#!/usr/bin/perl
use strict;
use warnings;
use CGI qw(:standard);

my $q = CGI->new;

if ($q->param('theme')) {
    my $theme = $q->param('theme');
    my $c = cookie(-name=>'theme', -value=>$theme, -expires=>'+1y', -path=>'/', -secure=>1, -httponly=>1, -samesite=>'Lax');
    print $q->header(-cookie=>$c, -charset=>'UTF-8');
    print "<h2>Тему збережено: $theme</h2>";
} else {
    my $current = cookie('theme') // 'light';
    print $q->header(-charset=>'UTF-8');
    print "<h1>Поточна тема: $current</h1>";
    print qq{
        <form method="get">
            <select name="theme">
                <option value="light">Світла</option>
                <option value="dark">Темна</option>
            </select>
            <button>Зберегти</button>
        </form>
    };
}