@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Montserrat:wght@600;700;800;900&display=swap');

:root {
  --bg: #f7f9fd;
  --bg-end: #deefff;
  --surface: rgba(255, 255, 255, 0.84);
  --surface-strong: #ffffff;
  --surface-soft: rgba(245, 249, 255, 0.9);
  --text: #0f172a;
  --text-soft: #49617f;
  --line: rgba(53, 85, 126, 0.16);
  --shadow: 0 18px 42px rgba(31, 54, 89, 0.14);
  --glow: 0 0 0 1px rgba(58, 134, 255, 0.05), 0 0 30px rgba(58, 134, 255, 0.08);
  --brand-blue: #3a86ff;
  --brand-cyan: #00b4d8;
  --brand-indigo: #4e36bc;
  --success: #06d6a0;
  --danger: #ef476f;
  --warning: #ffbe0b;
  --board-border: rgba(31, 54, 89, 0.9);
  --board-cell: #ffffff;
  --board-cell-hover: #edf4ff;
  --board-cell-open: #ecf4ff;
  --board-cell-flag: #ffe4ea;
  --board-cell-mine: #ffe8cc;
  --board-cell-wrong: #ffd8e5;
  --board-cell-hit: #ffcedb;
  --number-1: #1d4ed8;
  --number-2: #15803d;
  --number-3: #dc2626;
  --number-4: #6d28d9;
  --number-5: #b45309;
  --number-6: #0891b2;
  --number-7: #111827;
  --number-8: #64748b;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #020617;
    --bg-end: #0a1830;
    --surface: rgba(15, 23, 42, 0.82);
    --surface-strong: #111827;
    --surface-soft: rgba(15, 23, 42, 0.94);
    --text: #f8fafc;
    --text-soft: #93a4bf;
    --line: rgba(148, 163, 184, 0.18);
    --shadow: 0 24px 50px rgba(2, 6, 23, 0.48);
    --glow: 0 0 0 1px rgba(58, 134, 255, 0.16), 0 0 40px rgba(58, 134, 255, 0.16);
    --board-border: rgba(219, 234, 254, 0.92);
    --board-cell: #0f172a;
    --board-cell-hover: #1d2a42;
    --board-cell-open: #18253a;
    --board-cell-flag: #412536;
    --board-cell-mine: #47351a;
    --board-cell-wrong: #5a2436;
    --board-cell-hit: #7f1d2d;
    --number-1: #60a5fa;
    --number-2: #4ade80;
    --number-3: #fb7185;
    --number-4: #c4b5fd;
    --number-5: #fdba74;
    --number-6: #67e8f9;
    --number-7: #e5e7eb;
    --number-8: #94a3b8;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', sans-serif;
  color: var(--text);
  line-height: 1.5;
  background:
    radial-gradient(circle at 0% 0%, rgba(58, 134, 255, 0.18) 0%, rgba(58, 134, 255, 0) 42%),
    radial-gradient(circle at 84% 10%, rgba(0, 180, 216, 0.16) 0%, rgba(0, 180, 216, 0) 36%),
    linear-gradient(160deg, var(--bg) 0%, var(--bg-end) 100%);
  transition: color 180ms ease, background-color 180ms ease;
}

#app {
  min-height: 100vh;
  padding: 16px;
}

.app-shell {
  width: min(100%, 1100px);
  margin: 0 auto;
  display: grid;
  gap: 14px;
}

.hero-card,
.board-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: var(--shadow), var(--glow);
  backdrop-filter: blur(16px);
}

.hero-card {
  padding: 18px;
  display: grid;
  gap: 16px;
}

.brand-lockup {
  display: grid;
  gap: 4px;
}

.eyebrow {
  margin: 0;
  color: var(--brand-indigo);
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-size: 0.72rem;
  font-weight: 800;
}

.brand-lockup h1 {
  margin: 0;
  font-family: 'Montserrat', sans-serif;
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 0.96;
  letter-spacing: -0.05em;
}

.lede {
  margin: 0;
  max-width: 58ch;
  color: var(--text-soft);
  font-size: 0.98rem;
}

.controls-row {
  display: grid;
  gap: 10px;
  grid-template-columns: 1fr;
}

.custom-controls {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  align-items: end;
  width: 100%;
  grid-column: 1 / -1;
}

.custom-controls[hidden] {
  display: none;
}

.field {
  display: grid;
  gap: 7px;
}

.field span,
.stat-card span,
.board-subtitle,
.hint,
.overlay-kicker {
  color: var(--text-soft);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-weight: 700;
}

.field select {
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface-strong);
  color: var(--text);
  padding: 12px 14px;
  font: inherit;
  font-weight: 700;
}

.field input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface-strong);
  color: var(--text);
  padding: 12px 14px;
  font: inherit;
  font-weight: 700;
}

.button {
  border: 0;
  border-radius: 16px;
  min-height: 48px;
  padding: 0 16px;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
  transition: transform 140ms ease, box-shadow 140ms ease, background-color 140ms ease, color 140ms ease, opacity 140ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(0);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.button--primary {
  color: #fff;
  background: linear-gradient(135deg, var(--brand-indigo), var(--brand-blue));
  box-shadow: 0 14px 28px rgba(58, 134, 255, 0.22);
}

