:root{--fb-blue: #1877f2;--fb-blue-dark: #0b5fce;--fb-bg: #f0f2f5;--fb-card: #ffffff;--fb-text: #14171a;--fb-muted: #65676b;--fb-line: #dcdfe4;--fb-radius: 12px}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--fb-bg);color:var(--fb-text)}.fb-screen{max-width:480px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column;background:var(--fb-bg)}.fb-topbar{display:flex;align-items:center;justify-content:space-between;padding:14px 16px;background:var(--fb-card);border-bottom:1px solid var(--fb-line)}.fb-wordmark{font-weight:800;letter-spacing:-.03em;color:var(--fb-blue)}.fb-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;width:100%;padding:12px;border:none;border-radius:var(--fb-radius);background:var(--fb-blue);color:#fff;font-weight:650;font-size:15px;cursor:pointer}.fb-btn:disabled{opacity:.5;cursor:default}.fb-btn.sec{background:var(--fb-card);color:var(--fb-text);border:1px solid var(--fb-line)}.fb-field{display:flex;flex-direction:column;gap:4px;margin-bottom:12px}.fb-field label{font-size:12px;font-weight:600;color:var(--fb-muted)}.fb-field input{padding:11px 12px;border:1px solid var(--fb-line);border-radius:var(--fb-radius);font-size:15px;background:var(--fb-card)}.fb-icon{width:1.4em;height:1.4em;stroke:currentColor;fill:none;stroke-width:1.9;stroke-linecap:round;stroke-linejoin:round;vertical-align:middle}