/* ============================================================
   锅老师少儿编程 · 古色古香 · 极简
   ============================================================ */
:root {
  --paper: #F7F2E7;          /* 宣纸米白 */
  --paper-deep: #EFE6D3;
  --ink: #2B2A26;            /* 墨色 */
  --ink-soft: #6E6657;
  --ink-faint: #9A9284;
  --cinnabar: #A03C2C;       /* 朱砂 */
  --cinnabar-deep: #7E2C1F;
  --line: rgba(43, 42, 38, .18);
  --line-strong: rgba(43, 42, 38, .38);
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 10px;
  --shadow: 0 10px 30px rgba(60, 45, 20, .08);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--serif);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.95;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "kern";
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

h1, h2, h3, h4 { font-family: var(--serif); font-weight: 700; letter-spacing: .5px; }
.wrap { max-width: 1000px; margin: 0 auto; padding: 0 28px; }

/* ---------- 印章 Logo ---------- */
.seal {
  display: inline-flex; align-items: center; justify-content: center;
  width: 44px; height: 44px;
  background: var(--cinnabar);
  color: var(--paper);
  font-size: 24px; font-weight: 700;
  border-radius: 6px;
  letter-spacing: 0;
  box-shadow: inset 0 0 0 2px rgba(247, 242, 231, .35);
  user-select: none;
}
.seal.small { width: 36px; height: 36px; font-size: 19px; border-radius: 5px; }
.seal img { display: block; width: 100%; height: 100%; object-fit: cover; border-radius: inherit; }

/* ---------- 左侧固定导航（参考单栏布局，不出现滚动条） ---------- */
.sidebar {
  position: fixed; left: 0; top: 0; bottom: 0; z-index: 50;
  width: 260px;
  display: flex; flex-direction: column; justify-content: flex-start;
  background: var(--paper);
  border-right: 1px solid var(--line);
  padding: 32px 26px 30px;
  overflow: hidden;                 /* 关键：永不出现滚动条 */
}
.brand { display: flex; align-items: center; gap: 12px; padding: 0 2px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.3; min-width: 0; }
.brand-name { font-family: var(--serif); font-size: 19px; font-weight: 700; letter-spacing: 2px; overflow-wrap: anywhere; }
.brand-sub { font-size: 11px; color: var(--ink-faint); letter-spacing: .5px; margin-top: 2px; overflow-wrap: anywhere; }

.nav-links { display: flex; flex-direction: column; gap: 2px; margin-top: 44px; }
.nav-links a {
  display: flex; align-items: center; gap: 12px;
  font-family: var(--sans); font-size: 14.5px; font-weight: 500;
  color: var(--ink-soft); letter-spacing: 2px;
  padding: 9px 12px; border-radius: 7px;
  transition: color .2s, background .2s;
}
.nav-links a .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--line-strong); flex: none;
  transition: background .2s, transform .2s;
}
.nav-links a:hover { color: var(--ink); background: rgba(43, 42, 38, .05); }
.nav-links a.active { color: var(--cinnabar); background: rgba(160, 60, 44, .07); }
.nav-links a.active .dot { background: var(--cinnabar); transform: scale(1.5); }

.page-body { margin-left: 260px; min-height: 100vh; display: flex; flex-direction: column; }
.page-body main { flex: 1; }

/* 矮屏保险：压缩导航间距，副标题始终显示 */
@media (max-height: 620px) { .nav-links { margin-top: 24px; } }

/* ---------- 首页 Hero ---------- */
.hero { padding: 96px 0 72px; text-align: center; }
.hero .seal { width: 76px; height: 76px; font-size: 40px; border-radius: 10px; }
.hero h1 { margin-top: 26px; font-size: 44px; font-weight: 700; letter-spacing: 6px; }
.hero .subtitle { margin-top: 14px; font-size: 18px; color: var(--ink-soft); letter-spacing: 3px; }
.hero .line-sep {
  width: 56px; height: 1px; background: var(--cinnabar);
  margin: 28px auto; position: relative;
}
.hero .line-sep::after {
  content: "◆"; position: absolute; left: 50%; top: -9px; transform: translateX(-50%);
  font-size: 12px; color: var(--cinnabar);
}
.hero .lead { max-width: 640px; margin: 0 auto; color: var(--ink-soft); font-size: 16px; }
.hero-cta { margin-top: 34px; display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block; padding: 10px 26px;
  border: 1px solid var(--cinnabar); border-radius: 999px;
  font-size: 15px; letter-spacing: 2px; cursor: pointer;
  transition: all .25s;
}
.btn-primary { background: var(--cinnabar); color: var(--paper); }
.btn-primary:hover { background: var(--cinnabar-deep); }
.btn-ghost { color: var(--cinnabar); background: transparent; }
.btn-ghost:hover { background: rgba(160, 60, 44, .08); }
/* 小号按钮（详情页文末导航等场景，手机端防换行） */
.btn-sm { padding: 6px 14px; font-size: 13px; letter-spacing: 1px; }

