/* Ben — quiet black and white. System fonts only, so it loads fast everywhere (incl. mainland China). */
:root {
  --paper: #ffffff;
  --ink: #111111;
  --body: #5a5a5a;
  --muted: #9a9a9a;
  --hair: #ececec;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Helvetica Neue", sans-serif;
  --display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Hiragino Sans GB", "Helvetica Neue", sans-serif;
  --rounded: ui-rounded, "SF Pro Rounded", -apple-system, "PingFang SC", sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0b0b0b;
    --ink: #f2f2f2;
    --body: #a3a3a3;
    --muted: #6b6b6b;
    --hair: #222222;
  }
}

* { box-sizing: border-box; }
html { background: var(--paper); }
body {
  margin: 0;
  background: var(--paper);
  color: var(--body);
  font: 16px/1.7 var(--sans);
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
}
::selection { background: var(--ink); color: var(--paper); }

.doc { max-width: 600px; margin: 0 auto; padding: 32px 16px 64px; }

/* Header: logo + wordmark, language on the right */
.top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 96px; }
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none;
  font: 700 19px/1 var(--rounded); letter-spacing: -0.02em;
}
.mark { width: 30px; height: 30px; display: block; overflow: visible; }
.mark rect { fill: #ffffff; stroke: rgba(0, 0, 0, 0.12); stroke-width: 1; vector-effect: non-scaling-stroke; }
.mark path { fill: #111111; }
.lang { font-size: 14px; color: var(--muted); text-decoration: none; }
.lang:hover { color: var(--ink); }

/* Title block */
h1 {
  margin: 0;
  color: var(--ink);
  font: 500 40px/1.15 var(--display);
  letter-spacing: -0.025em;
}
.meta { margin: 10px 0 0; font-size: 14px; color: var(--muted); }
.lede {
  margin: 40px 0 56px;
  color: var(--ink);
  font: 400 20px/1.55 var(--display);
  letter-spacing: -0.01em;
  opacity: 0.78;
}

/* Body */
p { margin: 0 0 1em; }
h2 {
  margin: 56px 0 12px;
  color: var(--ink);
  font: 600 18px/1.4 var(--display);
  letter-spacing: -0.01em;
}
ul, ol { margin: 0 0 1em; padding-left: 1.1em; }
li { margin: 6px 0; padding-left: 0.15em; }
li::marker { color: var(--muted); }
ul ul, ol ol, ul ol, ol ul { margin: 6px 0 2px; }
strong { color: var(--ink); font-weight: 600; }
a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  text-decoration-color: var(--hair);
}
a:hover { text-decoration-color: var(--ink); }
code { font: 0.9em ui-monospace, "SF Mono", Menlo, monospace; color: var(--ink); }

/* The policy ends with the contact section; the footer repeats it quietly */
.foot {
  display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between;
  margin-top: 96px; padding-top: 20px;
  border-top: 1px solid var(--hair);
  font-size: 13px; color: var(--muted);
}
.foot a { color: var(--muted); text-decoration: none; }
.foot a:hover { color: var(--ink); }

@media (max-width: 520px) {
  .top { margin-bottom: 64px; }
  h1 { font-size: 34px; }
  .lede { font-size: 18px; margin: 32px 0 44px; }
  h2 { margin-top: 44px; }
}