/* ─────────────────────────────────────────────────────────────
   Đen và Trắng — stylesheet
   Đơn sắc + một màu nhấn (gỗ kaya). Sáng/tối theo hệ thống,
   hoặc theo nút chuyển (lưu trong localStorage: dvt-theme).
   ───────────────────────────────────────────────────────────── */

:root {
  --paper:   #f6f5f1;
  --ink:     #141414;
  --muted:   #5c5a55;
  --rule:    #e2dfd7;
  --line:    rgba(20, 20, 20, .12);
  --code-bg: #eeece6;
  --accent:  #8f6a2f;          /* gỗ kaya — chỉ cho hover, gạch chân, focus */
  --b-stroke: transparent;     /* viền quân đen (cần khi nền tối) */

  --serif: 'Lora', Georgia, 'Times New Roman', serif;
  --sans:  'Be Vietnam Pro', -apple-system, 'Helvetica Neue', Arial, sans-serif;
  --mono:  ui-monospace, 'SF Mono', Menlo, Consolas, monospace;

  --text:  640px;              /* cột chữ */
  --page:  760px;              /* header, danh sách */
  --wide:  1080px;             /* ảnh rộng */
}

:root[data-theme="dark"] {
  --paper:   #121212;
  --ink:     #ecebe7;
  --muted:   #a3a19b;
  --rule:    #2a2927;
  --line:    rgba(236, 235, 231, .12);
  --code-bg: #1c1c1b;
  --accent:  #d2ae6a;
  --b-stroke: #6b6964;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:   #121212;
    --ink:     #ecebe7;
    --muted:   #a3a19b;
    --rule:    #2a2927;
    --line:    rgba(236, 235, 231, .12);
    --code-bg: #1c1c1b;
    --accent:  #d2ae6a;
    --b-stroke: #6b6964;
  }
}

/* ── Nền tảng ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  transition: background-color .3s, color .3s;
}
a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent); }
:focus-visible { outline: 1px solid var(--accent); outline-offset: 3px; }
::selection { background: var(--ink); color: var(--paper); }
img { max-width: 100%; height: auto; display: block; }
abbr[title] { text-decoration: none; cursor: help; }

.wrap      { max-width: var(--page); margin: 0 auto; padding: 0 24px; }
.wrap-text { max-width: var(--text); margin: 0 auto; padding: 0 24px; }
.wrap-wide { max-width: var(--wide); margin: 0 auto; padding: 0 24px; }

/* ── Quân cờ ──────────────────────────────────────────────── */
.stone-b { fill: #141414; stroke: var(--b-stroke); stroke-width: 1; }
.stone-w { fill: #f7f6f2; stroke: #1a1a1a; stroke-width: 1; }
.stone {
  display: inline-block; flex: 0 0 9px;
  width: 9px; height: 9px; border-radius: 50%;
  align-self: center;
}
.stone.black { background: #141414; box-shadow: 0 0 0 1px var(--b-stroke); }
.stone.white { background: #f7f6f2; box-shadow: 0 0 0 1px #6b6964; }

/* ── Header ───────────────────────────────────────────────── */
.site-header {
  padding-top: 40px;
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
  gap: 16px;
}
.brand { display: flex; align-items: center; gap: 14px; font-size: 19px; letter-spacing: .01em; }
.brand:hover { color: var(--ink); }
.site-nav {
  display: flex; align-items: center; gap: 24px;
  font-family: var(--sans); font-size: 14px; font-weight: 300; color: var(--muted);
}
.site-nav a[aria-current="page"] { color: var(--ink); }
.theme-toggle {
  width: 44px; height: 44px; margin-right: -12px;
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: 0; padding: 0; cursor: pointer; color: var(--ink);
}
.theme-toggle:hover { color: var(--accent); }

/* ── Trang chủ ────────────────────────────────────────────── */
.intro { padding-top: 120px; padding-bottom: 96px; }
.intro p { margin: 0; max-width: 520px; font-size: 26px; line-height: 1.55; color: var(--muted); }

