:root { --bg:#ffffff; --text:#1f2937; --nav:#0f172a; }
body.dark { --bg:#020617; --text:#e5e7eb; --nav:#020617; }
body { font-family:Arial,sans-serif; margin:0; background:var(--bg); color:var(--text); transition:0.3s; }
header { background:var(--nav); padding:15px; display:flex; align-items:center; }
header img { height:40px; margin-right:20px; }
nav a { color:white; margin-right:15px; text-decoration:none; }
.toggle { margin-left:auto; cursor:pointer; color:white; }
section { padding:60px 20px; max-width:1100px; margin:auto; animation:fade 1s; }
@keyframes fade { from {opacity:0; transform:translateY(10px);} to {opacity:1;} }
footer { background:var(--nav); color:white; text-align:center; padding:20px; }