*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ── Themes ── */
:root {
  --bg: #f0f2f5;
  --surface: #ffffff;
  --accent: #ffffff;
  --accent-hover: #f3f4f6;
  --toggled: #22a55b;
  --toggled-hover: #1a8a4a;
  --text: #111827;
  --text-muted: #6b7280;
  --border: #d1d5db;
  --shadow: rgba(0,0,0,0.08);
  --radius: 8px;
}

[data-theme="dark"] {
  --bg: #111827;
  --surface: #1f2937;
  --accent: #1f2937;
  --accent-hover: #374151;
  --toggled: #22a55b;
  --toggled-hover: #1a8a4a;
  --text: #f9fafb;
  --text-muted: #9ca3af;
  --border: #374151;
  --shadow: rgba(0,0,0,0.3);
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  min-height: 100vh;
  transition: background 0.2s, color 0.2s;
}

/* ── Header ── */
header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 12px var(--shadow);
  transition: background 0.2s, border-color 0.2s;
}

.header-left {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.app-name {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--toggled);
}

h1 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.stats {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

#counter {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

#percent {
  font-size: 0.8rem;
  color: var(--toggled);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

/* ── Header buttons ── */
#theme-btn,
#reset-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 7px 12px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

#theme-btn:hover,
#reset-btn:hover {
  color: var(--text);
  background: var(--accent-hover);
  border-color: var(--text-muted);
}

#reset-btn:hover {
  color: #dc2626;
  border-color: #dc2626;
  background: rgba(220, 38, 38, 0.06);
}

/* ── Grid ── */
main {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(88px, 1fr));
  gap: 8px;
  padding: 20px;
  max-width: 1000px;
  margin: 0 auto;
}

/* ── State buttons ── */
.state-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  background: var(--accent);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 6px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, transform 0.1s, box-shadow 0.15s;
  user-select: none;
  position: relative;
  box-shadow: 0 1px 3px var(--shadow);
}

.state-btn:hover {
  background: var(--accent-hover);
  border-color: var(--text-muted);
  box-shadow: 0 2px 8px var(--shadow);
}

.state-btn:active {
  transform: scale(0.96);
}

.state-abbr {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
}

.state-name {
  font-size: 0.6rem;
  color: var(--text-muted);
  text-align: center;
  line-height: 1.2;
}

.state-btn.toggled {
  background: var(--toggled);
  border-color: var(--toggled);
  color: #fff;
}

.state-btn.toggled .state-name {
  color: rgba(255,255,255,0.75);
}

.state-btn.toggled:hover {
  background: var(--toggled-hover);
  border-color: var(--toggled-hover);
}

.state-btn.toggled::after {
  content: '✓';
  position: absolute;
  top: 4px;
  right: 6px;
  font-size: 0.65rem;
  opacity: 0.85;
}

/* ── Modal ── */
#modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  backdrop-filter: blur(3px);
}

#modal-overlay[hidden] {
  display: none;
}

#modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 32px;
  max-width: 380px;
  width: 90%;
  box-shadow: 0 8px 32px var(--shadow);
  animation: pop-in 0.15s ease;
}

@keyframes pop-in {
  from { transform: scale(0.92); opacity: 0; }
  to   { transform: scale(1);    opacity: 1; }
}

#modal h2 {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

#modal p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  line-height: 1.5;
}

.modal-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
}

.modal-actions button {
  border-radius: var(--radius);
  padding: 9px 20px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

#modal-cancel {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
}

#modal-cancel:hover {
  background: var(--accent-hover);
  color: var(--text);
}

#modal-confirm {
  background: #dc2626;
  color: #fff;
  border: 1px solid #dc2626;
}

#modal-confirm:hover {
  background: #b91c1c;
  border-color: #b91c1c;
}

/* ── Focus styles ── */
button:focus-visible {
  outline: 2px solid var(--toggled);
  outline-offset: 2px;
}

/* ── Responsive ── */
@media (max-width: 480px) {
  main {
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    padding: 12px;
    gap: 6px;
  }

  header {
    padding: 10px 14px;
  }

  h1 {
    font-size: 1rem;
  }
}