/* ============================================================
   YDWS 教學鷹架文件 共用樣式
   給國中小學生閱讀的程式設計概念補充文件
   ============================================================ */

:root{
  --ink:#242832;
  --sub:#5b6270;
  --bg:#f7f8fb;
  --card:#ffffff;
  --line:#e3e6ed;
  --brand:#5b6fee;
  --brand-dark:#3f4fc0;
  --brand-light:#eef0ff;
  --tier-a:#e8536b;
  --tier-a-bg:#fdeaee;
  --tier-b:#2c9a6b;
  --tier-b-bg:#e7f7f0;
  --tier-c:#c5891a;
  --tier-c-bg:#fbf1de;
  --warn:#c5891a;
  --warn-bg:#fff6e6;
  --warn-line:#f0d38a;
  --tip:#2c9a6b;
  --tip-bg:#eafaf3;
  --tip-line:#a9e6cb;
  --new:#8b5cf6;
  --new-bg:#f3effe;
  --code-bg:#2b2f3a;
  --code-ink:#eef0ff;
  --radius:16px;
  --radius-sm:10px;
  --shadow:0 2px 10px rgba(40,45,70,.06);
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  font-family:"Noto Sans TC","PingFang TC","Microsoft JhengHei",-apple-system,BlinkMacSystemFont,sans-serif;
  background:var(--bg);
  color:var(--ink);
  line-height:1.85;
  font-size:16.5px;
}

.page{max-width:880px;margin:0 auto;padding:0 20px 80px;}

/* ---------- Header ---------- */
.hero{
  padding:44px 20px 34px;
  background:linear-gradient(155deg,var(--brand) 0%,var(--brand-dark) 100%);
  color:#fff;
  border-radius:0 0 28px 28px;
  margin-bottom:34px;
}
.hero-inner{max-width:880px;margin:0 auto;}
.breadcrumb{
  font-size:14px;opacity:.85;margin-bottom:14px;
}
.breadcrumb a{color:#fff;text-decoration:none;border-bottom:1px dotted rgba(255,255,255,.5);}
.tier-badge{
  display:inline-flex;align-items:center;gap:6px;
  font-size:13px;font-weight:700;
  padding:4px 12px;border-radius:999px;
  background:rgba(255,255,255,.18);
  margin-bottom:14px;
  letter-spacing:.5px;
}
.hero h1{font-size:clamp(28px,5vw,38px);margin:0 0 10px;font-weight:900;letter-spacing:1px;}
.hero .course-tag{
  font-size:15px;opacity:.92;
  display:flex;flex-wrap:wrap;gap:8px;margin-top:14px;
}
.hero .course-tag span{
  background:rgba(255,255,255,.16);
  padding:4px 12px;border-radius:8px;font-weight:600;
}

/* ---------- Section headings ---------- */
h2.section-title{
  font-size:23px;font-weight:900;
  margin:56px 0 18px;
  padding-left:16px;
  border-left:6px solid var(--brand);
  color:var(--ink);
  display:flex;align-items:center;gap:10px;
}
h2.section-title .num{
  display:inline-flex;align-items:center;justify-content:center;
  width:30px;height:30px;border-radius:50%;
  background:var(--brand);color:#fff;font-size:15px;flex:none;
}
p.lead{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:22px 24px;
  box-shadow:var(--shadow);
  font-size:16.5px;
}
p.lead strong{color:var(--brand-dark);}

/* ---------- Concept cards ---------- */
.concept{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:24px 26px;
  margin-bottom:22px;
  box-shadow:var(--shadow);
  position:relative;
}
.concept-head{
  display:flex;align-items:center;gap:12px;margin-bottom:12px;
}
.concept-num{
  flex:none;
  width:36px;height:36px;border-radius:10px;
  background:var(--brand-light);color:var(--brand-dark);
  display:flex;align-items:center;justify-content:center;
  font-weight:900;font-size:16px;
}
.concept-head h3{margin:0;font-size:19px;font-weight:800;}

.todo-box{
  background:var(--brand-light);
  border-radius:var(--radius-sm);
  padding:14px 16px;margin:12px 0;
  font-size:15.5px;
}
.todo-box b.tag{color:var(--brand-dark);}

