TITLE: HELIOS/OS FILE: 019-phosphor-terminal.html === PROMPT (exact prompt used) === Build "HELIOS/OS v2.3", a retro CRT terminal operating system simulation. Full-screen phosphor green (#33ff66 on #031a07) with themes for amber (#ffb000 on #1a0f00) and ice (#9fe7ff). CRT effects in CSS/canvas: scanlines, subtle screen curvature (vignette, rounded corners, inner shadow), phosphor glow/bloom text-shadow, gentle flicker and a rolling refresh bar. On load: a believable BIOS boot sequence (memory check counting up, device list) followed by a login banner. A working shell with an input line and blinking block caret supporting: help, ls, cat (several short fictional files including a poem and a mission log), clear, date, whoami, theme , matrix (glyph rain for a few seconds), weather (ASCII art), snake (a small playable ASCII snake game inside the terminal), command history with ↑/↓, and tab completion. Typography: a monospace stack. Keyboard-first, with tap-to-focus on phones so the soft keyboard appears. Optional typing sounds (Web Audio clicks, off by default). SHARED REQUIREMENTS (apply to every page in this 100-page collection): 1. One standalone HTML5 file. All CSS inline in