:root{
  --blue:#0C2D4E;
  --orange:#FF7A00;
  --bg:#F6F8FB;
  --card:#FFFFFF;
  --line:#E2E8F0;
  --text:#111827;
  --muted:#475569;
  --warn-bg:#FFF7ED;
  --warn-line:#FDBA74;
  --info-bg:#EFF6FF;
  --info-line:#93C5FD;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;padding:0;
  font-family:system-ui,-apple-system,"Noto Sans TC","PingFang TC","Microsoft JhengHei",sans-serif;
  background:var(--bg);color:var(--text);
  line-height:1.8;font-size:18px;
  -webkit-text-size-adjust:100%;
}
a{color:var(--blue);text-decoration:underline;text-underline-offset:3px}
.site-header{
  background:linear-gradient(180deg,var(--blue) 0%, #0A2440 100%);
  color:#fff;padding:16px 16px 12px;
  position:sticky;top:0;z-index:20;
  border-bottom:3px solid var(--orange);
}
.header-inner{max-width:1280px;margin:0 auto;display:flex;gap:20px;flex-wrap:wrap;justify-content:space-between;align-items:flex-start}
.brand{display:flex;gap:12px}
.brand-dot{width:12px;height:12px;background:var(--orange);border-radius:50%;margin-top:8px;flex:0 0 12px}
.brand h1{margin:0;font-size:20px;line-height:1.3}
.brand p{margin:4px 0 0;font-size:14px;opacity:.9;line-height:1.6}
.progress-wrap{min-width:260px;flex:1;max-width:460px}
.progress-top{display:flex;justify-content:space-between;font-size:14px;font-weight:700}
.progress-bar{height:10px;background:rgba(255,255,255,.22);border-radius:999px;overflow:hidden;margin-top:6px}
#progressBarFill{height:100%;width:0%;background:var(--orange);transition:width .3s}
.progress-note{font-size:14px;opacity:.85;margin-top:6px;line-height:1.7}
.storage-warning{margin-top:8px;background:#FEF2F2;border:1px solid #FECACA;color:#991B1B;border-radius:10px;padding:8px 10px;font-size:14px}
.hidden{display:none!important}
.layout{max-width:1280px;margin:0 auto;display:flex;min-height:calc(100vh - 86px)}
.side-nav{width:300px;flex:0 0 300px;background:#fff;border-right:1px solid var(--line);padding:14px;position:sticky;top:86px;align-self:flex-start;height:calc(100vh - 86px);overflow:auto}
.nav-mobile-top{display:none;margin-bottom:10px}
#mobileNav{width:100%;height:44px;border-radius:12px;border:1px solid var(--line);padding:0 12px;font-size:16px;background:#fff}
.nav-list{display:flex;flex-direction:column;gap:6px}
.nav-item{width:100%;text-align:left;min-height:44px;border-radius:12px;border:1px solid transparent;background:#fff;color:var(--text);padding:10px 12px;font-size:15px;line-height:1.6;cursor:pointer;display:flex;justify-content:space-between;align-items:center}
.nav-item.active{background:var(--blue);color:#fff;border-color:var(--blue)}
.nav-actions{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.btn{min-height:44px;height:44px;border-radius:12px;border:1px solid var(--line);padding:0 14px;font-size:14px;font-weight:700;cursor:pointer;display:inline-flex;align-items:center;justify-content:center}
.btn-secondary{background:var(--blue);color:#fff;border-color:var(--blue)}
.btn-ghost{background:#fff;color:var(--blue)}
.nav-legend{margin-top:18px;padding:12px;background:#F8FAFC;border:1px solid var(--line);border-radius:12px}
.nav-legend h4{margin:0 0 6px;font-size:14px}
.nav-legend p{margin:0;font-size:14px;color:var(--muted);line-height:1.7}
.small{font-size:14px;color:var(--muted)}
.muted{color:var(--muted)}
.content{flex:1;min-width:0;padding:20px 18px 40px;max-width:980px}
.unit-section{display:none}
.unit-section.active{display:block}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:22px 18px;margin-bottom:16px;box-shadow:0 1px 2px rgba(15,23,42,.04)}
.card h2{margin:0 0 10px;font-size:22px;line-height:1.4}
.card h3{margin:20px 0 8px;font-size:18px;line-height:1.5}
.card ul,.card ol{margin:8px 0;padding-left:22px}
.card li{margin:6px 0;font-size:18px;line-height:1.8}
.callout{border-radius:12px;padding:14px 14px;margin:14px 0;font-size:15px;line-height:1.8}
.callout.warn{background:var(--warn-bg);border:1px solid var(--warn-line)}
