/* ==========================================================================
   事业单位D类·手写笔记样式
   米黄横线纸 + 楷体 + 荧光笔 + 红笔批注
   ========================================================================== */

/* ---------- 变量 ---------- */
:root {
  --paper:        #fdfaf0;
  --paper-edge:   #f0e8d0;
  --line:         rgba(176, 152, 110, 0.32);
  --line-strong:  rgba(176, 152, 110, 0.55);

  --ink:          #2c2416;
  --ink-soft:     #5d4f38;
  --ink-light:    #8a7a5f;

  --pen-blue:     #1a4d8f;
  --pen-blue-dk:  #0f3461;
  --pen-red:      #c0392b;
  --pen-red-dk:   #8b2820;

  --hl-yellow:    rgba(255, 232, 102, 0.55);
  --hl-pink:      rgba(255, 148, 190, 0.50);
  --hl-green:     rgba(150, 222, 150, 0.50);
  --hl-orange:    rgba(255, 184, 120, 0.55);
  --hl-blue:      rgba(140, 196, 250, 0.50);
  --hl-purple:    rgba(200, 160, 235, 0.50);

  --tape:         rgba(255, 220, 120, 0.55);

  --note-width:   880px;
}

/* ---------- 重置 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: "Kaiti SC", "KaiTi", "STKaiti", "DFKai-SB",
               "楷体", "PingFang SC", "Hiragino Sans GB", serif;
  color: var(--ink);
  line-height: 1.95;
  font-size: 17px;
  /* 米黄纸 + 横线 */
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    radial-gradient(circle at 20% 10%, rgba(255, 240, 200, 0.4) 0%, transparent 60%),
    radial-gradient(circle at 80% 90%, rgba(255, 230, 180, 0.3) 0%, transparent 60%);
  background-size: 100% 34px, 100% 100%, 100% 100%;
  background-position: 0 12px;
  background-attachment: fixed;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

/* ---------- 容器 ---------- */
.page {
  max-width: var(--note-width);
  margin: 0 auto;
  padding: 28px 36px 120px;
}

/* ---------- 页眉 ---------- */
.page-header {
  margin-bottom: 28px;
  padding-bottom: 14px;
  border-bottom: 3px double var(--pen-blue);
  position: relative;
}
.page-header::before {
  content: "";
  position: absolute;
  left: -36px; right: -36px; top: -28px; height: 28px;
  background: linear-gradient(180deg, transparent 60%, rgba(26, 77, 143, 0.08));
  pointer-events: none;
}
.breadcrumb {
  font-size: 13px;
  color: var(--ink-light);
  font-family: "Hannotate SC", "PingFang SC", sans-serif;
  margin-bottom: 6px;
}
.breadcrumb a {
  color: var(--pen-blue);
  text-decoration: none;
  border-bottom: 1px dashed var(--pen-blue);
}
.breadcrumb a:hover { color: var(--pen-red); border-color: var(--pen-red); }
.breadcrumb .sep { margin: 0 6px; opacity: 0.6; }

h1.note-title {
  font-family: "Baoli SC", "Kaiti SC", "STKaiti", serif;
  font-size: 32px;
  font-weight: normal;
  color: var(--pen-blue-dk);
  margin: 4px 0 0;
  letter-spacing: 2px;
  text-shadow: 1px 1px 0 rgba(26, 77, 143, 0.1);
}
.note-meta {
  font-size: 13px;
  color: var(--ink-light);
  font-family: "Hannotate SC", "PingFang SC", sans-serif;
  margin-top: 4px;
}

