/* ============ 设计变量 ============ */
:root {
  --bg: #ffffff;
  --bg-soft: #f6f5f1;
  --bg-hover: #f1efe9;
  --ink: #18181b;
  --ink-2: #43434b;
  --ink-3: #7b7b85;
  --line: #e8e6e0;
  --line-2: #d9d6ce;
  --brand: #ffd60a;
  --brand-ink: #18181b;
  --mark: #fff3b0;
  --answer-bg: #fffbea;
  --answer-line: #f2cf27;
  --ok: #16803c;
  --accent: #c2410c;
  --link: #1f5fbf;
  --code-bg: #f6f5f1;
  --shadow: 0 1px 2px rgba(0,0,0,.04), 0 12px 32px rgba(0,0,0,.08);
  --radius: 10px;
  --top-h: 58px;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  /* 代码高亮 */
  --c-kw: #a626a4; --c-str: #2f7d32; --c-num: #b35a00; --c-com: #8b8b93; --c-fn: #1f5fbf; --c-type: #b8860b;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #141416; --bg-soft: #1c1c20; --bg-hover: #232328; --ink: #ececea; --ink-2: #bcbcb8; --ink-3: #85858c;
    --line: #2b2b31; --line-2: #3a3a42; --mark: #5a4a00; --answer-bg: #241f0c; --answer-line: #b89a10; --ok: #4cc488;
    --accent: #ff8a5c; --link: #7fb0ff; --code-bg: #1b1b1f; --shadow: 0 1px 2px rgba(0,0,0,.4), 0 12px 32px rgba(0,0,0,.5);
    --c-kw: #d58cf0; --c-str: #8fd18f; --c-num: #f0b26b; --c-com: #7d7d86; --c-fn: #7fb0ff; --c-type: #e5c76b;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #141416; --bg-soft: #1c1c20; --bg-hover: #232328; --ink: #ececea; --ink-2: #bcbcb8; --ink-3: #85858c;
  --line: #2b2b31; --line-2: #3a3a42; --mark: #5a4a00; --answer-bg: #241f0c; --answer-line: #b89a10; --ok: #4cc488;
  --accent: #ff8a5c; --link: #7fb0ff; --code-bg: #1b1b1f; --shadow: 0 1px 2px rgba(0,0,0,.4), 0 12px 32px rgba(0,0,0,.5);
  --c-kw: #d58cf0; --c-str: #8fd18f; --c-num: #f0b26b; --c-com: #7d7d86; --c-fn: #7fb0ff; --c-type: #e5c76b;
  color-scheme: dark;
}

/* ============ 基础 ============ */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: calc(var(--top-h) + 16px); }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.7 -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", sans-serif;
  -webkit-font-smoothing: antialiased;
}
body.no-scroll { overflow: hidden; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; }
button { font: inherit; color: inherit; }
kbd { font: 12px var(--mono); padding: 1px 6px; border: 1px solid var(--line-2); border-bottom-width: 2px; border-radius: 5px; color: var(--ink-3); background: var(--bg); }
:focus-visible { outline: 2px solid var(--link); outline-offset: 2px; border-radius: 4px; }
.skip { position: absolute; left: -999px; top: 8px; z-index: 100; background: var(--ink); color: var(--bg); padding: 6px 12px; border-radius: 6px; }
.skip:focus { left: 8px; }
.wrap { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.narrow { max-width: 820px; }
.center { text-align: center; }
.muted { color: var(--ink-3); }
.block { padding-top: 40px; padding-bottom: 8px; }
.page-title { font-size: clamp(26px, 3.5vw, 34px); line-height: 1.3; margin: 8px 0 12px; letter-spacing: -.3px; }
.page-title small, .list-head h1 small, .day h2 small { font-size: 15px; font-weight: 400; color: var(--ink-3); margin-left: 10px; letter-spacing: 0; }
.lead { font-size: 17px; color: var(--ink-2); margin: 0 0 20px; max-width: 720px; }
.more { color: var(--ink-2); font-size: 15px; }
.more:hover { color: var(--ink); }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; padding: 9px 18px; border: 1px solid var(--ink); border-radius: 9px; background: var(--ink); color: var(--bg); font-weight: 600; cursor: pointer; white-space: nowrap; line-height: 1.4; }
.btn:hover { opacity: .88; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line-2); }
.btn-ghost:hover { border-color: var(--ink); opacity: 1; }
.btn-ghost.on { border-color: var(--ok); color: var(--ok); }
.btn-sm { padding: 5px 12px; font-size: 14px; }
.btn-lg { padding: 12px 26px; font-size: 17px; }

