/* ═══════════════════════════════════════
   AI 素養教育工作坊 — 課堂筆記
   ═══════════════════════════════════════ */

:root {
  --bg:       #fbfbfd;
  --surface:  #ffffff;
  --text:     #1d2330;
  --muted:    #6a7280;
  --line:     #e3e6ec;
  --navy:     #1b2f5e;
  --navy-lt:  #35528f;
  --accent:   #c9852c;
  --good:     #2f7d52;
  --danger:   #b4482f;
  --radius: 12px;
  --wrap: 48rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:      #12151b;
    --surface: #1a1e26;
    --text:    #e5e7ec;
    --muted:   #98a0ae;
    --line:    #2c313b;
    --navy:    #8fb0e8;
    --navy-lt: #a9c3f0;
    --accent:  #e0ab5c;
    --good:    #6bbd8c;
    --danger:  #e0836c;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 4.5rem; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Noto Sans TC", "Microsoft JhengHei", "PingFang TC",
               -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 1.25rem; }

/* ── Hero ─────────────────────────────── */

.hero {
  background: linear-gradient(155deg, #16264c, #24406f 55%, #3b5a92);
  color: #fff;
  padding: 4.5rem 0 4rem;
  text-align: center;
}

.hero .kicker {
  margin: 0 0 .75rem;
  font-size: .78rem;
  letter-spacing: .3em;
  text-indent: .3em;
  opacity: .72;
}

.hero h1 {
  margin: 0 0 .35rem;
  font-size: clamp(1.9rem, 5.5vw, 2.8rem);
  letter-spacing: .04em;
  line-height: 1.3;
}

.hero .sub {
  margin: 0 0 1.75rem;
  font-size: .82rem;
  letter-spacing: .16em;
  opacity: .6;
}

.hero .lede { margin: 0 0 2rem; font-size: .95rem; line-height: 1.9; opacity: .9; }

.hero .oneline {
  margin: 0 auto;
  max-width: 28rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255,255,255,.22);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: .03em;
}

/* ── 目錄 ─────────────────────────────── */

.toc {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.toc .wrap {
  display: flex; gap: .3rem;
  overflow-x: auto; scrollbar-width: none;
  padding-top: .5rem; padding-bottom: .5rem;
}
.toc .wrap::-webkit-scrollbar { display: none; }

.toc a {
  flex: none; padding: .3rem .7rem; border-radius: 99px;
  color: var(--muted); font-size: .86rem; text-decoration: none; white-space: nowrap;
  transition: background .15s, color .15s;
}
.toc a:hover { background: color-mix(in srgb, var(--navy) 13%, transparent); color: var(--navy); }

/* ── 區塊 ─────────────────────────────── */

main { padding-bottom: 2rem; }

section { padding: 3.5rem 0 1rem; border-bottom: 1px solid var(--line); }
section:last-child { border-bottom: 0; }

.chapter {
  margin: 0 0 .3rem;
  font-size: .74rem;
  letter-spacing: .26em;
  color: var(--accent);
  font-weight: 700;
}

h2 {
  margin: 0 0 1.5rem;
  font-size: 1.65rem;
  line-height: 1.4;
  letter-spacing: .02em;
}

h3 { font-size: 1.1rem; margin: 0 0 .6rem; line-height: 1.6; }

h3.sub {
  margin: 2.5rem 0 .9rem;
  padding-bottom: .4rem;
  border-bottom: 1px dashed var(--line);
  color: var(--navy);
}

h4 { font-size: .98rem; margin: 0 0 .5rem; }

p { margin: 0 0 1rem; }

.note { color: var(--muted); font-size: .9rem; }

.insight {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border-left: 3px solid var(--accent);
  padding: .9rem 1.15rem;
  border-radius: 0 var(--radius) var(--radius) 0;
}

blockquote {
  margin: 0 0 1rem;
  padding: .9rem 1.2rem;
  border-left: 3px solid var(--line);
  color: var(--muted);
  font-size: .95rem;
}

/* ── 卡片 ─────────────────────────────── */

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.35rem 1rem;
}

.card .n {
  display: block;
  font-size: .74rem;
  letter-spacing: .2em;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: .4rem;
}

