:root {
  --bg: #f7f5f2;
  --surface: #ffffff;
  --text: #1d1b19;
  --muted: #6b6560;
  --line: #e4dfd8;
  --accent: #c2410c;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141312;
    --surface: #1d1c1a;
    --text: #f2efeb;
    --muted: #a39d96;
    --line: #2f2c29;
    --accent: #fb923c;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px 16px 72px;
}

header.site {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.brand-mark {
  display: grid;
  grid-template-columns: repeat(2, 11px);
  gap: 3px;
}

.brand-mark span {
  width: 11px;
  height: 11px;
  border-radius: 2px;
  background: var(--accent);
}

.brand-mark span:nth-child(2) { opacity: 0.7; }
.brand-mark span:nth-child(3) { opacity: 0.45; }
.brand-mark span:nth-child(4) { opacity: 0.85; }

nav.lang {
  display: flex;
  gap: 4px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
}

nav.lang a {
  padding: 4px 12px;
  border-radius: 999px;
  color: var(--muted);
  font-size: 14px;
  text-decoration: none;
}

nav.lang a[aria-current="true"] {
  background: var(--text);
  color: var(--bg);
}

h1 {
  margin: 0 0 6px;
  font-size: 34px;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h2 {
  margin: 40px 0 10px;
  font-size: 21px;
  line-height: 1.3;
}

h3 {
  margin: 24px 0 6px;
  font-size: 17px;
}

p, ul { margin: 0 0 14px; }

ul { padding-left: 22px; }

li { margin-bottom: 6px; }

a { color: var(--accent); }

.meta {
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 15px;
}

.summary {
  margin: 0 0 8px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
}

.summary ul { margin: 0; }

details {
  border-top: 1px solid var(--line);
  padding: 14px 0;
}

details:last-of-type { border-bottom: 1px solid var(--line); }

summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  position: relative;
  padding-right: 28px;
}

summary::-webkit-details-marker { display: none; }

summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  top: -1px;
  color: var(--muted);
  font-weight: 400;
  font-size: 20px;
}

details[open] > summary::after { content: "−"; }

details > *:not(summary) { margin-top: 10px; }

.contact {
  margin-top: 40px;
  padding: 18px 20px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--line);
}

footer {
  margin-top: 56px;
  color: var(--muted);
  font-size: 14px;
}

footer a { color: var(--muted); }

/* With JavaScript, only the chosen language shows; without it, both do. */
.js [data-lang]:not(.active) { display: none; }

[data-lang] + [data-lang] {
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid var(--line);
}

.js [data-lang] + [data-lang] {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

@media (max-width: 480px) {
  body { font-size: 16px; }
  main { padding-top: 24px; }
  h1 { font-size: 28px; }
}