/* ============ 顶栏 ============ */
.top { position: sticky; top: 0; z-index: 20; height: var(--top-h); background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: saturate(1.4) blur(10px); -webkit-backdrop-filter: saturate(1.4) blur(10px); border-bottom: 1px solid var(--line); }
.top-in { display: flex; align-items: center; gap: 8px; height: 100%; max-width: 1440px; margin: 0 auto; padding: 0 20px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; white-space: nowrap; margin-right: 16px; }
.logo-mark { display: grid; place-items: center; width: 30px; height: 30px; border-radius: 8px; background: var(--brand); color: var(--brand-ink); font-weight: 900; font-size: 17px; }
.nav { display: flex; gap: 2px; }
.nav a { padding: 6px 12px; border-radius: 8px; color: var(--ink-2); font-size: 15px; white-space: nowrap; }
.nav a:hover { color: var(--ink); background: var(--bg-soft); }
.nav a[aria-current] { color: var(--ink); font-weight: 600; background: var(--bg-soft); }
.search-btn { margin-left: auto; display: flex; align-items: center; gap: 8px; width: 240px; padding: 7px 10px 7px 12px; border: 1px solid var(--line); border-radius: 9px; background: var(--bg-soft); color: var(--ink-3); cursor: pointer; font-size: 14px; }
.search-btn:hover { border-color: var(--line-2); color: var(--ink-2); }
.search-btn span { flex: 1; text-align: left; }
.icon-btn { display: grid; place-items: center; width: 36px; height: 36px; border: 1px solid transparent; border-radius: 9px; background: none; color: var(--ink-2); cursor: pointer; }
.icon-btn:hover { background: var(--bg-soft); color: var(--ink); }
.icon-btn.user { border-color: var(--line); font-weight: 700; }
.vip { display: inline-block; padding: 0 5px; border-radius: 4px; background: var(--brand); color: var(--brand-ink); font-size: 11px; font-weight: 800; line-height: 18px; }

/* ============ 首页 ============ */
.hero { padding: 64px 0 40px; border-bottom: 1px solid var(--line); background:
  radial-gradient(900px 300px at 85% -40%, color-mix(in srgb, var(--brand) 22%, transparent), transparent 70%), var(--bg); }
.hero h1 { font-size: clamp(32px, 5.2vw, 56px); line-height: 1.15; margin: 0 0 18px; letter-spacing: -1px; }
.hero .lead { font-size: 18px; max-width: 760px; }
.br-m { display: none; }
.hero-search { position: relative; display: flex; gap: 8px; max-width: 640px; margin-top: 28px; }
.hero-search > svg { position: absolute; left: 16px; top: 50%; transform: translateY(-50%); color: var(--ink-3); pointer-events: none; }
.hero-search input { flex: 1; min-width: 0; padding: 14px 16px 14px 44px; font: inherit; font-size: 17px; border: 1.5px solid var(--line-2); border-radius: 12px; background: var(--bg); color: var(--ink); box-shadow: 0 1px 2px rgba(0,0,0,.04); }
.hero-search input:focus { outline: none; border-color: var(--ink); }
.hero-search .btn { border-radius: 12px; padding: 0 22px; font-size: 16px; }
.hot { margin: 14px 0 0; font-size: 14px; color: var(--ink-3); display: flex; flex-wrap: wrap; gap: 6px 12px; }
.hot a { color: var(--ink-2); border-bottom: 1px dashed var(--line-2); }
.hot a:hover { color: var(--ink); border-color: var(--ink); }

.block-head { display: flex; justify-content: space-between; align-items: baseline; gap: 16px; margin-bottom: 14px; }
.block-head h2 { font-size: 21px; margin: 0; }
.block-head > a { color: var(--ink-3); font-size: 14px; white-space: nowrap; }
.block-head > a:hover { color: var(--ink); }

