:root {
  --bg: #0b0e14;
  --surface: #151a24;
  --card: #111624;
  --text: #e6e8ed;
  --muted: #9aa3b2;
  --accent: #8ecae6;
  --accent-2: #ffd166;
  --success: #06d6a0;
  --danger: #ef476f;
  --chip: #1b2333;
  --border: #222a3a;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.45 system-ui, -apple-system, Segoe UI, Roboto, Inter, "Helvetica Neue", Arial, "Noto Sans", "Apple Color Emoji", "Segoe UI Emoji";
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: rgba(11,14,20,0.85);
  backdrop-filter: blur(6px);
}

.title h1 { margin: 0 0 4px 0; font-size: 22px; }
.subtitle { color: var(--muted); font-size: 14px; }

.nav button {
  background: var(--chip);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 10px;
  margin-left: 8px;
  cursor: pointer;
}
.nav button:hover { border-color: var(--accent); }

.grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(12, 1fr);
  padding: 16px;
  max-width: 1200px;
  margin: 0 auto;
}

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

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px;
  grid-column: span 6;
}

.card.wide { grid-column: span 12; }

.holidays li { margin-bottom: 6px; }
.muted { color: var(--muted); }
.tiny { font-size: 12px; }

.otd h3 { margin-bottom: 8px; }
.otd ul, .otd ol { margin-top: 6px; }

#numbers-panel .block {
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 10px 12px;
  margin-bottom: 12px;
  background: #0e1320;
}
.block .base { font-weight: 700; }
.block .prime { color: var(--success); }
.block .not-prime { color: var(--accent-2); }
.block .lines { margin-top: 6px; display: flex; gap: 8px; flex-wrap: wrap; }
.block .line-chip {
  background: var(--chip);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 10px;
}

.chips { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 6px; }
.chip {
  background: var(--chip);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 10px;
}

.note-actions { display: flex; align-items: center; gap: 10px; margin-top: 8px; }

.footer {
  padding: 16px;
  text-align: center;
  color: var(--muted);
  border-top: 1px solid var(--border);
  margin-top: 16px;
}

@media (max-width: 900px) {
  .card { grid-column: span 12; }
  .nav button { padding: 8px 8px; }
  .grid-inner { grid-template-columns: 1fr; }
}