:root {
  --primary: #4f46e5;
  --primary-dark: #3730a3;
  --accent: #0d9488;
  --bg: #f6f7fb;
  --card-bg: #ffffff;
  --text: #1f2430;
  --muted: #667085;
  --border: #e4e7ee;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(16,24,40,.06), 0 6px 16px rgba(16,24,40,.05);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, sans-serif;
  line-height: 1.6;
}

header.site {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  padding: 28px 16px 22px;
  text-align: center;
}
header.site h1 { font-size: 1.5rem; font-weight: 700; }
header.site h1 a { color: #fff; text-decoration: none; }
header.site p { margin-top: 6px; color: rgba(255,255,255,.85); font-size: .9rem; }

.wrap { max-width: 880px; margin: 0 auto; padding: 24px 16px 40px; }

.back-link {
  display: inline-block; margin-bottom: 16px;
  color: var(--primary); text-decoration: none; font-size: .9rem;
}
.back-link:hover { text-decoration: underline; }

/* 首頁工具卡片 */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 20px;
}
.tool-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 20px;
  text-decoration: none;
  color: var(--text);
  transition: transform .15s ease, box-shadow .15s ease;
}
.tool-card:hover { transform: translateY(-3px); box-shadow: 0 4px 10px rgba(16,24,40,.1), 0 12px 24px rgba(16,24,40,.08); }
.tool-card .icon { font-size: 2rem; margin-bottom: 10px; display: block; }
.tool-card h3 { font-size: 1.05rem; margin-bottom: 6px; }
.tool-card p { color: var(--muted); font-size: .85rem; }

.intro { margin: 18px 0 4px; color: var(--muted); font-size: .95rem; max-width: 640px; }

/* 卡片式工具容器 */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
  margin-bottom: 20px;
}
.card h2 { font-size: 1.15rem; margin-bottom: 14px; }

.field-row {
  display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 14px;
}
input[type="text"], input[type="number"], select {
  font-size: 1rem;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
  font-family: inherit;
}
input[type="number"] { width: 180px; }
input[type="text"] { flex: 1; min-width: 200px; }
select { min-width: 140px; }
button {
  font-size: .95rem;
  padding: 10px 18px;
  border: none;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  cursor: pointer;
  font-weight: 600;
}
button:hover { background: var(--primary-dark); }
button.secondary {
  background: #fff; color: var(--primary); border: 1px solid var(--primary);
}

.toggle-group { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.toggle-group button {
  background: #fff; color: var(--muted); border-radius: 0; font-weight: 500; padding: 8px 16px;
}
.toggle-group button.active { background: var(--primary); color: #fff; }

table.result-table { width: 100%; border-collapse: collapse; margin-top: 4px; }
table.result-table th, table.result-table td {
  text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--border); font-size: .93rem;
}
table.result-table th { color: var(--muted); font-weight: 600; font-size: .82rem; text-transform: uppercase; letter-spacing: .03em; }
table.result-table td.val { font-variant-numeric: tabular-nums; font-weight: 600; }
table.result-table tr:last-child td { border-bottom: none; }

.hint { color: var(--muted); font-size: .82rem; margin-top: 4px; }
.error-box { background: #fef2f2; border: 1px solid #fecaca; color: #b91c1c; padding: 12px 14px; border-radius: 8px; font-size: .9rem; margin-top: 10px; }
.loading { color: var(--muted); font-size: .9rem; padding: 6px 0; }

.info-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(160px,1fr)); gap: 12px; margin-top: 4px; }
.info-item { background: var(--bg); border-radius: 8px; padding: 10px 12px; }
.info-item .label { color: var(--muted); font-size: .78rem; }
.info-item .value { font-weight: 700; font-size: 1.02rem; margin-top: 2px; word-break: break-all; }

/* 廣告預留位（AdSense 核可後改放 adsbygoogle 單元） */
.ad-slot {
  margin: 22px 0;
  min-height: 90px;
  display: flex; align-items: center; justify-content: center;
  background: #eef0f6;
  border: 1px dashed var(--border);
  border-radius: 10px;
}
.ad-placeholder { color: var(--muted); font-size: .8rem; letter-spacing: .05em; }

article h2 { margin: 20px 0 8px; font-size: 1.15rem; }
article h2:first-child { margin-top: 0; }
article h3 { margin: 14px 0 6px; font-size: 1rem; }
article p, article li { color: var(--text); font-size: .95rem; margin-bottom: 8px; }
article ul { padding-left: 20px; }

footer.site {
  text-align: center; color: var(--muted); font-size: .82rem; padding: 24px 16px 40px;
}
footer.site nav { margin-bottom: 8px; }
footer.site nav a { color: var(--muted); text-decoration: none; margin: 0 8px; }
footer.site nav a:hover { text-decoration: underline; color: var(--primary); }

@media (max-width: 480px) {
  input[type="number"] { width: 100%; }
  .field-row { flex-direction: column; align-items: stretch; }
}