.dirs { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(320px, 100%), 1fr)); gap: 14px; }
.dir { min-width: 0; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px 12px; background: var(--bg); transition: border-color .15s; }
.dir:hover { border-color: var(--line-2); }
.dir-head { display: flex; justify-content: space-between; align-items: baseline; gap: 8px; }
.dir-head h3 { margin: 0; font-size: 17px; }
.dir-head:hover h3 { text-decoration: underline; text-underline-offset: 3px; }
.dir-count { color: var(--ink-3); font-size: 13px; white-space: nowrap; }
.dir-count.has-progress { color: var(--ok); }
.dir-desc { margin: 4px 0 8px; color: var(--ink-3); font-size: 13.5px; line-height: 1.6; }
.dir ul { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.dir li a { display: block; padding: 7px 0; font-size: 14.5px; color: var(--ink-2); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; border-bottom: 1px solid var(--line); }
.dir li:last-child a { border-bottom: 0; }
.dir li a:hover { color: var(--ink); }

.series-cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.series-card { position: relative; display: block; padding: 20px; border-radius: var(--radius); background: var(--bg-soft); border: 1px solid var(--line); transition: border-color .15s, transform .15s; }
.series-card:hover { border-color: var(--ink); transform: translateY(-2px); }
.series-card h3 { margin: 0 0 6px; font-size: 18px; padding-right: 56px; }
.series-card p { margin: 0; color: var(--ink-2); font-size: 14px; line-height: 1.65; }
.series-count { position: absolute; top: 20px; right: 20px; font-size: 12px; font-weight: 700; background: var(--brand); color: var(--brand-ink); padding: 1px 8px; border-radius: 999px; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; padding-bottom: 40px; }

/* ============ 题目行 ============ */
.rows { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.row { display: grid; grid-template-columns: 46px minmax(0, 1fr) auto 18px; align-items: center; gap: 10px; padding: 10px 8px; border-bottom: 1px solid var(--line); }
.rows li[hidden] { display: none; }
.row:hover { background: var(--bg-soft); }
.row-no { font: 13px var(--mono); color: var(--ink-3); white-space: nowrap; }
.row-title { font-size: 15.5px; line-height: 1.5; }
.row:hover .row-title { color: var(--ink); text-decoration: underline; text-decoration-color: var(--line-2); text-underline-offset: 3px; }
.row-cat { font-size: 12.5px; color: var(--ink-3); white-space: nowrap; }
.row-state { width: 18px; text-align: center; font-size: 13px; }
.is-read .row-title { color: var(--ink-3); }
.is-read .row-state::after { content: "·"; color: var(--ink-3); font-size: 22px; line-height: 1; }
.is-done .row-state::after { content: "✓"; color: var(--ok); font-size: 14px; font-weight: 700; }

/* ============ 列表页 ============ */
.list-page { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 40px; max-width: 1200px; padding-top: 28px; padding-bottom: 40px; }
.side-nav { position: sticky; top: calc(var(--top-h) + 20px); align-self: start; display: flex; flex-direction: column; gap: 1px; max-height: calc(100vh - var(--top-h) - 40px); overflow: auto; }
.side-title { margin: 14px 10px 6px; font-size: 12px; font-weight: 700; color: var(--ink-3); letter-spacing: .5px; }
.side-title:first-child { margin-top: 0; }
.side-nav a { display: flex; justify-content: space-between; gap: 8px; padding: 6px 10px; border-radius: 7px; font-size: 14.5px; color: var(--ink-2); }
.side-nav a:hover { background: var(--bg-soft); color: var(--ink); }
.side-nav a[aria-current] { background: var(--ink); color: var(--bg); font-weight: 600; }
.side-nav i { font-style: normal; font-size: 12.5px; color: var(--ink-3); }
.side-nav a[aria-current] i { color: inherit; opacity: .7; }
.side-nav i.has-progress { color: var(--ok); }
.list-head h1 { font-size: 28px; margin: 0 0 4px; line-height: 1.3; }
.list-desc { margin: 0 0 4px; color: var(--ink-3); }
.list-tools { display: flex; gap: 12px; align-items: center; margin: 16px 0 12px; flex-wrap: wrap; }
.filter { position: relative; flex: 1; min-width: 200px; max-width: 420px; }
.filter svg { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); color: var(--ink-3); }
.filter input { width: 100%; padding: 9px 12px 9px 38px; font: inherit; font-size: 15px; border: 1px solid var(--line-2); border-radius: 9px; background: var(--bg); color: var(--ink); }
.filter input:focus { outline: none; border-color: var(--ink); }
.seg { display: inline-flex; padding: 3px; border-radius: 9px; background: var(--bg-soft); border: 1px solid var(--line); }
.seg a { padding: 5px 12px; border-radius: 7px; font-size: 14px; color: var(--ink-3); }
.seg a[aria-current] { background: var(--bg); color: var(--ink); font-weight: 600; box-shadow: 0 1px 2px rgba(0,0,0,.08); }
.chips { display: none; gap: 6px; overflow-x: auto; padding: 2px 0 6px; margin-top: 12px; scrollbar-width: none; }
.chips::-webkit-scrollbar { display: none; }
.chips a { flex: none; padding: 4px 12px; border: 1px solid var(--line); border-radius: 999px; font-size: 13.5px; color: var(--ink-2); }
.chips a[aria-current] { background: var(--ink); border-color: var(--ink); color: var(--bg); }
.empty { color: var(--ink-3); padding: 40px 0; text-align: center; }
.empty a { color: var(--link); }