/* ---------- 标题层级 ---------- */
h2.section-title {
  font-family: "Baoli SC", "Kaiti SC", serif;
  font-size: 26px;
  font-weight: normal;
  color: var(--pen-blue-dk);
  margin: 40px 0 18px;
  padding-bottom: 8px;
  border-bottom: 3px double var(--pen-blue);
  letter-spacing: 1.5px;
  position: relative;
}
h2.section-title::before {
  content: "❀";
  color: var(--pen-red);
  margin-right: 8px;
  font-size: 22px;
}

h3.subsection-title {
  font-family: "Baoli SC", "Kaiti SC", serif;
  font-size: 21px;
  font-weight: normal;
  color: var(--pen-red-dk);
  margin: 28px 0 12px;
  letter-spacing: 1px;
}
h3.subsection-title::before {
  content: "▶ ";
  color: var(--pen-red);
  font-size: 16px;
}

h4.minor-title {
  font-family: "Baoli SC", "Kaiti SC", serif;
  font-size: 18px;
  font-weight: normal;
  color: var(--ink);
  margin: 20px 0 10px;
  padding: 2px 6px;
  background: linear-gradient(transparent 55%, var(--hl-yellow) 55%);
  display: inline-block;
}

/* ---------- 正文 ---------- */
p { margin: 10px 0; }
strong { color: var(--pen-red-dk); font-weight: 700; }
em { font-style: normal; border-bottom: 2px dotted var(--ink-light); padding-bottom: 1px; }
code {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: rgba(180, 160, 120, 0.15);
  padding: 1px 5px;
  border-radius: 3px;
}
ul, ol { margin: 8px 0 12px; padding-left: 28px; }
li { margin: 4px 0; }
a { color: var(--pen-blue); }

/* ---------- 荧光笔（inline） ---------- */
.mark-y { background: linear-gradient(transparent 55%, var(--hl-yellow) 55%); padding: 0 2px; }
.mark-p { background: linear-gradient(transparent 55%, var(--hl-pink)   55%); padding: 0 2px; }
.mark-g { background: linear-gradient(transparent 55%, var(--hl-green)  55%); padding: 0 2px; }
.mark-o { background: linear-gradient(transparent 55%, var(--hl-orange) 55%); padding: 0 2px; }
.mark-b { background: linear-gradient(transparent 55%, var(--hl-blue)   55%); padding: 0 2px; }
.mark-u { background: linear-gradient(transparent 55%, var(--hl-purple) 55%); padding: 0 2px; }

/* 整句涂抹 */
.mark-line-y { display: block; background: var(--hl-yellow); padding: 2px 6px; margin: 4px 0; border-radius: 2px; }
.mark-line-p { display: block; background: var(--hl-pink);   padding: 2px 6px; margin: 4px 0; border-radius: 2px; }
.mark-line-g { display: block; background: var(--hl-green);  padding: 2px 6px; margin: 4px 0; border-radius: 2px; }

/* ---------- 红色手写批注 ---------- */
.annotate {
  color: var(--pen-red);
  font-family: "Hannotate SC", "Kaiti SC", cursive;
  font-size: 0.95em;
  margin-left: 4px;
}
.annotate::before { content: "  ※ "; color: var(--pen-red); }

.annotate-block {
  background: rgba(255, 245, 235, 0.85);
  border-left: 4px solid var(--pen-red);
  border-radius: 0 6px 6px 0;
  padding: 12px 16px 12px 40px;
  margin: 14px 0;
  position: relative;
  font-family: "Hannotate SC", "Kaiti SC", cursive;
  color: var(--pen-red-dk);
  font-size: 0.97em;
}
.annotate-block::before {
  content: "批注";
  position: absolute;
  left: -8px; top: 8px;
  background: var(--pen-red);
  color: #fff;
  font-size: 12px;
  padding: 2px 8px;
  border-radius: 3px;
  font-family: "PingFang SC", sans-serif;
  transform: rotate(-2deg);
}

