/* 株式会社buy4 コーポレートサイト
   色・書体はサービス紹介資料（2026）とそろえています */
:root{
  --bg:#FCFCFD; --bg2:#F6F7F9; --fg:#1A1F2B; --muted:#4A5263; --line:#D6DEE8;
  --blue:#0068B7; --blue2:#0A5FAE; --navy:#0F2340; --navy2:#18325A; --sky:#8DB8E8;
  --on-navy:#F3F6FA; --on-navy2:#BFD0E6; --chip-bg:#E3ECF7; --chip-fg:#0B3F78; --danger:#B23A3A;
  --display:'Zen Kaku Gothic New','Noto Sans JP','Hiragino Kaku Gothic ProN',Meiryo,sans-serif;
  --body:'Noto Sans JP','Hiragino Kaku Gothic ProN',Meiryo,sans-serif;
  --max:1120px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);font-family:var(--body);font-size:16px;line-height:1.8;-webkit-text-size-adjust:100%}
img{max-width:100%;height:auto;display:block}
a{color:var(--blue2)}
h1,h2,h3{margin:0;text-wrap:balance;line-height:1.4;word-break:auto-phrase}
p{margin:0}
.in{max-width:var(--max);margin:0 auto;padding-inline:20px}
.skip{position:absolute;left:-9999px}.skip:focus{left:12px;top:12px;background:var(--bg);padding:8px 12px;z-index:99}
:focus-visible{outline:2px solid var(--blue);outline-offset:3px}

/* header */
.site-header{position:sticky;top:0;z-index:20;background:rgba(252,252,253,.94);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.site-header .in{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:68px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--fg)}
.brand img{width:34px}
.brand span{font-family:var(--display);font-weight:700;font-size:15px;letter-spacing:.02em}
.gnav ul{display:flex;align-items:center;gap:26px;list-style:none;margin:0;padding:0;font-size:14px;font-weight:700}
.gnav a{color:var(--fg);text-decoration:none}
.gnav a:hover,.gnav a[aria-current="page"]{color:var(--blue)}
.menu-btn{display:none;font:inherit;font-weight:700;font-size:14px;background:none;border:1px solid var(--line);border-radius:8px;padding:6px 12px;color:var(--fg);cursor:pointer}
@media (max-width:820px){
  .menu-btn{display:block}
  .gnav{display:none;position:absolute;left:0;right:0;top:100%;background:var(--bg);border-bottom:1px solid var(--line)}
  .gnav.open{display:block}
  .gnav ul{flex-direction:column;align-items:stretch;gap:0;padding:8px 20px 16px}
  .gnav li a{display:block;padding:12px 0;border-bottom:1px solid var(--line)}
  .gnav li:last-child a{border:0;margin-top:12px;text-align:center}
}

/* buttons */
.btn{display:inline-block;background:var(--blue);color:#FFFFFF;font-weight:700;border-radius:999px;padding:12px 26px;font-size:15px;text-decoration:none;border:1.5px solid var(--blue);transition:background .15s}
.btn:hover{background:var(--blue2)}
.btn.ghost{background:transparent;color:var(--blue)}
.btn.ghost:hover{background:var(--chip-bg)}
.btn.white{background:#FFFFFF;color:var(--blue);border-color:#FFFFFF}
.btn.sm{padding:7px 16px;font-size:13px}
.gnav .btn{color:#FFFFFF}

.eyebrow{font-size:12px;font-weight:700;color:var(--blue2);letter-spacing:.14em}

/* hero */
.hero .in{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(0,1fr);gap:48px;align-items:center;padding-block:72px 56px}
@media (max-width:820px){.hero .in{grid-template-columns:minmax(0,1fr);padding-block:44px 36px;gap:28px}}
.hero h1{font-family:var(--display);font-weight:900;font-size:clamp(30px,4.4vw,50px);line-height:1.35;margin-top:14px}
.hero h1 span{display:inline-block}
.hero .lead{color:var(--muted);margin-top:18px;font-size:16.5px;max-width:34em}
.hero .ctas{display:flex;gap:12px;margin-top:28px;flex-wrap:wrap}
.net{margin:0;background:var(--navy);border-radius:20px;aspect-ratio:1/1;max-width:440px;width:100%;justify-self:end;overflow:hidden}
@media (max-width:820px){.net{justify-self:stretch;max-width:100%;aspect-ratio:16/10}}
.net canvas{width:100%;height:100%;display:block}

/* stats */
.stats{border-block:1px solid var(--line);background:var(--bg)}
.stats .in{display:grid;grid-template-columns:repeat(4,minmax(0,1fr))}
@media (max-width:820px){.stats .in{grid-template-columns:repeat(2,minmax(0,1fr))}}
.stat{padding:22px 18px;display:flex;flex-direction:column;gap:2px;border-left:1px solid var(--line)}
.stat:first-child{border-left:0}
@media (max-width:820px){.stat:nth-child(3){border-left:0}.stat:nth-child(n+3){border-top:1px solid var(--line)}}
.stat b{font-family:var(--display);font-size:clamp(22px,2.6vw,30px);font-weight:900;color:var(--blue2);font-variant-numeric:tabular-nums;line-height:1.25}
.stat span{font-size:13px;color:var(--muted)}