/* ============ 文章页（三栏） ============ */
.doc { display: grid; grid-template-columns: 270px minmax(0, 1fr) 220px; gap: 48px; max-width: 1440px; margin: 0 auto; padding: 0 20px; }
.doc-nav { position: sticky; top: var(--top-h); align-self: start; height: calc(100vh - var(--top-h)); overflow-y: auto; padding: 24px 12px 40px 0; border-right: 1px solid var(--line); scrollbar-width: thin; }
.doc-nav-title { display: flex; justify-content: space-between; align-items: baseline; margin: 0 0 8px 8px; font-weight: 700; font-size: 15px; }
.doc-nav-title span { font-weight: 400; font-size: 12.5px; color: var(--ink-3); }
.doc-nav ol { list-style: none; margin: 0; padding: 0; }
.doc-nav li a { display: grid; grid-template-columns: 40px 1fr; gap: 4px; padding: 5px 8px; border-radius: 7px; font-size: 13.5px; line-height: 1.5; color: var(--ink-2); }
.doc-nav li a:hover { background: var(--bg-soft); color: var(--ink); }
.doc-nav li a[aria-current] { background: color-mix(in srgb, var(--brand) 30%, transparent); color: var(--ink); font-weight: 600; }
.doc-nav .n { font: 12px/1.9 var(--mono); color: var(--ink-3); white-space: nowrap; }
.doc-nav .is-read .t { color: var(--ink-3); }
.doc-nav .is-done .t::after { content: " ✓"; color: var(--ok); font-weight: 700; }

.doc-main { min-width: 0; max-width: 760px; width: 100%; margin: 0 auto; padding: 28px 0 48px; }
.crumb { font-size: 13.5px; color: var(--ink-3); display: flex; gap: 6px; flex-wrap: wrap; }
.crumb a:hover { color: var(--ink); }
.doc-main h1 { font-size: clamp(25px, 3.2vw, 34px); line-height: 1.3; margin: 10px 0 10px; letter-spacing: -.3px; }
.meta { display: flex; flex-wrap: wrap; gap: 4px 16px; margin: 0 0 24px; color: var(--ink-3); font-size: 14px; }
.meta .state { color: var(--ok); font-weight: 600; }
.keywords { margin: -14px 0 24px; color: var(--ink-2); font-size: 14.5px; }
.level { display: inline-block; padding: 0 8px; border-radius: 999px; font-size: 12px; line-height: 20px; font-weight: 600; white-space: nowrap; }
.level-基础 { background: color-mix(in srgb, var(--ok) 15%, transparent); color: var(--ok); }
.level-进阶 { background: color-mix(in srgb, #d97706 18%, transparent); color: #b45309; }
.level-高阶 { background: color-mix(in srgb, var(--accent) 15%, transparent); color: var(--accent); }
.level-简单 { background: color-mix(in srgb, var(--ok) 15%, transparent); color: var(--ok); }
.level-中等 { background: color-mix(in srgb, #d97706 18%, transparent); color: #b45309; }
.level-困难 { background: color-mix(in srgb, var(--accent) 15%, transparent); color: var(--accent); }

.toc-m { display: none; margin: 0 0 20px; border: 1px solid var(--line); border-radius: var(--radius); padding: 10px 14px; }
.toc-m summary { cursor: pointer; font-weight: 600; font-size: 15px; }
.toc-m ol { margin: 8px 0 0; padding-left: 20px; font-size: 14.5px; }
.toc-m li { padding: 3px 0; }

