/* JavaWeb 复习讲义 · 静态站点样式
   设计目标：长文好读、代码不挤、手机可用、打印干净。 */

:root {
  --bg: #f7f8fa;
  --panel: #ffffff;
  --ink: #1c1f23;
  --ink-2: #4a5159;
  --ink-3: #7b848d;
  --line: #e3e7ec;
  --brand: #1f4e79;
  --brand-soft: #eaf1f8;
  --code-bg: #f4f6f9;
  --code-ink: #24292f;
  --add: #1f6feb;
  --err: #b42318;
  --cmp: #6b3fa0;
  --key: #0f7b4f;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 8px 24px rgba(16, 24, 40, .06);
  --radius: 10px;
  --side-w: 268px;
  --read-w: 860px;
}

html[data-theme="dark"] {
  --bg: #14171a;
  --panel: #1b1f24;
  --ink: #e6e9ec;
  --ink-2: #b6bec6;
  --ink-3: #8b949d;
  --line: #2b3138;
  --brand: #6ea8dc;
  --brand-soft: #1d2833;
  --code-bg: #161a1e;
  --code-ink: #d7dde3;
  --add: #5aa2ff;
  --err: #ff7b72;
  --cmp: #b48ef0;
  --key: #4cc38a;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.78 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", sans-serif;
  text-rendering: optimizeLegibility;
}

/* ---------------------------------------------------------------- 顶栏 */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 10px;
  height: 54px;
  padding: 0 16px;
  background: color-mix(in srgb, var(--panel) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.brand {
  font-weight: 700;
  font-size: 15px;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: .02em;
  white-space: nowrap;
}

.spacer { flex: 1; }

.icon-btn,
.search-btn {
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink-2);
  border-radius: 8px;
  height: 34px;
  min-width: 34px;
  padding: 0 10px;
  font-size: 14px;
  cursor: pointer;
  transition: .15s;
}
.icon-btn:hover,
.search-btn:hover { border-color: var(--brand); color: var(--brand); }

.search-btn { font-size: 13px; display: inline-flex; align-items: center; gap: 8px; }
.menu-btn { display: none; }

.top-link {
  display: inline-flex;
  align-items: center;
  height: 34px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  color: var(--ink-2);
  font-size: 13px;
  text-decoration: none;
  white-space: nowrap;
  transition: .15s;
}
.top-link:hover { border-color: var(--brand); color: var(--brand); }
@media (max-width: 520px) { .top-link { display: none; } }

kbd {
  font: 11px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  padding: 3px 5px;
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 4px;
  color: var(--ink-3);
  background: var(--bg);
}

/* ---------------------------------------------------------------- 布局 */
.layout {
  display: flex;
  align-items: flex-start;
  gap: 0;
  max-width: 1400px;
  margin: 0 auto;
}

.sidebar {
  position: sticky;
  top: 54px;
  flex: 0 0 var(--side-w);
  width: var(--side-w);
  height: calc(100vh - 54px);
  overflow-y: auto;
  padding: 18px 10px 60px 16px;
  border-right: 1px solid var(--line);
  font-size: 13.5px;
  scrollbar-width: thin;
}
.sidebar::-webkit-scrollbar { width: 8px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--line); border-radius: 4px; }

.nav-part {
  margin: 14px 0 6px;
  padding: 0 8px;
  font-weight: 700;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--ink-3);
}
.nav-group:first-child .nav-part { margin-top: 0; }

.side-nav ul { list-style: none; margin: 0; padding: 0; }
.side-nav li { margin: 1px 0; }
.side-nav a {
  display: block;
  padding: 5px 8px;
  border-radius: 6px;
  color: var(--ink-2);
  text-decoration: none;
  line-height: 1.45;
}
.side-nav a:hover { background: var(--brand-soft); color: var(--brand); }
.side-nav a.active {
  background: var(--brand-soft);
  color: var(--brand);
  font-weight: 700;
}

.content {
  flex: 1 1 auto;
  min-width: 0;
  max-width: calc(var(--read-w) + 96px);
  margin: 0 auto;
  padding: 34px 48px 80px;
}

/* ---------------------------------------------------------------- 正文 */
.content h1 {
  font-size: 30px;
  line-height: 1.35;
  margin: 8px 0 18px;
  letter-spacing: -.01em;
}
.content h2 {
  font-size: 21px;
  line-height: 1.4;
  margin: 42px 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 70px;
}
.content h3 {
  font-size: 17px;
  margin: 26px 0 8px;
  color: var(--ink);
  scroll-margin-top: 70px;
}
.content h2.chap-h { border-bottom: none; }

.doc-title { border-bottom: 3px solid var(--brand); padding-bottom: 14px; }

.part-tag {
  display: inline-block;
  margin-bottom: 6px;
  padding: 3px 10px;
  border-radius: 99px;
  background: var(--brand-soft);
  color: var(--brand);
  font-size: 12px;
  font-weight: 700;
}

