:root{--primary:#2563EB;--accent:#3B82F6;--bg:#EFF6FF;--text:#1E3A8A;--text-muted:#64748B;--card-bg:#fff;--radius:12px;--nav-h:52px;--contact-footer-h:72px;--safe-bottom:env(safe-area-inset-bottom,0px)}
.theme-dark{--bg:#0F172A;--text:#E2E8F0;--text-muted:#94A3B8;--card-bg:#1E293B}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--text);line-height:1.5;padding-bottom:calc(var(--nav-h) + var(--contact-footer-h) + var(--safe-bottom))}
.hidden{display:none!important}
.skip-link{position:absolute;left:-9999px}
.skip-link:focus{left:8px;top:8px;z-index:10001;background:#fff;padding:8px}
#app-main{padding:12px 16px;max-width:960px;margin:0 auto}
.btn{display:inline-flex;align-items:center;justify-content:center;padding:10px 16px;border-radius:999px;border:none;font-size:.875rem;cursor:pointer;text-decoration:none}
.btn-primary{background:var(--primary);color:#fff}
.btn-secondary{background:var(--card-bg);color:var(--text);border:1px solid #cbd5e1}
.btn-block{width:100%}
.btn-sm{padding:6px 12px;font-size:.75rem}
.muted{color:var(--text-muted);font-size:.875rem}
.reveal{opacity:0;transform:translateY(12px);transition:.5s}
.reveal.revealed{opacity:1;transform:none}
.section-title{font-size:1.1rem;margin:16px 0 8px}
.app-loader{position:fixed;inset:0;background:var(--bg);z-index:9998;display:flex;flex-direction:column;align-items:center;justify-content:center;transition:opacity .5s}
.loader-logo{font-size:3rem;animation:pulse 1s infinite}
@keyframes pulse{50%{transform:scale(1.1)}}
.top-bar{position:sticky;top:0;z-index:800;background:var(--card-bg);border-bottom:1px solid #e2e8f0;padding:8px 12px}
.top-brand{font-weight:700;font-size:.875rem;display:block;margin-bottom:6px}
.mode-nav{display:flex;gap:6px;overflow-x:auto}
.mode-tab{flex-shrink:0;padding:6px 12px;border-radius:999px;font-size:.75rem;text-decoration:none;color:var(--text-muted);border:1px solid transparent}
.mode-tab.active{color:var(--primary);border-color:var(--primary);font-weight:600;background:rgba(37,99,235,.08)}