:root {
  --bg: #f4f1ea;
  --surface: #fffdfa;
  --surface-muted: #efe7d9;
  --ink: #1f1c18;
  --ink-soft: #5a5348;
  --line: #d8cfbf;
  --accent: #1f6d43;
  --accent-strong: #144d2f;
  --danger: #be3f2f;
  --shadow: 0 18px 40px rgba(31, 28, 24, 0.08);
  --radius: 20px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: linear-gradient(180deg, #f8f5ef 0%, #efe7da 100%);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

body {
  min-height: 100vh;
}

button {
  font: inherit;
}

button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(31, 109, 67, 0.28);
  outline-offset: 2px;
}

.app-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.game-shell {
  width: min(100%, 880px);
  background: rgba(255, 253, 250, 0.92);
  border: 1px solid rgba(216, 207, 191, 0.85);
  border-radius: 28px;
  box-shadow: var(--shadow);
  padding: 28px;
  display: grid;
  gap: 20px;
  backdrop-filter: blur(10px);
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}

.topbar-tools {
  display: flex;
  justify-content: flex-end;
}

.heading-group {
  max-width: 580px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 12px;
}

h1 {
  margin: 0;
  font-size: clamp(36px, 8vw, 56px);
  line-height: 0.95;
}

.subtitle {
  margin: 12px 0 0;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.5;
}

.language-select,
.control-button,
.primary-button,
.secondary-button {
  border: 1px solid transparent;
  cursor: pointer;
  transition: none;
  touch-action: manipulation;
}

.language-select,
.primary-button,
.secondary-button {
  border-radius: 999px;
}

.language-select-wrap {
  min-height: 48px;
  background: var(--surface-muted);
  display: inline-grid;
  grid-auto-flow: column;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  border-radius: 999px;
}

.language-select-label {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
}

.language-select {
  min-width: 120px;
  padding: 0;
  background: transparent;
  color: var(--ink);
  appearance: none;
  border: none;
  font-weight: 600;
}

.language-select:focus {
  outline: none;
}

.status-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.status-card {
  padding: 14px 16px;
  border-radius: 18px;
  background: var(--surface-muted);
  display: grid;
  gap: 6px;
}

.status-label {
  color: var(--ink-soft);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.status-value {
  font-size: 22px;
}

.message {
  margin: 0;
  min-height: 24px;
  color: var(--ink-soft);
}

.board-wrap {
  padding: 18px;
  background: var(--surface-muted);
  border-radius: 24px;
  overflow: hidden;
}

.board {
  width: min(100%, 520px);
  margin: 0 auto;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(var(--grid-columns), minmax(0, 1fr));
  grid-template-rows: repeat(var(--grid-rows), minmax(0, 1fr));
  gap: 2px;
  background: rgba(31, 28, 24, 0.08);
  border-radius: 18px;
  padding: 2px;
}

.board-settings {
  display: flex;
  justify-content: flex-end;
}

.settings-button {
  white-space: nowrap;
}

.cell {
  background: rgba(255, 253, 250, 0.95);
  border-radius: 5px;
}

.cell-snake {
  background: var(--accent);
}

.cell-head {
  background: var(--accent-strong);
}

.cell-food {
  background: var(--danger);
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.primary-button,
.secondary-button {
  padding: 12px 18px;
  min-height: 48px;
}

.primary-button {
  background: var(--ink);
  color: #fff;
}

.secondary-button {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--line);
}

.primary-button:disabled,
.secondary-button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.controls-panel {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(260px, 0.9fr);
  gap: 18px;
  align-items: center;
}

.size-panel {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 1fr);
  gap: 18px;
  align-items: end;
  padding-top: 8px;
}

.section-title {
  margin: 0 0 10px;
  font-size: 18px;
}

.controls-copy p,
.size-copy p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.6;
}

.boundary-note {
  margin-top: 12px !important;
}

.size-note {
  margin-top: 12px !important;
}

.size-form {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  align-items: end;
}

.field {
  display: grid;
  gap: 8px;
}

.field-label {
  font-size: 13px;
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.field-input {
  min-height: 48px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  color: var(--ink);
  font: inherit;
}

.control-pad {
  display: grid;
  grid-template-columns: repeat(3, minmax(64px, 1fr));
  grid-template-rows: repeat(3, minmax(64px, 1fr));
  gap: 10px;
  justify-self: end;
}

.control-button {
  background: var(--surface);
  border-color: var(--line);
  color: var(--ink);
  font-size: 26px;
  border-radius: 22px;
}

.control-up {
  grid-column: 2;
  grid-row: 1;
}

.control-left {
  grid-column: 1;
  grid-row: 2;
}

.control-down {
  grid-column: 2;
  grid-row: 2;
}

.control-right {
  grid-column: 3;
  grid-row: 2;
}

@media (max-width: 760px) {
  .app-shell {
    padding: 16px;
  }

  .game-shell {
    padding: 20px;
    gap: 18px;
  }

  .topbar,
  .controls-panel,
  .size-panel {
    grid-template-columns: 1fr;
    display: grid;
  }

  .status-strip {
    grid-template-columns: 1fr;
  }

  .topbar-tools,
  .board-settings,
  .control-pad {
    justify-self: start;
  }

  .size-form {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .control-pad {
    width: 100%;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}