.answer { border: 1px solid var(--answer-line); border-left-width: 4px; background: var(--answer-bg); border-radius: var(--radius); padding: 16px 20px 14px; margin: 0 0 36px; }
.answer-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 6px; }
.answer-head h2 { margin: 0; font-size: 15px; letter-spacing: .5px; }
.copy-btn { display: inline-flex; align-items: center; gap: 4px; padding: 3px 10px; border: 1px solid var(--answer-line); border-radius: 7px; background: transparent; font-size: 13px; color: var(--ink-2); cursor: pointer; }
.copy-btn:hover { background: var(--bg); color: var(--ink); }
.answer-body { font-size: 16.5px; line-height: 1.85; }
.answer-body p { margin: 0 0 .6em; }
.answer-body p:last-child { margin-bottom: 0; }
.answer-foot { margin: 10px 0 0; font-size: 13px; color: var(--ink-3); }
.detail-title { font-size: 13px; font-weight: 700; letter-spacing: 1px; color: var(--ink-3); margin: 0 0 4px; }

.doc-toc { position: sticky; top: calc(var(--top-h) + 28px); align-self: start; max-height: calc(100vh - var(--top-h) - 56px); overflow-y: auto; padding-top: 28px; font-size: 13.5px; }
.doc-toc-title { margin: 0 0 8px; font-size: 12px; font-weight: 700; color: var(--ink-3); letter-spacing: .5px; }
.doc-toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.doc-toc a { display: block; padding: 4px 0 4px 12px; margin-left: -1px; border-left: 2px solid transparent; color: var(--ink-3); line-height: 1.5; }
.doc-toc a:hover { color: var(--ink); }
.doc-toc a.on { color: var(--ink); border-left-color: var(--ink); font-weight: 600; }

/* 正文排版 */
.prose { font-size: 17px; line-height: 1.85; overflow-wrap: anywhere; }
.prose h2 { font-size: 22px; line-height: 1.4; margin: 2.2em 0 .7em; padding-top: .2em; }
.prose h3 { font-size: 18.5px; margin: 1.8em 0 .5em; }
.prose h4 { font-size: 16.5px; margin: 1.5em 0 .4em; }
.prose > :first-child { margin-top: 0; }
.prose p { margin: 0 0 1em; }
.prose a { color: var(--link); border-bottom: 1px solid color-mix(in srgb, var(--link) 35%, transparent); }
.prose strong { font-weight: 700; background: linear-gradient(transparent 60%, var(--mark) 60%); }
.prose img { display: block; margin: 1.4em auto; max-height: 75vh; width: auto; border-radius: 8px; border: 1px solid var(--line); cursor: zoom-in; background: #fff; }
.prose blockquote { margin: 1.2em 0; padding: 10px 18px; border-left: 3px solid var(--line-2); background: var(--bg-soft); border-radius: 0 8px 8px 0; color: var(--ink-2); }
.prose blockquote p:last-child { margin: 0; }
.prose code { font-family: var(--mono); font-size: .86em; background: var(--code-bg); border: 1px solid var(--line); padding: 1px 5px; border-radius: 5px; }
.prose pre { position: relative; background: var(--code-bg); border: 1px solid var(--line); padding: 14px 16px; border-radius: 10px; overflow-x: auto; line-height: 1.6; font-size: 14px; }
.prose pre code { background: none; border: 0; padding: 0; font-size: inherit; }
.code-copy { position: absolute; top: 8px; right: 8px; padding: 2px 8px; font-size: 12px; border: 1px solid var(--line); border-radius: 6px; background: var(--bg); color: var(--ink-3); cursor: pointer; opacity: 0; transition: opacity .15s; }
.prose pre:hover .code-copy, .code-copy:focus { opacity: 1; }
.prose table { display: block; max-width: 100%; overflow-x: auto; border-collapse: collapse; margin: 1.2em 0; font-size: 15px; line-height: 1.6; }
.prose th, .prose td { border: 1px solid var(--line); padding: 8px 12px; text-align: left; vertical-align: top; }
.prose th { background: var(--bg-soft); white-space: nowrap; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2.2em 0; }
.prose ul, .prose ol { padding-left: 1.4em; margin: 0 0 1em; }
.prose li { margin: .3em 0; }
.prose li > p { margin: 0; }

/* 代码高亮（highlight.js 类名） */
.hljs-keyword, .hljs-selector-tag, .hljs-meta .hljs-keyword { color: var(--c-kw); }
.hljs-string, .hljs-regexp, .hljs-addition { color: var(--c-str); }
.hljs-number, .hljs-literal { color: var(--c-num); }
.hljs-comment, .hljs-quote, .hljs-deletion { color: var(--c-com); font-style: italic; }
.hljs-title, .hljs-section, .hljs-function .hljs-title, .hljs-title.function_ { color: var(--c-fn); }
.hljs-type, .hljs-built_in, .hljs-class .hljs-title, .hljs-attr, .hljs-attribute, .hljs-variable, .hljs-params { color: var(--c-type); }
.hljs-meta { color: var(--c-com); }

