:root { color-scheme: light dark; --bg: #fff; --fg: #1a1a1a; --muted: #666; --line: #ddd; --accent: #1a1a1a; --on-accent: #fff; --bad: #b3261e; }
@media (prefers-color-scheme: dark) { :root { --bg: #161616; --fg: #eee; --muted: #aaa; --line: #3a3a3a; --accent: #eee; --on-accent: #161616; --bad: #f2b8b5; } }
* { box-sizing: border-box; }
body { margin: 0; min-height: 100dvh; display: grid; place-items: center; padding: 16px; background: var(--bg); color: var(--fg); font: 16px/1.45 system-ui, -apple-system, "Segoe UI", sans-serif; }
main { width: 100%; max-width: 340px; display: grid; gap: 14px; }
h1 { margin: 0 0 6px; font-size: 22px; font-weight: 600; }
button { width: 100%; min-height: 46px; border: 1px solid var(--accent); border-radius: 8px; background: var(--accent); color: var(--on-accent); font: inherit; font-weight: 600; cursor: pointer; }
button:disabled { opacity: 0.5; cursor: default; }
#check { background: transparent; color: var(--fg); }
#status { margin: 0; min-height: 1.45em; color: var(--muted); }
#status.bad { color: var(--bad); }
details { border-top: 1px solid var(--line); padding-top: 12px; }
details[open] { display: grid; gap: 10px; }
summary { cursor: pointer; color: var(--muted); }
label { display: block; margin-top: 10px; font-size: 14px; color: var(--muted); }
input { width: 100%; min-height: 46px; padding: 0 12px; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: var(--fg); font: 16px ui-monospace, Consolas, monospace; letter-spacing: 0.04em; }
[hidden] { display: none; }