:root{font-family:Trebuchet MS,Tahoma,sans-serif;color:#1e2326;background:radial-gradient(circle at 50% 12%,#d8f0ff,#b7dbf2 45%,#88acc4)}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh}#app{display:grid;min-height:100vh;place-items:center;padding:1.5rem}.page{width:min(760px,100%);text-align:center}h1{margin:0 0 .4rem;font-size:clamp(1.8rem,4vw,2.4rem)}.subtitle{margin:0 0 1rem;color:#3f4a50}.runner-stage{position:relative;height:min(58vw,360px);min-height:240px;border:2px solid #2e4f57;border-radius:14px;overflow:hidden;background:radial-gradient(circle at 72% 24%,#fffac2,#fff0 18%),linear-gradient(180deg,#b9e6ff,#9fd0ef 52%,#7ab1da)}.runner-stage:before{content:"";position:absolute;inset:0;background:repeating-linear-gradient(125deg,#ffffff20 0 12px,#ffffff06 12px 24px);animation:drift 14s linear infinite}.hills{position:absolute;left:-8%;width:116%;border-radius:50%}.hills-far{bottom:34%;height:34%;background:#6d9f86;opacity:.75}.hills-near{bottom:20%;height:36%;background:#4e7f67;opacity:.95}.ground{position:absolute;inset:auto 0 0;height:22%;background:repeating-linear-gradient(90deg,#56753a 0 16px,#4a662f 16px 32px),linear-gradient(180deg,#6c9446,#4a662f);border-top:3px solid #7fa551;animation:scroll-ground .9s linear infinite}.runner{position:absolute;left:28%;bottom:17%;width:96px;height:96px;image-rendering:pixelated;filter:drop-shadow(0 3px 0 #2f4a2a)}@keyframes scroll-ground{0%{background-position:0 0,0 0}to{background-position:-32px 0,0 0}}@keyframes drift{0%{background-position:0 0}to{background-position:220px 0}}@media(max-width:520px){.runner-stage{height:300px;min-height:220px}.runner{left:22%;width:84px;height:84px}}