/* ---------- 核心知识框 ---------- */
.key-box {
  background: rgba(220, 245, 220, 0.6);
  border: 2px solid #4a8b4a;
  border-radius: 8px;
  padding: 16px 20px 16px 24px;
  margin: 18px 0;
  position: relative;
  box-shadow: 2px 3px 0 rgba(74, 139, 74, 0.15);
}
.key-box .box-label {
  position: absolute;
  top: -12px; left: 18px;
  background: #4a8b4a;
  color: #fff;
  padding: 2px 12px;
  border-radius: 12px;
  font-size: 13px;
  font-family: "Baoli SC", sans-serif;
  letter-spacing: 2px;
  transform: rotate(-1deg);
}

/* ---------- 高频考点框 ---------- */
.exam-box {
  background: rgba(255, 230, 225, 0.75);
  border: 2px dashed var(--pen-red);
  border-radius: 8px;
  padding: 16px 20px 16px 24px;
  margin: 18px 0;
  position: relative;
  box-shadow: 2px 3px 0 rgba(192, 57, 43, 0.15);
}
.exam-box .box-label {
  position: absolute;
  top: -12px; left: 18px;
  background: var(--pen-red);
  color: #fff;
  padding: 2px 12px;
  border-radius: 12px;
  font-size: 13px;
  font-family: "Baoli SC", sans-serif;
  letter-spacing: 2px;
  transform: rotate(-1deg);
}

/* ---------- 记忆口诀框 ---------- */
.mnemonic-box {
  background: linear-gradient(135deg, rgba(255, 248, 220, 0.9), rgba(255, 240, 200, 0.7));
  border: 2px dashed #d4a017;
  border-radius: 10px;
  padding: 20px 24px;
  margin: 20px 0;
  position: relative;
  text-align: center;
}
.mnemonic-box::before {
  content: "★";
  position: absolute;
  top: -14px; left: 50%;
  transform: translateX(-50%);
  background: var(--paper);
  color: #d4a017;
  font-size: 20px;
  padding: 0 8px;
}
.mnemonic-text {
  font-family: "Kaiti SC", "STKaiti", serif;
  font-size: 22px;
  color: var(--pen-blue-dk);
  letter-spacing: 4px;
  line-height: 1.7;
  font-weight: bold;
}
.mnemonic-tip {
  display: block;
  font-size: 13px;
  color: var(--ink-light);
  margin-top: 8px;
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 0;
}

/* ---------- 易错易混框 ---------- */
.warn-box {
  background: rgba(255, 240, 220, 0.7);
  border: 2px dashed #d97a2c;
  border-left: 5px solid #d97a2c;
  border-radius: 6px;
  padding: 14px 18px;
  margin: 16px 0;
  position: relative;
}
.warn-box::before {
  content: "⚠ 易错";
  display: inline-block;
  background: #d97a2c;
  color: #fff;
  font-size: 12px;
  padding: 1px 8px;
  border-radius: 3px;
  margin-right: 8px;
  font-family: "PingFang SC", sans-serif;
}

/* ---------- 提示框 ---------- */
.tip-box {
  background: rgba(230, 240, 255, 0.7);
  border-left: 5px solid var(--pen-blue);
  border-radius: 0 6px 6px 0;
  padding: 12px 18px;
  margin: 14px 0;
  font-size: 0.96em;
}
.tip-box::before {
  content: "💡 提示｜";
  color: var(--pen-blue-dk);
  font-weight: bold;
}

/* ---------- 引用 ---------- */
blockquote {
  margin: 14px 0;
  padding: 10px 18px;
  border-left: 4px solid var(--ink-light);
  color: var(--ink-soft);
  font-style: italic;
  background: rgba(0, 0, 0, 0.025);
}