/* ---------- 区块通用 ---------- */
.section { padding: 72px 0; }
.section + .section { border-top: 1px solid var(--line); }
.sec-head { text-align: center; margin-bottom: 48px; }
.sec-head h2 { font-size: 28px; font-weight: 700; letter-spacing: 5px; }
.sec-head .en { font-size: 13px; color: var(--ink-faint); letter-spacing: 3px; margin-top: 6px; }
.sec-head::after {
  content: ""; display: block; width: 44px; height: 1px; background: var(--cinnabar);
  margin: 18px auto 0;
}

/* ---------- 卡片 ---------- */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: var(--paper);
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px 26px;
  transition: transform .3s, box-shadow .3s, border-color .3s;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: var(--line-strong); }
.card h3 { font-size: 19px; letter-spacing: 2px; }
.card .tag { display: inline-block; margin-top: 8px; font-size: 12px; color: var(--cinnabar); letter-spacing: 1px; }
.card p { margin-top: 14px; font-size: 14.5px; color: var(--ink-soft); }
.card .cta { display: inline-block; margin-top: 18px; font-size: 14px; color: var(--cinnabar); border-bottom: 1px solid var(--cinnabar); }

/* ---------- 首页数据统计 ---------- */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; text-align: center; }
.stat { padding: 26px 10px; border: 1px solid var(--line); border-radius: var(--radius); }
.stat .num { font-size: 40px; font-weight: 700; color: var(--cinnabar); letter-spacing: 2px; }
.stat .label { margin-top: 6px; font-size: 14px; color: var(--ink-soft); letter-spacing: 2px; }

/* ---------- 时间轴 ---------- */
.timeline { position: relative; max-width: 720px; margin: 0 auto; padding-left: 28px; }
.timeline::before { content: ""; position: absolute; left: 6px; top: 8px; bottom: 8px; width: 1px; background: var(--line-strong); }
.tl-item { position: relative; padding: 0 0 40px 22px; }
.tl-item::before {
  content: ""; position: absolute; left: -29px; top: 6px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--paper); border: 2px solid var(--cinnabar);
}
.tl-item .period { font-size: 13px; color: var(--cinnabar); letter-spacing: 1px; }
.tl-item h3 { font-size: 20px; margin-top: 4px; letter-spacing: 2px; }
.tl-item p { margin-top: 8px; color: var(--ink-soft); font-size: 15px; }

/* ---------- 列表项（十讲/随笔） ---------- */
.item-list { display: flex; flex-direction: column; gap: 14px; }
.item {
  display: flex; align-items: baseline; gap: 18px;
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 24px; transition: transform .25s, border-color .25s, box-shadow .25s;
}
.item:hover { transform: translateY(-3px); border-color: var(--line-strong); box-shadow: var(--shadow); }
.item .idx { font-size: 22px; font-weight: 700; color: var(--cinnabar); min-width: 56px; letter-spacing: 1px; }
.item h3 { font-size: 17px; letter-spacing: 1px; }
.item .meta { font-size: 12.5px; color: var(--ink-faint); margin-top: 4px; letter-spacing: 1px; }
.item .summary { font-size: 14px; color: var(--ink-soft); margin-top: 6px; }
.item .arrow { margin-left: auto; color: var(--ink-faint); font-size: 20px; }