.done-bar { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin: 36px 0 0; padding-top: 20px; border-top: 1px solid var(--line); }
.done-tip { color: var(--ink-3); font-size: 13px; }
.prevnext { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 20px; }
.prevnext a { display: block; padding: 12px 16px; border: 1px solid var(--line); border-radius: var(--radius); font-weight: 600; line-height: 1.5; font-size: 15px; }
.prevnext a:hover { border-color: var(--ink); }
.prevnext small { display: block; color: var(--ink-3); font-weight: 400; font-size: 13px; margin-bottom: 2px; }
.pn-next { text-align: right; }
.related { margin-top: 40px; }
.related h2 { font-size: 18px; margin: 0 0 10px; }
.lock { margin-top: 12px; padding: 24px; border: 1.5px dashed var(--line-2); border-radius: var(--radius); text-align: center; color: var(--ink-2); }

/* ============ 专题 / 最新 ============ */
.series-sec { margin: 36px 0; }
.series-sec .block-head { margin-bottom: 4px; }
.series-sec h2 a:hover { text-decoration: underline; text-underline-offset: 4px; }
.series-sec > p { margin: 0 0 12px; }
.series-sec .more { display: inline-block; margin-top: 10px; }
.lessons { list-style: none; margin: 24px 0 40px; padding: 0; border-top: 1px solid var(--line); }
.lessons a { display: grid; grid-template-columns: 44px minmax(0, 1fr) auto 18px; gap: 12px; align-items: center; padding: 14px 8px; border-bottom: 1px solid var(--line); }
.lessons a:hover { background: var(--bg-soft); }
.lesson-n { font: 600 15px var(--mono); color: var(--ink-3); text-align: center; }
.lesson-body b { display: block; font-size: 16px; line-height: 1.5; }
.lesson-body small { display: block; color: var(--ink-3); font-size: 13px; margin-top: 2px; }
.lessons .is-read .lesson-body b { color: var(--ink-3); }
.day { margin: 28px 0; }
.day h2 { font-size: 17px; margin: 0 0 8px; }
.crumb + .page-title { margin-top: 4px; }

/* ============ 搜索弹窗 ============ */
.search-pop { position: fixed; inset: 0; z-index: 50; background: rgba(10,10,12,.45); display: flex; justify-content: center; align-items: flex-start; padding: 10vh 16px 16px; }
.search-pop[hidden] { display: none; }
.search-box { width: 100%; max-width: 640px; background: var(--bg); border: 1px solid var(--line); border-radius: 14px; box-shadow: var(--shadow); overflow: hidden; }
.search-field { display: flex; align-items: center; gap: 10px; padding: 0 16px; border-bottom: 1px solid var(--line); color: var(--ink-3); }
.search-field input { flex: 1; min-width: 0; border: 0; background: none; padding: 16px 0; font: inherit; font-size: 17px; color: var(--ink); }
.search-field input:focus { outline: none; }
.search-results { list-style: none; margin: 0; padding: 6px; max-height: 56vh; overflow-y: auto; }
.search-results:empty { display: none; }
.search-results a { display: flex; justify-content: space-between; gap: 12px; padding: 9px 12px; border-radius: 8px; }
.search-results [aria-selected] a, .search-results a:hover { background: var(--bg-soft); }
.sr-t { line-height: 1.5; }
.sr-t mark { background: var(--mark); color: inherit; border-radius: 2px; }
.sr-c { color: var(--ink-3); font-size: 13px; white-space: nowrap; }
.search-empty { padding: 14px 12px; color: var(--ink-3); }
.search-empty a { color: var(--link); }
.search-hint { margin: 0; padding: 8px 16px; border-top: 1px solid var(--line); color: var(--ink-3); font-size: 12.5px; }
.search-hint a { color: var(--ink-2); }