/* ---------- 表格 ---------- */
.table-wrapper {
  margin: 18px 0;
  overflow-x: auto;
}
.table-wrapper table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.97em;
  background: rgba(255, 252, 240, 0.6);
  border: 2px solid var(--pen-blue);
  border-radius: 6px;
  overflow: hidden;
}
.table-wrapper th {
  background: var(--pen-blue);
  color: #fff;
  font-family: "Baoli SC", "Kaiti SC", sans-serif;
  font-weight: normal;
  letter-spacing: 1px;
  padding: 8px 12px;
  text-align: left;
  border-right: 1px dashed rgba(255,255,255,0.3);
}
.table-wrapper td {
  padding: 8px 12px;
  border: 1px dashed rgba(26, 77, 143, 0.3);
  vertical-align: top;
}
.table-wrapper tr:nth-child(even) td {
  background: rgba(180, 160, 120, 0.06);
}

/* ---------- 便签卡片网格 ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 18px 0;
}
.knowledge-card {
  background: #fffbe5;
  padding: 16px 14px 14px;
  border-radius: 2px;
  box-shadow: 2px 3px 6px rgba(0,0,0,0.1);
  position: relative;
  min-height: 100px;
  transform: rotate(-0.5deg);
  transition: transform 0.2s;
}
.knowledge-card:nth-child(even) { transform: rotate(0.6deg); background: #fff0f0; }
.knowledge-card:nth-child(3n)   { transform: rotate(-0.3deg); background: #edf7ed; }
.knowledge-card:nth-child(4n)   { transform: rotate(0.4deg); background: #eaf2ff; }
.knowledge-card:hover { transform: rotate(0) translateY(-3px); }
.knowledge-card::before {
  content: "";
  position: absolute;
  top: -8px; left: 50%;
  transform: translateX(-50%) rotate(-3deg);
  width: 60px; height: 18px;
  background: var(--tape);
  box-shadow: 0 1px 2px rgba(0,0,0,0.08);
}
.knowledge-card h5 {
  margin: 4px 0 8px;
  color: var(--pen-blue-dk);
  font-family: "Baoli SC", sans-serif;
  font-size: 17px;
  font-weight: normal;
  border-bottom: 1px dashed var(--pen-blue);
  padding-bottom: 4px;
}

/* ---------- 目录 ---------- */
.toc {
  background: rgba(255, 250, 230, 0.7);
  border: 2px dashed var(--ink-light);
  border-radius: 8px;
  padding: 18px 24px 18px 20px;
  margin: 20px 0 30px;
  position: relative;
}
.toc::before {
  content: "目录";
  position: absolute;
  top: -12px; left: 20px;
  background: var(--ink);
  color: var(--paper);
  padding: 2px 14px;
  font-size: 13px;
  font-family: "Baoli SC", sans-serif;
  letter-spacing: 3px;
  border-radius: 12px;
  transform: rotate(-1deg);
}
.toc ol { padding-left: 26px; margin: 6px 0; }
.toc li { margin: 4px 0; }
.toc a { color: var(--ink); text-decoration: none; border-bottom: 1px dotted var(--ink-light); }
.toc a:hover { color: var(--pen-red); border-color: var(--pen-red); }

/* ---------- 章节末尾分隔 ---------- */
.section-divider {
  text-align: center;
  margin: 40px 0 20px;
  color: var(--line-strong);
  letter-spacing: 12px;
  font-size: 14px;
}