.example-box{
  background:#f5f6fa;
  border:1px dashed #c7cbe0;
  border-radius:var(--radius-sm);
  padding:14px 16px;margin:12px 0;
  font-size:15px;
}
.example-box .tag{
  display:inline-block;font-weight:800;color:var(--brand-dark);
  margin-bottom:6px;font-size:13.5px;
}

.pitfall{
  background:var(--warn-bg);
  border:1px solid var(--warn-line);
  border-radius:var(--radius-sm);
  padding:14px 16px;margin:14px 0 0;
  font-size:15px;
}
.pitfall .tag{
  display:flex;align-items:center;gap:6px;
  font-weight:800;color:var(--warn);margin-bottom:6px;font-size:14px;
}

.tip{
  background:var(--tip-bg);
  border:1px solid var(--tip-line);
  border-radius:var(--radius-sm);
  padding:14px 16px;margin:14px 0 0;
  font-size:15px;
}
.tip .tag{
  display:flex;align-items:center;gap:6px;
  font-weight:800;color:var(--tip);margin-bottom:6px;font-size:14px;
}

.newcontent{
  background:var(--new-bg);
  border:1px solid #d9cdfa;
  border-radius:var(--radius-sm);
  padding:14px 16px;margin:14px 0 0;
  font-size:14.5px;
}
.newcontent .tag{
  display:flex;align-items:center;gap:6px;
  font-weight:800;color:var(--new);margin-bottom:6px;font-size:13.5px;
}
.new-badge{
  display:inline-block;
  background:var(--new);color:#fff;
  font-size:11.5px;font-weight:700;
  padding:2px 8px;border-radius:999px;
  vertical-align:middle;margin-left:8px;
}

.problem-chip{
  display:inline-block;
  background:#fff;border:1px solid var(--line);
  border-radius:999px;padding:4px 12px;margin:3px 4px 3px 0;
  font-size:13.5px;color:var(--sub);
}
.problem-chip b{color:var(--ink);}

/* ---------- code ---------- */
pre.code{
  background:var(--code-bg);color:var(--code-ink);
  border-radius:var(--radius-sm);
  padding:16px 18px;overflow-x:auto;
  font-family:"JetBrains Mono","Cascadia Code",Consolas,monospace;
  font-size:14px;line-height:1.7;margin:12px 0;
}
code.inline{
  background:#eef0f8;color:var(--brand-dark);
  padding:2px 6px;border-radius:6px;font-size:14px;
  font-family:"JetBrains Mono",Consolas,monospace;
}

/* ---------- diagrams ---------- */
.diagram{
  background:#fbfbfe;
  border:1px solid var(--line);
  border-radius:var(--radius-sm);
  padding:20px;margin:14px 0;
  overflow-x:auto;
}
.diagram .caption{
  font-size:13px;color:var(--sub);margin-top:10px;text-align:center;
}
.cellrow{display:flex;gap:8px;flex-wrap:wrap;justify-content:center;align-items:flex-end;}
.cell{
  min-width:44px;height:44px;
  display:flex;align-items:center;justify-content:center;
  background:#fff;border:2px solid #c7cbe0;border-radius:8px;
  font-weight:700;font-size:15px;position:relative;
}
.cell.idx::before{
  content:attr(data-idx);
  position:absolute;top:-20px;left:50%;transform:translateX(-50%);
  font-size:11px;color:var(--sub);font-weight:400;
}
.cell.active{background:var(--brand);color:#fff;border-color:var(--brand-dark);}
.cell.done{background:var(--tip-bg);border-color:var(--tip-line);color:var(--tip);}
.cell.faded{opacity:.35;}
.cell.window{background:#fff3cf;border-color:#e6c15a;}
.cell.max{background:var(--tier-a-bg);border-color:var(--tier-a);color:var(--tier-a);}

.arrow-down{text-align:center;font-size:20px;color:var(--brand);margin:2px 0;}
.pointer{
  text-align:center;color:var(--brand-dark);font-weight:800;font-size:13px;margin-top:4px;
}