.card h3 { color: var(--navy); }
.card p:last-child { margin-bottom: .4rem; }

.card .method {
  font-size: .82rem;
  color: var(--muted);
  border-bottom: 1px dashed var(--line);
  padding-bottom: .5rem;
}

/* ── 問答框 ───────────────────────────── */

.qa-box {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.2rem 1.35rem .8rem;
  margin: 1.5rem 0;
}

.qa-box .q {
  margin: 0 0 .8rem;
  padding-left: 2rem;
  position: relative;
  font-weight: 700;
  color: var(--navy);
}
.qa-box .q::before {
  content: "問";
  position: absolute; left: 0; top: 0;
  color: var(--good);
  font-weight: 700;
}

.qa-box .a {
  margin: 0; padding-left: 2rem; list-style: none; position: relative;
}
.qa-box .a::before {
  content: "答";
  position: absolute; left: 0; top: 0;
  color: var(--accent);
  font-weight: 700;
}
.qa-box .a li { margin-bottom: .4rem; }

/* ── 對照欄 ───────────────────────────── */

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}

.side {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem 1.3rem .9rem;
}

.side h4 { color: var(--navy); }
.side p:last-child { margin-bottom: .35rem; }

.side .tag {
  display: inline-block;
  padding: .12rem .6rem;
  border-radius: 99px;
  background: color-mix(in srgb, var(--good) 16%, transparent);
  color: var(--good);
  font-size: .8rem;
  font-weight: 700;
}
.side .tag.alt { background: color-mix(in srgb, var(--navy) 15%, transparent); color: var(--navy); }
.side .tag.danger { background: color-mix(in srgb, var(--danger) 15%, transparent); color: var(--danger); }

.side .big { font-weight: 700; line-height: 1.75; }

.warn-side { border-left: 3px solid var(--danger); }
.good-side { border-left: 3px solid var(--good); }

/* ── 三階段 ───────────────────────────── */

.stages { display: grid; gap: .8rem; margin: 1.5rem 0; }

.stage {
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 3px solid var(--navy-lt);
  border-radius: var(--radius);
  padding: 1.15rem 1.3rem .8rem;
}

.stage.hl { border-left-color: var(--accent); background: color-mix(in srgb, var(--accent) 7%, var(--surface)); }

.stage h4 { color: var(--navy); margin-bottom: .2rem; }
.stage .en { font-size: .88rem; color: var(--muted); margin-bottom: .6rem; }
.stage ul { margin: 0; padding-left: 1.2rem; }
.stage li { margin-bottom: .25rem; }

/* ── 規則框 ───────────────────────────── */

.rule {
  background: linear-gradient(135deg, color-mix(in srgb, var(--navy) 12%, transparent), transparent);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.3rem 1rem;
  text-align: center;
  margin: 1.5rem 0;
}
.rule .big { font-size: 1.12rem; font-weight: 700; color: var(--navy); margin-bottom: .3rem; }
.rule .small { font-size: .85rem; color: var(--muted); margin: 0; }

/* ── 清單 ─────────────────────────────── */

.reasons { list-style: none; padding: 0; margin: 0 0 1.25rem; }
.reasons li { position: relative; padding-left: 1.4rem; margin-bottom: .6rem; }
.reasons li::before {
  content: ""; position: absolute; left: .2rem; top: .8em;
  width: 6px; height: 6px; border-radius: 50%; background: var(--navy-lt);
}

/* ── 表格 ─────────────────────────────── */

.tablewrap {
  overflow-x: auto;
  margin: 0 0 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

table { width: 100%; border-collapse: collapse; font-size: .94rem; background: var(--surface); }

th, td { padding: .7rem .9rem; text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); }

thead th {
  background: color-mix(in srgb, var(--navy) 11%, transparent);
  color: var(--navy);
  white-space: nowrap;
}
tbody th { font-weight: 600; color: var(--muted); white-space: nowrap; width: 1%; }
tbody tr:last-child th, tbody tr:last-child td { border-bottom: 0; }

/* ── 投影片 ───────────────────────────── */

.shot { margin: 1.6rem 0; }
.shot img {
  display: block; width: 100%; height: auto;
  border: 1px solid var(--line); border-radius: var(--radius);
}
.shot figcaption {
  margin-top: .5rem; color: var(--muted); font-size: .86rem; text-align: center;
}
.shot figcaption:empty { display: none; }

