:root{--bg: #ffffff;--fg: #1a1a1a;--muted: #666666;--border: #dddddd;--primary: #1f6feb;--correct: #1a7f37;--wrong: #cf222e;--correct-bg: #dafbe1;--wrong-bg: #ffebe9}*{box-sizing:border-box}html,body{margin:0;background:var(--bg);color:var(--fg);font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;font-size:16px;line-height:1.4}main{max-width:640px;margin:0 auto;padding:16px max(16px,env(safe-area-inset-right));padding-left:max(16px,env(safe-area-inset-left));padding-bottom:calc(16px + env(safe-area-inset-bottom))}.bar{position:sticky;top:0;z-index:1;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px;padding:8px max(16px,env(safe-area-inset-right)) 8px max(16px,env(safe-area-inset-left));padding-top:calc(8px + env(safe-area-inset-top));background:var(--bg);border-bottom:1px solid var(--border)}.bar h1{margin:0;font-size:1.25rem}button,select,a.button{min-height:44px;padding:10px 16px;border:1px solid var(--border);border-radius:8px;background:var(--bg);color:var(--fg);font:inherit;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}button.primary,a.button.primary{background:var(--primary);border-color:var(--primary);color:#fff}button:disabled{opacity:.6;cursor:default}.row{display:flex;gap:8px;flex-wrap:wrap}.error{color:var(--wrong)}.muted{color:var(--muted)}.pass{color:var(--correct)}