:root {
  color-scheme: dark;
  --bg: #0C0D0E;
  --surface: #141618;
  --surface-alt: #191B1E;
  --surface-raised: #212427;
  --border: #2C2F33;
  --border-strong: #3A3E44;
  --text: #E8E9EA;
  --text-muted: #969A9F;
  --text-faint: #5E636A;
  --accent: #F5A524;
  --accent-text: #0C0D0E;
  --accent-dim: rgba(245, 165, 36, 0.22);
  --success: #3DBE78;
  --error: #E5564B;
  --grid-minor: #16181B;
  --grid-major: #202327;
  --hazard: repeating-linear-gradient(135deg, var(--accent-text) 0 4px, var(--accent) 4px 8px);
  --font-ui: ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', 'Cascadia Code', Consolas, Menlo, monospace;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body { margin: 0; font-family: var(--font-ui); background: var(--bg); color: var(--text); font-size: 13px; }

#app { display: grid; grid-template-columns: 340px 1fr; height: 100vh; }
#panel {
  position: relative;
  padding: 20px; border-right: 1px solid var(--grid-major); overflow-y: auto;
  display: flex; flex-direction: column; gap: 12px;
  counter-reset: sec;
  background-color: var(--bg);
}
/* animated copper-trace backdrop (traces-bg.js) sits behind the panel content;
   it fades out toward the right edge so the panel/viewer seam stays soft */
.trace-bg {
  position: absolute; top: 0; left: 0; z-index: 0; display: block; pointer-events: none;
  -webkit-mask-image: linear-gradient(to right, #000 0, #000 calc(100% - 44px), transparent 100%);
  mask-image: linear-gradient(to right, #000 0, #000 calc(100% - 44px), transparent 100%);
}
#panel > .brand, #panel > .card, #panel > .panel-foot { position: relative; z-index: 1; }

/* footer — repo link + author credit, pinned to the bottom of the panel */
.panel-foot { margin-top: auto; padding-top: 12px; display: flex; flex-direction: column; gap: 8px; }
.foot-repo {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 34px; border: 1px solid var(--border-strong); border-radius: 2px; background: var(--surface-alt);
  color: var(--text-muted); text-decoration: none;
  font-family: var(--font-mono); font-size: 11px; font-weight: 600; letter-spacing: 0.10em; text-transform: uppercase;
  transition: color 120ms ease, border-color 120ms ease, background 120ms ease;
}
.foot-repo:hover { color: var(--text); border-color: var(--text-faint); background: var(--surface-raised); }
.foot-repo svg { flex: none; }
.foot-by {
  text-align: center; text-decoration: none;
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-faint);
  transition: color 120ms ease;
}
.foot-by:hover { color: var(--text-muted); }
.foot-name { color: var(--accent); }
#viewer { position: relative; overflow: hidden; }

/* wordmark — stamped domain badge */
.brand h1 {
  font-family: var(--font-mono); font-size: 14px; font-weight: 600; letter-spacing: 0.16em;
  text-transform: uppercase; margin: 0; color: var(--text); display: inline-block;
  padding: 5px 9px; border: 1px solid var(--border-strong); border-radius: 2px; background: var(--surface-raised);
}
.brand h1::after { content: ".online"; color: var(--accent); }
.brand p { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.10em; text-transform: uppercase; color: var(--text-muted); margin: 8px 0 0; }
.brand::after { content: ""; display: block; width: 56px; height: 5px; margin-top: 10px; background: var(--hazard); }

/* eyebrows — indexed, over an engraved ruler */
.eyebrow {
  font-family: var(--font-mono); font-size: 11px; font-weight: 600; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--text-muted); margin: 0; padding-bottom: 6px; position: relative;
}
.card > .eyebrow::before { content: counter(sec, decimal-leading-zero) " / "; color: var(--text-faint); }
.eyebrow::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 4px;
  background: repeating-linear-gradient(90deg, var(--border) 0 1px, transparent 1px 8px);
}
.group-eyebrow {
  font-family: var(--font-mono); font-size: 10px; font-weight: 600; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--text-muted); margin: 12px 0 6px;
  display: flex; align-items: center; gap: 6px;
}
.group-eyebrow::before { content: ""; width: 5px; height: 5px; background: var(--accent); flex: none; }

