:root{--primary-color:#4a90d9;--background-color:#fff;--text-color:#333;--sidebar-bg:#2c3e50;--sidebar-text:#ecf0f1;--sidebar-active:#34495e;--border-color:#e0e0e0;--danger-color:#e74c3c;--success-color:#27ae60}*{box-sizing:border-box;margin:0;padding:0}body{background:var(--background-color);color:var(--text-color);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;line-height:1.6}a{color:var(--primary-color);text-decoration:none}a:hover{text-decoration:underline}button{cursor:pointer;border:none;border-radius:4px;padding:8px 16px;font-size:14px;transition:opacity .2s}button:hover{opacity:.85}button:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--primary-color);color:#fff}.btn-danger{background:var(--danger-color);color:#fff}.btn-secondary{color:#fff;background:#95a5a6}input,select,textarea{border:1px solid var(--border-color);border-radius:4px;width:100%;padding:8px 12px;font-size:14px}input:focus,select:focus,textarea:focus{outline:2px solid var(--primary-color);border-color:#0000}table{border-collapse:collapse;width:100%}th,td{text-align:left;border-bottom:1px solid var(--border-color);padding:10px 12px}th{background:#f8f9fa;font-weight:600}.container{max-width:1200px;margin:0 auto;padding:20px}