:root{--sky-color:#64b0ff;--grass-color:#8bce25;--text-color:#fff;--ui-bg:#000}*{box-sizing:border-box;margin:0;padding:0;font-family:"Press Start 2P",cursive}body{background-color:#000;justify-content:center;align-items:center;height:100vh;display:flex;overflow:hidden}#game-container{background-color:var(--sky-color);cursor:none;width:100vw;max-width:1024px;height:100vh;max-height:768px;position:relative;overflow:hidden;box-shadow:0 0 20px #00000080}#sky{background-color:var(--sky-color);width:100%;height:75%;position:absolute;top:0;left:0}#grass{background-color:var(--grass-color);border-top:4px solid #5a8c18;width:100%;height:25%;position:absolute;bottom:0;left:0}#game-canvas{z-index:10;pointer-events:none;width:100%;height:100%;position:absolute;top:0;left:0}#ui-layer{z-index:20;pointer-events:none;width:100%;height:100%;position:absolute;top:0;left:0}.score-board,.ammo-board{background-color:var(--ui-bg);color:var(--text-color);border:4px solid #fff;padding:10px;font-size:16px;position:absolute;bottom:20px}.score-board{right:20px}.ammo-board{left:20px}#message-overlay{text-align:center;z-index:30;pointer-events:auto;background-color:#000c;flex-direction:column;justify-content:center;align-items:center;width:100%;height:100%;display:flex;position:absolute;top:0;left:0}#message-overlay.hidden{display:none}#main-message{color:#fff;text-shadow:4px 4px #000;margin-bottom:20px;font-size:32px}#sub-message{color:#aaa;margin-bottom:40px;font-size:12px;line-height:1.5}#start-btn{color:#fff;cursor:pointer;background-color:red;border:4px solid #fff;padding:15px 30px;font-size:20px;transition:transform .1s}#start-btn:active{transform:scale(.95)}#crosshair{z-index:25;pointer-events:none;border:4px solid red;border-radius:50%;justify-content:center;align-items:center;width:40px;height:40px;display:flex;position:absolute;transform:translate(-50%,-50%)}#crosshair.hidden{display:none}.crosshair-center{background-color:red;border-radius:50%;width:8px;height:8px}#flash-effect{opacity:0;z-index:15;pointer-events:none;background-color:#fff;width:100%;height:100%;transition:opacity .1s ease-out;position:absolute;top:0;left:0}#flash-effect.active{opacity:1;transition:none}#calibration-overlay{text-align:center;z-index:28;pointer-events:auto;background-color:#000000e6;flex-direction:column;justify-content:center;align-items:center;width:100%;height:100%;display:flex;position:absolute;top:0;left:0}#calibration-overlay.hidden{display:none}#calibration-title{color:#ffb800;margin-bottom:20px;font-size:28px}#calibration-inst{color:#fff;font-size:14px;line-height:1.5}#calibration-target{border:4px solid #fff;border-radius:50%;justify-content:center;align-items:center;width:60px;height:60px;animation:1s infinite alternate pulse;display:flex;position:absolute}.target-center{background-color:red;border-radius:50%;width:15px;height:15px}@keyframes pulse{0%{border-color:#fff;transform:scale(1)}to{border-color:red;transform:scale(1.2)}}