:root{--brand:#008c69;--brand-dark:#006b51;--brand-light:#e6f5f0;--ink:#0a0a0a;--bg:#f5f7f6;--card:#fff;--muted:#8a8f8c;--warn:#e8943a;--border:#e7ebe9;--radius:14px}*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}body,html{margin:0;padding:0;background:var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Microsoft YaHei,sans-serif}a{color:var(--brand);text-decoration:none}button{font-family:inherit}.app-shell{max-width:480px;margin:0 auto;min-height:100vh;background:var(--bg);position:relative;padding-bottom:64px}.topbar{background:var(--brand);color:#fff;padding:14px 16px;font-weight:600;font-size:17px;position:-webkit-sticky;position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between}.topbar .sub{font-size:12px;opacity:.85;font-weight:400}.card{background:var(--card);border-radius:var(--radius);padding:16px;margin:12px;box-shadow:0 2px 10px rgba(0,0,0,.04)}.btn{display:block;width:100%;border:none;border-radius:999px;background:var(--brand);color:#fff;padding:13px;font-size:16px;font-weight:600;cursor:pointer}.btn:active{background:var(--brand-dark)}.btn.ghost{background:#fff;color:var(--brand);border:1px solid var(--brand)}.btn.warn{background:var(--warn)}.btn[disabled]{opacity:.5}.tabbar{position:fixed;bottom:0;left:50%;transform:translateX(-50%);width:100%;max-width:480px;display:flex;background:#fff;border-top:1px solid var(--border);z-index:30}.tabbar a{flex:1 1;text-align:center;padding:8px 0;font-size:11px;color:var(--muted)}.tabbar a.active{color:var(--brand)}.tabbar a .ic{font-size:20px;display:block;line-height:1.1}.tag{display:inline-block;background:var(--brand-light);color:var(--brand);border-radius:6px;padding:2px 8px;font-size:12px}.tier-badge{background:var(--brand);color:#fff;border-radius:999px;padding:4px 12px;font-size:13px;font-weight:600}.muted{color:var(--muted);font-size:13px}input,select,textarea{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:10px;font-size:15px;margin:6px 0;background:#fff}.q{background:#fff;border-radius:12px;padding:14px;margin:10px 12px}.q .stem{font-size:15px;font-weight:500}.opt{display:block;padding:11px 12px;border:1px solid var(--border);border-radius:10px;margin-top:8px;cursor:pointer}.opt.sel{border-color:var(--brand);background:var(--brand-light)}.bubble{padding:10px 12px;border-radius:12px;margin:8px 0;max-width:85%}.bubble.user{background:var(--brand);color:#fff;margin-left:auto}.bubble.ai{background:#fff;border:1px solid var(--border)}.row{display:flex;gap:10px}.row>*{flex:1 1}.center{text-align:center}.big{font-size:30px;font-weight:700;color:var(--brand)}