/* ===== 2027 考研计算机 408 · 共享样式（沿袭考研数学一模板） ===== */
:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --primary-light: #dbeafe;
  --hot: #d97706;        /* 高频考点 */
  --hot-bg: #fef3c7;
  --warn: #dc2626;       /* 易错 */
  --warn-bg: #fee2e2;
  --real: #7c3aed;       /* 真题风格 */
  --real-bg: #ede9fe;
  --method: #059669;     /* 方法技巧 */
  --method-bg: #d1fae5;
  --bg: #f8fafc;
  --card: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --text-light: #64748b;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
  font-size: 16px;
}

/* ===== 侧边栏 ===== */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: 264px;
  height: 100vh;
  overflow-y: auto;
  background: var(--card);
  border-right: 1px solid var(--border);
  padding: 20px 16px 40px;
}
.sidebar .back-link {
  display: inline-block;
  font-size: 13px;
  color: var(--text-light);
  text-decoration: none;
  margin-bottom: 12px;
}
.sidebar .back-link:hover { color: var(--primary); }
.sidebar h1 {
  font-size: 18px;
  margin: 0 0 4px;
  color: var(--primary-dark);
  line-height: 1.4;
}
.sidebar .subtitle {
  font-size: 12px;
  color: var(--text-light);
  margin-bottom: 16px;
}
.toc-title {
  font-size: 12px;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin: 12px 0 6px;
}
.toc a {
  display: block;
  padding: 5px 10px;
  color: #475569;
  text-decoration: none;
  border-radius: 6px;
  font-size: 14px;
  border-left: 3px solid transparent;
}
.toc a:hover { background: var(--primary-light); color: var(--primary); }
.toc a.active {
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
  border-left-color: var(--primary);
}
.toc a.sub { padding-left: 24px; font-size: 13px; }

/* ===== 主内容区 ===== */
.main {
  margin-left: 264px;
  max-width: 900px;
  padding: 32px 44px 90px;
}
@media (max-width: 960px) {
  .sidebar { position: static; width: auto; height: auto; }
  .main { margin-left: 0; padding: 16px 18px 60px; }
}

.chapter-header {
  background: linear-gradient(135deg, #1e3a8a, #2563eb);
  color: #fff;
  border-radius: 14px;
  padding: 28px 32px;
  margin-bottom: 32px;
}
.chapter-header .kicker {
  font-size: 13px;
  opacity: .85;
  letter-spacing: 2px;
  margin-bottom: 6px;
}
.chapter-header h1 {
  margin: 0 0 8px;
  font-size: 28px;
  line-height: 1.4;
}
.chapter-header .meta { font-size: 13px; opacity: .9; }

section { margin-bottom: 48px; }
h2 {
  font-size: 23px;
  color: var(--primary-dark);
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 8px;
  margin: 40px 0 18px;
}
h3 {
  font-size: 18px;
  margin: 28px 0 10px;
  color: var(--text);
}
h4 { font-size: 16px; margin: 20px 0 8px; }

/* ===== 徽章 ===== */
.badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  padding: 1px 9px;
  border-radius: 999px;
  vertical-align: 2px;
  margin-left: 8px;
  white-space: nowrap;
}
.badge-hot   { background: var(--hot-bg);   color: var(--hot); }
.badge-warn  { background: var(--warn-bg);  color: var(--warn); }
.badge-real  { background: var(--real-bg);  color: var(--real); }
.badge-method{ background: var(--method-bg);color: var(--method); }

/* ===== 内容框 ===== */
.concept-box, .theorem-box, .warn-box, .tip-box {
  border-radius: 10px;
  padding: 14px 18px;
  margin: 14px 0;
  border: 1px solid var(--border);
}
.concept-box { background: #f0f7ff; border-left: 4px solid var(--primary); }
.theorem-box { background: #f0fdf4; border-left: 4px solid var(--method); }
.warn-box    { background: var(--warn-bg); border-left: 4px solid var(--warn); }
.tip-box     { background: #fffbeb; border-left: 4px solid var(--hot); }
.concept-box .box-tag, .theorem-box .box-tag, .warn-box .box-tag, .tip-box .box-tag {
  font-weight: 700;
  font-size: 13px;
  margin-right: 6px;
}
.concept-box .box-tag { color: var(--primary); }
.theorem-box .box-tag { color: var(--method); }
.warn-box .box-tag    { color: var(--warn); }
.tip-box .box-tag     { color: var(--hot); }