/* ---------- 首页专用 ---------- */
.home-hero {
  text-align: center;
  padding: 60px 20px 40px;
}
.home-hero h1 {
  font-family: "Baoli SC", "Kaiti SC", serif;
  font-size: 42px;
  color: var(--pen-blue-dk);
  letter-spacing: 6px;
  margin: 0 0 12px;
  text-shadow: 2px 2px 0 rgba(192, 57, 43, 0.1);
}
.home-hero p {
  color: var(--ink-soft);
  font-size: 16px;
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 2px;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin: 30px 0;
}
.module-card {
  background: rgba(255, 252, 240, 0.7);
  border: 2px solid var(--pen-blue);
  border-radius: 10px;
  padding: 22px 24px;
  text-decoration: none;
  color: var(--ink);
  position: relative;
  transition: transform 0.2s, box-shadow 0.2s;
}
.module-card:hover {
  transform: translateY(-4px) rotate(-0.5deg);
  box-shadow: 4px 6px 12px rgba(0,0,0,0.1);
}
.module-card h3 {
  margin: 0 0 8px;
  color: var(--pen-blue-dk);
  font-family: "Baoli SC", sans-serif;
  font-size: 22px;
  font-weight: normal;
  letter-spacing: 2px;
}
.module-card .desc {
  color: var(--ink-soft);
  font-size: 14px;
  font-family: "Hannotate SC", sans-serif;
  margin: 0 0 10px;
}
.module-card .chapters {
  font-size: 13px;
  color: var(--ink-light);
  line-height: 1.7;
}
.module-card .chapters a {
  display: block;
  color: var(--pen-blue);
  text-decoration: none;
  padding: 2px 0;
  border-bottom: 1px dotted transparent;
}
.module-card .chapters a:hover { border-color: var(--pen-blue); }
.module-card.coming-soon { opacity: 0.55; }
.module-card.coming-soon::after {
  content: "敬请期待";
  position: absolute;
  top: 10px; right: 12px;
  background: var(--ink-light);
  color: var(--paper);
  padding: 2px 8px;
  font-size: 11px;
  border-radius: 3px;
  font-family: "PingFang SC", sans-serif;
  letter-spacing: 1px;
}

/* ==========================================================================
   升级组件 · 科目卡片 / 统计栏 / 章节导航 / 浮动按钮 / Hero
   ========================================================================== */

/* ---------- Hero 升级 ---------- */
.home-hero-v2 {
  text-align: center;
  padding: 50px 20px 30px;
  position: relative;
}
.home-hero-v2 .hero-deco-top {
  font-size: 28px;
  letter-spacing: 14px;
  color: var(--pen-red);
  margin-bottom: 10px;
}
.home-hero-v2 h1 {
  font-family: "Baoli SC", serif;
  font-size: 44px;
  color: var(--pen-blue-dk);
  letter-spacing: 6px;
  margin: 0 0 12px;
  text-shadow: 2px 2px 0 rgba(192, 57, 43, 0.1);
}
.home-hero-v2 .hero-subtitle {
  color: var(--ink-soft);
  font-size: 16px;
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 2px;
  margin-bottom: 8px;
}
.home-hero-v2 .hero-date {
  color: var(--ink-light);
  font-size: 13px;
  font-family: "Hannotate SC", sans-serif;
}

/* ---------- 升级版科目卡片 ---------- */
.subject-card {
  position: relative;
  display: block;
  background: rgba(255, 252, 240, 0.85);
  border: 2px solid var(--pen-blue);
  border-radius: 14px;
  padding: 26px 28px;
  text-decoration: none;
  color: var(--ink);
  overflow: hidden;
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}
.subject-card::before {
  content: "";
  position: absolute;
  top: -30px; right: -30px;
  width: 140px; height: 140px;
  background: radial-gradient(circle, rgba(26,77,143,0.1) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}
.subject-card:hover {
  transform: translateY(-5px) rotate(-0.3deg);
  box-shadow: 5px 10px 25px rgba(0,0,0,0.13);
  border-color: var(--pen-red);
}
.subject-card .subject-icon {
  font-size: 36px;
  display: block;
  margin-bottom: 6px;
}
.subject-card h3 {
  font-family: "Baoli SC", serif;
  font-size: 24px;
  color: var(--pen-blue-dk);
  margin: 0 0 10px;
  letter-spacing: 2px;
  position: relative;
  z-index: 1;
}
.subject-card .desc {
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.8;
  margin: 0 0 14px;
  font-family: "Hannotate SC", sans-serif;
  position: relative;
  z-index: 1;
}
.subject-card .progress-bar {
  height: 6px;
  background: rgba(180, 160, 120, 0.2);
  border-radius: 3px;
  overflow: hidden;
  margin: 12px 0 6px;
  position: relative;
  z-index: 1;
}
.subject-card .progress-bar > div {
  height: 100%;
  background: linear-gradient(90deg, var(--pen-blue), #4a8b4a);
  border-radius: 3px;
  transition: width 0.5s;
}
.subject-card .progress-text {
  font-size: 12px;
  color: var(--ink-light);
  font-family: "Hannotate SC", sans-serif;
  position: relative;
  z-index: 1;
}
.subject-card .chapter-links {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--line-strong);
  position: relative;
  z-index: 1;
}
.subject-card .chapter-links a {
  display: block;
  color: var(--pen-blue);
  text-decoration: none;
  font-size: 13px;
  padding: 3px 0;
  border-bottom: 1px dotted transparent;
}
.subject-card .chapter-links a:hover {
  border-color: var(--pen-blue);
  color: var(--pen-red);
}
.subject-card.coming-soon { opacity: 0.7; }
.subject-card.coming-soon::after {
  content: "待整理";
  position: absolute;
  top: 14px; right: 16px;
  background: var(--ink-light);
  color: var(--paper);
  padding: 2px 10px;
  font-size: 11px;
  border-radius: 3px;
  font-family: "PingFang SC", sans-serif;
  letter-spacing: 1px;
  z-index: 2;
}