.post-list { list-style: none; margin: 0; padding: 0; border-bottom: 1px solid var(--rule); }
.post-list .row {
  display: flex; align-items: baseline; gap: 20px;
  padding: 16px 0; border-top: 1px solid var(--rule);
}
.post-list .row:hover { color: inherit; }
.post-list .t { flex: 1 1 auto; min-width: 0; font-size: 20px; line-height: 1.4; }
.post-list .row:hover .t {
  text-decoration: underline; text-decoration-color: var(--accent);
  text-decoration-thickness: 1px; text-underline-offset: 4px;
}
.move {
  flex: 0 0 52px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; letter-spacing: .04em;
  color: var(--muted); white-space: nowrap;
}
.post-list time {
  flex: 0 0 auto;
  font-family: var(--sans); font-size: 13px; font-weight: 300;
  font-variant-numeric: tabular-nums; color: var(--muted);
}

.home-photo { padding-top: 120px; }
.home-photo figure, figure.flickr { margin: 0; }
.home-photo figcaption, figure.flickr figcaption {
  margin-top: 12px;
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 24px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
}
.home-photo figcaption span { font-family: var(--serif); font-size: 15px; font-style: italic; color: var(--ink); }

/* ── Bài viết ─────────────────────────────────────────────── */
.post-head { padding-top: 120px; padding-bottom: 56px; }
.post-meta {
  margin: 0 0 18px; display: flex; gap: 14px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.post-meta .move { flex: none; }
.post-head h1 {
  margin: 0; font-weight: 400;
  font-size: clamp(32px, 4.2vw, 44px); line-height: 1.2; letter-spacing: -.005em;
}

.prose { font-size: 19px; line-height: 1.85; }
.prose > * { margin-top: 0; margin-bottom: 26px; }
.prose h2, .prose h3 { font-weight: 500; line-height: 1.3; margin-top: 56px; margin-bottom: 18px; }
.prose h2 { font-size: 26px; }
.prose h3 { font-size: 21px; }
.prose a { text-decoration: underline; text-decoration-color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
.prose blockquote { margin-left: 0; margin-right: 0; padding-left: 28px; font-style: italic; color: var(--muted); }
.prose blockquote > :last-child { margin-bottom: 0; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose li { margin-bottom: 6px; }
.prose hr {
  border: 0; height: 6px; width: 6px; border-radius: 50%;
  background: var(--ink); margin: 56px auto;
}
.prose table { border-collapse: collapse; width: 100%; font-size: 16px; display: block; overflow-x: auto; }
.prose th, .prose td { padding: 8px 12px; border-bottom: 1px solid var(--rule); text-align: left; }
.prose th { font-family: var(--sans); font-weight: 500; font-size: 13px; color: var(--muted); }

.prose code {
  font-family: var(--mono); font-size: .84em;
  background: var(--code-bg); padding: .1em .35em; border-radius: 3px;
}
.prose pre {
  font-family: var(--mono); font-size: 14px; line-height: 1.6;
  background: var(--code-bg); padding: 18px 20px; overflow-x: auto; border-radius: 3px;
}
.prose pre code { background: none; padding: 0; font-size: inherit; }
.prose .highlighter-rouge { margin-bottom: 26px; }
.prose .highlighter-rouge pre { margin: 0; }
/* Tô cú pháp đơn sắc */
.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs, .highlight .cp { color: var(--muted); font-style: italic; }
.highlight .k, .highlight .kd, .highlight .kn, .highlight .kr, .highlight .kc, .highlight .ow, .highlight .nf, .highlight .nc { font-weight: 600; }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sd, .highlight .m, .highlight .mi, .highlight .mf { color: var(--muted); }

/* Công thức: cuộn ngang khi quá rộng */
mjx-container[display="true"] { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

/* Ảnh Flickr trong bài */
figure.flickr { margin: 40px 0; }
figure.flickr.wide {
  width: min(calc(var(--wide) - 48px), calc(100vw - 48px));
  position: relative; left: 50%; transform: translateX(-50%);
  margin-top: 64px; margin-bottom: 64px;
}

/* Ván cờ SGF (assets/js/sgf.js) */
/* --board: mặt bàn. Sáng: trong suốt. Tối: sáng hơn nền trang một chút để quân đen nổi lên. */
:root { --grid: rgba(20, 20, 20, .32); --board: transparent; }
:root[data-theme="dark"] { --grid: rgba(236, 235, 231, .22); --board: #34322e; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --grid: rgba(236, 235, 231, .22); --board: #34322e; } }
.sgf-bg { fill: var(--board); }

