:root{--bg:#f7f8fa;--card:#fff;--text:#1a1d23;--muted:#5f6772;--line:#e3e6ea;--accent:#1f5eff;--accent-2:#e8eeff;--ok:#0f8a4c;--warn:#b7791f;--radius:12px;--max:1080px}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo","Pretendard","Noto Sans KR","Malgun Gothic",system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.7;font-size:16px;word-break:keep-all}
a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}
img{max-width:100%}
.wrap{max-width:var(--max);margin:0 auto;padding:0 16px}
header.site{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
header.site .wrap{display:flex;align-items:center;justify-content:space-between;height:58px}
.logo{font-weight:800;font-size:20px;color:var(--text);letter-spacing:-.5px}
.logo span{color:var(--accent)}
nav.main a{margin-left:18px;color:var(--muted);font-size:15px;font-weight:600}
nav.main a:hover{color:var(--accent);text-decoration:none}
@media(max-width:640px){nav.main a{margin-left:12px;font-size:14px}}
main{padding:28px 0 48px}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:32px}
@media(max-width:900px){.layout{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
@media(max-width:640px){.card{padding:18px 16px}}
h1{font-size:28px;line-height:1.3;letter-spacing:-.5px;margin:0 0 10px}
@media(max-width:640px){h1{font-size:23px}}
h2{font-size:21px;margin:36px 0 12px;letter-spacing:-.3px;padding-left:12px;border-left:4px solid var(--accent)}
h3{font-size:17px;margin:24px 0 8px}
p{margin:0 0 14px}
.lead{color:var(--muted);font-size:16px;margin-bottom:20px}
.meta{color:var(--muted);font-size:13px;margin-bottom:18px}
table{width:100%;border-collapse:collapse;margin:12px 0 18px;font-size:15px;background:#fff}
th,td{border:1px solid var(--line);padding:9px 10px;text-align:left;vertical-align:top}
th{background:#f1f3f7;font-weight:700}
.table-wrap{overflow-x:auto}
ul,ol{padding-left:22px;margin:0 0 14px}li{margin-bottom:4px}
.callout{background:#fff8e6;border:1px solid #f2dd9c;border-radius:10px;padding:14px 16px;margin:16px 0}
.example{background:var(--accent-2);border-radius:10px;padding:16px 18px;margin:18px 0}
.example h3{margin-top:0}
/* calculator */
.calc{display:grid;gap:14px}
.field{display:grid;gap:6px}
.field label{font-weight:700;font-size:14px}
.field small{color:var(--muted);font-size:12px}
.field input,.field select{width:100%;font-size:16px;padding:11px 12px;border:1px solid #cfd4db;border-radius:8px;background:#fff;color:var(--text)}
.field input:focus,.field select:focus{outline:2px solid var(--accent);border-color:var(--accent)}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media(max-width:560px){.row2{grid-template-columns:1fr}}
.radio{display:flex;flex-wrap:wrap;gap:8px}
.radio label{font-weight:500;font-size:14px;border:1px solid #cfd4db;border-radius:999px;padding:7px 14px;cursor:pointer;background:#fff}
.radio input{display:none}
.radio input:checked+span{color:var(--accent);font-weight:700}
.radio label:has(input:checked){border-color:var(--accent);background:var(--accent-2)}
.btn{display:inline-block;background:var(--accent);color:#fff;border:0;border-radius:8px;padding:13px 22px;font-size:16px;font-weight:700;cursor:pointer}
.btn:hover{filter:brightness(1.05)}
.btn.ghost{background:#fff;color:var(--text);border:1px solid #cfd4db}
.result{margin-top:22px;border-top:2px dashed var(--line);padding-top:18px}
.result .big{font-size:30px;font-weight:800;color:var(--accent);letter-spacing:-.5px}
.result .big small{font-size:15px;color:var(--muted);font-weight:500;margin-left:6px}
.kv{display:grid;grid-template-columns:1fr auto;gap:6px 16px;font-size:15px;margin:12px 0}
.kv div:nth-child(even){text-align:right;font-variant-numeric:tabular-nums;font-weight:600}
.kv .sub{color:var(--muted);font-weight:400;font-size:14px}
.note{font-size:13px;color:var(--muted);margin-top:14px}
/* sidebar & lists */
aside .card{margin-bottom:20px}
aside h4{margin:0 0 10px;font-size:15px}
aside ul{list-style:none;padding:0;margin:0}
aside li{padding:7px 0;border-bottom:1px solid var(--line);font-size:14px}
aside li:last-child{border:0}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:14px;margin:16px 0}
.tile{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:18px;color:var(--text);transition:.15s}
.tile:hover{border-color:var(--accent);text-decoration:none;transform:translateY(-2px)}
.tile b{display:block;font-size:16px;margin-bottom:6px}
.tile span{font-size:13px;color:var(--muted)}
.tile .ico{font-size:22px;margin-bottom:8px;display:block}
.hero{background:linear-gradient(135deg,#1f5eff 0%,#3d7bff 60%,#6ea0ff 100%);color:#fff;border-radius:16px;padding:40px 28px;margin-bottom:28px}
.hero h1{color:#fff;font-size:32px;margin-bottom:8px}
.hero p{color:#e6eeff;font-size:17px;margin:0}
@media(max-width:640px){.hero{padding:28px 20px}.hero h1{font-size:25px}}
.posts{list-style:none;padding:0;margin:0}
.posts li{border-bottom:1px solid var(--line);padding:14px 0}
.posts li:last-child{border:0}
.posts a{font-weight:700;color:var(--text);font-size:17px}
.posts a:hover{color:var(--accent)}
.posts p{margin:4px 0 0;color:var(--muted);font-size:14px}
.tag{display:inline-block;font-size:12px;color:var(--accent);background:var(--accent-2);border-radius:6px;padding:2px 8px;margin-right:6px}
.crumb{font-size:13px;color:var(--muted);margin-bottom:12px}
.crumb a{color:var(--muted)}
.disclaimer{font-size:13px;color:var(--muted);background:#f1f3f7;border-radius:8px;padding:12px 14px;margin-top:28px}
.related{margin-top:28px}
.ad-slot{margin:22px 0;min-height:0;text-align:center}
.ad-slot.side{min-height:0}
footer.site{border-top:1px solid var(--line);background:#fff;padding:26px 0;color:var(--muted);font-size:13px}
footer.site .wrap{display:flex;flex-wrap:wrap;gap:8px 20px;justify-content:space-between}
footer.site a{color:var(--muted);margin-right:14px}
.toc{background:#f1f3f7;border-radius:10px;padding:14px 18px;margin:16px 0 22px;font-size:14px}
.toc b{display:block;margin-bottom:6px}
.toc a{display:block;padding:2px 0;color:var(--text)}