*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%;overflow:hidden;font-family:system-ui,Arial,sans-serif;background:#87ceeb}
canvas{position:fixed;inset:0;width:100%;height:100%;display:block}
#crosshair{position:fixed;left:50%;top:50%;transform:translate(-50%,-50%);color:#fff;font-size:22px;text-shadow:0 0 3px #000;pointer-events:none;z-index:5}
#hud{position:fixed;left:0;right:0;bottom:0;background:rgba(20,24,32,.82);color:#fff;padding:10px 14px;z-index:6;backdrop-filter:blur(4px)}
.row{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:4px 0}
.lbl{width:60px;font-size:13px;opacity:.8}
#shapes,#colors{display:flex;gap:6px;flex-wrap:wrap}
.shape{padding:6px 10px;border:1px solid #444;border-radius:6px;background:#2b3240;color:#fff;cursor:pointer;font-size:13px}
.shape.sel{background:#4caf50;border-color:#8f8}
.sw{width:26px;height:26px;border-radius:5px;border:2px solid #333;cursor:pointer}
.sw.sel{border-color:#fff;box-shadow:0 0 0 2px #4caf50}
#reset{padding:7px 12px;border:none;border-radius:6px;background:#ff5252;color:#fff;cursor:pointer;font-size:13px}
#reset:hover{background:#ff6e6e}
#status{font-size:12px;opacity:.75;margin-left:auto}
#overlay{position:fixed;inset:0;background:rgba(10,14,22,.9);display:flex;align-items:center;justify-content:center;z-index:20}
.panel{background:#1d2430;color:#eee;padding:28px 34px;border-radius:14px;max-width:420px;text-align:center;box-shadow:0 12px 40px rgba(0,0,0,.5)}
.panel h1{margin-bottom:10px;color:#7ec8ff}
.panel p{opacity:.85;margin-bottom:14px}
.panel ul{text-align:left;margin:0 auto 18px;line-height:1.8;font-size:14px;display:inline-block}
#play{padding:12px 26px;border:none;border-radius:8px;background:#4caf50;color:#fff;font-size:16px;cursor:pointer}
#play:hover{background:#5bc25f}