/* Layout: a short promise up top, then form on the left and a sticky preview on the right; one column on phones.
   Single dark theme by design: black ground, white type, no accent colour. Red is reserved for errors. */
:root {
  --bg: #0f1011;
  --surface: #18191b;
  --raised: #222326;
  --line: #2e3034;
  --ink: #f4f4f5;
  --muted: #a1a3a8;
  --faint: #8a8d93;
  --error: #ff7a7a;
  --font: "Roboto", system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
  --mono: "Roboto Mono", ui-monospace, Menlo, Consolas, monospace;
  --radius: 12px;
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 16px/1.55 var(--font);
  padding-inline: 16px;
  padding-block: max(32px, env(safe-area-inset-top, 0px)) max(48px, env(safe-area-inset-bottom, 0px));
}
.wrap { max-width: 1040px; margin: 0 auto; display: grid; gap: 40px; }

/* Promise */
header { display: grid; gap: 20px; }
.lang { display: flex; justify-content: flex-end; gap: 16px; font-size: 14px; margin-bottom: -8px; }
.lang a { color: var(--muted); text-decoration: none; }
.lang a:hover { color: var(--ink); }
.lang [aria-current] { color: var(--ink); }
.nowrap { white-space: nowrap; }
h1 {
  font: 700 clamp(28px, 5vw, 44px)/1.12 var(--font);
  letter-spacing: -0.02em;
  margin: 0;
  max-width: 18ch;
  text-wrap: balance;
}
.facts { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; }
@media (max-width: 900px) { .facts { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 600px) {
  .wrap { gap: 28px; }
  header { gap: 14px; }
  h1 { font-size: 28px; }
  .facts { grid-template-columns: minmax(0, 1fr); gap: 10px; }
  .facts li { padding-top: 10px; }
  .facts li.extra { display: none; }
}
.facts li { display: grid; gap: 4px; align-content: start; border-top: 1px solid var(--line); padding-top: 12px; }
.facts b { font-weight: 500; }
.facts span { color: var(--muted); font-size: 15px; }

.layout { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 400px); gap: 32px; align-items: start; }
@media (max-width: 860px) { .layout { grid-template-columns: minmax(0, 1fr); } }

.form { display: grid; gap: 32px; min-width: 0; }
section.block { display: grid; gap: 14px; min-width: 0; }
h2 { font: 500 20px/1.3 var(--font); margin: 0; }
label { font-weight: 500; font-size: 15px; }
.hint { color: var(--muted); font-size: 14px; margin: 0; }
.field { display: grid; gap: 6px; min-width: 0; }

input[type="text"], input[type="url"] {
  width: 100%;
  font: 400 16px/1.4 var(--mono);
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px;
}
input::placeholder { color: var(--faint); }
input[type="text"]:hover, input[type="url"]:hover { border-color: var(--faint); }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
input[type="text"]:focus-visible, input[type="url"]:focus-visible { outline-offset: 0; border-color: var(--ink); }

.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }

button, .file-btn, a.btn {
  font: 500 15px/1 var(--font);
  border-radius: 8px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  text-decoration: none;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
}
button:hover, .file-btn:hover, a.btn:hover { border-color: var(--muted); }
button.primary { background: var(--ink); color: var(--bg); border-color: var(--ink); }
button.primary:hover { background: #ffffff; }
button:disabled { opacity: .35; cursor: not-allowed; }
.file-btn { position: relative; }
.file-btn input { position: absolute; inset: 0; opacity: 0; cursor: pointer; }

.url-row { display: flex; gap: 8px; }
.url-row input { flex: 1 1 auto; min-width: 0; }
.url-row .btn { flex: none; padding-inline: 14px; }

/* Notices: state is carried by a leading mark; only errors use colour */
.notices { display: grid; gap: 6px; }
.notices:empty { display: none; }
.notice { font-size: 14px; display: flex; gap: 8px; align-items: flex-start; color: var(--muted); }
.notice::before { flex: none; width: 1.1em; text-align: center; font-weight: 700; }
.notice.ok { color: var(--ink); }
.notice.ok::before { content: "✓"; }
.notice.info::before { content: "·"; }
.notice.warn { color: var(--ink); }
.notice.warn::before { content: "!"; }
.notice.bad { color: var(--error); }
.notice.bad::before { content: "×"; }

