Ok figured out the text sizing, but now to redesign\recode the nav so it actually stretches for the bigger font (or would you say keeping the nav font the same but just increasing the content is ok?)
Also how do you read cookie data on the same page they were set? Or do you have to temporarily use a session?
I wouldn't bother with a font-size changer - people who need to have larger/smaller text already know how to, or have another method of, resizing browser text. Save yourself the headache of managing it. Instead just use a scalable unit for your CSS font-sizing- em or %. Simplest 'fix' would be to apply
font-size: 62.5% to body {}, and then a value of 1em will equate to what you're using for 12px.
I also agree on the comments about the width. I think it would benefit from an extra couple of hundred extra px horizontally - give the text some breathing space, and improve the legibility.
I highly recommend using encoded mailto: links, or a contact form, to save the company a ton of spam from email-harvesting bots.
Minor thing, but the footer looks about 15px off-centre, to the right.
Make the "A1" logo clickable, back to the homepage? Some like having that, some don't.
Other than that, looks good to me

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