:root { color-scheme: dark; --bg: #0d1117; --fg: #e6edf3; --muted: #8b949e; --acc: #3fb950; }
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; background: var(--bg); color: var(--fg); font: 18px/1.5 system-ui, sans-serif; display: grid; place-items: center; padding: 16px; }
main { max-width: 640px; width: 100%; }
h1 { color: var(--acc); font-family: ui-monospace, monospace; margin: 0 0 .25em; }
.nivel { color: var(--muted); font-family: ui-monospace, monospace; }
.pista { border-left: 4px solid var(--acc); padding: .5em 1em; background: #161b22; }
code { background: #161b22; padding: .1em .35em; border-radius: 4px; }
form { display: flex; gap: 8px; margin-top: 1.5em; flex-wrap: wrap; }
input, button { font: inherit; padding: .5em .75em; border-radius: 6px; border: 1px solid #30363d; background: #161b22; color: var(--fg); }
input { flex: 1; min-width: 12em; }
button { background: var(--acc); color: #0d1117; border: 0; font-weight: 700; cursor: pointer; }
#error { color: #f85149; min-height: 1.5em; }