:root {
  color-scheme: light;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  --bg: #f7f8fb;
  --surface: #ffffff;
  --text: #101828;
  --muted: #475467;
  --border: #d0d5dd;
  --accent: #0b63f6;
  --accent-hover: #0953cd;
  --danger: #b42318;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
}

.container {
  width: min(760px, calc(100% - 2rem));
  margin: 2rem auto;
  padding: 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
}

h1 {
  margin: 0 0 0.5rem;
}

.subtitle {
  margin: 0 0 1rem;
  color: var(--muted);
}

label {
  display: block;
  margin: 0.9rem 0 0.35rem;
  font-weight: 600;
}

textarea,
input,
button,
pre {
  width: 100%;
  border-radius: 8px;
  font: inherit;
}

textarea,
input {
  border: 1px solid var(--border);
  padding: 0.65rem 0.75rem;
  background: #fff;
}

textarea {
  resize: vertical;
}

button {
  margin-top: 1rem;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  padding: 0.7rem 1rem;
  font-weight: 600;
  cursor: pointer;
}

button:hover {
  background: var(--accent-hover);
}

button:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

pre {
  margin-top: 0.35rem;
  min-height: 140px;
  border: 1px solid var(--border);
  background: #0f172a;
  color: #e2e8f0;
  padding: 0.75rem;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-word;
}

.error {
  color: var(--danger);
}

@media (max-width: 640px) {
  .container {
    width: calc(100% - 1rem);
    margin: 0.5rem auto;
    padding: 1rem;
    border-radius: 10px;
  }
}