:root{--color-bg:#f4f6fa;--color-card:#fff;--color-primary:#38bdf8;--color-secondary:#2563eb;--color-heading:#0f172a;--color-text:#334155;--color-success:#059669;--color-error:#e11d48;--color-border:#e5e7eb;--color-shadow:0 2px 12px rgba(0,0,0,.07)}[data-theme=dark]{--color-bg:#101624;--color-card:#1e2636;--color-primary:#38bdf8;--color-secondary:#2563eb;--color-heading:#e0e7ef;--color-text:#cbd5e1;--color-success:#34d399;--color-error:#f87171;--color-border:#334155;--color-shadow:0 2px 12px rgba(56,189,248,.07)}body{margin:0;padding:0;font-family:Inter,Segoe UI,Roboto,Arial,sans-serif;background:var(--color-bg);color:var(--color-text);transition:background .3s,color .3s}nav{background:#2d3748;padding:1rem 2rem;display:flex;gap:2rem;align-items:center}nav,nav a{color:#fff}nav a{text-decoration:none;font-weight:500}nav a.active{border-bottom:2px solid #38b2ac}.card{background:var(--color-card);border-radius:12px;box-shadow:var(--color-shadow);padding:1.5rem 1.2rem;margin-bottom:1.5rem;transition:background .3s,box-shadow .3s}.container{max-width:900px;margin:0 auto;padding:1.5rem .5rem}h1,h2,h3{color:var(--color-heading);font-family:inherit;font-weight:700;margin-top:0}a{color:var(--color-primary);text-decoration:none;transition:color .2s}a:hover{color:var(--color-secondary)}::-webkit-scrollbar{width:8px;background:var(--color-bg)}::-webkit-scrollbar-thumb{background:var(--color-border);border-radius:8px}