/* sections */
.sec{padding-block:80px}
@media (max-width:820px){.sec{padding-block:56px}}
.sec .in{display:flex;flex-direction:column;gap:32px}
.sec.alt{background:var(--bg2)}
.sec.dark{background:var(--navy);color:var(--on-navy)}
.sec.dark .eyebrow{color:var(--sky)}
.sec-h h2{font-family:var(--display);font-size:clamp(23px,2.8vw,32px);font-weight:700;margin-top:8px}
.sec-h p{color:var(--muted);margin-top:10px;max-width:40em}
.sec.dark .sec-h p{color:var(--on-navy2)}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.grid4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}
@media (max-width:980px){.grid4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:820px){.grid3{grid-template-columns:minmax(0,1fr)}}
@media (max-width:560px){.grid4{grid-template-columns:minmax(0,1fr)}}

.card{background:var(--bg);border-radius:16px;padding:30px;display:flex;flex-direction:column;gap:12px;box-shadow:0 4px 24px rgba(16,40,80,.08)}
.card .num{font-family:var(--display);font-weight:900;font-size:34px;color:var(--blue2);line-height:1}
.card h3{font-size:19px;font-weight:700;line-height:1.5}
.card p{font-size:14.5px;color:var(--muted)}

.pcard{background:var(--navy2);border-radius:16px;padding:24px;display:flex;flex-direction:column;gap:8px}
.pcard b{font-family:var(--display);font-size:30px;font-weight:900;color:var(--sky);font-variant-numeric:tabular-nums;line-height:1.2}
.pcard h3{font-size:17px;color:var(--on-navy)}
.pcard p{font-size:13.5px;color:var(--on-navy2)}
.pcard .tag{align-self:flex-start;margin-top:auto;font-size:12px;font-weight:700;background:var(--sky);color:var(--navy);border-radius:999px;padding:2px 12px}

.partner{display:grid;grid-template-columns:minmax(0,200px) minmax(0,1fr);gap:20px;align-items:center;border:1px solid rgba(141,184,232,.35);border-radius:16px;padding:24px}
@media (max-width:560px){.partner{grid-template-columns:minmax(0,1fr);gap:10px}}
.partner-h{display:flex;flex-direction:column;gap:6px;align-items:flex-start}
.partner-h b{font-family:var(--display);font-size:30px;font-weight:900;color:var(--sky);font-variant-numeric:tabular-nums;line-height:1.2}
.partner .tag{font-size:12px;font-weight:700;background:var(--sky);color:var(--navy);border-radius:999px;padding:2px 12px}
.partner h3{font-size:17px;color:var(--on-navy)}
.partner p{font-size:14px;color:var(--on-navy2);margin-top:4px}
.case{background:var(--bg);border-radius:14px;padding:24px;display:flex;flex-direction:column;gap:10px;border:1px solid var(--line)}
.chip{align-self:flex-start;font-size:12px;font-weight:700;color:var(--chip-fg);background:var(--chip-bg);border-radius:999px;padding:2px 12px}
.case h3{font-size:16.5px;line-height:1.55}
.case dl{display:grid;grid-template-columns:auto 1fr;gap:4px 12px;font-size:13.5px;color:var(--muted);margin:auto 0 0;border-top:1px solid var(--line);padding-top:12px}
.case dt{font-weight:700;color:var(--fg)}.case dd{margin:0}

.steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;list-style:none;margin:0;padding:0}
@media (max-width:820px){.steps{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:480px){.steps{grid-template-columns:minmax(0,1fr)}}
.steps li{border-top:3px solid var(--blue2);padding-top:14px;display:flex;flex-direction:column;gap:6px}
.steps b{font-size:16.5px}
.steps p{font-size:14px;color:var(--muted)}

.cta{background:var(--blue);color:#FFFFFF;border-radius:20px;padding:40px;display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
@media (max-width:560px){.cta{padding:28px}}
.cta h2{font-family:var(--display);font-size:clamp(20px,2.4vw,26px);font-weight:700}
.cta p{font-size:14.5px;opacity:.92;margin-top:6px}
.cta .side{display:flex;flex-direction:column;gap:10px;align-items:flex-start}
.cta .tel{font-family:var(--display);font-size:26px;font-weight:900;font-variant-numeric:tabular-nums;color:#FFFFFF;text-decoration:none}

/* sub pages */
.ph{padding-block:56px 16px}
.ph h1{font-family:var(--display);font-size:clamp(28px,3.6vw,40px);font-weight:900;margin-top:8px}
.ph p{color:var(--muted);margin-top:12px;max-width:42em}
.svc{display:grid;grid-template-columns:minmax(0,260px) minmax(0,1fr);gap:28px;padding-block:36px;border-top:1px solid var(--line)}
@media (max-width:720px){.svc{grid-template-columns:minmax(0,1fr);gap:12px}}
.svc h2{font-family:var(--display);font-size:22px;font-weight:700;margin-top:6px}
.svc ul{margin:12px 0 0;padding-left:1.2em;color:var(--muted);font-size:15px}
.methods{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px;list-style:none;padding:0}
.methods li{border:1px solid var(--line);background:var(--bg);border-radius:999px;padding:5px 14px;font-size:14px}