/* ===== 例题 / 练习卡片 ===== */
.example, .practice {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  margin: 16px 0;
  box-shadow: 0 1px 3px rgba(0,0,0,.04);
}
.example .q-title, .practice .q-title {
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 8px;
}
.practice .q-title { color: var(--method); }

/* 折叠答案 */
details.solution {
  margin-top: 12px;
  border-top: 1px dashed var(--border);
  padding-top: 10px;
}
details.solution summary {
  cursor: pointer;
  color: var(--primary);
  font-weight: 600;
  font-size: 14px;
  user-select: none;
  list-style: none;
}
details.solution summary::before { content: "▸ "; }
details.solution[open] summary::before { content: "▾ "; }
details.solution summary::-webkit-details-marker { display: none; }
details.solution .answer-body { padding: 8px 4px 2px; }

/* ===== 表格 ===== */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  background: var(--card);
  font-size: 15px;
}
th, td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
  vertical-align: top;
}
th { background: #f1f5f9; color: var(--primary-dark); }
tbody tr:nth-child(even) { background: #fafcfe; }

/* ===== 其他 ===== */
ul, ol { padding-left: 26px; }
li { margin: 4px 0; }
a { color: var(--primary); }
code {
  background: #f1f5f9;
  border-radius: 4px;
  padding: 1px 6px;
  font-size: 14px;
}
.divider { border: none; border-top: 1px dashed var(--border); margin: 28px 0; }
.formula-table td { text-align: center; }

/* 首页卡片 */
.subject-grid { display: grid; grid-template-columns: 1fr; gap: 28px; }
.subject-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px 26px;
}
.subject-card h3 { margin-top: 0; }
.chapter-list { list-style: none; padding: 0; margin: 8px 0 0; }
.chapter-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 10px;
  border-radius: 8px;
  margin: 2px 0;
}
.chapter-list li a { text-decoration: none; color: var(--text); flex: 1; }
.chapter-list li a:hover { color: var(--primary); }
.status {
  font-size: 12px;
  font-weight: 600;
  padding: 1px 10px;
  border-radius: 999px;
}
.status-done { background: var(--method-bg); color: var(--method); }
.status-todo { background: #f1f5f9; color: var(--text-light); }

/* ===== 代码块（计算机科目专用） ===== */
pre.code-box {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 10px;
  padding: 14px 18px;
  overflow-x: auto;
  font-size: 14px;
  line-height: 1.6;
  font-family: "SF Mono", Menlo, Consolas, "Courier New", monospace;
  margin: 10px 0;
}
pre.code-box code { background: none; padding: 0; color: inherit; font-size: inherit; }
.code-title {
  font-weight: 600;
  font-size: 14px;
  color: var(--text-light);
  margin: 14px 0 0;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}

/* ===== 图示（figure） ===== */
.figure-box {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 12px 6px;
  margin: 16px 0;
  box-shadow: 0 1px 3px rgba(0,0,0,.04);
  overflow-x: auto;
}
.figure-box svg { display: block; margin: 0 auto; max-width: 100%; height: auto; }
.figure-caption {
  font-size: 13px;
  color: var(--text-light);
  text-align: center;
  margin: 8px 0 8px;
  line-height: 1.6;
}
svg text { font-family: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif; }
svg .svg-title { font-size: 13px; font-weight: 700; fill: var(--primary-dark); }
svg .svg-label { font-size: 12px; fill: #475569; }
svg .svg-node { fill: var(--primary-light); stroke: var(--primary); stroke-width: 1.5; }
svg .svg-node-leaf { fill: var(--method-bg); stroke: var(--method); stroke-width: 1.5; }
svg .svg-node-mid { fill: var(--hot-bg); stroke: var(--hot); stroke-width: 1.5; }
svg .svg-edge { stroke: #94a3b8; stroke-width: 1.6; fill: none; }
svg .svg-arrow { stroke: #94a3b8; stroke-width: 1.8; fill: none; }
svg .svg-cell { fill: var(--primary-light); stroke: var(--primary); stroke-width: 1.4; }
svg .svg-cell2 { fill: #fff; stroke: #94a3b8; stroke-width: 1.4; }
svg .svg-axis { stroke: #475569; stroke-width: 1.6; fill: none; }

