:root{--bg:#121212;--fg:#e6e6e6;--muted:#999;--accent:#00d4ff;--surface:#1a1a1a}*{box-sizing:border-box}html,body,#app{height:100%}body{margin:0;background:var(--bg);color:var(--fg);font-family:system-ui,Segoe UI,Roboto,Helvetica,Arial,"Apple Color Emoji","Segoe UI Emoji"}main{max-width:720px;margin:0 auto;padding:24px}header{display:flex;gap:8px;align-items:center;justify-content:space-between;padding:16px 24px;background:var(--surface);position:sticky;top:0}nav{display:flex;gap:12px;flex-wrap:wrap}button,.btn{appearance:none;border:none;background:var(--surface);color:var(--fg);padding:18px 24px;border-radius:14px;font-size:18px;cursor:pointer;min-width:140px}button.primary,.btn.primary{background:var(--accent);color:#002a33}button:focus-visible{outline:2px solid var(--accent)}.page-title{font-size:24px;margin:16px 0}.card{background:var(--surface);padding:20px;border-radius:16px}footer{padding:24px;color:var(--muted);text-align:center}.link{color:var(--accent);text-decoration:none}