.content p { margin: 10px 0; color: var(--ink); }
.content strong { font-weight: 700; }
.content em { font-style: italic; color: var(--ink-2); }

.content a {
  color: var(--brand);
  text-decoration: none;
  border-bottom: 1px solid color-mix(in srgb, var(--brand) 35%, transparent);
}
.content a:hover { border-bottom-color: var(--brand); }

.content ul,
.content ol { margin: 10px 0; padding-left: 26px; }
.content li { margin: 5px 0; }
.content li > ul,
.content li > ol { margin: 5px 0; }

.content hr {
  border: none;
  border-top: 1px dashed var(--line);
  margin: 40px 0;
}

/* 行内代码 */
.content code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: .89em;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 1px 5px;
  color: var(--code-ink);
  word-break: break-word;
}

/* ---------------------------------------------------------------- 代码块 */
.code-block {
  position: relative;
  margin: 16px 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--code-bg);
  overflow: hidden;
}
.code-block::before {
  content: attr(data-lang);
  position: absolute;
  top: 6px;
  right: 10px;
  font: 11px/1 ui-monospace, Menlo, Consolas, monospace;
  color: var(--ink-3);
  text-transform: uppercase;
  letter-spacing: .06em;
  opacity: .8;
  pointer-events: none;
}
.code-block pre {
  margin: 0;
  padding: 16px 18px;
  overflow-x: auto;
  scrollbar-width: thin;
}
.code-block pre code {
  display: block;
  background: none;
  border: none;
  padding: 0;
  font-size: 13px;
  line-height: 1.62;
  color: var(--code-ink);
  white-space: pre;
  tab-size: 4;
}
.copy {
  position: absolute;
  top: 6px;
  left: 10px;
  opacity: 0;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink-3);
  border-radius: 6px;
  font-size: 11px;
  padding: 3px 8px;
  cursor: pointer;
  transition: .15s;
}
.code-block:hover .copy { opacity: 1; }
.copy:hover { color: var(--brand); border-color: var(--brand); }
.copy.done { color: var(--key); border-color: var(--key); }

/* ---------------------------------------------------------------- 表格 */
.table-wrap {
  margin: 16px 0;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  scrollbar-width: thin;
}
table {
  border-collapse: collapse;
  width: 100%;
  font-size: 14px;
}
thead th {
  position: sticky;
  top: 0;
  background: var(--brand-soft);
  color: var(--brand);
  font-weight: 700;
  text-align: left;
  white-space: nowrap;
}
th, td {
  padding: 8px 12px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  line-height: 1.6;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:nth-child(even) { background: color-mix(in srgb, var(--bg) 55%, transparent); }
td code { white-space: nowrap; }

/* ---------------------------------------------------------------- 提示块 */
.tip {
  position: relative;
  margin: 18px 0;
  padding: 14px 18px 14px 20px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  border-left: 4px solid var(--add);
  background: var(--panel);
  box-shadow: var(--shadow);
}
.tip > *:first-child { margin-top: 0; }
.tip > *:last-child { margin-bottom: 0; }
.tip-head {
  display: inline-block;
  margin-bottom: 6px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--add);
}
.tip-err { border-left-color: var(--err); }
.tip-err .tip-head { color: var(--err); }
.tip-cmp { border-left-color: var(--cmp); }
.tip-cmp .tip-head { color: var(--cmp); }
.tip-key { border-left-color: var(--key); }
.tip-key .tip-head { color: var(--key); }
.tip .table-wrap { background: var(--bg); }
.tip .code-block { background: var(--code-bg); }

/* 无标签引用块：章首难度行、参考答案抬头、原文注意事项等 */
.meta {
  margin: 16px 0;
  padding: 12px 18px;
  border-left: 3px solid var(--line);
  border-radius: 0 8px 8px 0;
  background: var(--panel);
  color: var(--fg-soft, var(--fg));
  font-size: 14.5px;
}
.meta > *:first-child { margin-top: 0; }
.meta > *:last-child { margin-bottom: 0; }
.meta strong { color: var(--fg); }

/* 段落开头的强调块 */
.lead-note {
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--brand-soft);
}

/* ---------------------------------------------------------------- 本页目录卡 */
.toc-card {
  margin: 18px 0 26px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  font-size: 14px;
}
.toc-card summary {
  cursor: pointer;
  font-weight: 700;
  color: var(--ink-2);
  font-size: 13px;
  letter-spacing: .03em;
}
.toc-card ul { list-style: none; margin: 10px 0 0; padding: 0; }
.toc-card li { margin: 3px 0; }
.toc-card li.l2 { padding-left: 0; }
.toc-card li.l3 { padding-left: 18px; font-size: 13px; }
.toc-card a { border-bottom: none; color: var(--ink-2); }
.toc-card a:hover { color: var(--brand); }

