:root{--brand:#6c63ff;--brand-dark:#4b44cc;--brand-light:#ede9ff;--bg:#f8f8fc;--surface:#fff;--text:#1a1a2e;--text-muted:#6b7280;--border:#e5e7eb;--danger:#ef4444;--success:#10b981;--radius:10px;--shadow:0 1px 4px #00000014}*{box-sizing:border-box;margin:0;padding:0}body{background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-size:15px;line-height:1.5}.btn{border-radius:var(--radius);cursor:pointer;border:none;justify-content:center;align-items:center;gap:6px;padding:10px 20px;font-size:14px;font-weight:600;text-decoration:none;transition:opacity .15s,transform .1s;display:inline-flex}.btn:active{transform:scale(.98)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--brand);color:#fff}.btn-primary:hover{background:var(--brand-dark)}.btn-secondary{background:var(--border);color:var(--text)}.btn-secondary:hover{background:#d1d5db}.btn-danger{background:var(--danger);color:#fff}.btn-full{width:100%}.form-group{flex-direction:column;gap:6px;margin-bottom:16px;display:flex}.form-group label{color:var(--text-muted);text-transform:uppercase;letter-spacing:.05em;font-size:13px;font-weight:600}.form-group input,.form-group select{border:1.5px solid var(--border);border-radius:var(--radius);background:var(--surface);color:var(--text);outline:none;padding:10px 14px;font-size:15px;transition:border-color .15s}.form-group input:focus,.form-group select:focus{border-color:var(--brand)}.card{background:var(--surface);border-radius:var(--radius);box-shadow:var(--shadow);border:1px solid var(--border);padding:24px}.auth-page{background:linear-gradient(135deg,#f0eeff 0%,#f8f8fc 100%);justify-content:center;align-items:center;min-height:100vh;padding:24px;display:flex}.auth-card{background:var(--surface);border-radius:16px;width:100%;max-width:420px;padding:40px;box-shadow:0 4px 24px #6c63ff1a}.auth-logo{color:var(--brand);letter-spacing:-.03em;margin-bottom:8px;font-size:2rem;font-weight:800}.auth-subtitle{color:var(--text-muted);margin-bottom:28px;font-size:14px}.auth-footer{text-align:center;color:var(--text-muted);margin-top:20px;font-size:14px}.auth-footer a{color:var(--brand);font-weight:600;text-decoration:none}.alert{border-radius:var(--radius);margin-bottom:16px;padding:12px 16px;font-size:14px}.alert-error{color:var(--danger);background:#fef2f2;border:1px solid #fecaca}.alert-success{color:var(--success);background:#f0fdf4;border:1px solid #bbf7d0}.app-layout{height:100vh;display:flex;overflow:hidden}.sidebar{background:var(--surface);border-right:1px solid var(--border);flex-direction:column;flex-shrink:0;width:300px;display:flex}.sidebar-header{border-bottom:1px solid var(--border);justify-content:space-between;align-items:center;padding:20px;display:flex}.sidebar-logo{color:var(--brand);letter-spacing:-.03em;font-size:1.3rem;font-weight:800}.sidebar-content{flex:1;overflow-y:auto}.main-content{flex-direction:column;flex:1;display:flex;overflow:hidden}.conv-list{padding:8px}.conv-item{border-radius:var(--radius);cursor:pointer;margin-bottom:2px;padding:12px;transition:background .1s}.conv-item:hover{background:var(--bg)}.conv-item--active{background:var(--brand-light)}.conv-item-name{font-size:14px;font-weight:600}.conv-item-preview{color:var(--text-muted);white-space:nowrap;text-overflow:ellipsis;margin-top:2px;font-size:13px;overflow:hidden}.chat-header{border-bottom:1px solid var(--border);background:var(--surface);padding:16px 20px;font-weight:600}.chat-messages{flex-direction:column;flex:1;gap:12px;padding:20px;display:flex;overflow-y:auto}.chat-input-row{border-top:1px solid var(--border);background:var(--surface);gap:10px;padding:16px;display:flex}.chat-input{border:1.5px solid var(--border);resize:none;border-radius:24px;outline:none;flex:1;padding:10px 14px;font-size:15px}.chat-input:focus{border-color:var(--brand)}.bubble-wrap{flex-direction:column;max-width:70%;display:flex}.bubble-wrap--own{align-self:flex-end;align-items:flex-end}.bubble-wrap--other{align-self:flex-start;align-items:flex-start}.bubble{border-radius:18px;padding:10px 14px;font-size:15px;line-height:1.4}.bubble--own{background:var(--brand);color:#fff;border-bottom-right-radius:4px}.bubble--other{background:var(--surface);border:1px solid var(--border);border-bottom-left-radius:4px}.bubble-meta{color:var(--text-muted);margin-top:4px;font-size:11px}.empty-state{color:var(--text-muted);text-align:center;flex-direction:column;flex:1;justify-content:center;align-items:center;gap:12px;padding:40px;display:flex}.empty-state-icon{font-size:3rem}.usage-bar-track{background:var(--border);border-radius:99px;height:6px;margin-top:6px;overflow:hidden}.usage-bar-fill{background:var(--brand);border-radius:99px;height:100%;transition:width .3s}.page{max-width:800px;margin:0 auto;padding:32px}.page-header{justify-content:space-between;align-items:center;margin-bottom:28px;display:flex}.page-title{font-size:1.5rem;font-weight:700}@media (width<=640px){.sidebar{z-index:10;width:100%;position:absolute}.auth-card{padding:28px 20px}}