/* ============================================================================
   assets/site.css  ·  全站通用样式（设计令牌 + 站点外壳）
   首页与所有课件页共用。课件页另加载 assets/kid3d/engine.css（3D 舞台与叠层）。
   ========================================================================== */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --ink: #1e2536;
  --ink-2: #5b6a86;
  --ink-3: #93a1ba;
  --line: #e2e9f3;
  --card: #ffffff;
  --accent: #ff8a3d;
  --accent-2: #e26a1f;
  --radius: 20px;
  --shadow: 0 10px 30px rgba(28, 42, 80, .07);
  --shadow-hi: 0 16px 40px rgba(28, 42, 80, .12);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
          "Noto Sans", "Microsoft YaHei", sans-serif;
}

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

body {
  min-height: 100vh;
  color: var(--ink);
  background: radial-gradient(120% 90% at 50% 0%, #fbfdff 0%, #eaf1fa 42%, #dde7f4 100%);
  background-attachment: fixed;
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  padding: 28px 20px 56px;
}

.wrap { max-width: 960px; margin: 0 auto; }

/* ── 顶部工具条（站点级：返回首页 + 面包屑）──────────────────────────────── */
.sitebar {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  font-size: 13px; color: var(--ink-3); margin-bottom: 22px;
}
.sitebar a { color: var(--ink-2); text-decoration: none; }
.sitebar a:hover { color: var(--accent-2); }
.sitebar .sep { color: #c7d3e4; }
.sitebar .lang {
  margin-left: auto; font-size: 12px; color: var(--ink-3); text-decoration: none;
  border: 1px solid var(--line); background: #fff; border-radius: 999px; padding: 5px 12px;
}
.sitebar .lang[hidden] { display: none; }

/* ── 页头 ───────────────────────────────────────────────────────────────── */
.page-head { margin-bottom: 22px; }
.page-head h1 {
  font-size: clamp(21px, 3.6vw, 30px); line-height: 1.3; letter-spacing: -.3px; margin-bottom: 8px;
}
.page-head .lede { font-size: 14px; line-height: 1.8; color: var(--ink-2); max-width: 720px; }

/* ── 按钮 ───────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 7px; cursor: pointer;
  font: inherit; font-size: 13px; font-weight: 700; color: var(--ink-2);
  background: #fff; border: 1px solid var(--line); border-radius: 999px; padding: 9px 16px;
  text-decoration: none; transition: .16s;
}
.btn:hover { border-color: #ffcda6; color: var(--accent-2); }
.btn-primary {
  color: #fff; border: 0; background: linear-gradient(180deg, #ffb073, #ff7a2e);
  box-shadow: 0 10px 24px rgba(255, 122, 46, .34);
}
.btn-primary:hover { color: #fff; transform: translateY(-1px); box-shadow: 0 14px 30px rgba(255, 122, 46, .44); }

/* ── 面板 ───────────────────────────────────────────────────────────────── */
.panel {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px 24px; box-shadow: var(--shadow);
}
section.block { margin-top: 34px; }
h2.sec {
  font-size: 12.5px; font-weight: 700; letter-spacing: .8px; text-transform: uppercase;
  color: var(--ink-3); margin-bottom: 14px; padding-left: 2px;
}

/* ── 词表（给搜索引擎看的真实文本内容）──────────────────────────────────── */
.wordtable { width: 100%; border-collapse: collapse; font-size: 14px; }
.wordtable caption { text-align: left; font-size: 13px; color: var(--ink-3); padding-bottom: 10px; }
.wordtable th, .wordtable td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; }
.wordtable th { font-size: 11.5px; text-transform: uppercase; letter-spacing: .6px; color: var(--ink-3); font-weight: 700; }
.wordtable td.en { font-weight: 700; }
.wordtable td.ipa { color: var(--ink-3); font-size: 13px; white-space: nowrap; }
.wordtable tr:last-child td { border-bottom: 0; }
.wordtable tbody tr:hover { background: #f7fafe; }

/* ── FAQ ───────────────────────────────────────────────────────────────── */
.faq details {
  border: 1px solid var(--line); border-radius: 14px; background: #fff;
  padding: 14px 18px; margin-bottom: 10px;
}
.faq summary { cursor: pointer; font-size: 14px; font-weight: 700; color: var(--ink); list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "＋"; color: var(--accent); margin-right: 8px; font-weight: 800; }
.faq details[open] summary::before { content: "－"; }
.faq p { font-size: 13.5px; line-height: 1.85; color: var(--ink-2); margin-top: 10px; }

/* ── 同类课程内链 ────────────────────────────────────────────────────────── */
.related ul { list-style: none; display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.related a {
  display: flex; align-items: center; gap: 12px; text-decoration: none; color: var(--ink);
  background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 13px 16px;
  font-size: 14px; font-weight: 700; transition: .16s;
}
.related a:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: #ffcda6; }
.related a i { font-style: normal; font-size: 20px; }
.related a small { display: block; font-size: 11.5px; font-weight: 500; color: var(--ink-3); margin-top: 3px; }

/* ── 广告位（拿到 AdSense 代码后替换内部占位即可；CSS 保持 → CLS = 0）────── */
.ad-slot {
  display: flex; align-items: center; justify-content: center;
  min-height: 100px; margin-top: 30px; border: 1px dashed #d7e1ef; border-radius: 16px;
  background: rgba(255, 255, 255, .55); overflow: hidden;
}
.ad-slot .ad-placeholder { font-size: 11px; letter-spacing: 1.4px; text-transform: uppercase; color: #b6c3d6; }
.ad-slot[hidden] { display: none; }

/* ── 页脚 ───────────────────────────────────────────────────────────────── */
footer.site-foot { margin-top: 48px; text-align: center; font-size: 12px; color: var(--ink-3); line-height: 1.9; }
footer.site-foot a { color: var(--ink-2); text-decoration: none; }
footer.site-foot a:hover { color: var(--accent-2); }
/* 信任页互链（隐私政策等）：AdSense 要求从任意页面都点得到 */
footer.site-foot .foot-links {
  margin-top: 12px; display: flex; flex-wrap: wrap; gap: 4px 10px; justify-content: center; align-items: center;
}
footer.site-foot .foot-links a { border-bottom: 1px solid transparent; }
footer.site-foot .foot-links a:hover { border-bottom-color: #ffcda6; }
footer.site-foot .foot-links .sep { color: #c7d3e4; }

@media (max-width: 640px) {
  body { padding: 18px 14px 44px; }
  .panel { padding: 18px 16px; border-radius: 16px; }
  .wordtable th, .wordtable td { padding: 9px 8px; }
  .wordtable td.ipa { font-size: 12px; }
  section.block { margin-top: 26px; }
}