:root {
  --bg: #eef2f7;
  --panel: #ffffff;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --text: #1e293b;
  --muted: #64748b;
  --line: #cbd5e1;
  --line-strong: #475569;
  --hl: #e2e8f0;
  --hl-box: #dbeafe;
  --sel: #93c5fd;
  --same: #bfdbfe;
  --danger: #dc2626;
  --danger-bg: #fee2e2;
  --fixed-color: #0f172a;
  --user-color: #2563eb;
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  overscroll-behavior: none;
}

.app {
  width: 100%;
  max-width: 440px;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  padding: 14px 14px max(14px, env(safe-area-inset-bottom));
  gap: 12px;
}

/* ---------- 顶部栏 ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.title {
  font-size: 22px;
  font-weight: 800;
  margin: 0;
  letter-spacing: 2px;
  color: var(--primary-dark);
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.level-select {
  appearance: none;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: 7px 26px 7px 10px;
  font-size: 14px;
  color: var(--text);
  background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%),
    linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: calc(100% - 14px) 55%, calc(100% - 10px) 55%;
  background-size: 4px 4px;
  background-repeat: no-repeat;
  cursor: pointer;
}

.btn-primary {
  border: none;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  padding: 8px 14px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

.btn-primary:active {
  background: var(--primary-dark);
}

/* ---------- 状态栏 ---------- */
.statusbar {
  display: flex;
  justify-content: space-between;
  padding: 0 4px;
  font-size: 14px;
  color: var(--muted);
}

.status-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.status-item strong {
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.dot-timer {
  background: var(--primary);
}

.dot-mistake {
  background: var(--danger);
}

/* ---------- 棋盘 ---------- */
.board-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 0;
}

.board {
  width: min(100%, 100vw - 28px);
  max-width: 430px;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  background: var(--line);
  border: 2px solid var(--line-strong);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 8px 24px rgba(30, 41, 59, 0.12);
  user-select: none;
}

.cell {
  position: relative;
  background: var(--panel);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.08s;
}

.cell.vr {
  border-right: 2px solid var(--line-strong);
}

.cell.hr {
  border-bottom: 2px solid var(--line-strong);
}

.cell.hl-row,
.cell.hl-col,
.cell.hl-box {
  background: var(--hl);
}

.cell.hl-box {
  background: var(--hl-box);
}

.cell.same-num {
  background: var(--same);
}

.cell.selected {
  background: var(--sel);
}

.value {
  font-size: clamp(16px, 5.6vw, 28px);
  line-height: 1;
  font-weight: 700;
}

.value.fixed {
  color: var(--fixed-color);
}

.value.user {
  color: var(--user-color);
  font-weight: 600;
}

.value.conflict {
  color: var(--danger);
}

.cell.selected .value.conflict,
.cell.selected .value.user,
.cell.selected .value.fixed {
  color: var(--fixed-color);
}

.pencil {
  display: none;
  position: absolute;
  inset: 0;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  padding: 6%;
}

.pencil span {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(7px, 2vw, 11px);
  font-weight: 500;
  color: var(--muted);
}

/* ---------- 数字键盘 ---------- */
.pad {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.numpad {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 6px;
}

.num-btn {
  aspect-ratio: 1;
  border: none;
  border-radius: 10px;
  background: var(--panel);
  color: var(--text);
  font-size: clamp(17px, 5vw, 22px);
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(30, 41, 59, 0.08);
  transition: background 0.12s, transform 0.06s;
}

.num-btn:active {
  background: var(--hl-box);
  transform: scale(0.94);
}

.num-btn.disabled {
  opacity: 0.35;
  pointer-events: none;
}

.tools {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.tool {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  color: var(--text);
  padding: 9px 0;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s;
}

.tool:active {
  background: var(--hl);
}

.tool.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.tool.disabled {
  opacity: 0.4;
  pointer-events: none;
}

/* ---------- 弹窗 ---------- */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
  animation: fadeIn 0.2s ease;
}

.overlay.hidden {
  display: none;
}

.modal {
  background: var(--panel);
  border-radius: 16px;
  padding: 26px 28px;
  width: min(100%, 320px);
  text-align: center;
  box-shadow: 0 16px 48px rgba(15, 23, 42, 0.3);
  animation: pop 0.22s ease;
}

.modal-title {
  font-size: 22px;
  font-weight: 800;
  margin: 0 0 14px;
}

.modal-sub {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 18px;
  line-height: 1.7;
}

.modal-sub b {
  color: var(--text);
}

.modal-btn {
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  width: 100%;
  padding: 12px 0;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
}

.modal-btn:active {
  background: var(--primary-dark);
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes pop {
  from { transform: scale(0.9); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}