:root{--cos-bg:#0f0f12;--cos-surface:#121218;--cos-surface-elevated:#1a1a1f;--cos-border:#2a2a32;--cos-border-muted:#3f3f46;--cos-text:#f5f5f7;--cos-text-muted:#a1a1aa;--cos-text-dim:#71717a;--cos-accent:#6366f1;--cos-accent-hover:#818cf8;--cos-danger:#f87171;--cos-success:#4ade80;--cos-radius:12px;--cos-radius-sm:8px;--cos-space-xs:0.25rem;--cos-space-sm:0.5rem;--cos-space-md:1rem;--cos-space-lg:1.5rem;--cos-space-xl:2rem;--cos-font-sans:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;--cos-max-width:1200px;--cos-nav-height:56px}*{box-sizing:border-box}body,html{margin:0;padding:0;background:var(--cos-bg);color:var(--cos-text);font-family:var(--cos-font-sans);line-height:1.5}a{color:inherit}.cos-container{max-width:var(--cos-max-width);margin:0 auto;padding:var(--cos-space-xl) var(--cos-space-lg)}.cos-card{background:var(--cos-surface-elevated);border:1px solid var(--cos-border);border-radius:var(--cos-radius)}.cos-btn{display:inline-flex;align-items:center;justify-content:center;padding:.5rem 1rem;border-radius:var(--cos-radius-sm);border:none;background:var(--cos-accent);color:#fff;font-size:.875rem;cursor:pointer;text-decoration:none}.cos-btn:disabled{opacity:.6;cursor:wait}.cos-btn-ghost{background:transparent;border:1px solid var(--cos-border-muted);color:var(--cos-text-muted)}.cos-chat-layout{display:grid;grid-template-columns:260px 1fr;grid-gap:var(--cos-space-lg);gap:var(--cos-space-lg);align-items:start}@media (max-width:768px){.cos-chat-layout{grid-template-columns:1fr}}.cos-login-page{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:var(--cos-space-lg);background:radial-gradient(ellipse 80% 60% at 50% -10%,rgba(99,102,241,.18),transparent),var(--cos-bg)}.cos-login-card{width:100%;max-width:420px;padding:var(--cos-space-xl);box-shadow:0 24px 48px rgba(0,0,0,.35)}.cos-login-eyebrow{margin:0 0 var(--cos-space-sm);font-size:.75rem;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--cos-accent-hover)}.cos-login-title{margin:0 0 var(--cos-space-sm);font-size:1.75rem;font-weight:700;line-height:1.2}.cos-login-lead{margin:0 0 var(--cos-space-lg);color:var(--cos-text-muted);font-size:.95rem}.cos-login-error{margin:0 0 var(--cos-space-md);padding:var(--cos-space-sm) var(--cos-space-md);border-radius:var(--cos-radius-sm);background:rgba(248,113,113,.1);border:1px solid rgba(248,113,113,.35);color:var(--cos-danger);font-size:.875rem;text-align:left;word-break:break-word}.cos-login-actions{display:flex;flex-direction:column;gap:var(--cos-space-sm)}.cos-login-btn-primary,.cos-login-btn-secondary{width:100%;padding:.75rem 1rem;font-size:.95rem}.cos-login-spinner{width:2rem;height:2rem;margin:var(--cos-space-md) auto 0;border:2px solid var(--cos-border);border-top-color:var(--cos-accent);border-radius:50%;animation:cos-spin .8s linear infinite}@keyframes cos-spin{to{transform:rotate(1turn)}}