:root {
  --bg: #0b1220;
  --panel: rgba(255, 255, 255, 0.06);
  --panel2: rgba(255, 255, 255, 0.08);
  --text: rgba(255, 255, 255, 0.92);
  --muted: rgba(255, 255, 255, 0.72);
  --border: rgba(255, 255, 255, 0.14);
  --shadow: 0 16px 40px rgba(0, 0, 0, 0.45);

  --cell: rgba(255, 255, 255, 0.06);
  --cell2: rgba(255, 255, 255, 0.04);
  --given: rgba(255, 255, 255, 0.10);
  --bad: rgba(255, 77, 109, 0.22);
  --good: rgba(42, 245, 152, 0.16);
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: radial-gradient(1200px 800px at 20% 10%, rgba(80, 120, 255, 0.18), transparent 60%),
              radial-gradient(900px 650px at 90% 10%, rgba(0, 255, 170, 0.14), transparent 55%),
              radial-gradient(900px 650px at 40% 100%, rgba(255, 180, 0, 0.10), transparent 60%),
              var(--bg);
}

.app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 18px;
}

.topbar {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.topbarCenter {
  flex: 1;
  display: flex;
  justify-content: center;
}

.brand {
  font-family: ui-rounded, "Segoe Print", "Segoe Script", "Bradley Hand", "Comic Sans MS", ui-sans-serif;
  font-size: 15px;
  font-weight: 900;
  letter-spacing: 0.8px;
  background: linear-gradient(90deg, rgba(255, 209, 102, 0.95), rgba(124, 92, 255, 0.95));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 10px 26px rgba(0,0,0,0.35);
}

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

.status {
  margin-top: 6px;
  color: var(--muted);
  font-size: 14px;
}

.info {
  margin-top: 4px;
  color: var(--muted);
  font-size: 14px;
}

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

.select {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--panel2);
  color: var(--text);
  font-weight: 800;
}

.select span { color: var(--muted); }

.select select {
  background: transparent;
  border: none;
  color: var(--text);
  font-weight: 900;
  outline: none;
}

.select select option {
  background: #0b1220;
  color: var(--text);
}

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--panel2);
  color: var(--text);
  padding: 10px 12px;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 900;
}

.main {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 16px;
  margin-top: 16px;
}

@media (max-width: 940px) {
  .main { grid-template-columns: 1fr; }
}

.boardPanel {
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 16px;
}

.board {
  width: min(80vh, 720px);
  max-width: 100%;
  aspect-ratio: 1 / 1;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 2px;
  padding: 2px;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(0, 0, 0, 0.18);
}

.cell {
  display: grid;
  place-items: center;
  background: linear-gradient(180deg, var(--cell), var(--cell2));
  border-radius: 10px;
  padding: 0;
  position: relative;
}

.cell.thickRight { box-shadow: inset -2px 0 0 rgba(255,255,255,0.16); }
.cell.thickBottom { box-shadow: inset 0 -2px 0 rgba(255,255,255,0.16); }
.cell.thickCorner { box-shadow: inset -2px 0 0 rgba(255,255,255,0.16), inset 0 -2px 0 rgba(255,255,255,0.16); }

.cell input {
  width: 100%;
  height: 100%;
  border: 1px solid rgba(255, 255, 255, 0.10);
  border-radius: 10px;
  background: transparent;
  color: var(--text);
  text-align: center;
  font-size: clamp(16px, 3vw, 26px);
  font-weight: 900;
  outline: none;
}

.cell input:focus {
  border-color: rgba(255, 255, 255, 0.28);
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.14);
}

.cell.given input {
  background: var(--given);
  border-color: rgba(255, 255, 255, 0.18);
  cursor: default;
}

.cell.bad input {
  background: var(--bad);
  border-color: rgba(255, 77, 109, 0.55);
}

.cell.good input {
  background: var(--good);
  border-color: rgba(42, 245, 152, 0.45);
}

.side {
  display: grid;
  gap: 16px;
}

.card {
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 14px 16px;
}

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

.card p {
  margin: 8px 0;
  color: var(--muted);
  line-height: 1.35;
}