/* ===== 错题本 ===== */
/* 章节页：题目标题右上角的标错按钮 */
.example, .practice { position: relative; }
.wb-mark {
  position: absolute;
  top: 12px;
  right: 14px;
  font-size: 12px;
  font-weight: 600;
  padding: 2px 11px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #f8fafc;
  color: var(--text-light);
  cursor: pointer;
  line-height: 1.6;
}
.wb-mark:hover { border-color: var(--warn); color: var(--warn); background: var(--warn-bg); }
.wb-mark.active {
  background: var(--warn-bg);
  border-color: var(--warn);
  color: var(--warn);
}
.practice .q-title, .example .q-title { padding-right: 84px; }

/* 目录底部的错题本入口 */
.toc a.wb-toc-link {
  margin-top: 12px;
  border-top: 1px dashed var(--border);
  border-radius: 0;
  border-left: 3px solid transparent;
  color: var(--warn);
  font-weight: 600;
}
.toc a.wb-toc-link:hover { background: var(--warn-bg); color: var(--warn); }

/* 错题本页 */
.wb-stats { font-size: 15px; color: var(--text-light); margin-bottom: 14px; }
.wb-stats strong { color: var(--warn); font-size: 18px; }
.wb-tools { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: space-between; margin-bottom: 20px; }
.wb-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.wb-chip {
  font-size: 13px;
  font-weight: 600;
  padding: 4px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text-light);
  cursor: pointer;
}
.wb-chip:hover { border-color: var(--primary); color: var(--primary); }
.wb-chip.active { background: var(--primary); border-color: var(--primary); color: #fff; }
.wb-ops { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.wb-ops select {
  font-size: 13px;
  padding: 4px 8px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
}
.wb-btn {
  font-size: 13px;
  font-weight: 600;
  padding: 4px 13px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text-light);
  cursor: pointer;
}
.wb-btn:hover { border-color: var(--primary); color: var(--primary); }
.wb-btn-warn:hover { border-color: var(--warn); color: var(--warn); background: var(--warn-bg); }
.wb-btn-ok:hover { border-color: var(--method); color: var(--method); background: var(--method-bg); }
.wb-btn-danger:hover { border-color: var(--warn); color: var(--warn); background: var(--warn-bg); }

.wb-entry {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  margin: 16px 0;
  box-shadow: 0 1px 3px rgba(0,0,0,.04);
}
.wb-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  font-size: 13px;
  color: var(--text-light);
  border-bottom: 1px dashed var(--border);
  padding-bottom: 10px;
  margin-bottom: 6px;
}
.wb-subj {
  font-size: 12px;
  font-weight: 700;
  padding: 1px 10px;
  border-radius: 999px;
  background: var(--primary-light);
  color: var(--primary-dark);
  white-space: nowrap;
}
.wb-src { text-decoration: none; color: var(--primary-dark); font-weight: 600; }
.wb-src:hover { color: var(--primary); text-decoration: underline; }
.wb-count { color: var(--warn); font-weight: 700; white-space: nowrap; }
.wb-time { font-size: 12px; }
.wb-body .practice, .wb-body .example { border: none; box-shadow: none; padding: 6px 0; margin: 4px 0; position: static; }
.wb-empty {
  text-align: center;
  color: var(--text-light);
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 40px 20px;
  margin: 16px 0;
}
@media (max-width: 960px) {
  .wb-tools { flex-direction: column; align-items: flex-start; }
}

