/* a1d2.org — self-contained, no external assets. System fonts only (Google Fonts is blocked in CN). */

:root {
  --ink: #1b1a17;
  --muted: #6d6a63;
  --line: #e7e1d6;
  --bg: #fffdf9;
  --soft: #f8f4ec;
  --accent: #b45309;
  --accent-soft: #fdf1e2;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
               "Noto Sans SC", "Microsoft YaHei", system-ui, "Segoe UI", Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
}

.wrap { max-width: 720px; margin: 0 auto; padding: 0 24px; }

/* ---------- header ---------- */

header.site {
  position: sticky; top: 0; z-index: 5;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 253, 249, 0.93);
  -webkit-backdrop-filter: saturate(1.5) blur(10px);
  backdrop-filter: saturate(1.5) blur(10px);
}

header.site .bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 14px 0;
}

.brand {
  display: flex; align-items: center; gap: 12px;
  color: inherit; text-decoration: none;
}

.brand img { display: block; width: 40px; height: 40px; border-radius: 10px; }

.brand .name { font-size: 17px; font-weight: 600; letter-spacing: 0.01em; line-height: 1.2; }
.brand .sub { display: block; font-size: 12px; font-weight: 400; color: var(--muted); letter-spacing: 0.06em; }

nav.site-nav { display: flex; align-items: center; gap: 4px; }
nav.site-nav a {
  color: var(--muted); text-decoration: none;
  font-size: 14px; padding: 6px 10px; border-radius: 8px;
}
nav.site-nav a:hover { color: var(--accent); background: var(--accent-soft); }

/* ---------- language toggle ---------- */

.langswitch { display: inline-flex; border: 1px solid var(--line); border-radius: 9px; overflow: hidden; }
.langswitch button {
  appearance: none; border: 0; background: transparent;
  font: inherit; font-size: 13px; color: var(--muted);
  padding: 5px 11px; cursor: pointer;
}
.langswitch button.on { background: var(--soft); color: var(--ink); font-weight: 600; }

/* ---------- hero ---------- */

.hero { padding: 68px 0 44px; }
.hero .icon { width: 88px; height: 88px; border-radius: 22px; display: block; margin-bottom: 28px; }
.hero h1 { margin: 0 0 8px; font-size: 40px; line-height: 1.2; letter-spacing: -0.01em; }
.hero .alt { color: var(--muted); font-size: 17px; letter-spacing: 0.02em; margin: 0 0 22px; }
.hero p.lede { font-size: 19px; color: #3d3a34; margin: 0 0 30px; max-width: 34em; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 8px; }

.btn {
  display: inline-block; text-decoration: none; font-size: 15px; font-weight: 600;
  padding: 11px 20px; border-radius: 11px; border: 1px solid var(--line);
  color: var(--ink); background: #fff;
}
.btn:hover { border-color: #d6cec0; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: #9a4608; border-color: #9a4608; }
.btn[aria-disabled="true"] { color: var(--muted); background: var(--soft); cursor: default; }
.btn[aria-disabled="true"]:hover { border-color: var(--line); }

/* ---------- sections ---------- */

section { padding: 44px 0; border-top: 1px solid var(--line); }
section h2 { font-size: 22px; margin: 0 0 20px; letter-spacing: -0.005em; }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; }

.card { background: var(--soft); border: 1px solid var(--line); border-radius: 14px; padding: 20px; }
.card h3 { margin: 0 0 6px; font-size: 16px; }
.card p { margin: 0; font-size: 15px; color: var(--muted); line-height: 1.65; }

ul.checks { list-style: none; padding: 0; margin: 0; }
ul.checks li { position: relative; padding-left: 26px; margin-bottom: 10px; }
ul.checks li::before {
  content: ""; position: absolute; left: 4px; top: 0.72em;
  width: 6px; height: 6px; border-radius: 50%; background: var(--accent);
}

/* ---------- callouts ---------- */

.note {
  background: var(--accent-soft); border: 1px solid #f0dcc0;
  border-radius: 12px; padding: 16px 18px; font-size: 15px; color: #5b4525;
}
.note strong { color: #7a3c06; }

/* ---------- policy prose ---------- */

article.prose { padding: 44px 0 8px; }
article.prose h1 { font-size: 30px; margin: 0 0 6px; letter-spacing: -0.01em; }
article.prose .effective { color: var(--muted); font-size: 15px; margin: 0 0 34px; }
article.prose h2 {
  font-size: 20px; margin: 40px 0 12px; padding-top: 8px;
  border-top: 1px solid var(--line);
}
article.prose h2:first-of-type { border-top: 0; }
article.prose p { margin: 0 0 14px; }
article.prose ul { padding-left: 22px; margin: 0 0 16px; }
article.prose li { margin-bottom: 8px; }
article.prose code {
  background: var(--soft); border: 1px solid var(--line);
  border-radius: 5px; padding: 1px 5px; font-size: 0.88em;
}

table { width: 100%; border-collapse: collapse; margin: 8px 0 22px; font-size: 15px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--soft); font-weight: 600; font-size: 14px; }
td { color: #45423c; }

.lang-jump { display: flex; gap: 10px; margin: 0 0 30px; }

/* ---------- faq ---------- */

details.faq {
  border: 1px solid var(--line); border-radius: 12px;
  padding: 14px 18px; margin-bottom: 10px; background: #fff;
}
details.faq[open] { background: var(--soft); }
details.faq summary { cursor: pointer; font-weight: 600; font-size: 16px; }
details.faq p { margin: 10px 0 0; color: var(--muted); font-size: 15px; }

/* ---------- footer ---------- */

footer.site {
  border-top: 1px solid var(--line); margin-top: 40px;
  padding: 34px 0 56px; font-size: 14px; color: var(--muted);
}
footer.site a { color: var(--muted); }
footer.site .disclaimer { margin-top: 14px; font-size: 13px; line-height: 1.65; }

/* ---------- personal hub ---------- */

.monogram {
  display: grid; place-items: center;
  width: 40px; height: 40px; border-radius: 10px;
  background: var(--accent); color: #fff;
  font-size: 15px; font-weight: 600; letter-spacing: 0.04em;
}

.project {
  display: flex; gap: 16px; align-items: flex-start;
  padding: 20px; margin-bottom: 14px;
  background: var(--soft); border: 1px solid var(--line); border-radius: 14px;
}
.project img { display: block; width: 56px; height: 56px; border-radius: 14px; flex: 0 0 auto; }
.project h3 { margin: 0 0 4px; font-size: 17px; }
.project p { margin: 0 0 10px; font-size: 15px; color: var(--muted); line-height: 1.65; }
.project .more { font-size: 15px; font-weight: 600; color: var(--accent); text-decoration: none; }
.project .more:hover { text-decoration: underline; }

.backlink { font-size: 13px; color: var(--muted); text-decoration: none; }
.backlink:hover { color: var(--accent); background: transparent; }

.hint { font-size: 14px; color: var(--muted); margin-top: 18px; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  .hero { padding: 44px 0 30px; }
  .hero h1 { font-size: 32px; }
  .hero .icon { width: 72px; height: 72px; border-radius: 18px; margin-bottom: 22px; }
  nav.site-nav a { font-size: 13px; padding: 6px 7px; }
  .brand .sub { display: none; }
}