/* ============================================================
   TERA AI LAB — blog.css
   白背景・濃紺テキスト・薄青グレーワイヤー
   ============================================================ */

:root{
  --bg-top:#f0f6fb;
  --bg-bot:#ffffff;
  --en:'Inter',sans-serif;
  --jp:'Noto Sans JP',sans-serif;
  --mono:'JetBrains Mono',monospace;
  --accent:#0f6e56;
  --text:#1a2e42;
  --text-dim:#2c4460;
  --text-mute:#6a8aaa;
  --border:rgba(26,46,66,.1);
  --surface:rgba(26,46,66,.04);
  --surface-hover:rgba(26,46,66,.07);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:var(--jp),var(--en);font-weight:300;line-height:1.8;letter-spacing:.02em;
  color:var(--text);background:linear-gradient(160deg,var(--bg-top) 0%,var(--bg-bot) 100%) fixed;
  min-height:100vh;-webkit-font-smoothing:antialiased;
}
#bgCanvas{position:fixed;inset:0;width:100%;height:100%;z-index:0;pointer-events:none;opacity:.35;}
.blog-hdr{
  position:fixed;top:0;left:0;right:0;z-index:100;padding:18px 40px;
  display:flex;align-items:center;justify-content:space-between;
  background:rgba(255,255,255,.9);backdrop-filter:blur(16px);border-bottom:.5px solid var(--border);
}
.blog-hdr-logo{font-family:var(--en);font-size:14px;font-weight:300;letter-spacing:.22em;color:#1a2e42;text-decoration:none;}
.blog-hdr-logo b{font-weight:500}
.blog-hdr-nav{display:flex;align-items:center;gap:28px}
.blog-hdr-nav a{font-family:var(--en);font-size:9px;letter-spacing:.14em;color:rgba(26,46,66,.5);text-decoration:none;transition:color .2s;}
.blog-hdr-nav a:hover{color:#1a2e42}
.blog-back-btn{font-family:var(--en);font-size:9px;letter-spacing:.16em;color:rgba(26,46,66,.5);text-decoration:none;padding:6px 14px;border:.5px solid var(--border);border-radius:2px;transition:all .2s;}
.blog-back-btn:hover{color:#1a2e42;border-color:rgba(26,46,66,.3);background:var(--surface)}
.article-wrap{position:relative;z-index:10;max-width:760px;margin:0 auto;padding:120px 40px 100px;}
.article-meta-bar{display:flex;align-items:center;gap:14px;margin-bottom:32px;}
.article-category{font-family:var(--en);font-size:9px;letter-spacing:.18em;padding:3px 10px;border:.5px solid rgba(26,46,66,.25);border-radius:2px;color:var(--text-mute);}
.article-date{font-family:var(--en);font-size:11px;color:var(--text-mute);letter-spacing:.08em;}
.article-title{font-size:clamp(22px,3.2vw,38px);font-weight:200;line-height:1.4;color:var(--text);margin-bottom:20px;letter-spacing:.01em;}
.article-byline{display:flex;align-items:center;gap:12px;font-size:12px;color:var(--text-mute);padding-bottom:28px;border-bottom:.5px solid var(--border);margin-bottom:44px;font-family:var(--en);letter-spacing:.06em;}
.article-body{font-size:15px;line-height:2;color:var(--text-dim);font-weight:300;}
.article-body p{margin-bottom:1.4em}
.article-body strong{font-weight:500;color:var(--text)}
.article-body em{font-style:normal;color:var(--text-dim)}
.article-body h2{font-size:clamp(17px,2.2vw,24px);font-weight:300;color:var(--text);margin:3em 0 .9em;padding-bottom:.5em;border-bottom:.5px solid var(--border);letter-spacing:.02em;}
.article-body h2::before{content:'';display:inline-block;width:3px;height:1em;background:rgba(26,46,66,.3);margin-right:12px;vertical-align:middle;border-radius:1px;}
.article-body h3{font-size:clamp(14px,1.6vw,17px);font-weight:400;color:var(--text-dim);margin:2em 0 .6em;letter-spacing:.03em;}
.article-body ul,.article-body ol{padding-left:1.4em;margin-bottom:1.4em;}
.article-body li{margin-bottom:.5em;color:var(--text-dim)}
.article-body li strong{color:var(--text)}
.article-toc{background:var(--surface);border:.5px solid var(--border);border-radius:4px;padding:22px 26px;margin:2.4em 0;}
.toc-label{font-family:var(--en);font-size:9px;letter-spacing:.2em;color:var(--text-mute);margin-bottom:14px;}
.article-toc ol{padding-left:1.2em}
.article-toc li{margin-bottom:.4em}
