:root{
  --ink:#1d3348;
  --muted:#5c7186;
  --bg:#f2f6fa;
  --card:#ffffff;
  --line:#dbe6ef;
  --blue:#1789c7;
  --blue-dark:#0f5e8a;
  --red:#d94f3d;
  --amber:#f0a92e;
  --green:#3ba05a;
  --radius:14px;
  --shadow:0 2px 10px rgba(23,60,90,.08);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:"PingFang TC","Microsoft JhengHei","Noto Sans TC",system-ui,-apple-system,sans-serif;
  background:var(--bg);
  color:var(--ink);
  line-height:1.85;
  font-size:17px;
}
a{color:var(--blue-dark)}
.wrap{max-width:900px;margin:0 auto;padding:0 16px}

/* ---------- top nav ---------- */
.topbar{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,.94);
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--line);
}
.topbar .wrap{display:flex;align-items:center;gap:10px;padding-top:8px;padding-bottom:8px;flex-wrap:wrap}
.brand{font-weight:800;color:var(--blue-dark);text-decoration:none;white-space:nowrap;font-size:1.02rem}
.brand small{color:var(--muted);font-weight:600;margin-left:6px}
.navlinks{display:flex;gap:4px;flex-wrap:wrap;margin-left:auto}
.navlinks a{
  text-decoration:none;color:var(--muted);font-size:.85rem;font-weight:600;
  padding:5px 10px;border-radius:999px;
}
.navlinks a:hover{background:var(--bg);color:var(--blue-dark)}

/* ---------- hero ---------- */
.hero{
  background:linear-gradient(135deg,#0f5e8a 0%,#1789c7 60%,#2aa7c9 100%);
  color:#fff;padding:44px 0 52px;
}
.hero .kicker{display:inline-block;background:rgba(255,255,255,.18);border:1px solid rgba(255,255,255,.35);
  padding:3px 14px;border-radius:999px;font-size:.85rem;letter-spacing:.12em;font-weight:700}
.hero h1{margin:14px 0 6px;font-size:2.1rem;line-height:1.3}
.hero p{margin:0;color:rgba(255,255,255,.88)}
.hero .meta{margin-top:18px;display:flex;gap:10px;flex-wrap:wrap}
.hero .meta span{background:rgba(0,0,0,.18);padding:4px 14px;border-radius:8px;font-size:.88rem}

/* ---------- cards / sections ---------- */
main{padding:34px 0 60px}
h2.sec{font-size:1.35rem;margin:38px 0 16px;display:flex;align-items:center;gap:10px}
h2.sec::before{content:"";width:8px;height:26px;border-radius:4px;background:var(--blue);flex:none}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:16px}
.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:20px;display:flex;flex-direction:column;gap:8px;
  text-decoration:none;color:inherit;transition:transform .15s ease, box-shadow .15s ease;
}
.card:hover{transform:translateY(-3px);box-shadow:0 8px 20px rgba(23,60,90,.14)}
.card .tag{font-size:.75rem;font-weight:700;letter-spacing:.08em;color:#fff;background:var(--blue);
  align-self:flex-start;padding:2px 10px;border-radius:999px}
.card h3{margin:2px 0 0;font-size:1.08rem;line-height:1.5}
.card p{margin:0;color:var(--muted);font-size:.88rem;flex:1}
.card .go{color:var(--blue-dark);font-size:.85rem;font-weight:700}
.card.warm .tag{background:var(--amber);color:#5a3d00}
.card.rose .tag{background:var(--red)}
.card.green .tag{background:var(--green)}

/* ---------- article ---------- */
article.paper{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:34px 38px;margin-top:26px;
}
@media (max-width:640px){article.paper{padding:22px 18px}}
article.paper h1{font-size:1.7rem;line-height:1.45;margin:8px 0 4px}
.crumb{font-size:.85rem;color:var(--muted)}
.paper .lede{color:var(--muted);font-size:.95rem}
.paper h2{font-size:1.25rem;margin:30px 0 10px;padding-left:12px;border-left:6px solid var(--blue)}
.paper h3{font-size:1.05rem;margin:22px 0 8px;color:var(--blue-dark)}
.paper p{margin:10px 0}
.paper figure{margin:18px 0}
.paper figure img{max-width:100%;border-radius:10px;border:1px solid var(--line);display:block}
.paper figcaption{font-size:.82rem;color:var(--muted);margin-top:6px}

.keywords{display:flex;gap:8px;flex-wrap:wrap;margin:14px 0}
.keywords span{background:#e7f3fb;color:var(--blue-dark);border:1px solid #c8e2f4;
  padding:3px 12px;border-radius:999px;font-size:.85rem;font-weight:600}

.tipbox{background:#fff8e9;border:1px solid #f2dfb5;border-radius:10px;padding:14px 18px;margin:16px 0}
.tipbox b{color:#8a6100}
.sdgbox{background:#eef7f0;border:1px solid #cfe8d6;border-radius:10px;padding:14px 18px;margin:16px 0}

