:root {
  --sidebar-w: 300px;
  --bg: #ffffff;
  --bg-soft: #f6f8fa;
  --bg-sidebar: #fbfcfd;
  --text: #1f2328;
  --text-soft: #656d76;
  --border: #e3e8ee;
  --accent: #00add8;        /* Go 官方青蓝 */
  --accent-dark: #007d9c;
  --accent-soft: #e6f7fb;
  --code-bg: #f6f8fa;
  --code-text: #1f2328;
  --kw: #cf222e;
  --str: #0a3069;
  --num: #0550ae;
  --com: #6e7781;
  --fn: #8250df;
  --typ: #953800;
  --shadow: 0 1px 3px rgba(0,0,0,.06), 0 8px 24px rgba(0,0,0,.04);
}

[data-theme="dark"] {
  --bg: #0d1117;
  --bg-soft: #161b22;
  --bg-sidebar: #0f141a;
  --text: #e6edf3;
  --text-soft: #8b949e;
  --border: #21262d;
  --accent: #29c7ee;
  --accent-dark: #56d4f5;
  --accent-soft: #0e2a33;
  --code-bg: #161b22;
  --code-text: #e6edf3;
  --kw: #ff7b72;
  --str: #a5d6ff;
  --num: #79c0ff;
  --com: #8b949e;
  --fn: #d2a8ff;
  --typ: #ffa657;
  --shadow: 0 1px 3px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.3);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

#app { display: flex; min-height: 100vh; }

/* ---------- 顶栏 (移动端) ---------- */
.topbar {
  display: none;
  position: sticky; top: 0; z-index: 40;
  align-items: center; gap: 10px;
  padding: 10px 14px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
.topbar-title { font-weight: 700; flex: 1; display: flex; align-items: center; gap: 8px; }
.icon-btn {
  background: transparent; border: none; color: var(--text-soft);
  padding: 6px; border-radius: 8px; cursor: pointer; display: inline-flex;
}
.icon-btn:hover { background: var(--bg-soft); color: var(--text); }

/* ---------- 侧边栏 ---------- */
.sidebar {
  width: var(--sidebar-w);
  flex: 0 0 var(--sidebar-w);
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  height: 100vh; position: sticky; top: 0;
  display: flex; flex-direction: column;
  overflow: hidden;
}
.brand {
  display: flex; align-items: center; gap: 12px;
  padding: 20px 20px 14px;
}
.gopher { font-size: 26px; }
.brand-title { font-weight: 800; font-size: 17px; letter-spacing: .2px; }
.brand-sub { font-size: 12px; color: var(--text-soft); text-transform: uppercase; letter-spacing: 1px; }

.search-box {
  margin: 0 16px 10px; padding: 8px 12px;
  display: flex; align-items: center; gap: 8px;
  background: var(--bg-soft); border: 1px solid var(--border);
  border-radius: 10px; color: var(--text-soft);
}
.search-box input {
  border: none; background: transparent; outline: none;
  color: var(--text); width: 100%; font-size: 14px;
}

.nav { flex: 1; overflow-y: auto; padding: 4px 10px 20px; }
.nav::-webkit-scrollbar { width: 8px; }
.nav::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }

.nav-group { margin-bottom: 4px; }
.nav-group-title {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 12px; margin-top: 6px;
  font-size: 12px; font-weight: 700; letter-spacing: .6px;
  color: var(--text-soft); text-transform: uppercase;
  cursor: pointer; border-radius: 8px; user-select: none;
}
.nav-group-title:hover { background: var(--bg-soft); }
.nav-group-title .chev { transition: transform .2s; opacity: .6; }
.nav-group.collapsed .chev { transform: rotate(-90deg); }
.nav-group.collapsed .nav-items { display: none; }

.nav-items { display: flex; flex-direction: column; gap: 1px; }
.nav-item {
  display: block; padding: 7px 12px 7px 22px;
  font-size: 14px; color: var(--text-soft);
  text-decoration: none; border-radius: 8px;
  border-left: 2px solid transparent;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.nav-item:hover { background: var(--bg-soft); color: var(--text); }
.nav-item.active {
  background: var(--accent-soft); color: var(--accent-dark);
  font-weight: 600; border-left-color: var(--accent);
}
[data-theme="dark"] .nav-item.active { color: var(--accent); }

.sidebar-footer {
  padding: 12px 20px; font-size: 11px; color: var(--text-soft);
  border-top: 1px solid var(--border);
}

.overlay {
  display: none; position: fixed; inset: 0;
  background: rgba(0,0,0,.4); z-index: 30;
}

/* ---------- 内容 ---------- */
.content {
  flex: 1; min-width: 0;
  display: flex; flex-direction: column;
}
.article {
  max-width: 860px; width: 100%;
  margin: 0 auto; padding: 46px 40px 20px;
  flex: 1;
}
.article h1 {
  font-size: 34px; font-weight: 800; margin: 0 0 6px;
  letter-spacing: -.5px;
}
.article .lead { color: var(--text-soft); font-size: 17px; margin: 0 0 30px; }
.article h2 {
  font-size: 24px; font-weight: 700; margin: 40px 0 14px;
  padding-bottom: 8px; border-bottom: 1px solid var(--border);
}
.article h3 { font-size: 18px; font-weight: 700; margin: 28px 0 10px; }
.article p { margin: 12px 0; }
.article ul, .article ol { margin: 12px 0; padding-left: 24px; }
.article li { margin: 5px 0; }
.article a { color: var(--accent-dark); text-decoration: none; }
[data-theme="dark"] .article a { color: var(--accent); }
.article a:hover { text-decoration: underline; }

