:root {
  --bg: #0f1115; --surface: #1a1d24; --border: #2a2f3a;
  --text: #e8eaed; --muted: #9aa0a6; --accent: #5b8def;
  --radius: 12px; --font: system-ui, -apple-system, sans-serif;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--font); background: var(--bg); color: var(--text); min-height: 100vh; padding: 24px 16px; }
.container { max-width: 640px; margin: 0 auto; }
header { text-align: center; margin-bottom: 20px; }
h1 { font-size: 1.5rem; margin-bottom: 6px; }
.subtitle { color: var(--muted); font-size: 0.9rem; }
.tabs { display: flex; gap: 8px; justify-content: center; margin-bottom: 16px; flex-wrap: wrap; }
.tab { background: var(--surface); border: 1px solid var(--border); color: var(--muted); padding: 8px 14px; border-radius: 999px; cursor: pointer; font-size: 0.85rem; }
.tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.panel { display: none; }
.panel.active { display: block; }
textarea {
  width: 100%; height: 120px; background: var(--surface); border: 1px solid var(--border);
  color: var(--text); padding: 12px; border-radius: 8px; font-family: ui-monospace, monospace;
  font-size: 0.9rem; resize: vertical; outline: none; margin-bottom: 10px;
}
textarea:focus { border-color: var(--accent); }
.toolbar { display: flex; gap: 8px; margin-bottom: 10px; }
.toolbar button {
  background: var(--accent); color: #fff; border: none; padding: 10px 16px;
  border-radius: 8px; cursor: pointer; font-weight: 600;
}
footer { text-align: center; margin-top: 28px; color: var(--muted); font-size: 0.8rem; }