.tbl{width:100%;border-collapse:collapse;font-size:15px}
.tbl th{width:28%;text-align:left;font-weight:700;padding:16px 14px;border-bottom:1px solid var(--line);vertical-align:top;background:var(--bg2)}
.tbl td{padding:16px 14px;border-bottom:1px solid var(--line)}
@media (max-width:560px){.tbl th,.tbl td{display:block;width:100%}.tbl th{border-bottom:0;padding-bottom:4px}.tbl td{padding-top:4px}}

/* contact */
.contact-grid{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(0,1fr);gap:40px;align-items:start}
@media (max-width:860px){.contact-grid{grid-template-columns:minmax(0,1fr)}}
.form{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
@media (max-width:560px){.form{grid-template-columns:minmax(0,1fr)}}
.field{display:flex;flex-direction:column;gap:6px;font-size:14px;font-weight:700;min-width:0}
.full{grid-column:1/-1}
.req{color:var(--danger);font-size:11px;font-weight:700;margin-left:6px}
.form input,.form select,.form textarea{font:inherit;font-weight:400;font-size:15px;border:1px solid var(--line);border-radius:10px;padding:10px 12px;background:#FFFFFF;color:var(--fg);width:100%}
.form textarea{resize:vertical}
fieldset.field{border:0;padding:0;margin:0}
fieldset.field legend{padding:0;margin-bottom:6px}
.radios{display:flex;flex-wrap:wrap;gap:8px 18px;font-weight:400}
.radios label{display:flex;align-items:center;gap:6px}
.form-note{font-size:13px;color:var(--muted);font-weight:400}
.form-msg{grid-column:1/-1;font-size:14px;color:var(--danger)}
.form-msg.ok{color:var(--blue2)}
.aside-box{background:var(--bg2);border-radius:16px;padding:28px;display:flex;flex-direction:column;gap:14px}
.aside-box h2{font-family:var(--display);font-size:18px}
.aside-box .big{font-family:var(--display);font-size:24px;font-weight:900;color:var(--blue2);text-decoration:none;font-variant-numeric:tabular-nums}

/* news */
.news-list{list-style:none;margin:0;padding:0;border-top:1px solid var(--line)}
.news-list li{border-bottom:1px solid var(--line)}
.news-list a{display:grid;grid-template-columns:110px 96px minmax(0,1fr);gap:14px;align-items:baseline;padding:18px 4px;color:var(--fg);text-decoration:none}
.news-list a:hover h3{color:var(--blue)}
@media (max-width:560px){.news-list a{grid-template-columns:auto 1fr;gap:6px 12px}.news-list a h3{grid-column:1/-1}}
.news-list time{color:var(--muted);font-variant-numeric:tabular-nums;font-size:14px}
.news-list h3{font-size:16px;font-weight:500}
.article{max-width:760px}
.article .meta{display:flex;gap:12px;align-items:center;color:var(--muted);font-size:14px}
.article h1{font-family:var(--display);font-size:clamp(24px,3vw,32px);font-weight:700;margin-top:10px}
.article .body{margin-top:28px;display:flex;flex-direction:column;gap:18px;font-size:16px}
.back{display:inline-block;margin-top:40px;font-weight:700;font-size:14px}

/* footer */
.site-footer{background:var(--navy);color:var(--on-navy2);font-size:13.5px;padding-block:44px}
.site-footer .in{display:flex;justify-content:space-between;gap:28px;flex-wrap:wrap}
.site-footer b{color:var(--on-navy);font-size:15px}
.site-footer ul{list-style:none;margin:0;padding:0;display:flex;gap:20px;flex-wrap:wrap}
.site-footer a{color:var(--on-navy2);text-decoration:none}
.site-footer a:hover{color:var(--on-navy)}
.site-footer small{display:block;margin-top:14px;font-size:12px}

@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}

/* スマホ調整 2026-10-16 */
.form input[type=radio]{width:18px;height:18px;padding:0;margin:0;flex:none;accent-color:var(--blue2)}
.radios label{border:1px solid var(--line);border-radius:999px;padding:8px 14px;background:#FFFFFF;cursor:pointer;line-height:1.4}
.radios label:has(input:checked){border-color:var(--blue2);background:var(--chip-bg)}
@media (max-width:560px){
  .radios{flex-direction:column;align-items:stretch;gap:8px}
  .radios label{border-radius:10px;padding:12px 14px}
  .hero .ctas .btn{flex:1 1 100%;justify-content:center;text-align:center}
  .cta .btn{width:100%;justify-content:center;text-align:center}
  .form .btn{width:100%;justify-content:center}
  .case{padding:20px}
  .case dl{grid-template-columns:3em 1fr}
}
@media (max-width:420px){
  .stat{padding:18px 12px}
  .stat b{font-size:19px;white-space:nowrap}
  .stat span{font-size:12px}
}
.stat span{word-break:auto-phrase}
.news-list .chip{justify-self:start}