:root{--bg:#f4f6f8;--text:#222;--primary:#1f2937;--accent:#3b82f6}body{background:var(--bg);color:var(--text);font-family:system-ui,sans-serif;margin:0}.header{background:var(--primary);color:#fff;padding:1rem 2rem}.header-inner{align-items:center;display:flex;justify-content:space-between}.layout{display:grid;grid-template-columns:240px 1fr;min-height:calc(100vh - 64px)}.sidebar{background:#fff;border-right:1px solid #ddd;padding:1rem}.sidebar ul{list-style:none;padding:0}.sidebar a{border-radius:6px;color:var(--primary);display:block;padding:.5rem;text-decoration:none}.sidebar a:hover{background:var(--accent);color:#fff}.content{background:#fff;padding:2rem}footer{background:var(--primary);color:#fff;padding:1rem;text-align:center}body.dark{--bg:#111827;--text:#f9fafb;--primary:#030712}