:root{--bg:#f5f5f7;--card-bg:#fff;--text:#1d1d1f;--border:#d2d2d7;--sidebar-bg:#e8e8ed;--primary:#007aff}[data-theme="dark"]{--bg:#1e1e1e;--card-bg:#2c2c2e;--text:#f5f5f7;--border:#3a3a3c;--sidebar-bg:#000}*{box-sizing:border-box;margin:0;padding:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}body{background:var(--bg);color:var(--text)}.app-container{display:flex;height:100vh}.sidebar{width:240px;background:var(--sidebar-bg);padding:20px;display:flex;flex-direction:column;border-right:1px solid var(--border)}.sidebar-header h3{font-size:24px;font-weight:800;margin-bottom:30px;color:var(--primary)}.sidebar nav a{text-decoration:none;color:var(--text);padding:12px;border-radius:8px;margin-bottom:5px;display:block}.sidebar nav a:hover,.sidebar nav a.active{background:var(--card-bg)}.main-content{flex:1;overflow-y:auto}.topbar{padding:20px 40px;border-bottom:1px solid var(--border);background:var(--bg);position:sticky;top:0;z-index:10}.content-area{padding:40px}.card{background:var(--card-bg);border-radius:12px;padding:20px;box-shadow:0 4px 12px rgba(0,0,0,.05);border:1px solid var(--border);margin-bottom:20px}.grid-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:20px}.login-container{display:flex;justify-content:center;align-items:center;height:100vh}.login-card{background:var(--card-bg);padding:40px;border-radius:20px;width:400px;text-align:center}.login-card input,.form-input{width:100%;padding:14px;margin-bottom:15px;border-radius:10px;border:1px solid var(--border);background:var(--bg);color:var(--text)}.btn-primary{width:100%;padding:14px;border-radius:10px;border:none;background:var(--primary);color:#fff;font-weight:600;cursor:pointer}.btn-danger{background:#ff3b30;color:#fff;padding:5px 10px;border:none;border-radius:6px;cursor:pointer;text-decoration:none;font-size:12px}.alert{background:#ff3b30;color:#fff;padding:10px;border-radius:8px;margin-bottom:15px}