:root {
  --bg: #0f1419; --card: #171d26; --line: #263041; --fg: #e6edf3;
  --muted: #8b98a9; --accent: #3b82f6; --ok: #22c55e; --warn: #f59e0b; --err: #ef4444;
}
@media (prefers-color-scheme: light) {
  :root { --bg:#f4f6f9; --card:#fff; --line:#dfe4ec; --fg:#1a2230; --muted:#5b6779; }
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--fg); line-height: 1.6;
  font-family: "IBM Plex Sans Thai", "Noto Sans Thai", system-ui, sans-serif;
}
nav {
  display: flex; gap: 1.25rem; align-items: center; flex-wrap: wrap;
  padding: .85rem 1.5rem; background: var(--card); border-bottom: 1px solid var(--line);
}
nav .brand { font-weight: 700; letter-spacing: .3px; }
nav a { color: var(--fg); text-decoration: none; opacity: .8; }
nav a:hover { opacity: 1; text-decoration: underline; }
nav .right { margin-left: auto; }
main { max-width: 1000px; margin: 0 auto; padding: 1.5rem; }
.grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(330px, 1fr)); }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: 10px;
  padding: 1.25rem 1.4rem; margin-bottom: 1rem;
}
.card.narrow { max-width: 420px; margin: 4rem auto; }
h1, h2 { margin: 0 0 .6rem; font-size: 1.25rem; }
h1 { font-size: 1.5rem; }
h3 { margin: 1.4rem 0 .4rem; font-size: .95rem; color: var(--muted);
     text-transform: uppercase; letter-spacing: .5px; }
label { display: block; margin: .7rem 0; font-size: .92rem; }
label.check { display: flex; gap: .5rem; align-items: center; }
label.check input { width: auto; margin: 0; }
input, textarea {
  width: 100%; margin-top: .3rem; padding: .55rem .7rem; border-radius: 6px;
  border: 1px solid var(--line); background: var(--bg); color: var(--fg);
  font-family: inherit; font-size: .95rem;
}
textarea { font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: .85rem; }
button, .btn {
  display: inline-block; margin-top: .9rem; padding: .55rem 1.2rem; border: 0;
  border-radius: 6px; background: var(--accent); color: #fff; font: inherit;
  font-weight: 600; cursor: pointer; text-decoration: none;
}
button:hover, .btn:hover { filter: brightness(1.1); }
button:disabled { opacity: .45; cursor: not-allowed; }
button.danger { background: var(--err); }
button.link { background: none; color: var(--fg); padding: 0; margin: 0;
              font-weight: 400; opacity: .8; text-decoration: underline; }
form.inline { display: inline; }
.mt { margin-top: 1rem; }
.muted { color: var(--muted); font-size: .88rem; }
.error { color: var(--err); font-weight: 600; }
.ok { color: var(--ok); font-weight: 600; }
.warn { color: var(--warn); }
code { background: var(--bg); padding: .1rem .35rem; border-radius: 4px;
       font-size: .85em; border: 1px solid var(--line); }
table { width: 100%; border-collapse: collapse; margin-top: .5rem; font-size: .9rem; }
th, td { text-align: left; padding: .4rem .6rem; border-bottom: 1px solid var(--line); }
th { color: var(--muted); font-weight: 600; }
pre.log {
  background: #0b0f14; color: #cbd5e1; padding: 1rem; border-radius: 8px;
  overflow-x: auto; max-height: 65vh; overflow-y: auto; font-size: .82rem;
  white-space: pre-wrap; word-break: break-word; border: 1px solid var(--line);
}