:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --line: #d1d5db;
  --text: #1f2937;
  --muted: #4b5563;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --warning-bg: #fff7ed;
  --warning-line: #fed7aa;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", "Hiragino Sans", "Meiryo", sans-serif;
  line-height: 1.6;
}

.container {
  max-width: 1180px;
  margin: 24px auto;
  padding: 0 16px 32px;
}

.hero {
  margin-bottom: 16px;
}

.eyebrow {
  margin: 0 0 4px;
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 700;
}

h1,
h2 {
  margin-top: 0;
}

h1 {
  margin-bottom: 8px;
  font-size: clamp(1.6rem, 2.5vw, 2.2rem);
}

h2 {
  margin-bottom: 12px;
  font-size: 1.25rem;
}

.lead {
  margin: 0;
  color: var(--muted);
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 18px;
  margin-bottom: 16px;
}

.caution {
  background: var(--warning-bg);
  border-color: var(--warning-line);
}

.caution ul,
.card ul {
  margin-bottom: 0;
  padding-left: 1.4rem;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.select-label {
  font-weight: 700;
}

select,
textarea,
button {
  font: inherit;
}

select,
textarea {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

select {
  min-width: 220px;
  padding: 9px 10px;
}

button {
  border: none;
  border-radius: 8px;
  padding: 10px 14px;
  background: var(--primary);
  color: #ffffff;
  cursor: pointer;
  font-weight: 700;
}

button:hover,
button:focus-visible {
  background: var(--primary-dark);
}

button.secondary {
  background: #475569;
}

button.secondary:hover,
button.secondary:focus-visible {
  background: #334155;
}

button.subtle {
  background: #6b7280;
}

button.subtle:hover,
button.subtle:focus-visible {
  background: #4b5563;
}

.panes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.pane {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
  font-weight: 700;
}

textarea {
  width: 100%;
  min-height: 520px;
  padding: 12px;
  color: var(--text);
  font-family: Consolas, "Courier New", monospace;
  font-size: 0.95rem;
  line-height: 1.55;
  resize: vertical;
}

textarea[readonly] {
  background: #f8fafc;
}

.status {
  min-height: 1.4em;
  margin: 12px 0 0;
  color: var(--muted);
  font-weight: 700;
}

code {
  background: #eef2ff;
  border-radius: 4px;
  padding: 0.1em 0.3em;
}

@media (max-width: 900px) {
  .panes {
    grid-template-columns: 1fr;
  }

  textarea {
    min-height: 360px;
  }
}