/* ---------- 视频卡片 ---------- */
.video-card { position: relative; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius); display: flex; flex-direction: column; background: var(--paper); }
.video-card .thumb { position: relative; aspect-ratio: 3/4; display: flex; align-items: center; justify-content: center; background: var(--paper-deep); color: var(--ink-faint); font-size: 13px; letter-spacing: 2px; overflow: hidden; }
.video-card .play {
  width: 46px; height: 46px; border-radius: 50%;
  background: var(--cinnabar); display: flex; align-items: center; justify-content: center;
  margin: 0 auto 10px;
}
.video-card .play::after { content: "▶"; color: var(--paper); font-size: 16px; margin-left: 2px; }
.video-card .thumb-title {
  display: flex; align-items: center; justify-content: flex-start;
  width: 100%; height: 100%;
  padding: 28px 16px 0; text-align: center;
  background: linear-gradient(150deg, var(--cinnabar) 0%, #c96f4a 60%, #d98a5f 100%);
  color: var(--paper);
  font-family: var(--serif); font-size: 15px; letter-spacing: 2px; line-height: 1.7;
}
.video-card .thumb-title span { margin: 0 auto; }
.video-card .thumb-play {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
  width: 54px; height: 54px; border-radius: 50%;
  background: rgba(160, 60, 44, .9);
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 4px 20px rgba(0, 0, 0, .28);
  transition: transform .25s, background .25s;
  cursor: pointer;
}
.video-card .thumb-play::after { content: "▶"; color: var(--paper); font-size: 19px; margin-left: 4px; }
.video-card:hover .thumb-play { transform: translate(-50%, -50%) scale(1.12); background: var(--cinnabar); }
.video-card .v-title {
  padding: 14px 14px 16px;
  font-size: 15px; font-weight: 600; letter-spacing: 1px; line-height: 1.6;
  text-align: center;
  border-top: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
}

/* ---------- 富文本正文 ---------- */
.rich-body { max-width: 760px; margin: 0 auto; font-size: 16px; }
.rich-body p { margin-bottom: 16px; }
.rich-body img { border-radius: 8px; margin: 20px auto; }
.rich-body h2, .rich-body h3 { margin: 28px 0 12px; letter-spacing: 2px; }
.rich-body blockquote {
  border-left: 3px solid var(--cinnabar); padding: 10px 18px;
  background: var(--paper-deep); border-radius: 4px; margin: 18px 0; color: var(--ink-soft);
}
.rich-body ul, .rich-body ol { padding-left: 24px; margin-bottom: 16px; }
.rich-body table { border-collapse: collapse; width: 100%; margin: 18px 0; }
.rich-body th, .rich-body td { border: 1px solid var(--line-strong); padding: 8px 12px; }

.page-head { padding: 64px 0 40px; text-align: center; }
.page-head h1 { font-size: 32px; letter-spacing: 5px; }
.page-head p { margin-top: 10px; color: var(--ink-soft); letter-spacing: 1px; }

/* ---------- 关于我 ---------- */
.about-grid { display: grid; grid-template-columns: 220px 1fr; gap: 48px; align-items: start; }
.avatar-frame {
  border: 1px solid var(--line-strong); border-radius: 8px; padding: 14px;
  background: var(--paper);
}
.avatar-frame .avatar {
  width: 100%; aspect-ratio: 1; border-radius: 4px;
  background: var(--paper-deep); display: flex; align-items: center; justify-content: center;
  color: var(--ink-faint); font-size: 60px; font-weight: 700; letter-spacing: 2px;
  overflow: hidden;
}
.avatar-frame .avatar img { width: 100%; height: 100%; object-fit: cover; }
.about-text p { margin-bottom: 16px; }

/* ---------- 联系 ---------- */
.contact-box {
  max-width: 560px; margin: 0 auto; text-align: center;
  border: 1px solid var(--line); border-radius: var(--radius); padding: 40px 30px;
}
.contact-box .row { margin: 18px 0; font-size: 16px; }
.contact-box .row span { color: var(--ink-faint); font-size: 13px; margin-right: 10px; letter-spacing: 1px; }
.contact-codes { display: flex; flex-wrap: wrap; gap: 18px; justify-content: center; margin-top: 30px; }
.code-card { width: 150px; text-align: center; }
.code-card img {
  width: 150px; height: 150px; object-fit: contain;
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--paper); padding: 8px; box-shadow: 0 2px 10px rgba(43, 42, 38, .06);
}
.code-label { margin-top: 10px; font-size: 14px; color: var(--ink-soft); letter-spacing: 1px; }
@media (max-width: 480px) {
  .code-card { width: 132px; }
  .code-card img { width: 132px; height: 132px; }
}

