Visual review: does the page actually look right?
Code review checks the code. Visual review checks what the user sees. A two-line style change can completely transform a page, and the code diff won't show that.
You changed two lines of CSS. The code diff looks tiny and harmless. But those two lines moved a button off-screen on mobile, made the text overlap the header, and broke the spacing on three other sections. Code diffs don't show visual impact. Only looking at the actual page does.
After any styling change, look at the page at three sizes: mobile phone (about 375px wide), tablet (about 768px), and desktop (about 1280px). Check that nothing overlaps, nothing overflows, and everything is still readable and usable. Take screenshots if you want to compare before and after.
After every change that touches layout, spacing, fonts, or colors. Technical changes that don't affect visuals can skip this.
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