/* cards — CAD sheet with amber corner brackets */
.card {
  position: relative; counter-increment: sec; background: var(--surface-alt); border: 1px solid var(--border);
  border-radius: 2px; padding: 14px; display: flex; flex-direction: column; gap: 12px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.02);
}
.card::before {
  content: ""; position: absolute; inset: -1px; pointer-events: none;
  background:
    linear-gradient(var(--accent), var(--accent)) top left / 9px 1px no-repeat,
    linear-gradient(var(--accent), var(--accent)) top left / 1px 9px no-repeat,
    linear-gradient(var(--accent), var(--accent)) bottom right / 9px 1px no-repeat,
    linear-gradient(var(--accent), var(--accent)) bottom right / 1px 9px no-repeat;
}
.card::after {
  content: ""; position: absolute; inset: -1px; pointer-events: none;
  background:
    linear-gradient(var(--accent), var(--accent)) top right / 9px 1px no-repeat,
    linear-gradient(var(--accent), var(--accent)) top right / 1px 9px no-repeat,
    linear-gradient(var(--accent), var(--accent)) bottom left / 9px 1px no-repeat,
    linear-gradient(var(--accent), var(--accent)) bottom left / 1px 9px no-repeat;
}

/* segmented — detented machine switch */
.seg { display: flex; background: var(--surface); border: 1px solid var(--border-strong); border-radius: 2px; }
.seg-btn {
  flex: 1; border: 0; border-right: 1px solid var(--border); border-radius: 0; background: transparent;
  color: var(--text-muted); font-family: var(--font-mono); font-size: 11px; font-weight: 600;
  letter-spacing: 0.10em; text-transform: uppercase; padding: 8px 6px; cursor: pointer; line-height: 1.25;
  transition: background 120ms ease, color 120ms ease;
}
.seg-btn:last-child { border-right: 0; }
.seg-btn small { display: block; font-size: 8px; letter-spacing: 0.06em; color: var(--text-faint); font-weight: 400; margin-top: 2px; text-transform: uppercase; }
.seg-btn[aria-selected="true"] { background: var(--surface-raised); color: var(--text); box-shadow: inset 0 -2px 0 var(--accent); }
.seg-btn[aria-selected="true"] small { color: var(--text-muted); }
.seg-btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* fields / inputs — DRO wells */
.field { display: flex; flex-direction: column; gap: 6px; }
label { font-family: var(--font-mono); font-size: 10px; font-weight: 600; letter-spacing: 0.10em; text-transform: uppercase; color: var(--text-muted); }
input[type=number], input[type=file], select {
  width: 100%; height: 34px; padding: 0 10px; background: var(--surface); border: 1px solid var(--border);
  border-radius: 2px; color: var(--text); font-family: var(--font-mono); font-size: 13px; font-variant-numeric: tabular-nums;
}
input[type=file] { padding: 7px 10px; height: auto; }
input:focus, select:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-dim); }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; }

/* dropzone — squared fiducial well */
.dropzone {
  display: block; border: 1px dashed var(--border-strong); border-radius: 2px; padding: 18px 12px;
  text-align: center; background: var(--surface); cursor: pointer; color: var(--text-muted);
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.06em; text-transform: uppercase;
  transition: background 120ms ease, border-color 120ms ease, color 120ms ease;
}
.dropzone:hover, .dropzone.drag { background: var(--surface-raised); border-color: var(--accent); color: var(--text); }
.dropzone input { display: none; }
.dropzone .name { color: var(--success); font-family: var(--font-mono); text-transform: none; letter-spacing: 0; margin-top: 4px; word-break: break-all; }
.dropzone.bottom { border-left: 2px solid var(--accent); margin-top: 4px; }