.button--ghost {
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.2);
  color: var(--text);
}

.stats-grid {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.stat-card {
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 12px 14px;
  display: grid;
  gap: 4px;
}

.stat-card strong {
  font-family: 'Montserrat', sans-serif;
  font-size: clamp(1rem, 2vw, 1.3rem);
  letter-spacing: 0.02em;
}

.board-shell {
  display: grid;
  width: 100%;
  justify-content: stretch;
}

.board-panel {
  padding: 14px;
  width: 100%;
  max-width: 100%;
  overflow: visible;
}

.board-header {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 12px;
}

.board-title {
  margin: 0;
  font-family: 'Montserrat', sans-serif;
  font-size: 1.05rem;
  font-weight: 800;
}

.hint {
  margin: 0;
  white-space: nowrap;
}

.board-scroll {
  max-width: 100%;
  width: 100%;
  display: block;
  overflow-x: auto;
  overflow-y: hidden;
  padding: 10px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.2);
}

.board-scroll::-webkit-scrollbar {
  height: 10px;
}

.board-scroll::-webkit-scrollbar-thumb {
  background: rgba(53, 85, 126, 0.28);
  border-radius: 999px;
}

.board-container {
  --cell-size: 30px;
  display: grid;
  grid-template-columns: repeat(var(--board-cols), var(--cell-size));
  grid-auto-rows: var(--cell-size);
  width: max-content;
  margin-inline: auto;
  border: 3px solid var(--board-border);
  padding: 6px;
  border-radius: 16px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.12);
}

.board-explainer {
  margin: 12px 2px 0;
  color: var(--text-soft);
  font-size: 0.92rem;
  line-height: 1.45;
  max-width: 72ch;
}

.cell {
  appearance: none;
  -webkit-appearance: none;
  border: 1px solid rgba(31, 54, 89, 0.16);
  background: var(--board-cell);
  color: var(--text);
  padding: 0;
  display: grid;
  place-items: center;
  font-family: 'Montserrat', sans-serif;
  font-weight: 900;
  font-size: clamp(0.78rem, 2vw, 1.08rem);
  cursor: pointer;
  user-select: none;
  transition: transform 120ms ease, background-color 120ms ease, color 120ms ease, box-shadow 120ms ease;
}

.cell:hover {
  background: var(--board-cell-hover);
}

.cell:active {
  transform: scale(0.97);
}

.cell:focus-visible {
  outline: 3px solid rgba(58, 134, 255, 0.5);
  outline-offset: -3px;
}

.cell.is-focus {
  box-shadow: inset 0 0 0 2px rgba(58, 134, 255, 0.4);
}

.cell.is-revealed,
.cell.is-mine {
  background: var(--board-cell-open);
}

.cell.is-empty {
  background: var(--board-cell-open);
}

.cell.is-flagged {
  background: var(--board-cell-flag);
}

.cell.is-hit {
  background: var(--board-cell-hit);
  color: #7f1d1d;
}

.cell.is-wrong-flag {
  background: var(--board-cell-wrong);
}

.cell.is-correct-flag {
  background: color-mix(in srgb, var(--board-cell-flag) 80%, var(--success));
}

.cell.is-number[data-number='1'] .cell-value {
  color: var(--number-1);
}

.cell.is-number[data-number='2'] .cell-value {
  color: var(--number-2);
}

.cell.is-number[data-number='3'] .cell-value {
  color: var(--number-3);
}

.cell.is-number[data-number='4'] .cell-value {
  color: var(--number-4);
}

.cell.is-number[data-number='5'] .cell-value {
  color: var(--number-5);
}

.cell.is-number[data-number='6'] .cell-value {
  color: var(--number-6);
}

.cell.is-number[data-number='7'] .cell-value {
  color: var(--number-7);
}

.cell.is-number[data-number='8'] .cell-value {
  color: var(--number-8);
}

.cell-value {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
}

.cell.is-flagged .cell-value,
.cell.is-hit .cell-value,
.cell.is-wrong-flag .cell-value,
.cell.is-correct-flag .cell-value {
  font-size: 1.05em;
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(8, 21, 41, 0.44);
  display: none;
  place-items: center;
  padding: 20px;
  z-index: 20;
}

.overlay:not([hidden]) {
  display: grid;
}

.overlay-card {
  width: min(100%, 380px);
  background: var(--surface-strong);
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: var(--shadow), var(--glow);
  padding: 22px;
  display: grid;
  gap: 10px;
}

.overlay-card h2 {
  margin: 0;
  font-family: 'Montserrat', sans-serif;
  font-size: 2rem;
  line-height: 1;
}

.overlay-card p {
  margin: 0;
  color: var(--text-soft);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
  white-space: nowrap;
}

@media (min-width: 720px) {
  .hero-card {
    padding: 22px;
  }

  .controls-row {
    grid-template-columns: minmax(300px, 520px) auto auto;
    align-items: end;
  }

  .field--difficulty {
    min-width: 220px;
  }

  .board-panel {
    padding: 18px;
  }
}

@media (max-width: 719px) {
  #app {
    padding: 12px;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .controls-row {
    grid-template-columns: 1fr;
  }

  .board-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .custom-controls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}