/* ---------- 统计栏（胶带便签）---------- */
.stats-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 14px;
  margin: 28px 0;
}
.stats-item {
  text-align: center;
  padding: 16px 10px;
  background: rgba(255, 250, 230, 0.7);
  border: 1px dashed var(--line-strong);
  border-radius: 10px;
  position: relative;
}
.stats-item::before {
  content: "";
  position: absolute;
  top: -6px; left: 50%;
  transform: translateX(-50%);
  width: 30px; height: 12px;
  background: var(--tape);
  opacity: 0.7;
}
.stats-num {
  font-family: "Baoli SC", serif;
  font-size: 30px;
  color: var(--pen-red-dk);
  display: block;
  line-height: 1;
}
.stats-label {
  font-size: 12px;
  color: var(--ink-light);
  margin-top: 6px;
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 1px;
}

/* ---------- 笔记页底部章节导航 ---------- */
.note-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 40px 0 20px;
}
.note-nav > a,
.note-nav > .placeholder {
  display: block;
  padding: 14px 18px;
  border: 2px solid var(--line-strong);
  border-radius: 10px;
  text-decoration: none;
  color: var(--ink);
  background: rgba(255, 252, 240, 0.7);
  transition: all 0.2s;
}
.note-nav > a:hover {
  border-color: var(--pen-blue);
  background: rgba(220, 240, 255, 0.5);
  transform: translateY(-2px);
}
.note-nav .nav-label {
  font-size: 12px;
  color: var(--ink-light);
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 1px;
}
.note-nav .nav-title {
  font-family: "Baoli SC", serif;
  font-size: 17px;
  color: var(--pen-blue-dk);
  margin-top: 4px;
}
.note-nav .nav-next { text-align: right; }
.note-nav > .placeholder {
  text-align: center;
  color: var(--ink-light);
  font-family: "Hannotate SC", sans-serif;
  font-size: 13px;
  border-style: dashed;
  background: rgba(180, 160, 120, 0.05);
}

/* ---------- 浮动返回顶部按钮 ---------- */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--pen-blue);
  color: #fff;
  border: 2px solid #fff;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 2px 3px 10px rgba(0,0,0,0.25);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, transform 0.2s, background 0.2s;
  z-index: 100;
  font-family: sans-serif;
  padding: 0;
  line-height: 1;
}
.back-to-top:hover {
  transform: translateY(-3px);
  background: var(--pen-red);
}
.back-to-top.visible {
  opacity: 0.9;
  visibility: visible;
}

