Header 3D lift makes every page 2-9 px wider than the screen

.site-header gets transform: translateZ(20px) inside a perspective parent, which scales it about 1 %: on a phone it pokes 2 px past both edges (document scrollWidth 392 on a 390 screen; 1036 on an 844 landscape screen because .hud-coords also spills). iOS lets the page wiggle sideways.

Keep the lift but compensate: transform: translateZ(20px) scale(calc(1 - 20 / var(--persp))), or drop translateZ under 900 px and use a box-shadow for depth. Clip .hud-bar (overflow:hidden) and hide .hud-coords under 900 px. (/learn, /beauty and /book-of-law already pin it locally.)