:root {
  color-scheme: light;
  --bg: #f4f7f6;
  --ink: #0f172a;
  --muted: #64748b;
  --card: #fff;
  --line: #e2e8f0;
  --accent: #0f766e;
  --accent-soft: #ccfbf1;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, sans-serif;
  background:
    radial-gradient(900px 400px at 10% -10%, var(--accent-soft) 0%, transparent 55%),
    radial-gradient(700px 360px at 100% 0%, #e0f2fe 0%, transparent 50%),
    var(--bg);
  color: var(--ink);
  min-height: 100vh;
}
main {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}
h1 {
  font-size: 1.5rem;
  margin: 0 0 0.35rem;
  letter-spacing: -0.02em;
}
.lead {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}
.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 0.75rem;
  margin: 0 0 1.25rem;
  font-size: 0.875rem;
}
.nav a {
  color: var(--accent);
  text-decoration: none;
}
.nav a:hover {
  text-decoration: underline;
}
.nav a.is-current {
  font-weight: 700;
  text-decoration: underline;
}
.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.75rem;
}
.out {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 10px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.875rem;
  word-break: break-all;
  white-space: pre-wrap;
}
.out strong {
  color: #5eead4;
  font-weight: 600;
}
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.85rem;
  align-items: center;
}
button,
.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink);
  border-radius: 8px;
  padding: 0.4rem 0.75rem;
  font-size: 0.875rem;
  cursor: pointer;
}
button:hover,
.btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}
button.is-on {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
label {
  font-size: 0.875rem;
  color: var(--muted);
}
input[type='text'],
textarea,
select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.5rem 0.65rem;
  font: inherit;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.875rem;
}
textarea {
  min-height: 4.5rem;
  resize: vertical;
}
.grid {
  display: grid;
  gap: 0.75rem;
}
.grid-2 {
  display: grid;
  gap: 0.75rem;
  grid-template-columns: 1fr 1fr;
}
@media (max-width: 640px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }
}
.hint {
  margin: 0.5rem 0 0;
  font-size: 0.8rem;
  color: var(--muted);
}
.list {
  margin: 0.35rem 0 0;
  padding-left: 1.1rem;
  font-size: 0.85rem;
  color: #cbd5e1;
}
.error {
  color: #fca5a5;
}