.callout.info{background:var(--info-bg);border:1px solid var(--info-line)}
.badge{display:inline-flex;align-items:center;padding:4px 10px;border-radius:999px;font-size:14px;font-weight:700;background:var(--blue);color:#fff}
.badge-warn{background:var(--orange);color:#fff;padding:6px 12px;border-radius:999px;font-size:14px;font-weight:700}
.steps{counter-reset:step}
.step-item{display:flex;gap:10px;margin:12px 0;padding:14px;border:1px solid #F1F5F9;border-radius:12px;background:#FBFDFF}
.step-num{flex:0 0 28px;height:28px;border-radius:50%;background:var(--blue);color:#fff;display:flex;align-items:center;justify-content:center;font-size:14px;font-weight:800}
.practice-box{background:#FFF7ED;border:1px dashed #FDBA74;border-radius:12px;padding:14px;margin-top:12px;font-size:16px;line-height:1.8}
.mistake-list li{font-size:16px;color:#334155}
.checklist{display:flex;flex-direction:column;gap:8px;margin-top:12px}
.check-item{display:flex;gap:10px;align-items:flex-start;min-height:44px;padding:12px;border:1px solid var(--line);border-radius:12px;background:#fff;cursor:pointer}
.check-item input{margin-top:4px;width:18px;height:18px;flex:0 0 18px}
.check-item.checked{background:#F0FDF4;border-color:#86EFAC}
.check-item span{font-size:16px;line-height:1.7}
.height-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:start}
.height-inputs label{display:block;margin-bottom:16px}
.height-inputs label>span.label-text{font-size:16px;font-weight:800;display:block;margin-bottom:6px}
.input-lg{width:100%;height:44px;border-radius:12px;border:1px solid var(--line);padding:0 12px;font-size:16px;font-family:monospace;background:#fff}
.input-lg.err{border-color:#F87171;background:#FEF2F2}
.hint{font-size:14px;color:var(--muted);display:block;margin-top:4px;line-height:1.6}
.error{font-size:14px;color:#DC2626;display:block;margin-top:4px;min-height:18px;line-height:1.5}
.result-box{background:#F8FAFC;border:1px solid var(--line);border-radius:12px;padding:14px}
.result-label{font-size:14px;color:var(--muted)}
.result-value{font-size:20px;font-weight:800;font-family:monospace;margin-top:2px}
.result-formula{font-size:14px;color:var(--muted);font-family:monospace;margin-top:2px}
.height-svg-wrap{border:1px solid var(--line);border-radius:16px;background:#FBFDFF;padding:12px;display:flex;flex-direction:column;align-items:center;overflow:hidden;min-width:0}
.height-svg{max-width:380px;width:100%;height:auto;display:block}
.faq-list{display:flex;flex-direction:column;gap:10px}
.faq-item{border:1px solid var(--line);border-radius:12px;background:#fff;padding:0 12px}
.faq-item summary{list-style:none;cursor:pointer;min-height:44px;display:flex;align-items:center;font-weight:700;font-size:16px;padding:10px 0}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item[open] summary{border-bottom:1px solid #F1F5F9}
.faq-item ol{padding:10px 0 14px 22px;margin:0}
.faq-item li{font-size:16px;margin:6px 0;line-height:1.8}
.summary-box{display:flex;gap:16px;flex-wrap:wrap;padding:12px;background:#F8FAFC;border:1px solid var(--line);border-radius:12px;margin-top:12px;font-size:15px;font-weight:700}
.link-list a{word-break:break-all}
@media (max-width: 900px){
  .layout{flex-direction:column}
  .side-nav{width:100%;flex:0 0 auto;position:static;height:auto;border-right:none;border-bottom:1px solid var(--line)}
  .nav-mobile-top{display:block}
  .nav-list{flex-direction:row;overflow:auto;white-space:nowrap;padding-bottom:6px;gap:8px}
  .nav-item{white-space:nowrap;flex:0 0 auto}
  .height-grid{grid-template-columns:1fr}
  .content{padding:14px 12px}
}
@media print{
  .site-header{position:static}
  .side-nav,.nav-actions,.no-print{display:none!important}
  .unit-section{display:none!important}
  #printArea{display:block!important}
  body{background:#fff}
}
#printArea{display:none}
@media print{
  #printArea{display:block!important}
}