/* ---------------------------------------------------------------- 翻页与页脚 */
.pager {
  display: flex;
  gap: 12px;
  justify-content: space-between;
  margin: 56px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}
.pn {
  flex: 1 1 0;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink-2) !important;
  text-decoration: none;
  border-bottom: 1px solid var(--line) !important;
  font-size: 14px;
  transition: .15s;
}
.pn span { display: block; font-size: 11px; color: var(--ink-3); letter-spacing: .06em; }
.pn:hover { border-color: var(--brand) !important; color: var(--brand) !important; }
.pn.next { text-align: right; }

.foot {
  margin-top: 34px;
  padding-top: 16px;
  color: var(--ink-3);
  font-size: 12.5px;
  line-height: 1.9;
  border-top: 1px solid var(--line);
}

.to-top {
  position: fixed;
  right: 22px;
  bottom: 26px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink-2);
  box-shadow: var(--shadow);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: .2s;
  font-size: 16px;
}
.to-top.show { opacity: 1; pointer-events: auto; }

/* ---------------------------------------------------------------- 搜索 */
.search-modal {
  position: fixed;
  inset: 0;
  z-index: 60;
  background: rgba(10, 14, 20, .45);
  backdrop-filter: blur(2px);
  padding: 12vh 16px 16px;
  overflow-y: auto;
}
.search-box {
  display: flex;
  gap: 8px;
  max-width: 720px;
  margin: 0 auto;
}
.search-box input {
  flex: 1;
  height: 50px;
  padding: 0 16px;
  font-size: 16px;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
  box-shadow: var(--shadow);
  outline: none;
}
.search-box input:focus { border-color: var(--brand); }
.close-search { height: 50px; background: var(--panel); }

.search-results {
  max-width: 720px;
  margin: 14px auto 40px;
  background: var(--panel);
  border-radius: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.search-results:empty { display: none; }
.sr-item {
  display: block;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  color: var(--ink);
  border-bottom-color: var(--line);
}
.sr-item:last-child { border-bottom: none; }
.sr-item:hover { background: var(--brand-soft); }
.sr-title { font-weight: 700; font-size: 14px; color: var(--brand); margin-bottom: 3px; }
.sr-snip { font-size: 13px; color: var(--ink-2); line-height: 1.6; }
.sr-snip mark { background: #ffe08a; color: #3a2b00; border-radius: 3px; padding: 0 2px; }
html[data-theme="dark"] .sr-snip mark { background: #6b5300; color: #ffe9a8; }
.sr-more { padding: 10px 16px; font-size: 12.5px; color: var(--ink-3); }

/* ---------------------------------------------------------------- 首页 hero */
.hero {
  margin: 6px 0 30px;
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--brand-soft), transparent 140%);
}
.hero p { margin: 0 0 14px; color: var(--ink-2); font-size: 15px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block;
  padding: 9px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  color: var(--ink) !important;
  font-size: 14px;
  text-decoration: none;
  border-bottom: 1px solid var(--line) !important;
  transition: .15s;
}
.btn:hover { border-color: var(--brand) !important; color: var(--brand) !important; }
.btn.primary {
  background: var(--brand);
  border-color: var(--brand) !important;
  color: #fff !important;
  font-weight: 700;
}
.btn.primary:hover { filter: brightness(1.08); color: #fff !important; }

/* ---------------------------------------------------------------- 响应式 */
@media (max-width: 1080px) {
  :root { --side-w: 240px; }
  .content { padding: 28px 28px 70px; }
}

@media (max-width: 860px) {
  .menu-btn { display: inline-flex; align-items: center; justify-content: center; }
  .sidebar {
    position: fixed;
    top: 54px;
    left: 0;
    z-index: 50;
    width: 82vw;
    max-width: 320px;
    height: calc(100vh - 54px);
    background: var(--panel);
    box-shadow: var(--shadow);
    transform: translateX(-102%);
    transition: transform .22s ease;
  }
  .sidebar.open { transform: none; }
  .content { padding: 22px 18px 60px; max-width: 100%; }
  .content h1 { font-size: 24px; }
  .content h2 { font-size: 19px; margin-top: 32px; }
  .content h3 { font-size: 16px; }
  body { font-size: 15.5px; }
  .pager { flex-direction: column; }
  .pn.next { text-align: left; }
  table { font-size: 13px; }
  th, td { padding: 7px 10px; }
  .search-modal { padding-top: 8vh; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}

/* ---------------------------------------------------------------- 打印 */
@media print {
  :root { --bg: #fff; --panel: #fff; }
  .topbar, .sidebar, .to-top, .pager, .copy, .search-modal, .toc-card { display: none !important; }
  .layout { display: block; }
  .content { max-width: none; padding: 0; }
  body { font-size: 11pt; }
  .content h1 { page-break-before: auto; }
  .tip, .code-block, table { page-break-inside: avoid; }
  a { color: #000; text-decoration: none; }
  .code-block pre code { font-size: 9pt; white-space: pre-wrap; word-break: break-word; }
}