/* ── 問答摺疊 ─────────────────────────── */

details {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: .6rem;
  overflow: hidden;
}

summary {
  padding: .85rem 1.15rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--navy);
  list-style: none;
  position: relative;
  padding-right: 2.5rem;
}
summary::-webkit-details-marker { display: none; }
summary::after {
  content: "+";
  position: absolute; right: 1.1rem; top: .78rem;
  color: var(--muted); font-size: 1.15rem; line-height: 1;
}
details[open] summary::after { content: "−"; }

details p { margin: 0; padding: 0 1.15rem 1rem; color: var(--text); }

/* ── 行動清單 ─────────────────────────── */

.todo { display: grid; gap: .1rem; }

.todo label {
  display: flex;
  gap: .75rem;
  align-items: flex-start;
  padding: .7rem .9rem;
  border-radius: 8px;
  cursor: pointer;
  transition: background .12s;
}
.todo label:hover { background: color-mix(in srgb, var(--navy) 6%, transparent); }

.todo input {
  margin-top: .45em;
  width: 1.05rem; height: 1.05rem;
  accent-color: var(--navy-lt);
  flex: none;
  cursor: pointer;
}

.todo input:checked + span { color: var(--muted); text-decoration: line-through; }

/* ── 相簿 ─────────────────────────────── */

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(6.5rem, 1fr));
  gap: .55rem;
}

.thumb {
  position: relative;
  margin: 0;
  cursor: pointer;
  border-radius: 7px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--surface);
  transition: transform .12s, box-shadow .12s;
}
.thumb:hover { transform: translateY(-2px); box-shadow: 0 4px 14px rgba(0,0,0,.14); }

.thumb img { display: block; width: 100%; height: 7.5rem; object-fit: cover; }

.thumb figcaption {
  position: absolute; left: 0; bottom: 0;
  padding: .1rem .45rem;
  background: rgba(0,0,0,.62);
  color: #fff;
  font-size: .72rem;
  border-radius: 0 6px 0 0;
}

/* ── 燈箱 ─────────────────────────────── */

.lightbox {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(8,10,14,.93);
  display: flex; align-items: center; justify-content: center;
  padding: 2.5rem 1rem;
}
.lightbox[hidden] { display: none; }

.lightbox img {
  max-width: 100%; max-height: 100%;
  object-fit: contain;
  border-radius: 6px;
}

.lightbox button {
  position: absolute;
  background: rgba(255,255,255,.11);
  border: 0; color: #fff;
  cursor: pointer;
  border-radius: 50%;
  width: 2.6rem; height: 2.6rem;
  font-size: 1.5rem; line-height: 1;
  display: grid; place-items: center;
  transition: background .15s;
}
.lightbox button:hover { background: rgba(255,255,255,.24); }

.lb-close { top: 1rem; right: 1rem; }
.lb-prev  { left: 1rem;  top: 50%; transform: translateY(-50%); }
.lb-next  { right: 1rem; top: 50%; transform: translateY(-50%); }

.lb-num {
  position: absolute; bottom: 1rem; left: 50%; transform: translateX(-50%);
  color: rgba(255,255,255,.72); font-size: .85rem;
  font-variant-numeric: tabular-nums;
}

/* ── 頁尾 ─────────────────────────────── */

footer {
  border-top: 1px solid var(--line);
  padding: 2.25rem 0;
  color: var(--muted);
  font-size: .88rem;
  text-align: center;
}
footer p { margin: 0 0 .45rem; }
footer a { color: var(--navy); }
footer .small { font-size: .8rem; opacity: .78; }

/* ── 手機 ─────────────────────────────── */

@media (max-width: 34rem) {
  body { font-size: 16px; }
  .hero { padding: 3.25rem 0 2.75rem; }
  section { padding-top: 2.75rem; }
  .split { grid-template-columns: 1fr; }
  .gallery { grid-template-columns: repeat(auto-fill, minmax(5rem, 1fr)); }
  .thumb img { height: 5.75rem; }
  .lb-prev, .lb-next { width: 2.2rem; height: 2.2rem; font-size: 1.25rem; }
}