:root{
  --ink:#16181d; --muted:#5b6270; --line:#e3e6eb; --bg:#ffffff; --soft:#f5f6f8;
  --accent:#1f3a68; --accent-soft:#e8edf5;
  --max:1080px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);
  font-family:"Pretendard Variable",Pretendard,-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo","Malgun Gothic",sans-serif;
  font-size:17px;line-height:1.7;word-break:keep-all;overflow-wrap:break-word}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;display:block}
.wrap{max-width:var(--max);margin:0 auto;padding:0 24px}

/* header */
.site-head{border-bottom:1px solid var(--line)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;height:68px;gap:16px}
.brand{color:var(--ink);font-weight:700;font-size:18px;letter-spacing:-.01em;white-space:nowrap}
.brand small{font-weight:400;color:var(--muted);font-size:14px;margin-left:8px}
.brand:hover{text-decoration:none}
.nav{display:flex;gap:24px;font-size:15px}
.nav a{color:var(--ink)}
.nav a[aria-current=page]{color:var(--accent);font-weight:600}

/* hero */
.hero{padding:88px 0 64px}
.hero h1{font-size:40px;line-height:1.3;letter-spacing:-.02em;margin:0 0 20px;font-weight:700}
.hero p{font-size:19px;color:var(--muted);max-width:640px;margin:0}

/* featured */
.featured{display:grid;grid-template-columns:240px 1fr;gap:48px;align-items:center;padding:48px 0;border-top:1px solid var(--line)}
.featured .label{font-size:13px;letter-spacing:.08em;color:var(--accent);font-weight:600;text-transform:uppercase}
.featured h2{font-size:28px;line-height:1.35;margin:8px 0 6px;letter-spacing:-.01em}
.featured .sub{color:var(--muted);margin:0 0 16px}
.cover{border:1px solid var(--line);box-shadow:0 1px 2px rgba(0,0,0,.04)}

/* section */
.section{padding:56px 0;border-top:1px solid var(--line)}
.section-head{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:28px}
.section-head h2{font-size:22px;margin:0}
.section-head a{font-size:15px}

/* grid */
.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:40px 28px;align-items:end}
.card{color:var(--ink)}
.card:hover{text-decoration:none}
.card:hover .cover{border-color:#b8c0cc}
.card .t{font-weight:600;font-size:16px;line-height:1.45;margin-top:14px}
.card .a{font-size:14px;color:var(--muted)}
.grid .card{display:flex;flex-direction:column;justify-content:flex-end;height:100%}

/* book detail */
.book{display:grid;grid-template-columns:300px 1fr;gap:56px;padding:56px 0}
.book h1{font-size:32px;line-height:1.35;margin:0 0 8px;letter-spacing:-.01em}
.book .sub{font-size:18px;color:var(--muted);margin:0 0 20px}
.meta{border-top:1px solid var(--line);margin-top:28px}
.meta div{display:flex;gap:16px;padding:10px 0;border-bottom:1px solid var(--line);font-size:15px}
.meta dt{width:120px;color:var(--muted);flex:none}
.meta dd{margin:0}
.buy{display:flex;flex-wrap:wrap;gap:10px;margin:24px 0 8px}
.btn{display:inline-block;padding:11px 18px;border-radius:6px;background:var(--accent);color:#fff;font-size:15px;font-weight:600}
.btn:hover{text-decoration:none;opacity:.92}
.btn.ghost{background:var(--accent-soft);color:var(--accent)}
.toc{padding-left:20px;margin:8px 0 0}
.back{font-size:15px;display:inline-block;margin-top:32px}

/* prose */
.prose{max-width:720px;padding:56px 0}
.prose h1{font-size:32px;margin:0 0 24px;letter-spacing:-.01em}
.prose h2{font-size:21px;margin:40px 0 12px}
.prose p{margin:0 0 16px}
.lead{font-size:19px}

/* languages */
.langs{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;margin-top:28px;align-items:end}
.langs .t{font-size:14px;margin:10px 0 6px;font-weight:600}
.langs .links{font-size:14px}

/* footer */
.site-foot{border-top:1px solid var(--line);margin-top:40px;padding:32px 0 48px;font-size:13px;color:var(--muted);line-height:1.8}
.site-foot strong{color:var(--ink)}

@media (max-width:820px){
  body{font-size:17px}
  .site-head .wrap{height:auto;padding-top:14px;padding-bottom:14px;flex-wrap:wrap}
  .brand small{display:none}
  .nav{gap:18px}
  .hero{padding:56px 0 40px}
  .hero h1{font-size:30px}
  .hero p{font-size:17px}
  .featured,.book{grid-template-columns:1fr;gap:28px}
  .featured .cover,.book .cover{max-width:220px}
  .grid,.langs{grid-template-columns:repeat(2,1fr);gap:32px 18px}
  .book h1,.prose h1{font-size:26px}
}