adjust: none; }
}
/* prefers-reduced-motion: no animation or transition anywhere (the Web Animations the views run are
   zeroed by motion.js; a view that times its own frames asks reducedMotion()). */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-delay: 0s !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; transition-delay: 0s !important; scroll-behavior: auto !important; }
}

/* /compose.html?cid=: the model panel (identity.js) */
#model .model-flat { display: block; max-width: 100%; max-height: 220px; margin: 8px 0; background: #fff; border: 1px solid var(--line, #d0d7de); border-radius: 4px; }
#model code { font-size: 11px; }