/* Màu theo theme của app (lib/theme.dart) */
:root {
  --body: #faf9f6; --card: #ffffff; --border: #e0e0e6; --divider: #efeff5;
  --text1: #1f2226; --text2: #333639; --text3: #767c82;
  --accent: #e8380d; --accent-soft: rgba(232, 56, 13, .08); --accent-line: rgba(232, 56, 13, .25);
  --shadow: 0 1px 2px rgba(16, 16, 20, .04), 0 8px 24px rgba(16, 16, 20, .06);
}
@media (prefers-color-scheme: dark) {
  :root {
    --body: #101014; --card: #18181c; --border: rgba(255,255,255,.12); --divider: rgba(255,255,255,.08);
    --text1: rgba(255,255,255,.9); --text2: rgba(255,255,255,.8); --text3: rgba(255,255,255,.52);
    --accent: #ff5a2e; --accent-soft: rgba(255, 90, 46, .12); --accent-line: rgba(255, 90, 46, .35);
    --shadow: none;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--body); color: var(--text2);
  font: 16px/1.7 Roboto, system-ui, -apple-system, "Segoe UI", sans-serif;
}

/* Header */
.top {
  position: sticky; top: 0; z-index: 1;
  background: color-mix(in srgb, var(--body) 85%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--divider);
}
.top .in { max-width: 760px; margin: 0 auto; padding: 12px 16px; display: flex; align-items: center; gap: 16px; }
.brand { white-space: nowrap; flex-shrink: 0; display: flex; align-items: center; gap: 10px; color: var(--text1); text-decoration: none; font-weight: 700; font-size: 17px; }
.brand img { width: 32px; height: 32px; border-radius: 9px; }
.top nav { margin-left: auto; display: flex; gap: 4px; }
.top nav a { white-space: nowrap; color: var(--text3); text-decoration: none; font-size: 14px; padding: 6px 10px; border-radius: 8px; }
.top nav a:hover { background: var(--accent-soft); color: var(--text1); }
.top nav a[aria-current] { color: var(--accent); font-weight: 600; }

/* Nội dung */
main {
  max-width: 760px; margin: 28px auto; padding: 40px 48px;
  background: var(--card); border: 1px solid var(--border); border-radius: 16px; box-shadow: var(--shadow);
}
h1 { color: var(--text1); font-size: 30px; line-height: 1.25; letter-spacing: -.01em; margin: 0 0 6px; }
.meta { color: var(--text3); font-size: 14px; margin: 0 0 24px; }
.lead { font-size: 17px; }
h2 {
  color: var(--text1); font-size: 19px; line-height: 1.35;
  margin: 36px 0 10px; padding-top: 28px; border-top: 1px solid var(--divider);
}
h1 + .meta + h2, .meta + h2 { border-top: 0; padding-top: 0; }
p { margin: 0 0 12px; }
ul, ol { margin: 0 0 12px; padding-left: 22px; }
li { margin: 6px 0; }
li::marker { color: var(--accent); }
b { color: var(--text1); font-weight: 600; }
a { color: var(--accent); text-underline-offset: 3px; text-decoration-color: var(--accent-line); }
a:hover { text-decoration-color: currentColor; }
code { font-size: 14px; background: var(--accent-soft); color: var(--text1); padding: 1px 6px; border-radius: 6px; }

/* Thẻ chọn trang (index) */
.cards { list-style: none; padding: 0; display: grid; gap: 12px; margin: 8px 0 24px; }
.cards li { margin: 0; }
.cards a {
  display: block; padding: 18px 20px; border: 1px solid var(--border); border-radius: 12px;
  color: var(--text1); text-decoration: none; font-weight: 600;
}
.cards a span { display: block; color: var(--text3); font-weight: 400; font-size: 14px; margin-top: 2px; }
.cards a:hover { border-color: var(--accent-line); background: var(--accent-soft); }

/* Footer */
footer { max-width: 760px; margin: 0 auto 40px; padding: 0 16px; color: var(--text3); font-size: 13px; text-align: center; }
footer a { color: var(--text3); }

@media (max-width: 640px) {
  main { margin: 0; padding: 28px 16px 36px; border: 0; border-radius: 0; box-shadow: none; }
  h1 { font-size: 25px; }
  .top .in { gap: 8px; }
  .top nav a { padding: 6px 6px; font-size: 13px; }
  footer { margin-top: 24px; }
}
@media (max-width: 370px) {
  .brand span { display: none; }
}