C
Все проще. Вот примерно вот так, думаю дальше разберешься:
<?php
$time = date('H');
if ($time >= 6 && $time < 12) {
$color = "lightblue";
echo "Утро";
} else if ($time >= 12 && $time < 18) {
$color = "yellow";
echo "День";
} else if ($time >= 18) {
$color = "orange";
echo "Вечер";
} else if ($time >= 0 && $time < 6) {
$color = "darkblue";
echo "Ночь ";
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body style="background-color: <?= $color ?>">
</body>
</html>
Ваще от души)