/* ---------- 文章赞赏 ---------- */
.reward {
  max-width: 760px; margin: 36px auto 0; text-align: center;
  padding: 24px 26px; border: 1px dashed var(--line-strong);
  border-radius: var(--radius); background: var(--paper-deep);
}
.reward-tip { font-size: 15px; color: var(--ink-soft); margin-bottom: 14px; letter-spacing: .5px; }
.reward-img { display: block; width: 130px; height: 130px; margin: 14px auto 0; object-fit: contain; border-radius: 8px; background: var(--paper); padding: 6px; box-shadow: 0 2px 10px rgba(43,42,38,.06); }
.reward-note { margin-top: 12px; font-size: 13px; color: var(--ink-faint); letter-spacing: 1px; }

/* ---------- 上一篇 / 下一篇 ---------- */
.post-nav { display: flex; gap: 16px; max-width: 760px; margin: 32px auto 0; }
.post-nav-item {
  flex: 1; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; text-decoration: none; color: var(--ink); background: var(--paper);
  transition: border-color .2s, transform .2s;
}
.post-nav-item:hover { border-color: var(--cinnabar); transform: translateY(-2px); }
.pn-label { display: block; font-size: 12px; color: var(--cinnabar); letter-spacing: 1px; }
.pn-title { display: block; margin-top: 6px; font-size: 15px; letter-spacing: .5px; overflow-wrap: anywhere; }

/* ---------- 移动端体验优化 ---------- */
@media (max-width: 620px) {
  .post-nav { flex-direction: column; }
  .post-nav-item { display: flex; align-items: baseline; gap: 8px; }
  .pn-label { flex: none; margin: 0; }
  .pn-title { margin-top: 0; }
  .page-head h1 { font-size: 24px; letter-spacing: 3px; }
  .rich-body { font-size: 15px; }
  .rich-body img { max-width: 100%; }
  .reward-img { width: 120px; height: 120px; }
}

/* ---------- 页脚 ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 36px 0; text-align: center; color: var(--ink-faint); font-size: 13px; letter-spacing: 1px; }
.site-footer a { color: var(--ink-soft); }
.site-footer a:hover { color: var(--cinnabar); }

/* ---------- 学生案例 · 家长反馈图片墙 ---------- */
.plan-box {
  max-width: 760px; margin: -6px auto 34px;
  background: rgba(160, 60, 44, .07);
  border: 1px solid rgba(160, 60, 44, .22);
  border-radius: var(--radius);
  padding: 20px 30px;
  text-align: left;
}
.plan-box p {
  font-size: 15px; color: var(--ink-soft);
  line-height: 1.9; letter-spacing: .5px;
  margin: 0;
}
@media (max-width: 620px) {
  .plan-box { padding: 16px 20px; }
  .plan-box p { font-size: 14px; line-height: 1.85; }
}
.case-gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.case-gallery-home {
  grid-template-columns: repeat(3, 1fr);
  max-width: 900px;
  margin: 0 auto;
}
.case-card {
  margin: 0;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(43, 42, 38, .04);
  transition: transform .25s, box-shadow .25s;
}
.case-card:hover { transform: translateY(-3px); box-shadow: 0 6px 22px rgba(43, 42, 38, .1); }
.case-card img {
  display: block; width: 100%; aspect-ratio: 3 / 4;
  object-fit: cover; background: var(--paper-deep);
}
.case-card figcaption {
  padding: 14px 16px 16px;
  font-size: 14px; color: var(--ink-soft);
  text-align: center; letter-spacing: .5px;
  border-top: 1px solid var(--line);
  background: var(--paper);
}
@media (max-width: 860px) { .case-gallery { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .case-gallery, .case-gallery-home { grid-template-columns: 1fr; } }