.steps{list-style:none;margin:14px 0;padding:0;counter-reset:step}
.steps li{position:relative;padding:12px 14px 12px 66px;border:1px solid var(--line);
  border-radius:10px;margin:10px 0;background:#fbfdff}
.steps li::before{
  counter-increment:step;content:"步驟 " counter(step);
  position:absolute;left:12px;top:14px;
  background:var(--red);color:#fff;font-size:.75rem;font-weight:700;
  padding:3px 8px;border-radius:6px;white-space:nowrap;
}
.steps .q{font-weight:700;margin:4px 0}
.steps ol{margin:6px 0;padding-left:22px}

details.answer{margin:10px 0;border:1px dashed #b9d8ee;border-radius:10px;background:#f4faff}
details.answer summary{
  cursor:pointer;list-style:none;padding:9px 16px;font-weight:700;color:var(--blue-dark);
  font-size:.92rem;user-select:none;
}
details.answer summary::before{content:"🔎 "}
details.answer[open] summary{border-bottom:1px dashed #b9d8ee}
details.answer .body{padding:8px 18px 14px}
details.answer .body p{margin:6px 0}

/* ---------- quiz ---------- */
.quiz{border:2px solid var(--blue);border-radius:12px;padding:18px 20px;margin:24px 0;background:#f4faff}
.quiz .qt{font-weight:800;color:var(--blue-dark);margin-bottom:10px}
.quiz .opt{
  display:block;width:100%;text-align:left;font:inherit;cursor:pointer;
  background:#fff;border:1.5px solid var(--line);border-radius:10px;
  padding:10px 14px;margin:8px 0;transition:border-color .12s, background .12s;
}
.quiz .opt:hover{border-color:var(--blue)}
.quiz .opt.correct{border-color:var(--green);background:#eaf7ee;font-weight:700}
.quiz .opt.wrong{border-color:var(--red);background:#fdeeec}
.quiz .fb{margin-top:10px;font-weight:700;min-height:1.4em}
.quiz .fb.ok{color:var(--green)}
.quiz .fb.no{color:var(--red)}

/* ---------- SDG grid ---------- */
.sdg-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:12px;margin:18px 0}
.sdg{
  color:#fff;border-radius:10px;padding:14px 12px 12px;min-height:120px;
  display:flex;flex-direction:column;justify-content:flex-end;gap:4px;
}
.sdg .no{font-size:.72rem;font-weight:700;opacity:.9;letter-spacing:.06em}
.sdg .nm{font-weight:800;font-size:1rem;line-height:1.35}
.sdg .ds{font-size:.74rem;opacity:.92;line-height:1.5}
.sdg.hl{outline:4px solid var(--ink);outline-offset:2px}

/* ---------- viewer ---------- */
.viewer{max-width:980px;margin:0 auto}
.viewer .stage{background:#233442;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.viewer .stage img{display:block;width:100%;height:auto}
.vbar{display:flex;align-items:center;gap:10px;margin:14px 0;flex-wrap:wrap}
.vbar button, .vbar a.btn{
  font:inherit;font-weight:700;cursor:pointer;border:1px solid var(--line);
  background:#fff;color:var(--blue-dark);border-radius:10px;padding:9px 18px;text-decoration:none;
}
.vbar button:disabled{opacity:.4;cursor:default}
.vbar .pageno{margin:0 auto;font-weight:800;color:var(--muted)}
.thumbs{display:grid;grid-template-columns:repeat(auto-fill,minmax(84px,1fr));gap:8px;margin-top:14px}
.thumbs a{display:block;border:2px solid transparent;border-radius:8px;overflow:hidden;background:#fff}
.thumbs a:hover{border-color:var(--blue)}
.thumbs img{display:block;width:100%;height:auto}
.hint{color:var(--muted);font-size:.85rem;margin-top:10px}

/* ---------- reader reflections ---------- */
.entry{border-left:5px solid var(--blue);background:#fbfdff;border-radius:0 10px 10px 0;
  padding:14px 18px;margin:14px 0}
.entry.win{border-left-color:var(--amber);background:#fffaf0}
.entry .who{font-weight:800;font-size:.9rem;color:var(--blue-dark)}
.entry.win .who{color:#8a6100}
.entry p{margin:8px 0 0}
.prize{background:linear-gradient(135deg,#fdeecd,#fdf6e6);border:1px solid #f0d9a0;
  border-radius:12px;padding:16px 20px;margin:18px 0}
.qrbox{display:flex;gap:18px;align-items:center;flex-wrap:wrap;background:#f4faff;
  border:1px solid #cfe4f5;border-radius:12px;padding:16px 20px;margin:18px 0}
.qrbox img{width:150px;height:150px;border-radius:8px;border:1px solid var(--line)}

/* ---------- footer ---------- */
footer{border-top:1px solid var(--line);background:#fff;padding:26px 0 34px;color:var(--muted);font-size:.85rem}
.pager{display:flex;justify-content:space-between;gap:10px;margin-top:30px}
.pager a{
  text-decoration:none;font-weight:700;color:var(--blue-dark);background:#fff;
  border:1px solid var(--line);border-radius:10px;padding:10px 16px;max-width:48%;
}
.pager a:hover{border-color:var(--blue)}
.pager .lbl{display:block;font-size:.72rem;color:var(--muted);font-weight:600}
@media (max-width:640px){
  .hero h1{font-size:1.55rem}
  .sdg-grid{grid-template-columns:repeat(2,1fr)}
}