:root {
  --bg-page: #f4f5f7;
  --bg-surface: #ffffff;
  --bg-panel: #f8f9fb;
  --bg-cell: #dfe6ef;
  --bg-cell-revealed: #f8fafc;
  --border-soft: #d9dee6;
  --border-strong: #c4ccd8;
  --text-primary: #111827;
  --text-muted: #5f6b7b;
  --accent: #2563eb;
  --danger: #c03737;
  --radius: 14px;
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.08);
  --shadow-md: 0 8px 24px rgba(16, 24, 40, 0.08);
  --space-1: 8px;
  --space-2: 12px;
  --space-3: 16px;
  --space-4: 20px;
  --cell-size: 30px;
  --font-ui: "Avenir Next", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: var(--space-3);
  font-family: var(--font-ui);
  background: linear-gradient(180deg, #f9fafb 0%, #f2f4f7 100%);
  color: var(--text-primary);
}

.game-shell {
  width: min(100%, 1040px);
  background: var(--bg-surface);
  border: 1px solid var(--border-soft);
  border-radius: calc(var(--radius) + 2px);
  box-shadow: var(--shadow-md);
  padding: var(--space-4);
}

h1 {
  margin: 0 0 var(--space-3);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  align-items: center;
  margin-bottom: var(--space-3);
}

label {
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--text-muted);
}

select,
#mode-toggle,
#restart-btn {
  font: inherit;
  min-height: 44px;
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  background: var(--bg-surface);
  color: var(--text-primary);
  transition: border-color 120ms ease, box-shadow 120ms ease,
    background-color 120ms ease;
}

select {
  padding: 0 12px;
}

#mode-toggle {
  padding: 0 14px;
  font-weight: 600;
}

.hud {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2);
  margin-bottom: var(--space-2);
  background: var(--bg-panel);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
}

.counter {
  background: #192230;
  color: #f5f7fb;
  font-family: "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 1.5rem;
  font-weight: 700;
  text-align: center;
  padding: 6px 10px;
  border: 1px solid #0f1722;
  border-radius: 10px;
  letter-spacing: 0.03em;
  min-width: 84px;
}

#restart-btn {
  width: 52px;
  font-size: 1.55rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
}

#restart-btn:hover {
  background: #f2f4f8;
}

#restart-btn:active {
  background: #e8ecf3;
}

.status-text {
  margin: 0 0 var(--space-2);
  min-height: 1.3em;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.board {
  display: grid;
  width: fit-content;
  max-width: 100%;
  overflow: auto;
  background: var(--bg-surface);
  border: 1px solid var(--border-soft);
  border-radius: 0;
}

.cell {
  width: var(--cell-size);
  height: var(--cell-size);
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 700;
  padding: 0;
  border: 1px solid #bec8d6;
  background: var(--bg-cell);
  color: var(--text-primary);
  cursor: pointer;
  user-select: none;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.35);
}

@media (hover: hover) and (pointer: fine) {
  .cell:hover {
    background: #d3dce8;
  }
}

.cell:focus-visible,
select:focus-visible,
#mode-toggle:focus-visible,
#restart-btn:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 1px;
  border-color: var(--accent);
}

.cell.revealed {
  border-color: #dbe3ee;
  background: var(--bg-cell-revealed);
  cursor: default;
  box-shadow: none;
}

.cell.flagged {
  color: #d54d2d;
}

.cell.mine {
  color: #111827;
}

.cell.exploded {
  background: #ffe0e0;
  border-color: #f2b1b1;
}

.cell.wrong-flag {
  background: #fff2f2;
  color: #8f2a2a;
}

.n1 {
  color: #1f56c2;
}
.n2 {
  color: #247739;
}
.n3 {
  color: #b23a3a;
}
.n4 {
  color: #4c46a6;
}
.n5 {
  color: #7d2d2d;
}
.n6 {
  color: #1e7272;
}
.n7 {
  color: #1f2937;
}
.n8 {
  color: #4b5563;
}

.records {
  margin-top: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background: var(--bg-panel);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
}

.records h2 {
  margin: 0 0 6px;
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 600;
}

.records ul {
  margin: 0;
  padding-left: 18px;
  line-height: 1.6;
}

@media (max-width: 900px) {
  :root {
    --cell-size: 27px;
  }
}

@media (max-width: 600px) {
  :root {
    --cell-size: 25px;
  }

  body {
    padding: var(--space-2);
  }

  .game-shell {
    padding: var(--space-3);
    border-radius: var(--radius);
  }

  h1 {
    font-size: 1.2rem;
    margin-bottom: var(--space-2);
  }

  .counter {
    font-size: 1.35rem;
    min-width: 74px;
  }
}