/* ---------- 案例原图 lightbox ---------- */
.case-zoom { display: block; cursor: zoom-in; }
.case-zoom img { transition: transform .3s; }
.case-card:hover .case-zoom img { transform: scale(1.03); }
.lightbox {
  position: fixed; inset: 0; z-index: 300;
  background: rgba(30, 29, 26, .92);
  display: flex; align-items: center; justify-content: center;
  padding: 56px 80px;
  opacity: 0; transition: opacity .2s;
}
.lightbox.show { opacity: 1; }
.lb-stage { text-align: center; max-width: 92vw; }
.lb-stage img {
  max-width: min(86vw, 900px); max-height: 76vh;
  border-radius: 8px; box-shadow: 0 10px 50px rgba(0, 0, 0, .55);
  background: #fff;
}
.lb-cap { margin-top: 16px; color: #f0ead9; font-size: 15px; letter-spacing: 1px; }
.lb-close {
  position: absolute; top: 16px; right: 16px;
  width: 42px; height: 42px; border: none; border-radius: 50%;
  background: rgba(255, 255, 255, .15); color: #fff;
  font-size: 24px; line-height: 1; cursor: pointer;
  transition: background .2s;
  z-index: 2;
}
.lb-close:hover { background: rgba(255, 255, 255, .3); }
.lb-prev, .lb-next {
  position: absolute; top: 50%; transform: translateY(-50%);
  width: 48px; height: 48px; border: none; border-radius: 50%;
  background: var(--cinnabar-deep); color: #fff;
  font-size: 30px; line-height: 1; cursor: pointer;
  transition: background .2s;
  z-index: 2;
}
.lb-prev { left: 18px; }
.lb-next { right: 18px; }
.lb-prev:hover, .lb-next:hover { background: #5E2016; }
.lb-hint {
  position: absolute; bottom: 18px; left: 0; right: 0;
  text-align: center; color: rgba(240, 234, 217, .6);
  font-size: 13px; letter-spacing: 1px; pointer-events: none;
}
@media (max-width: 620px) {
  .lightbox { padding: 44px 52px; }
  .lb-prev { left: 8px; }
  .lb-next { right: 8px; }
  .lb-hint { bottom: 12px; font-size: 12px; }
}

/* ---------- 滚动淡入 ---------- */
.fade-in { opacity: 0; transform: translateY(18px); transition: opacity .7s ease, transform .7s ease; }
.fade-in.visible { opacity: 1; transform: none; }

/* ---------- 汉堡按钮（仅手机端显示） ---------- */
.nav-toggle {
  display: none;
  position: fixed; top: 8px; right: 14px; z-index: 70;
  width: 44px; height: 44px;
  border: none; border-radius: 0; background: transparent;
  cursor: pointer; padding: 15px 12px;
  box-shadow: none;
}
.nav-toggle span {
  display: block; height: 2px; background: var(--ink); border-radius: 2px;
  transition: transform .3s, opacity .25s;
}
.nav-toggle span + span { margin-top: 5px; }
/* 打开态：三条线变叉 */
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-overlay {
  display: none;
  position: fixed; inset: 0; z-index: 45;
  background: rgba(43, 42, 38, .4);
  opacity: 0; transition: opacity .3s;
}
.nav-overlay.show { opacity: 1; }

/* 移动端顶部标题栏（仅手机显示，桌面隐藏） */
.m-topbar {
  display: none;
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  height: 56px; align-items: center; gap: 10px; padding: 0 16px 0 18px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 2px 12px rgba(43, 42, 38, .1);
}
.m-topbar .m-brand { display: flex; flex-direction: column; line-height: 1.25; }
.m-topbar .m-topbar-link { display: flex; align-items: center; gap: 10px; color: inherit; text-decoration: none; }
.m-topbar .m-brand b { font-family: var(--serif); font-size: 16px; letter-spacing: 2px; }
.m-topbar .m-brand em { font-style: normal; font-size: 10.5px; color: var(--ink-faint); letter-spacing: .5px; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .cards { grid-template-columns: 1fr 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .hero { padding: 76px 0 48px; }
  .hero h1 { font-size: 34px; }
  .page-body { margin-left: 0; padding-top: 56px; }
  .wrap { padding: 0 22px; }

  /* 抽屉里只留导航，不显示品牌（标题已移到顶部栏） */
  .sidebar { padding-top: 28px; }
  .sidebar .brand { display: none; }

  /* 手机端：侧边栏变左侧抽屉，默认隐藏，由汉堡按钮唤出 */
  .sidebar {
    width: 260px; justify-content: flex-start;
    transform: translateX(-100%);
    transition: transform .3s ease;
    box-shadow: 2px 0 24px rgba(43, 42, 38, .18);
  }
  .sidebar.open { transform: translateX(0); }
  .nav-toggle { display: block; }
  .nav-overlay { display: block; pointer-events: none; }
  .nav-overlay.show { pointer-events: auto; }
  .m-topbar { display: flex; }
}
@media (max-width: 620px) {
  .cards { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr; }
  .hero { padding: 64px 0 48px; }
  .btn-sm { padding: 5px 10px; font-size: 12px; letter-spacing: 0; }
  .lecture-nav { gap: 6px; }
}