/* AIラボ — Concept「手と回路のノート / Field Notes for Hands」 */
:root{
 --paper:#F3EDE2;--paper2:#E9E0D0;--ink:#231F1B;--sub:#6B6157;--rule:#CBBFAC;
 --terra:#B24E2A;--terra-d:#953F21;--amber:#D69A45;
 --steel:#3F5B6E;--steel-l:#8FA5B3; /* AI layer: restrained cool accent */
 --s1:8px;--s2:16px;--s3:24px;--s4:32px;--s5:48px;--s6:64px;--s7:96px;--s8:128px;--s9:160px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{-webkit-font-smoothing:antialiased}
body{background:var(--paper);color:var(--ink);font-family:'Noto Sans JP',sans-serif;font-size:15px;line-height:2;letter-spacing:.04em;font-feature-settings:"palt";word-break:normal;line-break:strict}
a{color:inherit;text-decoration:none}
img{display:block;width:100%;height:100%;object-fit:cover}
/* type scale: 12 mono / 15 body / 18 lead / 24 h3 / 40 h2 / 72 display */
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.lead{font-size:18px;line-height:2.1}
.h3{font-family:'Shippori Mincho',serif;font-weight:600;font-size:24px;line-height:1.6;letter-spacing:.04em}
.h2{font-family:'Shippori Mincho',serif;font-weight:600;font-size:40px;line-height:1.55;letter-spacing:.04em;font-feature-settings:"palt"}
.display{font-family:'Shippori Mincho',serif;font-weight:600;font-size:72px;line-height:1.42;letter-spacing:.02em;font-feature-settings:"palt"}
.sub{color:var(--sub)}.steel{color:var(--steel)}.terra{color:var(--terra)}
/* 12-col grid */
.g{display:grid;grid-template-columns:repeat(12,1fr);column-gap:var(--s4);max-width:1312px;margin:0 auto;padding:0 var(--s6)}
.sec{padding:var(--s9) 0;position:relative}
.sec.dense{padding:var(--s8) 0}
/* section index: journal numbering */
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.idx .n{font-family:'IBM Plex Mono';font-size:12px;color:var(--terra)}
.idx .t{font-family:'IBM Plex Mono';font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--sub)}
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.hair{border:0;border-top:1px solid var(--rule)}
/* header */
.hd{display:flex;justify-content:space-between;align-items:center;max-width:1312px;margin:0 auto;padding:var(--s3) var(--s6);border-bottom:1px solid var(--rule)}
.logo{font-family:'Shippori Mincho';font-weight:700;font-size:20px;letter-spacing:.14em;display:flex;align-items:baseline;gap:var(--s1)}
.logo i{font-style:normal;font-family:'IBM Plex Mono';font-size:11px;color:var(--steel);letter-spacing:.08em}
.nav{display:flex;gap:var(--s4);align-items:center;font-size:13px}
.nav a:not(.btn){color:var(--sub);transition:color .2s}.nav a:not(.btn):hover{color:var(--ink)}
/* buttons: one system */
.btn{display:inline-flex;align-items:center;gap:var(--s2);height:56px;padding:0 var(--s4);background:var(--ink);color:var(--paper);font-size:14px;font-weight:500;letter-spacing:.1em;transition:background .25s}
.btn:hover{background:var(--terra)}
.btn .ar{font-family:'IBM Plex Mono';font-size:13px}
.btn.sm{height:40px;padding:0 var(--s3);font-size:12px}
.btn.line{background:transparent;color:var(--ink);box-shadow:inset 0 0 0 1px var(--ink)}
.btn.line:hover{background:var(--ink);color:var(--paper)}
.btn.light{background:var(--paper);color:var(--ink)}.btn.light:hover{background:var(--ink);color:var(--paper)}
.lk{display:inline-flex;gap:var(--s1);font-size:14px;font-weight:500;border-bottom:1px solid currentColor;padding-bottom:2px;transition:color .2s}
.lk:hover{color:var(--terra)}
.tag{display:inline-block;font-family:'IBM Plex Mono';font-size:11px;letter-spacing:.06em;color:var(--steel);border:1px solid var(--steel-l);padding:1px 8px;line-height:1.6}
.tag.t{color:var(--terra);border-color:var(--terra)}
figure figcaption{margin-top:var(--s1)}
/* form */
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.f label b{font-family:'Noto Sans JP';font-weight:500;font-size:13px;color:var(--ink);text-transform:none;letter-spacing:.06em;margin-left:var(--s1)}
.f input,.f textarea{width:100%;background:transparent;border:0;border-bottom:1px solid var(--ink);padding:var(--s2) 0;margin-bottom:var(--s4);font:inherit;color:var(--ink)}
.f input::placeholder,.f textarea::placeholder{color:#A89C8D}
.seg{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--ink);margin:var(--s2) 0 var(--s5)}
.seg span{text-align:center;padding:var(--s2) 0;font-size:13px;border-right:1px solid var(--ink)}.seg span:last-child{border:0}
.seg .on{background:var(--ink);color:var(--paper)}
/* footer */
.ft{max-width:1312px;margin:0 auto;padding:var(--s6) var(--s6) var(--s5)}
.ft a{display:block;color:var(--sub);font-size:13px;line-height:2.2}.ft a:hover{color:var(--ink)}

h1,h2,h3,.h2,.h3,.lead,.display{word-break:keep-all;overflow-wrap:anywhere}

.btn[aria-disabled]{pointer-events:none}
@media (max-width:900px){
 .g{grid-template-columns:1fr !important;padding:0 20px !important;column-gap:0}
 .g>*{grid-column:1/-1 !important;grid-row:auto !important}
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 .sec,.sec.dense{padding:80px 0}
 .display{font-size:38px !important;white-space:normal !important}.h2{font-size:28px !important;white-space:normal !important}
 .tate{display:none}
 section[style*="padding:var(--s6) 0 var(--s8)"] figure>div[style*="position:absolute"]{left:12px !important;bottom:48px !important}
 [style*="grid-template-columns:repeat(3"],[style*="grid-template-columns:1fr 1fr;column-gap"],[style*="grid-template-columns:96px"]{grid-template-columns:1fr !important;row-gap:24px}
 article[style*="grid-template-columns:96px"]>div{text-align:left !important;padding-top:0 !important}
 [style*="display:flex;gap:var(--s2);margin-top:var(--s5)"]{flex-direction:column}
 [style*="justify-content:space-between;align-items:end"],[style*="justify-content:space-between;align-items:center"]{flex-direction:column;align-items:flex-start !important;gap:16px}
 [style*="margin-top:var(--s8)"],[style*="margin-top:var(--s6)"]{margin-top:var(--s4) !important}
 form.f{padding:32px 20px !important}
 section[style*="height:640px"]{height:480px !important}
 .ft{padding:40px 0}.ft .g>div{text-align:left !important;margin-bottom:16px}
}@media (max-width:900px){
 h1.display{font-size:31px !important;letter-spacing:0 !important}
 .g>div[style*="padding-top:var(--s7)"]{padding-top:var(--s5) !important}
 section[style*="padding:var(--s6) 0 var(--s8)"]{padding-top:0 !important}
}