*{margin:0;padding:0;box-sizing:border-box}body{overflow:hidden;background:#000;font-family:Courier New,monospace}#game-container{position:fixed;top:0;right:0;bottom:0;left:0}#game-canvas{width:100%;height:100%;display:block}#sprint-indicator{position:fixed;bottom:50px;left:50%;transform:translate(-50%);color:#ff0;font-size:18px;font-weight:700;letter-spacing:4px;text-shadow:0 0 20px rgba(255,255,0,.8);opacity:0;transition:opacity .2s;z-index:10}#sprint-indicator.active{opacity:1}#danger-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:radial-gradient(ellipse at center,transparent 40%,rgba(255,0,0,.4) 100%);opacity:0;pointer-events:none;z-index:5;transition:opacity .2s}#danger-overlay.active{opacity:1;animation:danger-pulse .4s infinite}@keyframes danger-pulse{0%,to{opacity:.5}50%{opacity:1}}#intro-screen{position:fixed;top:0;right:0;bottom:0;left:0;background:#000;display:flex;align-items:center;justify-content:center;z-index:100;cursor:default}#intro-screen.hidden{display:none}.intro-content{text-align:center;color:#0f0;max-width:600px;padding:40px}.intro-content h1{font-size:72px;margin-bottom:40px;text-shadow:0 0 30px rgba(0,255,0,.5);letter-spacing:15px}.intro-text{font-size:18px;line-height:2.2;margin-bottom:40px;min-height:150px;text-shadow:0 0 8px rgba(0,255,0,.4);white-space:pre-line}#start-btn,#restart-btn,#resume-btn{background:transparent;border:2px solid #0f0;color:#0f0;padding:15px 40px;font-size:18px;font-family:Courier New,monospace;cursor:pointer;transition:all .2s;letter-spacing:2px}#start-btn:hover,#restart-btn:hover,#resume-btn:hover{background:#0f0;color:#000}#pause-menu{position:fixed;top:0;right:0;bottom:0;left:0;background:#000000e6;display:flex;flex-direction:column;align-items:center;justify-content:center;z-index:100;cursor:default}#pause-menu.hidden{display:none}#pause-menu h2{color:#0f0;font-size:48px;margin-bottom:40px;letter-spacing:10px;text-shadow:0 0 20px rgba(0,255,0,.5)}.pause-hint{color:#0f06;font-size:14px;margin-top:20px}#game-over{position:fixed;top:0;right:0;bottom:0;left:0;background:#140000f2;display:flex;flex-direction:column;align-items:center;justify-content:center;z-index:100;cursor:default}#game-over.hidden{display:none}#game-over h1{color:red;font-size:48px;margin-bottom:40px;text-shadow:0 0 30px rgba(255,0,0,.8);animation:flicker .1s infinite;letter-spacing:5px}@keyframes flicker{0%,90%,to{opacity:1}92%,96%{opacity:.2}}#game-over #restart-btn{border-color:red;color:red}#game-over #restart-btn:hover{background:red;color:#000}#instructions{position:fixed;bottom:20px;left:50%;transform:translate(-50%);color:#fff6;font-size:14px;z-index:50}#instructions.hidden{display:none}