*{margin:0;padding:0;box-sizing:border-box}
:root{
  --primary:#42A5F5;
  --primary-deep:#1565C0;
  --accent:#FF7043;
  --bg-top:#E3F2FD;
  --bg-bot:#FFF3E0;
  --card-bg:rgba(255,255,255,0.92);
  --radius:16px;
  --shadow:0 6px 24px rgba(40,80,140,0.13);
}
body{
  min-height:100vh;
  background:linear-gradient(135deg,var(--bg-top),var(--bg-bot));
  font-family:'Segoe UI','PingFang SC','Microsoft YaHei',sans-serif;
  display:flex;flex-direction:column;align-items:center;
  overflow-x:hidden;
  user-select:none;-webkit-user-select:none;
}
.back-btn{
  position:fixed;top:12px;left:12px;z-index:100;
  background:var(--card-bg);color:var(--primary-deep);
  padding:7px 15px;border-radius:30px;
  text-decoration:none;font-size:14px;font-weight:600;
  box-shadow:var(--shadow);transition:transform .2s;
}
.back-btn:hover{transform:scale(1.06)}
.game-wrap{
  position:relative;
  width:min(520px,97vw);
  margin:46px auto 16px;
  display:flex;flex-direction:column;align-items:center;
}
.hud{
  display:flex;justify-content:space-around;width:100%;
  background:var(--card-bg);border-radius:var(--radius);
  padding:10px 6px;margin-bottom:8px;
  box-shadow:var(--shadow);
}
.hud-item{display:flex;flex-direction:column;align-items:center}
.hud .label{font-size:11px;color:#aaa;font-weight:600}
.hud .val{font-size:20px;font-weight:800;color:var(--primary-deep)}
#timer{color:var(--accent)}
#score{color:var(--primary)}
.toolbar{
  display:flex;gap:10px;margin-bottom:8px;
}
.tool-btn{
  padding:6px 16px;
  background:var(--card-bg);border:2px solid #E0E0E0;
  border-radius:24px;font-size:13px;font-weight:600;
  cursor:pointer;color:#555;
  box-shadow:0 2px 8px rgba(0,0,0,0.06);
  transition:transform .15s,border-color .2s;
}
.tool-btn:hover{transform:scale(1.05);border-color:var(--primary)}
.tool-btn:active{transform:scale(0.96)}
.tool-btn:disabled{opacity:0.4;cursor:not-allowed;transform:none}
canvas{
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  background:var(--card-bg);
  touch-action:none;
  max-width:100%;
}
.overlay{
  position:absolute;inset:0;
  display:flex;align-items:center;justify-content:center;
  background:rgba(227,242,253,0.88);
  border-radius:var(--radius);z-index:20;
  opacity:0;pointer-events:none;transition:opacity .3s;
}
.overlay.show{opacity:1;pointer-events:auto}
.card{
  background:var(--card-bg);border-radius:var(--radius);
  padding:28px 24px;text-align:center;
  box-shadow:var(--shadow);animation:pop .35s ease-out;
  max-width:340px;width:92%;
}
.card-emoji{font-size:42px;margin-bottom:6px}
.card h2{font-size:24px;color:var(--primary-deep);margin-bottom:8px}
.card p{color:#999;font-size:14px;line-height:1.6;margin-bottom:14px}
.card .final-score{font-size:48px;font-weight:800;color:var(--primary);margin:6px 0}
.card .stat-line{font-size:14px;color:#aaa;margin-bottom:8px}
.diff-btns{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}
.btn-start{
  padding:11px 26px;
  background:linear-gradient(135deg,var(--primary),var(--primary-deep));
  color:#fff;border:none;border-radius:30px;
  font-size:15px;font-weight:700;cursor:pointer;
  box-shadow:0 4px 14px rgba(21,101,192,0.3);transition:transform .15s;
}
.btn-start:hover{transform:scale(1.05)}
.btn-start:active{transform:scale(0.97)}
.btn-start.hard{background:linear-gradient(135deg,var(--accent),#E64A19)}
@keyframes pop{
  0%{transform:scale(0.7);opacity:0}
  70%{transform:scale(1.05)}
  100%{transform:scale(1);opacity:1}
}
@media(max-width:420px){
  .game-wrap{margin-top:40px}
  .hud .val{font-size:17px}
  .tool-btn{font-size:12px;padding:5px 12px}
}