:root {
  --bg: #0e1116;
  --fg: #e0e3e8;
  --muted: #8a93a4;
  --accent: #4ea1ff;
  --panel: #161b22;
  --border: #30363d;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--fg);
}
header {
  padding: 1rem 1.5rem 0.5rem;
  border-bottom: 1px solid var(--border);
}
header h1 { margin: 0; font-size: 1.4rem; }
header .tag {
  background: var(--accent);
  color: var(--bg);
  font-size: 0.7em;
  padding: 0.15em 0.5em;
  border-radius: 0.3em;
  margin-left: 0.4em;
}
header .sub { color: var(--muted); margin: 0.4rem 0; font-size: 0.85rem; }
header a { color: var(--accent); }
main { padding: 1rem 1.5rem; }
section { margin-bottom: 1rem; }
.controls, .run-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  padding: 0.5rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0.4em;
}
button, select, input[type="text"], input[type="file"] {
  background: #1f2630;
  color: var(--fg);
  border: 1px solid var(--border);
  padding: 0.3rem 0.6rem;
  border-radius: 0.3em;
  font: inherit;
}
button {
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--accent); }
button:disabled { opacity: 0.5; cursor: not-allowed; }
.status {
  margin-left: auto;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
.panes {
  display: grid;
  grid-template-columns: 1fr 1.5fr 1.5fr;
  grid-template-rows: auto auto auto;
  gap: 0.75rem;
}
@media (max-width: 800px) {
  .panes {
    grid-template-columns: 1fr;
  }
}
.boot-error {
  margin: 0.75rem 0;
  padding: 0.75rem 1rem;
  background: #4a1a1a;
  border: 1px solid #c0392b;
  border-radius: 0.4em;
  color: #ffd0d0;
  font: 0.85rem ui-monospace, SFMono-Regular, Menlo, monospace;
  white-space: pre-wrap;
}
.pane {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0.4em;
  padding: 0.6rem 0.8rem;
}
.pane h2 {
  margin: 0 0 0.4rem;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.05em;
}
.pane pre {
  margin: 0;
  font: 0.85rem ui-monospace, SFMono-Regular, Menlo, monospace;
  white-space: pre;
  overflow: auto;
  max-height: 320px;
}
.regs table { border-collapse: collapse; font: 0.85rem ui-monospace, SFMono-Regular, Menlo, monospace; }
.regs th, .regs td { padding: 0.2em 0.6em; text-align: left; vertical-align: top; }
.regs th { color: var(--muted); font-weight: normal; }
/* P-register stack: 3 monospace rows (hex / legend / bits) so the
   letter columns line up under their bit positions. */
.reg-p-stack { margin: 0; font: inherit; white-space: pre; line-height: 1.2; }
#key-capture {
  background: #1f2630;
  border: 1px dashed var(--border);
  padding: 1rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
  outline: none;
  cursor: text;
}
#key-capture:focus { border-color: var(--accent); color: var(--fg); }
footer {
  padding: 0.75rem 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.8rem;
}