/* ═══════════════════════════════════════════════════════════════
   首頁與主題頁共用樣式（全站一份）：紙感底色、課卡／主題卡、佔位卡
   ═══════════════════════════════════════════════════════════════ */
:root {
  --bg: #FAFBF8; --panel: #fff; --ink: #1C2B33; --ink-soft: #52646E;
  --grid: #E4E9E2; --green: #55A868; --cut: #C44E52;
  --sans: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: var(--sans); color: var(--ink);
  background: linear-gradient(var(--grid) 1px, transparent 1px) 0 0 / 100% 28px, var(--bg);
  min-height: 100vh;
}
.wrap { max-width: 720px; margin: 0 auto; padding: 72px 28px; }
a.back { font-size: 13.5px; font-weight: 800; color: var(--ink-soft); text-decoration: none; }
a.back:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 4px; }
.eyebrow { display: block; font-family: var(--mono); font-size: 12px; font-weight: 700; letter-spacing: .14em; color: var(--cut); }
a.back + .eyebrow { margin-top: 26px; }
h1 { font-size: clamp(30px, 5vw, 44px); font-weight: 900; margin: 10px 0 12px; }
.sub { color: var(--ink-soft); font-size: 15.5px; line-height: 1.9; max-width: 560px; }
.lessons { margin-top: 48px; display: grid; gap: 18px; }
.card {
  display: block; text-decoration: none; color: inherit;
  background: var(--panel); border: 2px solid var(--ink); border-radius: 14px;
  padding: 22px 26px; box-shadow: 6px 6px 0 var(--grid);
  transition: transform .15s, box-shadow .15s;
}
a.card:hover { transform: translate(-2px, -2px); box-shadow: 9px 9px 0 var(--grid); }
a.card:focus-visible { outline: 3px solid var(--green); outline-offset: 3px; }
.card .tag { font-family: var(--mono); font-size: 11.5px; font-weight: 700; letter-spacing: .1em; color: var(--green); }
.card h2 { font-size: 21px; font-weight: 900; margin: 6px 0 8px; }
.card p { font-size: 14px; color: var(--ink-soft); line-height: 1.8; }
.card .go { display: inline-block; margin-top: 12px; font-size: 13.5px; font-weight: 800; color: var(--cut); }
/* 尚未開課的佔位卡 */
.card.soon { border-style: dashed; box-shadow: none; opacity: .62; }
.card.soon .tag { color: var(--ink-soft); }
footer { margin-top: 72px; font-size: 12.5px; color: var(--ink-soft); line-height: 1.8; }
footer a { color: inherit; text-underline-offset: 3px; }
footer a:hover { color: var(--ink); }