.article-toc a{font-size:13px;color:var(--text-mute);text-decoration:none;transition:color .2s;letter-spacing:.02em;}
.article-toc a:hover{color:var(--text)}
.article-body blockquote{border-left:2px solid rgba(26,46,66,.2);padding:14px 20px;margin:1.6em 0;background:var(--surface);border-radius:0 4px 4px 0;}
.article-body blockquote p{margin-bottom:.6em;font-size:13px;color:var(--text-mute)}
.article-body blockquote p:last-child{margin-bottom:0}
.article-body blockquote a{color:var(--accent);text-decoration:underline;text-underline-offset:3px}
.article-body blockquote a:hover{color:#0a5040}
.article-body a{color:var(--accent);text-decoration:underline;text-underline-offset:3px;text-decoration-color:rgba(15,110,86,.3);transition:color .2s,text-decoration-color .2s;}
.article-body a:hover{color:#0a5040;text-decoration-color:rgba(15,110,86,.7)}
.article-body code{font-family:var(--mono);font-size:.85em;background:rgba(26,46,66,.06);border-radius:3px;padding:.1em .4em;color:var(--text-dim);border:.5px solid var(--border);}
.article-body pre{background:rgba(26,46,66,.05);border:.5px solid var(--border);border-radius:4px;padding:20px 22px;margin:1.6em 0;overflow-x:auto;}
.article-body pre code{background:none;border:none;padding:0;font-size:13px;line-height:1.7;color:var(--text-dim);}
.article-body hr{border:none;border-top:.5px solid var(--border);margin:3em 0;}
.article-foot{background:var(--surface);border:.5px solid var(--border);border-radius:4px;padding:28px 30px;margin:3em 0 2em;}
.article-foot h3{font-size:16px;font-weight:400;color:var(--text);margin-bottom:14px;}
.article-foot p{font-size:13px;color:var(--text-mute);margin-bottom:.7em;line-height:1.85}
.article-foot a{color:var(--accent);text-decoration:underline;text-underline-offset:3px;transition:color .2s;}
.article-foot a:hover{color:#0a5040}
.article-related-label{font-family:var(--en);font-size:9px;letter-spacing:.18em;color:var(--text-mute);margin-bottom:14px;}
.article-related{display:grid;grid-template-columns:1fr 1fr;gap:1px;background:var(--border);border-radius:4px;overflow:hidden;margin-bottom:3em;}
.article-related a{background:var(--surface);padding:18px 20px;text-decoration:none;transition:background .2s;display:block;}
.article-related a:hover{background:var(--surface-hover)}
.article-related .cat{font-family:var(--en);font-size:8px;letter-spacing:.14em;color:var(--text-mute);margin-bottom:8px;}
.article-related .title{font-size:12px;color:var(--text-dim);line-height:1.65;font-weight:300;}
.blog-footer{position:relative;z-index:10;border-top:.5px solid var(--border);padding:48px 40px 36px;max-width:760px;margin:0 auto;}
.blog-footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:32px;}
.blog-footer-logo{font-family:var(--en);font-size:13px;font-weight:300;letter-spacing:.2em;color:var(--text);margin-bottom:14px;}
.blog-footer-logo b{font-weight:500}
.blog-footer-desc{font-size:12px;color:var(--text-mute);line-height:1.9}
.blog-footer-col h5{font-family:var(--en);font-size:9px;letter-spacing:.15em;color:var(--text-mute);margin-bottom:12px;font-weight:400;}
.blog-footer-col ul{list-style:none}
.blog-footer-col li{margin-bottom:7px}
.blog-footer-col a{font-size:12px;color:var(--text-mute);text-decoration:none;transition:color .2s;}
.blog-footer-col a:hover{color:var(--text)}
.blog-footer-bottom{display:flex;justify-content:space-between;font-family:var(--en);font-size:10px;color:var(--text-mute);letter-spacing:.07em;border-top:.5px solid var(--border);padding-top:20px;}
@media(max-width:768px){
  .article-wrap{padding:90px 20px 60px}
  .blog-hdr{padding:16px 20px}
  .blog-hdr-nav{display:none}
  .article-related{grid-template-columns:1fr}
  .blog-footer{padding:40px 20px 28px}
  .blog-footer-grid{grid-template-columns:1fr 1fr;gap:24px}
}
@media(max-width:480px){.blog-footer-grid{grid-template-columns:1fr}}