static/styles.css

:root {
  color-scheme: light;
  --border: #e5e5e5;
  --bg: #fafafa;
  --text: #222;
  --muted: #666;
}

body {
  margin: 0;
  font-family:
    system-ui,
    -apple-system,
    Segoe UI,
    Roboto,
    "Noto Sans CJK SC",
    "Noto Sans SC",
    Arial,
    sans-serif;
  color: var(--text);
}

.header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  background: white;
}

.header h1 {
  margin: 0 0 12px 0;
  font-size: 18px;
}

.toolbar {
  display: flex;
  gap: 10px;
  align-items: center;
}

button,
select {
  height: 32px;
  padding: 0 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: white;
}

button {
  cursor: pointer;
}

.main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  padding: 16px;
}

.panel {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg);
  padding: 12px;
  min-height: 60vh;
}

.panel h2 {
  margin: 0 0 10px 0;
  font-size: 15px;
}

.hint {
  margin: 0 0 10px 0;
  color: var(--muted);
  font-size: 13px;
}

textarea {
  width: 100%;
  height: calc(60vh - 80px);
  resize: vertical;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 14px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

.output {
  background: white;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  min-height: calc(60vh - 50px);
  line-height: 2.1;
  white-space: pre-wrap;
}

ruby {
  ruby-position: over;
  ruby-align: center;
  padding: 0 1px;
}

rt {
  font-size: 12px;
  color: #6f2dbd;
}