/* ---------- 页脚信息 ---------- */
.page-footer {
  margin-top: 40px;
  padding: 20px 0 0;
  border-top: 2px dashed var(--line-strong);
  text-align: center;
  color: var(--ink-light);
  font-size: 12px;
  font-family: "Hannotate SC", sans-serif;
  letter-spacing: 1px;
}
.page-footer a {
  color: var(--pen-blue);
  text-decoration: none;
  border-bottom: 1px dotted var(--pen-blue);
}

/* ==========================================================================
   响应式 · 平板 / 手机
   ========================================================================== */
@media (max-width: 768px) {
  body { font-size: 16px; line-height: 1.9; background-size: 100% 30px; }
  .page { padding: 20px 22px 80px; }
  .page-header::before { left: -22px; right: -22px; }

  h1.note-title { font-size: 26px; letter-spacing: 1px; }
  h2.section-title { font-size: 22px; margin: 30px 0 14px; }
  h3.subsection-title { font-size: 19px; margin: 22px 0 10px; }
  h4.minor-title { font-size: 17px; }

  .home-hero { padding: 40px 16px 24px; }
  .home-hero h1 { font-size: 32px; letter-spacing: 3px; }

  ul, ol { padding-left: 22px; }
  .toc { padding: 16px 18px 14px; }
  .toc ol { padding-left: 20px; }

  .mnemonic-text { font-size: 19px; letter-spacing: 2px; }

  .table-wrapper { font-size: 0.92em; }
  .table-wrapper th, .table-wrapper td { padding: 6px 8px; }

  /* 升级组件响应式 */
  .subject-card { padding: 22px 24px; }
  .subject-card h3 { font-size: 21px; }
  .home-hero-v2 { padding: 36px 16px 22px; }
  .home-hero-v2 h1 { font-size: 32px; letter-spacing: 3px; }
  .home-hero-v2 .hero-deco-top { font-size: 22px; letter-spacing: 8px; }
  .stats-num { font-size: 26px; }
  .note-nav { grid-template-columns: 1fr; }
  .note-nav .nav-next { text-align: left; }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
    line-height: 1.85;
    background-size: 100% 28px;
    background-position: 0 10px;
  }
  .page { padding: 16px 16px 60px; }

  h1.note-title { font-size: 23px; }
  h2.section-title { font-size: 20px; letter-spacing: 1px; }
  h3.subsection-title { font-size: 18px; }
  h4.minor-title { font-size: 16px; }

  .home-hero h1 { font-size: 26px; letter-spacing: 2px; }
  .home-hero p { font-size: 14px; }

  .module-grid { gap: 16px; }
  .module-card { padding: 18px 18px; }

  .key-box, .exam-box, .warn-box, .tip-box, .annotate-block {
    padding: 12px 14px 12px 16px;
    margin: 14px 0;
  }
  .annotate-block { padding-left: 28px; }

  .card-grid { grid-template-columns: 1fr; gap: 12px; }
  .knowledge-card { padding: 14px 12px 12px; }

  .mnemonic-text { font-size: 17px; letter-spacing: 1px; }
  blockquote { padding: 8px 14px; margin: 10px 0; }

  /* 长表格横向滚动 */
  .table-wrapper { margin: 14px -16px; }
  .table-wrapper table { font-size: 0.88em; }

  /* 升级组件响应式 */
  .home-hero-v2 h1 { font-size: 26px; letter-spacing: 2px; }
  .subject-card { padding: 18px 18px; }
  .subject-card h3 { font-size: 19px; }
  .back-to-top { width: 40px; height: 40px; right: 16px; bottom: 16px; font-size: 18px; }
}

/* 大屏 */
@media (min-width: 1200px) {
  body { font-size: 18px; }
  .page { max-width: 920px; }
}

/* 打印 */
@media print {
  body { background: #fff; font-size: 12pt; }
  .page-header, .annotate-block::before { color: #000; }
  .key-box, .exam-box, .tip-box, .warn-box { break-inside: avoid; }
}