:root{--navy:#12243a;--blue:#1769aa;--green:#16794b;--red:#a52b2b;--ink:#203040;--muted:#617080;--pale:#f3f7fb;--line:#dce5ee}*{box-sizing:border-box}body{margin:0;color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans TC",Arial,sans-serif;line-height:1.65}.topbar{background:var(--navy)}.topbar nav{max-width:980px;margin:auto;padding:14px 20px;display:flex;justify-content:space-between;gap:20px}.topbar a{color:#fff;text-decoration:none}.brand{font-weight:800}main{max-width:900px;margin:auto;padding:0 20px 55px}.crumbs{padding:18px 0;color:var(--muted);font-size:14px}a{color:var(--blue)}.hero{padding:24px 0 30px}.hero h1{font-size:38px;line-height:1.2;color:var(--navy);margin:3px 0 12px}.hero p{color:var(--muted);margin:0}.eyebrow{color:var(--green)!important;font-weight:800;font-size:14px}.validator{border:1px solid var(--line);border-radius:16px;padding:28px;box-shadow:0 12px 30px rgba(18,36,58,.08)}h2{color:var(--navy);line-height:1.3}.validator h2{margin-top:0}label{display:block;font-weight:700;margin-bottom:7px}.input-row{display:flex}.input-row input{min-width:0;flex:1;border:2px solid var(--blue);border-radius:10px 0 0 10px;padding:15px;font:700 18px ui-monospace,monospace;text-transform:uppercase}.input-row button{border:0;border-radius:0 10px 10px 0;background:var(--blue);color:#fff;padding:0 22px;font-weight:800}.help{font-size:13px;color:var(--muted);margin:6px 0}.result{margin-top:22px;border-radius:12px;padding:20px}.result.valid{background:#eef9f3;border:1px solid #b9dfcb}.result.invalid{background:#fff2f2;border:1px solid #efc5c5}.status strong,.status span{display:block}.valid .status strong{color:var(--green)}.invalid .status strong{color:var(--red)}.status span,.normalized span,.parts dt,.parts small{color:var(--muted);font-size:13px}.normalized{display:flex;align-items:center;gap:12px;background:#fff;padding:12px;margin:15px 0;border-radius:8px}.normalized strong{font:800 18px ui-monospace,monospace;margin-right:auto}.copy{border:1px solid var(--line);background:var(--pale);border-radius:6px;padding:6px 10px}.parts{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:15px 0}.parts>div{background:#fff;padding:12px;border-radius:8px}.parts dd{margin:2px 0}.parts code{display:block;font-size:18px;font-weight:800}.hint{margin-top:12px}.hint ul{margin:0;padding-left:20px}.warning{margin:22px 0;background:#fff8e8;border-left:4px solid #dc9224;padding:16px 18px}.explain{padding:15px 0}.structure{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}.structure span{background:var(--pale);border-radius:9px;padding:13px;text-align:center}.structure b{display:block;font:800 18px ui-monospace,monospace;color:var(--blue)}footer{background:var(--navy);color:#cbd6df;text-align:center;padding:26px 20px;font-size:13px}footer a{color:#fff}@media(max-width:650px){.hero h1{font-size:29px}.validator{padding:20px}.input-row{display:block}.input-row input{width:100%;border-radius:9px}.input-row button{width:100%;padding:13px;border-radius:9px;margin-top:8px}.parts,.structure{grid-template-columns:1fr}.normalized{align-items:flex-start;flex-wrap:wrap}.normalized strong{width:100%}}