:root{--bg-primary: #ffffff;--bg-secondary: #f5f5f5;--bg-tertiary: #e8e8e8;--text-primary: #1a1a1a;--text-secondary: #666666;--text-muted: #999999;--accent: #4a90d9;--accent-hover: #3a7bc8;--border: #e0e0e0;--shadow: 0 2px 8px rgba(0, 0, 0, .08);--radius: 8px;--radius-sm: 4px;--danger: #e74c3c;--success: #27ae60;--warning: #f39c12;--msg-user: #e3f2fd;--msg-assistant: #f5f5f5}[data-theme=dark]{--bg-primary: #1a1a2e;--bg-secondary: #16213e;--bg-tertiary: #0f3460;--text-primary: #e0e0e0;--text-secondary: #a0a0a0;--text-muted: #707070;--accent: #64b5f6;--accent-hover: #42a5f5;--border: #2a2a4a;--shadow: 0 2px 8px rgba(0, 0, 0, .3);--danger: #ef5350;--success: #66bb6a;--warning: #ffa726;--msg-user: #1a3a5c;--msg-assistant: #1e1e3a}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg-primary);color:var(--text-primary);line-height:1.5;min-height:100vh}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}button{cursor:pointer;font-family:inherit;font-size:inherit}input,textarea,select{font-family:inherit;font-size:inherit}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border:none;border-radius:var(--radius-sm);font-weight:500;transition:background .2s,opacity .2s}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover:not(:disabled){background:var(--accent-hover)}.btn-secondary{background:var(--bg-tertiary);color:var(--text-primary);border:1px solid var(--border)}.btn-danger{background:var(--danger);color:#fff}.input{width:100%;padding:8px 12px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--bg-primary);color:var(--text-primary);outline:none;transition:border-color .2s}.input:focus{border-color:var(--accent)}.textarea{width:100%;padding:8px 12px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--bg-primary);color:var(--text-primary);outline:none;resize:vertical;min-height:100px;transition:border-color .2s}.textarea:focus{border-color:var(--accent)}