:root{
  --bg:#0b1220;
  --card:#0f1b33;
  --text:#e7eefc;
  --muted:#9fb0d3;
  --primary:#60a5fa;
  --border:rgba(255,255,255,.12);
  --radius:16px;
}

*{ box-sizing:border-box; }

body{
  margin:0;
  font-family:"Noto Sans JP",system-ui,sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.7;
}

.header{
  padding:2.5rem 1rem;
  text-align:center;
}

.lead{
  color:var(--muted);
}

.container{
  max-width:900px;
  margin:0 auto;
  padding:1rem;
}

.card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:1.5rem;
  margin-bottom:1.5rem;
}

h2{
  margin-top:0;
  color:var(--primary);
}

pre{
  background:#050a18;
  padding:1rem;
  border-radius:12px;
  overflow-x:auto;
}

.copy-btn{
  margin-top:.5rem;
  padding:.4em .8em;
  background:var(--primary);
  border:none;
  border-radius:8px;
  color:#000;
  cursor:pointer;
}

.footer{
  text-align:center;
  padding:2rem;
  color:var(--muted);
}


/* =========================
  Footer (SunStripe / Programming Lab)
  対象HTML:
  <footer class="footer">
    <div class="foot__copy">...</div>
    <nav class="foot__nav"><ul>...</ul></nav>
  </footer>
========================= */

footer{
  margin-top:18px;
  padding:18px 14px;
  border:1px solid rgba(33,115,70,.22);
  border-radius:14px;
  background:
    radial-gradient(900px 200px at 20% 0%, rgba(33,115,70,.18), transparent 65%),
    radial-gradient(700px 200px at 85% 10%, rgba(15,123,108,.12), transparent 70%),
    linear-gradient(180deg, rgba(255,255,255,.06), rgba(0,0,0,.06));
  box-shadow:0 14px 34px rgba(0,0,0,.25);
  color:var(--muted);
}

.foot__copy{
  font-size:12px;
  color:var(--muted);
  display:flex;
  flex-wrap:wrap;
  gap:6px;
  align-items:center;
  justify-content:flex-start;
  padding-bottom:12px;
  border-bottom:1px solid rgba(255,255,255,.10);
}

.foot__copy a{
  color:var(--excelWhite2, #d9ffe9);
  text-decoration:none;
  font-weight:800;
  border-bottom:1px solid rgba(33,115,70,.35);
}

.foot__copy a:hover{
  filter:brightness(1.08);
  border-bottom-color:rgba(33,115,70,.60);
}

.foot__nav{
  margin-top:12px;
}

.foot__nav ul{
  list-style:none;
  padding:0;
  margin:0;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  align-items:center;
}

.foot__nav li{
  margin:0;
}

/* Excel風リンクチップ */
.foot__nav a{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding:7px 10px;
  border-radius:999px;
  border:1px solid rgba(33,115,70,.26);
  background:
    linear-gradient(180deg, rgba(33,115,70,.18), rgba(0,0,0,.06));
  color:var(--excelWhite, #f3fff8);
  font-size:12px;
  letter-spacing:.02em;
  text-decoration:none;
  transition:transform .12s ease, filter .12s ease, border-color .12s ease;
  box-shadow:0 10px 22px rgba(0,0,0,.18);
  white-space:nowrap;
}

.foot__nav a:hover{
  filter:brightness(1.08);
  border-color:rgba(33,115,70,.55);
  transform:translateY(-1px);
}

.foot__nav a:active{
  transform:translateY(0);
}

/* 今いるページが分かるように（任意：bodyにdata-current="/programming/xlsx/"とか付けると便利） */
/*
body[data-current="/programming/xlsx/"] .foot__nav a[href="/programming/xlsx/"]{
  border-color:rgba(33,115,70,.75);
  background:linear-gradient(180deg, rgba(33,115,70,.40), rgba(33,115,70,.18));
  color:var(--excelWhite2, #d9ffe9);
}
*/

/* スマホで詰まりすぎないように */
@media (max-width:560px){
  footer{
    padding:16px 12px;
  }
  .foot__nav a{
    padding:7px 9px;
    font-size:12px;
  }
}