/* ===== 选择题勾选 ===== */
.opt-wrap { margin: 6px 0; }
.opt {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 8px 12px;
  margin: 6px 0;
  cursor: pointer;
  transition: border-color .15s, background .15s;
  background: #fcfdfe;
  line-height: 1.7;
  user-select: none;
}
.opt:hover { border-color: var(--primary); background: var(--primary-light); }
.opt-check {
  flex: none;
  width: 17px;
  height: 17px;
  border: 1.5px solid #cbd5e1;
  border-radius: 4px;
  background: #fff;
  margin-top: 5px;
  position: relative;
  transition: background .15s, border-color .15s;
}
.opt-check::after {
  content: '';
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 700;
  line-height: 1;
  color: #fff;
}
.opt.picked .opt-check { background: var(--primary); border-color: var(--primary); }
.opt.picked .opt-check::after { content: '✓'; }
.opt-wrap.judged .opt.correct .opt-check { background: var(--method); border-color: var(--method); }
.opt-wrap.judged .opt.correct .opt-check::after { content: '✓'; }
.opt-wrap.judged .opt.wrong .opt-check { background: var(--warn); border-color: var(--warn); }
.opt-wrap.judged .opt.wrong .opt-check::after { content: '✗'; }
.opt-ball {
  flex: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1.5px solid #cbd5e1;
  color: var(--text-light);
  font-size: 13px;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 3px;
}
.opt.picked { border-color: var(--primary); background: var(--primary-light); }
.opt.picked .opt-ball { background: var(--primary); border-color: var(--primary); color: #fff; }
.opt-wrap.judged .opt { cursor: default; }
.opt-wrap.judged .opt:hover { border-color: var(--border); background: #fcfdfe; }
.opt.correct { border-color: var(--method); background: var(--method-bg); }
.opt.correct .opt-ball { background: var(--method); border-color: var(--method); color: #fff; }
.opt.wrong { border-color: var(--warn); background: var(--warn-bg); }
.opt.wrong .opt-ball { background: var(--warn); border-color: var(--warn); color: #fff; }
.opt-wrap.judged .opt.correct:hover { border-color: var(--method); background: var(--method-bg); }
.opt-wrap.judged .opt.wrong:hover { border-color: var(--warn); background: var(--warn-bg); }
.choice-verdict { font-weight: 700; margin: 10px 0 2px; font-size: 14.5px; }
.choice-verdict.ok { color: var(--method); }
.choice-verdict.bad { color: var(--warn); }
.choice-verdict.info { color: var(--text-light); }

/* ===== 编程题代码编辑器 ===== */
details.code-lab {
  margin-top: 12px;
  border: 1px dashed #b6c4f0;
  border-radius: 10px;
  padding: 8px 14px 12px;
  background: #f7f9ff;
}
details.code-lab summary {
  cursor: pointer;
  color: var(--real);
  font-weight: 600;
  font-size: 14px;
  user-select: none;
  list-style: none;
}
details.code-lab summary::before { content: "▸ "; }
details.code-lab[open] summary::before { content: "▾ "; }
details.code-lab summary::-webkit-details-marker { display: none; }
.code-lab-bar { display: flex; align-items: center; gap: 10px; margin: 8px 0; flex-wrap: wrap; }
.lab-lang {
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  background: #fff;
  color: var(--text);
}
.lab-run {
  padding: 5px 18px;
  border: none;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  font-size: 14px;
}
.lab-run:hover { background: var(--primary-dark); }
.lab-run:disabled { opacity: .55; cursor: default; }
.lab-status { font-size: 13px; color: var(--text-light); }
.lab-code {
  width: 100%;
  min-height: 220px;
  box-sizing: border-box;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 10px;
  border: none;
  padding: 12px 14px;
  font-family: "SF Mono", Menlo, Consolas, "Courier New", monospace;
  font-size: 13.5px;
  line-height: 1.6;
  resize: vertical;
  tab-size: 4;
}
.lab-code:focus { outline: 2px solid var(--primary); outline-offset: 1px; }
.lab-out {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  font-family: "SF Mono", Menlo, Consolas, "Courier New", monospace;
  font-size: 13.5px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-all;
  margin: 8px 0 4px;
  max-height: 320px;
  overflow: auto;
}
.lab-out.err { border-color: var(--warn); color: var(--warn); background: #fff8f8; }
.lab-out:empty { display: none; }