/* switch rows */
.switch { display: flex; align-items: center; gap: 8px; }
.switch input { accent-color: var(--accent); width: 14px; height: 14px; }
.switch label { font-family: var(--font-ui); font-size: 12px; letter-spacing: 0; text-transform: none; color: var(--text); margin: 0; }

/* buttons */
.btn {
  width: 100%; height: 40px; border: 1px solid transparent; border-radius: 2px; font-family: var(--font-mono);
  font-size: 12px; font-weight: 600; letter-spacing: 0.10em; text-transform: uppercase; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
}
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: var(--accent-text); }
.btn-primary:hover:not(:disabled) { filter: brightness(1.06); }
.btn-primary:active:not(:disabled) { filter: brightness(0.96); }
.btn-secondary { background: transparent; color: var(--text); border-color: var(--border-strong); }
.btn-secondary:hover:not(:disabled) { background: var(--surface-raised); border-color: var(--text-faint); }
.btn-tertiary { background: transparent; color: var(--text-muted); border: 0; height: 32px; font-size: 11px; text-decoration: underline dotted var(--text-faint); text-underline-offset: 3px; }
.btn-tertiary:hover:not(:disabled) { color: var(--text); }

/* status — square panel LED */
.status { display: flex; align-items: center; gap: 8px; font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted); min-height: 18px; }
.status .dot { width: 6px; height: 6px; border-radius: 0; background: var(--text-faint); flex: none; }
.status.ok { color: var(--text); }
.status.ok .dot { background: var(--success); box-shadow: 0 0 7px var(--success); }
.status.err { color: var(--error); }
.status.err .dot { background: var(--error); box-shadow: 0 0 7px var(--error); }
.status.warn { color: var(--accent); text-transform: none; letter-spacing: 0; align-items: flex-start; line-height: 1.4; }
.status.warn .dot { background: var(--accent); box-shadow: 0 0 7px var(--accent); margin-top: 4px; }
.dims { font-family: var(--font-mono); font-size: 16px; font-weight: 600; color: var(--text); font-variant-numeric: tabular-nums; letter-spacing: 0.02em; }

.hidden { display: none !important; }

/* viewer overlays */
.viewer-tabs { position: absolute; top: 14px; left: 14px; }
.fit-btn {
  position: absolute; top: 14px; right: 14px; height: 32px; padding: 0 12px; border-radius: 999px;
  background: var(--surface-alt); border: 1px solid var(--border-strong); color: var(--text-muted);
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; cursor: pointer;
}
.fit-btn:hover { color: var(--text); border-color: var(--text-faint); }
.legend {
  position: absolute; bottom: 14px; left: 14px; background: var(--surface-alt); border: 1px solid var(--border-strong);
  border-radius: 2px; padding: 10px 12px; font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--text-muted); display: flex; flex-direction: column; gap: 6px;
}
.legend-row { display: flex; gap: 12px; align-items: center; }
.legend-item { display: flex; align-items: center; gap: 5px; }
.swatch { width: 14px; height: 0; border-top: 2px solid var(--c); }
.swatch.dash { border-top-style: dashed; }
.origin-label { position: absolute; transform: translate(-50%, -130%); font-family: var(--font-mono); font-size: 11px; color: var(--text); pointer-events: none; white-space: nowrap; text-shadow: 0 1px 3px var(--bg); }

/* busy LED (auto-preview) */
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.25; } }
.status.busy .dot { background: var(--accent); box-shadow: 0 0 7px var(--accent); animation: pulse 1s ease-in-out infinite; }
#viewer.dim { opacity: 0.6; transition: opacity 0.15s ease; }

/* collapsed advanced disclosure */
#gcodeAdvanced { margin-top: 10px; border-top: 1px solid var(--border); padding-top: 8px; }
#gcodeAdvanced summary {
  font-family: var(--font-mono); font-size: 10px; font-weight: 600; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--text-muted); cursor: pointer; list-style: none; padding: 2px 0;
}
#gcodeAdvanced summary::-webkit-details-marker { display: none; }
#gcodeAdvanced summary::before { content: "▸ "; color: var(--text-faint); }
#gcodeAdvanced[open] summary::before { content: "▾ "; }