.stack-col{display:flex;flex-direction:column-reverse;gap:6px;align-items:center;width:100px;margin:0 auto;}
.stack-col .cell{width:88px;}

.queue-row{display:flex;gap:6px;align-items:center;justify-content:center;}

.flow{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:10px;}
.flow .step{
  background:#fff;border:2px solid var(--brand);color:var(--brand-dark);
  border-radius:12px;padding:10px 16px;font-weight:700;font-size:14px;text-align:center;
  min-width:96px;
}
.flow .op{font-size:20px;color:var(--sub);}
.flow .loopback{
  width:100%;text-align:center;color:var(--sub);font-size:13px;margin-top:4px;
}

svg.diagram-svg{display:block;margin:0 auto;max-width:100%;height:auto;}

/* ---------- tables ---------- */
.table-wrap{overflow-x:auto;margin:14px 0;}
table.pretty{
  width:100%;border-collapse:collapse;
  background:var(--card);border-radius:var(--radius-sm);overflow:hidden;
  box-shadow:var(--shadow);font-size:14.5px;
}
table.pretty th{
  background:var(--brand);color:#fff;text-align:left;
  padding:12px 14px;font-weight:700;font-size:14px;
}
table.pretty td{padding:11px 14px;border-bottom:1px solid var(--line);}
table.pretty tr:last-child td{border-bottom:none;}
table.pretty tr:nth-child(even) td{background:#fafbfe;}
table.pretty td.center,table.pretty th.center{text-align:center;}

.compare-table th{text-align:center;}
.compare-table td{text-align:center;}

/* ---------- footer ---------- */
.footer{
  margin-top:60px;padding-top:24px;border-top:1px solid var(--line);
  font-size:13px;color:var(--sub);
}
.footer .source{margin-top:6px;}
.back-link{
  display:inline-block;margin-top:14px;color:var(--brand-dark);
  text-decoration:none;font-weight:700;font-size:14px;
}
.back-link:hover{text-decoration:underline;}

@media (max-width:600px){
  body{font-size:15.5px;}
  .hero{border-radius:0 0 20px 20px;padding:34px 16px 26px;}
  .concept{padding:18px 16px;}
  h2.section-title{font-size:20px;}
}

/* ---------- index / listing page ---------- */
.tier-group{margin:40px 0;}
.tier-group-head{
  display:flex;align-items:center;gap:10px;margin-bottom:16px;
}
.tier-group-head .dot{width:14px;height:14px;border-radius:50%;flex:none;}
.tier-group-head .dot.a{background:var(--tier-a);}
.tier-group-head .dot.b{background:var(--tier-b);}
.tier-group-head .dot.c{background:var(--tier-c);}
.tier-group-head h2{margin:0;font-size:20px;font-weight:900;}
.tier-group-desc{font-size:14px;color:var(--sub);margin:-8px 0 16px 24px;}

.doc-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));
  gap:16px;
}
.doc-card{
  display:block;background:var(--card);border:1px solid var(--line);
  border-radius:var(--radius);padding:18px 20px;box-shadow:var(--shadow);
  text-decoration:none;color:var(--ink);
  transition:transform .12s ease, box-shadow .12s ease;
}
.doc-card:hover{transform:translateY(-2px);box-shadow:0 6px 18px rgba(40,45,70,.12);}
.doc-card .doc-tier{
  display:inline-block;font-size:11.5px;font-weight:800;
  padding:3px 10px;border-radius:999px;margin-bottom:10px;
}
.doc-card.a .doc-tier{background:var(--tier-a-bg);color:var(--tier-a);}
.doc-card.b .doc-tier{background:var(--tier-b-bg);color:var(--tier-b);}
.doc-card.c .doc-tier{background:var(--tier-c-bg);color:var(--tier-c);}
.doc-card h3{margin:0 0 10px;font-size:17px;font-weight:800;}
.doc-card .doc-codes{display:flex;flex-wrap:wrap;gap:6px;}
.doc-card .doc-codes span{
  font-size:12px;font-weight:700;color:var(--sub);
  background:#f2f3f8;padding:3px 9px;border-radius:6px;
}