/* ============ 更新 / 热门 / 订阅 ============ */
.sub-link { display: inline-flex; align-items: center; gap: 6px; padding: 6px 10px; border-radius: 9px; color: var(--ink-2); font-size: 14px; white-space: nowrap; }
.sub-link:hover { background: var(--bg-soft); color: var(--ink); }
.tabs-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin: 4px 0 20px; }
.seg a i { font-style: normal; font-size: 12px; color: var(--ink-3); margin-left: 4px; }
.sub-inline { display: inline-flex; align-items: center; gap: 6px; font-size: 14px; color: var(--ink-2); }
.sub-inline:hover { color: var(--ink); }
.hint-box { padding: 10px 14px; border-radius: 9px; background: var(--bg-soft); color: var(--ink-2); font-size: 14px; margin: 0 0 16px; }
.row-views { display: block; font-size: 12px; color: var(--ink-3); margin-top: 1px; }
.rank { counter-reset: rank; }
.rank .row-no { font-size: 0; }
.rank .row-no::before { counter-increment: rank; content: counter(rank); font: 600 14px var(--mono); color: var(--ink-3); }
.rank li:nth-child(-n+3) .row-no::before { color: var(--accent); }
.sub-cta { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-top: 28px; padding: 14px 18px; border-radius: var(--radius); background: var(--bg-soft); border: 1px solid var(--line); }
.sub-cta p { margin: 0; font-size: 14.5px; color: var(--ink-2); }
.sub-ways { display: grid; gap: 14px; }
.sub-way { border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; }
.sub-way h2 { margin: 0 0 6px; font-size: 18px; }
.sub-way p { margin: 0 0 12px; color: var(--ink-2); }
.sub-way p:last-child { margin-bottom: 0; }
.sub-form { display: flex; gap: 8px; flex-wrap: wrap; }
.sub-form input { flex: 1; min-width: 200px; padding: 10px 12px; font: inherit; border: 1px solid var(--line-2); border-radius: 9px; background: var(--bg); color: var(--ink); }
.sub-form input:focus { outline: none; border-color: var(--ink); }
.copy-line { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.copy-line code { font: 14px var(--mono); padding: 6px 10px; border-radius: 7px; background: var(--bg-soft); border: 1px solid var(--line); overflow-wrap: anywhere; }
.copy-line .copy-btn { border-color: var(--line-2); }

/* ============ 页脚 ============ */
.foot { border-top: 1px solid var(--line); background: var(--bg-soft); margin-top: 48px; }
.p-article .foot { margin-top: 0; }
.foot-in { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 16px 40px; padding-top: 32px; padding-bottom: 32px; }
.foot-brand p { margin: 4px 0 0; color: var(--ink-3); font-size: 14px; }
.foot-links { display: flex; gap: 20px; flex-wrap: wrap; align-items: flex-start; }
.foot-links a { color: var(--ink-2); font-size: 14px; }
.foot-links a:hover { color: var(--ink); }
.foot-small { width: 100%; margin: 0; color: var(--ink-3); font-size: 13px; }

