:root {
  --bg: #fbfbfa;
  --fg: #16181f;
  --muted: #7a7f8e;
  --line: #e4e5ea;
  --field: #ffffff;
  --accent: #16181f;
  --sat: #178a4c;
  --unsat: #c7364f;
  --warn: #b8791e;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 12px 32px -16px rgba(0, 0, 0, 0.18);
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #101216;
    --fg: #e9eaef;
    --muted: #8a8f9e;
    --line: #272b35;
    --field: #171a21;
    --accent: #e9eaef;
    --sat: #3fc37d;
    --unsat: #f06a80;
    --warn: #e0a24c;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.5), 0 12px 32px -16px rgba(0, 0, 0, 0.8);
  }
}
:root[data-theme="dark"] {
  --bg: #101216; --fg: #e9eaef; --muted: #8a8f9e; --line: #272b35; --field: #171a21; --accent: #e9eaef;
  --sat: #3fc37d; --unsat: #f06a80; --warn: #e0a24c;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.55 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Inter, Roboto, sans-serif;
  display: flex;
  flex-direction: column;
}
code, textarea, .mono { font-family: ui-monospace, "JetBrains Mono", "SF Mono", Menlo, Consolas, monospace; }
a { color: inherit; text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--muted); }
a:hover { text-decoration-color: currentColor; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }

.page {
  width: 100%;
  max-width: 680px;
  margin: 0 auto;
  padding: clamp(3rem, 14vh, 9rem) 16px 2rem;
  flex: 1;
}
.title-row { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.gh {
  display: inline-flex;
  color: var(--muted);
  padding: 0.35rem;
  border-radius: 8px;
  transition: color 0.15s;
}
.gh:hover { color: var(--fg); }
.head h1 {
  margin: 0;
  font-size: 2rem;
  font-weight: 650;
  letter-spacing: -0.03em;
}
.sub { margin: 0.25rem 0 1.75rem; color: var(--muted); }

/* ── Entry ── */
textarea {
  display: block;
  width: 100%;
  resize: none;
  overflow: hidden;
  padding: 1rem 1.1rem;
  font-size: 1.35rem;
  line-height: 1.4;
  color: var(--fg);
  background: var(--field);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
  transition: border-color 0.15s;
}
textarea::placeholder { color: var(--muted); opacity: 0.6; }
textarea:focus { outline: none; border-color: var(--accent); }

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem;
  margin-top: 0.6rem;
  font-size: 0.85rem;
  color: var(--muted);
}
.toolbar button {
  font: inherit;
  cursor: pointer;
  color: var(--fg);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 0.15rem 0.55rem;
  min-width: 2rem;
  font-size: 1rem;
  line-height: 1.5;
}
.toolbar button:hover { border-color: var(--line); background: var(--field); }
.toolbar .spacer { flex: 1; }
.examples { display: flex; flex-wrap: wrap; align-items: center; gap: 0.2rem; }
.toolbar .ex { font-size: 0.85rem; color: var(--muted); font-family: ui-monospace, Menlo, Consolas, monospace; }
.toolbar .ex:hover { color: var(--fg); }

/* ── Output ── */
.out { margin-top: 2rem; min-height: 6rem; transition: opacity 0.15s; }
.out.stale { opacity: 0.35; }
.verdict {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.dot {
  flex: none;
  width: 0.7rem; height: 0.7rem;
  border-radius: 50%;
  background: var(--muted);
  transform: translateY(-0.05rem);
}
.sat .dot { background: var(--sat); }
.unsat .dot { background: var(--unsat); }
.error .dot { background: var(--warn); }
.pending .dot { animation: pulse 1s infinite ease-in-out; }
@keyframes pulse { 50% { opacity: 0.3; } }
.detail { margin: 0.35rem 0 0 1.3rem; color: var(--muted); }
.detail .mono { color: var(--fg); }
.assign {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.9rem 0 0 1.3rem;
}
.assign span {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.95rem;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--field);
}
.assign .t { border-color: color-mix(in srgb, var(--sat) 50%, transparent); }
.assign .f { border-color: color-mix(in srgb, var(--unsat) 50%, transparent); color: var(--muted); }
.meta {
  margin: 1.1rem 0 0 1.3rem;
  font-size: 0.82rem;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 0.9rem;
}
.meta button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 3px;
}
.meta button:hover { color: var(--fg); }
pre.cnf {
  margin: 0.6rem 0 0 1.3rem;
  padding: 0.75rem 1rem;
  font-size: 0.8rem;
  line-height: 1.45;
  background: var(--field);
  border: 1px solid var(--line);
  border-radius: 10px;
  max-height: 260px;
  overflow: auto;
}
.err-pos { display: block; margin-top: 0.3rem; white-space: pre-wrap; word-break: break-all; }
.err-pos mark { background: none; color: var(--warn); font-weight: 700; }

/* ── Footer ── */
.foot {
  max-width: 680px;
  margin: 0 auto;
  padding: 1rem 16px 2rem;
  width: 100%;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  font-size: 0.8rem;
  color: var(--muted);
}
.foot code { font-size: 0.78rem; }