.article code:not(pre code) {
  background: var(--code-bg); padding: 2px 6px; border-radius: 6px;
  font-family: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  font-size: 85%; color: var(--kw); border: 1px solid var(--border);
}

.note {
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
  padding: 12px 16px; border-radius: 0 8px 8px 0; margin: 18px 0;
}
.note.warn { border-left-color: #d29922; background: rgba(210,153,34,.12); }
.note.tip  { border-left-color: #2da44e; background: rgba(45,164,78,.12); }
.note strong { color: var(--text); }

table {
  width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 14px;
}
th, td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
th { background: var(--bg-soft); font-weight: 700; }

/* ---------- 代码块 ---------- */
.code-block {
  margin: 18px 0; border: 1px solid var(--border);
  border-radius: 12px; overflow: hidden; background: var(--code-bg);
  box-shadow: var(--shadow);
}
.code-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 14px; background: var(--bg-soft);
  border-bottom: 1px solid var(--border); font-size: 12px;
}
.code-head .dots { display: flex; gap: 6px; align-items: center; }
.code-head .dot { width: 11px; height: 11px; border-radius: 50%; }
.dot.r { background: #ff5f56; } .dot.y { background: #ffbd2e; } .dot.g { background: #27c93f; }
.code-head .fname { margin-left: 8px; color: var(--text-soft); font-family: monospace; }
.code-actions { display: flex; gap: 6px; }
.code-btn {
  border: 1px solid var(--border); background: var(--bg);
  color: var(--text-soft); font-size: 12px; padding: 4px 10px;
  border-radius: 7px; cursor: pointer; display: inline-flex; align-items: center; gap: 5px;
}
.code-btn:hover { color: var(--accent-dark); border-color: var(--accent); }
.code-btn.run { color: #fff; background: var(--accent); border-color: var(--accent); }
.code-btn.run:hover { background: var(--accent-dark); }
.code-block pre {
  margin: 0; padding: 16px 18px; overflow-x: auto;
  font-family: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  font-size: 13.5px; line-height: 1.6; color: var(--code-text);
}
.code-block pre::-webkit-scrollbar { height: 8px; }
.code-block pre::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }

/* 语法高亮 */
.tok-kw  { color: var(--kw); font-weight: 600; }
.tok-str { color: var(--str); }
.tok-num { color: var(--num); }
.tok-com { color: var(--com); font-style: italic; }
.tok-fn  { color: var(--fn); }
.tok-typ { color: var(--typ); }

.code-out {
  border-top: 1px dashed var(--border);
  padding: 10px 18px; font-family: monospace; font-size: 13px;
  color: var(--text-soft); background: var(--bg);
}
.code-out .out-label { color: var(--accent-dark); font-weight: 700; font-size: 11px; letter-spacing: .5px; }
[data-theme="dark"] .code-out .out-label { color: var(--accent); }
.code-out pre { margin: 4px 0 0; white-space: pre-wrap; color: var(--text); font-family: inherit; }

/* ---------- 翻页 ---------- */
.pager {
  max-width: 860px; width: 100%; margin: 20px auto 0; padding: 0 40px;
  display: flex; justify-content: space-between; gap: 14px;
}
.pager a {
  flex: 1; text-decoration: none; color: var(--text);
  border: 1px solid var(--border); border-radius: 12px;
  padding: 14px 18px; transition: border-color .15s, transform .15s;
  display: flex; flex-direction: column; gap: 3px;
}
.pager a:hover { border-color: var(--accent); transform: translateY(-1px); }
.pager a.next { text-align: right; align-items: flex-end; }
.pager .p-label { font-size: 12px; color: var(--text-soft); }
.pager .p-title { font-weight: 700; color: var(--accent-dark); }
[data-theme="dark"] .pager .p-title { color: var(--accent); }

.foot {
  max-width: 860px; width: 100%; margin: 30px auto 40px; padding: 20px 40px 0;
  border-top: 1px solid var(--border); color: var(--text-soft); font-size: 13px;
}
kbd {
  background: var(--bg-soft); border: 1px solid var(--border);
  border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px;
  font-family: monospace; font-size: 12px;
}

.no-result { padding: 20px 12px; color: var(--text-soft); font-size: 14px; text-align: center; }

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .topbar { display: flex; }
  .sidebar {
    position: fixed; top: 0; left: 0; z-index: 35;
    transform: translateX(-100%); transition: transform .25s ease;
  }
  #app.nav-open .sidebar { transform: translateX(0); }
  #app.nav-open .overlay { display: block; }
  .article { padding: 26px 20px 20px; }
  .article h1 { font-size: 27px; }
  .pager, .foot { padding-left: 20px; padding-right: 20px; }
  .pager { flex-direction: column; }
}