/* UTM */
.check { display: flex; gap: 12px; align-items: flex-start; font-weight: 400; cursor: pointer; }
.check input { width: 20px; height: 20px; margin: 1px 0 0; accent-color: var(--ink); flex: none; cursor: pointer; }
.check b { font-weight: 500; display: block; }
.utm { display: grid; gap: 16px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius); }
.utm-rules { margin: 0; padding-left: 18px; color: var(--muted); font-size: 14px; display: grid; gap: 2px; }
.utm .field label { display: flex; flex-wrap: wrap; gap: 4px 10px; align-items: baseline; }
.utm .field label code { font: 400 14px/1.3 var(--mono); }
.utm .field label span { font-weight: 400; color: var(--muted); font-size: 14px; }
.opt { color: var(--faint); font-size: 13px; font-weight: 400; }

/* Logo */
.logo-row { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; padding: 14px; border: 1px dashed var(--line); border-radius: var(--radius); }
.logo-row.over { border-color: var(--ink); }
.logo-thumb { width: 56px; height: 56px; border-radius: 8px; background: #ffffff; display: grid; place-items: center; overflow: hidden; flex: none; }
.logo-thumb img { max-width: 46px; max-height: 46px; }
.logo-thumb:empty { background: var(--raised); }
.logo-text { display: grid; gap: 2px; min-width: 0; flex: 1 1 180px; }
.logo-text span:first-child { overflow-wrap: anywhere; }
input[type="range"] { width: 100%; accent-color: var(--ink); }

/* Preview */
.preview { position: sticky; top: calc(env(safe-area-inset-top, 0px) + 16px); display: grid; gap: 18px; min-width: 0;
           background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
@media (max-width: 860px) { .preview { position: static; } }
.qr-box { background: #ffffff; border-radius: 8px; overflow: hidden; }
#qrCanvas { display: block; width: 100%; max-width: 100%; height: auto; aspect-ratio: 1; }
.qr-box.off #qrCanvas { opacity: .12; }
.status { font-size: 15px; font-weight: 500; }
.kv { display: grid; gap: 4px; }
.k { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--faint); }
.encoded { font: 400 13px/1.5 var(--mono); overflow-wrap: anywhere; color: var(--ink); }
.spec { font: 400 12px/1.4 var(--mono); color: var(--faint); font-variant-numeric: tabular-nums; }

.sizes { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 6px; }
.sizes label { position: relative; font: 500 14px/1 var(--font); font-variant-numeric: tabular-nums; }
.sizes input { position: absolute; opacity: 0; pointer-events: none; }
.sizes span { display: block; text-align: center; padding: 10px 2px; border: 1px solid var(--line); border-radius: 8px; cursor: pointer; }
.sizes input:checked + span { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.sizes input:focus-visible + span { outline: 2px solid var(--ink); outline-offset: 2px; }
.downloads { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; }
.downloads button { padding-inline: 6px; }

/* Tips */
.tips { display: grid; gap: 18px; }
.tips ol { margin: 0; padding: 0; list-style: none; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px 32px; counter-reset: tip; }
@media (max-width: 700px) { .tips ol { grid-template-columns: minmax(0, 1fr); } }
.tips li { display: grid; gap: 4px; align-content: start; }
.tips li b { font-weight: 500; }
.tips li span { color: var(--muted); font-size: 15px; }
.tips li a { color: var(--ink); }

/* FAQ */
.faq { display: grid; gap: 14px; }
.faq-list { display: grid; border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; list-style: none; padding: 16px 32px 16px 0; font-weight: 500; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 4px; top: 13px; font-size: 20px; color: var(--muted); }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 0 0 16px; color: var(--muted); max-width: 70ch; }

footer { color: var(--faint); font-size: 13px; border-top: 1px solid var(--line); padding-top: 16px; }
footer a { color: var(--muted); }

/* Article pages: one readable column, the same tokens as the generator */
.topbar { display: flex; justify-content: space-between; align-items: baseline; gap: 16px; font-size: 14px; }
.topbar a { color: var(--muted); text-decoration: none; }
.topbar a:hover { color: var(--ink); }
.topbar .lang { margin: 0; }
.article { max-width: 720px; display: grid; gap: 36px; }
.article header { gap: 16px; }
.article h1 { max-width: none; }
.lead { margin: 0; font-size: 18px; }
.article section { display: grid; gap: 12px; }
.article p { margin: 0; color: var(--muted); }
.article ul, .article ol { margin: 0; padding-left: 22px; color: var(--muted); display: grid; gap: 10px; }
.article li b { color: var(--ink); font-weight: 500; }
.article p a, .article li a { color: var(--ink); }
.article code { font: 400 14px/1.4 var(--mono); color: var(--ink); }
.callout { display: grid; gap: 14px; padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.callout p { color: var(--ink); }
a.cta { justify-self: start; background: var(--ink); color: var(--bg); border-color: var(--ink); }
a.cta:hover { background: #ffffff; border-color: #ffffff; }