/* ============ 付费相关页面（monetize 开启时） ============ */
.section { padding: 40px 16px; }
.sec-title { font-size: 20px; margin: 32px 0 14px; }
.sec-title small { font-size: 14px; color: var(--ink-3); font-weight: 400; margin-left: 8px; }
.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; max-width: 880px; margin: 32px auto; }
.plan { position: relative; border: 1px solid var(--line); border-radius: 14px; padding: 28px 24px; text-align: center; }
.plan.hot { border: 2px solid var(--ink); }
.plan-badge { position: absolute; top: -12px; left: 50%; transform: translateX(-50%); background: var(--accent); color: #fff; font-size: 12px; font-weight: 700; padding: 2px 10px; border-radius: 999px; }
.plan h2 { margin: 0; font-size: 19px; }
.price { font-size: 42px; font-weight: 800; margin: 6px 0 0; line-height: 1.2; }
.price small { font-size: 18px; }
.plan-days { color: var(--ink-3); margin: 0 0 8px; font-size: 14px; }
.how, .faq { max-width: 720px; margin: 40px auto 0; }
.how ol { padding-left: 20px; }
.how li span { display: block; color: var(--ink-2); }
.buy { display: flex; gap: 10px; flex-wrap: wrap; margin: 16px 0; }
.btn-static { cursor: default; }
.qr { display: block; margin: 16px auto; }
.faq details { border-bottom: 1px solid var(--line); padding: 12px 0; }
.faq summary { cursor: pointer; font-weight: 600; }
.books { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.book { position: relative; display: flex; flex-direction: column; gap: 4px; padding: 18px 20px; border: 1px solid var(--line); border-radius: var(--radius); }
.book-no { position: absolute; top: 14px; right: 16px; font: 700 12px var(--mono); color: var(--ink-3); }
.book h3 { margin: 0; font-size: 17px; padding-right: 28px; }
.book-slogan, .book-meta { margin: 0; color: var(--ink-3); font-size: 14px; }
.form { display: flex; flex-direction: column; gap: 14px; margin: 16px 0 24px; }
.form label { display: flex; flex-direction: column; gap: 6px; font-weight: 600; font-size: 15px; }
.form input, .form select { padding: 10px 12px; border: 1px solid var(--line-2); border-radius: 9px; background: var(--bg); color: var(--ink); font: inherit; font-weight: 400; }
.form-row { flex-direction: row; flex-wrap: wrap; }
.form-row input { flex: 1; min-width: 160px; }
.form .btn { align-self: flex-start; }
.hint { color: var(--ink-3); font-size: 14px; margin: 0; }
.alert { padding: 12px 16px; border-radius: 9px; background: color-mix(in srgb, var(--accent) 12%, transparent); color: var(--accent); font-weight: 600; }
.alert-ok { background: color-mix(in srgb, var(--ok) 12%, transparent); color: var(--ok); }
.acct-box, .kpis { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; }
.acct-box > div, .kpis > div { border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; }
.acct-box small, .kpis small { display: block; color: var(--ink-3); }
.acct-box b, .kpis b { font-size: 22px; }
progress { display: block; width: 100%; height: 6px; margin-top: 8px; }
.favs { list-style: none; padding: 0; }
.favs li { display: flex; justify-content: space-between; gap: 12px; padding: 8px 0; border-bottom: 1px solid var(--line); }
.logout { margin-top: 32px; }
.codes { width: 100%; font-family: var(--mono); padding: 12px; border: 1px solid var(--line-2); border-radius: 9px; background: var(--bg); color: var(--ink); }
.tbl { border-collapse: collapse; width: 100%; font-size: 14px; }
.tbl th, .tbl td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--line); }
.tbl th { color: var(--ink-3); font-weight: 600; }
.admin h3 { font-size: 15px; margin: 18px 0 8px; color: var(--ink-2); }

/* ============ 响应式 ============ */
@media (max-width: 1240px) {
  .doc { grid-template-columns: 250px minmax(0, 1fr); gap: 40px; }
  .doc-toc { display: none; }
  .toc-m { display: block; }
}
@media (max-width: 1100px) {
  .search-btn { width: 180px; }
  .series-cards { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 960px) {
  .doc { grid-template-columns: minmax(0, 1fr); }
  .doc-nav { display: none; }
  .list-page { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .side-nav { display: none; }
  .chips { display: flex; }
  .series-cards { grid-template-columns: 1fr; }
  .two-col { grid-template-columns: 1fr; gap: 32px; }
  .plans { grid-template-columns: 1fr; max-width: 420px; }
}
@media (max-width: 720px) {
  .top-in { padding: 0 12px; gap: 4px; }
  .logo { margin-right: 4px; }
  .logo-text { display: none; }
  .nav a { padding: 6px 9px; }
  .search-btn { width: auto; padding: 8px; border: 0; background: none; color: var(--ink-2); }
  .search-btn span, .search-btn kbd { display: none; }
  .sub-link span, .hide-m { display: none; }
  .row { grid-template-columns: 44px minmax(0, 1fr) 16px; }
  .sub-link { padding: 8px; }
  .sub-cta { flex-direction: column; align-items: flex-start; }
  .wrap, .doc { padding-left: 16px; padding-right: 16px; }
  .hero { padding: 36px 0 28px; }
  .hero .lead { font-size: 16px; }
  .br-m { display: inline; }
  .hero-search .btn { display: none; }
  .dirs { grid-template-columns: minmax(0, 1fr); }
  .row { gap: 8px; padding: 10px 4px; }
  .row-cat { display: none; }
  .doc-main { padding-top: 18px; }
  .prose { font-size: 16.5px; }
  .prose pre { margin-left: -16px; margin-right: -16px; border-radius: 0; border-left: 0; border-right: 0; }
  .answer { padding: 14px 16px 12px; }
  .prevnext { grid-template-columns: 1fr; }
  .pn-next { text-align: left; }
  .lessons a { grid-template-columns: 30px minmax(0, 1fr) 16px; }
  .lessons .level { display: none; }
  .search-pop { padding-top: 12px; }
  kbd { display: none; }
}