figure.sgf { margin: 48px 0; outline-offset: 8px; }
.sgf-view > * { max-width: 560px; margin-left: auto; margin-right: auto; }
.sgf-info {
  display: flex; flex-wrap: wrap; align-items: center; gap: 6px 18px; margin-bottom: 14px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
}
.sgf-player { display: inline-flex; align-items: center; gap: 8px; color: var(--ink); font-weight: 400; }
.sgf-player small { font-size: 12px; color: var(--muted); font-weight: 300; }
.sgf-meta { margin-left: auto; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.sgf-board svg { display: block; width: 100%; height: auto; }
.sgf-grid { stroke: var(--grid); stroke-width: 1; }
.sgf-edge { stroke: var(--ink); stroke-opacity: .6; stroke-width: 1.6; }
.sgf-hoshi { fill: var(--muted); }
.sgf-coord {
  font-family: var(--sans); font-size: 11px; fill: var(--muted);
  text-anchor: middle; dominant-baseline: central;
}
.sgf-num { font-family: var(--sans); font-weight: 500; text-anchor: middle; dominant-baseline: central; }
.sgf-num.on-b { fill: #f7f6f2; }
.sgf-num.on-w { fill: #141414; }
.sgf-last { fill: none; stroke-width: 1.6; }
.sgf-last.on-b { stroke: #f7f6f2; }
.sgf-last.on-w { stroke: #141414; }
.sgf-range { display: block; width: 100%; margin-top: 14px; accent-color: var(--ink); }
.sgf-controls {
  display: flex; align-items: center; justify-content: center; gap: 2px; margin-top: 4px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
}
.sgf-controls button {
  width: 44px; height: 44px; padding: 0; border: 0; background: none; cursor: pointer;
  font-family: var(--sans); font-size: 20px; line-height: 1; color: var(--ink);
}
.sgf-controls button:hover { color: var(--accent); }
.sgf-controls button:disabled { opacity: .25; cursor: default; color: var(--ink); }
.sgf-count { min-width: 120px; text-align: center; font-variant-numeric: tabular-nums; letter-spacing: .04em; }
.prose .sgf-comment {
  margin-top: 8px; margin-bottom: 0;
  font-size: 16px; line-height: 1.7; font-style: italic; color: var(--muted); white-space: pre-line;
  max-height: 13.6em; overflow-y: auto;          /* bình luận dài thì cuộn trong khung */
}
.sgf-foot {
  max-width: 560px; margin: 12px auto 0;
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 24px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
}
.prose .sgf-foot a { text-decoration: none; }
.sgf-error { font-family: var(--sans); font-size: 14px; color: var(--muted); }

.end-mark {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--ink); margin: 72px auto 0;
}

.post-foot {
  margin-top: 72px;
  display: flex; flex-direction: column; gap: 14px;
  font-family: var(--sans); font-size: 14px; font-weight: 300; color: var(--muted);
}
.post-foot .tags { margin: 0; display: flex; flex-wrap: wrap; gap: 16px; }
.post-nav { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }

.comments { margin-top: 56px; }

/* ── 404 ──────────────────────────────────────────────────── */
.notfound { padding-top: 160px; color: var(--muted); }
.notfound .big { font-size: 44px; color: var(--ink); margin: 0 0 16px; }
.notfound a { text-decoration: underline; text-decoration-color: var(--accent); text-underline-offset: 3px; }

/* ── Footer ───────────────────────────────────────────────── */
.site-footer {
  padding-top: 120px; padding-bottom: 48px;
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 16px;
  font-family: var(--sans); font-size: 13px; font-weight: 300; color: var(--muted);
}
.site-footer .links { display: flex; gap: 20px; }

/* ── Màn hình hẹp ─────────────────────────────────────────── */
@media (max-width: 600px) {
  body { font-size: 17px; }
  .site-header { padding-top: 24px; }
  .intro { padding-top: 72px; padding-bottom: 56px; }
  .intro p { font-size: 22px; }
  .post-list .row { flex-wrap: wrap; gap: 4px 14px; }
  .post-list .t { flex-basis: calc(100% - 23px); order: 3; margin-left: 23px; font-size: 18px; }
  .move { flex-basis: auto; }
  .post-list time { margin-left: auto; }
  .post-head { padding-top: 72px; padding-bottom: 40px; }
  .prose { font-size: 18px; line-height: 1.8; }
  .home-photo, .site-footer { padding-top: 80px; }
}

@media print {
  .site-header, .site-footer, .post-nav, .comments { display: none; }
  body { background: #fff; color: #000; }
}