/* arthonsys.com 2026: one stylesheet, no framework */
:root{--bg:#030712;--bg2:#0b1220;--card:#0f1a2b;--line:#1f2a3c;--ink:#f3f4f6;--mute:#9ca3af;--acc:#23a799;--acc2:#1abc9c;--deep:#206962;--r:14px}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--acc2);text-decoration:none}a:hover{text-decoration:underline}
img{max-width:100%;height:auto}
.wrap{max-width:1180px;margin:0 auto;padding:0 20px}.narrow{max-width:760px}
h1,h2,h3,h4{line-height:1.25;margin:0 0 .6em;font-weight:700}
h1{font-size:clamp(30px,4.6vw,52px);letter-spacing:-.02em}
h2{font-size:clamp(24px,3vw,34px);letter-spacing:-.01em}
h3{font-size:19px}h4{font-size:15px;color:var(--ink);text-transform:uppercase;letter-spacing:.06em}
p{margin:0 0 1em;color:#d1d5db}.muted,.sub{color:var(--mute)}.sub{font-size:18px;margin-top:-.3em}
.btn{display:inline-block;background:var(--acc);color:#04130f;font-weight:700;padding:12px 22px;border-radius:999px;border:0;cursor:pointer;font-size:16px}
.btn:hover{background:var(--acc2);text-decoration:none}.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn.sm{padding:8px 16px;font-size:14px}
/* header */
.top{position:sticky;top:0;z-index:50;background:rgba(3,7,18,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.bar{display:flex;align-items:center;justify-content:space-between;height:68px}
.logo img{display:block;height:40px;width:auto}
nav ul{list-style:none;margin:0;padding:0;display:flex;align-items:center;gap:6px}
nav li>a,nav summary{display:block;padding:8px 12px;color:var(--ink);font-size:15px;cursor:pointer;border-radius:8px;list-style:none}
nav summary::-webkit-details-marker{display:none}
nav summary::after{content:"▾";font-size:11px;margin-left:5px;color:var(--mute)}
nav li.on summary{color:var(--acc2)}
nav li>a:hover,nav summary:hover{background:var(--bg2);text-decoration:none}
.dd{position:relative}
.menu{position:absolute;top:44px;left:0;min-width:260px;background:var(--bg2);border:1px solid var(--line);border-radius:12px;padding:8px;box-shadow:0 12px 32px rgba(0,0,0,.5)}
.menu a{display:block;padding:7px 12px;color:#d1d5db;border-radius:8px;font-size:14.5px}.menu a:hover{background:var(--card);color:var(--ink);text-decoration:none}
.burger{display:none;font-size:26px;cursor:pointer;padding:6px 10px}
@media (max-width:1240px){
 .burger{display:block}
 nav{display:none;position:absolute;top:68px;left:0;right:0;background:var(--bg);border-bottom:1px solid var(--line);max-height:calc(100vh - 68px);overflow:auto}
 #navt:checked~nav{display:block}
 nav ul{flex-direction:column;align-items:stretch;padding:10px 16px 18px}
 .menu{position:static;box-shadow:none;border:0;background:transparent;padding:0 0 6px 12px}
 nav .btn.sm{text-align:center;margin-top:8px}
}
/* hero */
.hero{padding:72px 0 56px;background:radial-gradient(1000px 420px at 15% -10%,rgba(35,167,153,.28),transparent 60%),radial-gradient(800px 380px at 95% 0,rgba(32,105,98,.25),transparent 60%)}
.hero .lead{font-size:clamp(17px,2vw,20px);max-width:820px;color:#e5e7eb}
.crumb{font-size:14px;color:var(--mute)}.crumb a{color:var(--mute)}
.ticks{list-style:none;padding:0;margin:18px 0;display:grid;grid-template-columns:repeat(auto-fit,minmax(min(240px,100%),1fr));gap:8px 22px;max-width:820px}
.ticks li::before{content:"✓";color:var(--acc2);font-weight:700;margin-right:8px}
.cta{margin-top:26px;display:flex;gap:12px;flex-wrap:wrap}
/* sections */
.sec{padding:54px 0;border-top:1px solid var(--line)}.sec.alt{background:var(--bg2)}
.sec>.wrap>p{max-width:880px}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(260px,100%),1fr));gap:18px;margin:22px 0}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px}
.card p{font-size:15.5px;margin-bottom:.6em}.card ul{margin:.4em 0 0;padding-left:18px;color:#d1d5db;font-size:15px}
.chips{list-style:none;padding:0;margin:16px 0;display:flex;flex-wrap:wrap;gap:8px}
.chips li,.chips a{background:var(--card);border:1px solid var(--line);border-radius:999px;padding:6px 14px;font-size:14.5px;color:#e5e7eb}
.chips a:hover{border-color:var(--acc);text-decoration:none}
.list{padding-left:20px;color:#d1d5db;max-width:880px}.list li{margin:.3em 0}
.gallery{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(220px,100%),1fr));gap:14px;margin:18px 0}
.gallery img{width:100%;border-radius:12px;border:1px solid var(--line);background:#fff}
/* quote form */
.quote{background:linear-gradient(180deg,var(--bg2),var(--bg))}
.q2{display:grid;grid-template-columns:1fr 1.1fr;gap:40px;align-items:start}
@media (max-width:900px){.q2{grid-template-columns:1fr}}
.lead label{display:block;font-size:14px;color:var(--mute);margin-bottom:12px}
.lead input,.lead select,.lead textarea{display:block;width:100%;margin-top:5px;padding:11px 12px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink);font:inherit}
.lead input:focus,.lead select:focus,.lead textarea:focus{outline:2px solid var(--acc);border-color:transparent}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:12px}@media (max-width:600px){.row2{grid-template-columns:1fr}}
.lead .file input{padding:8px}.msg{margin-top:10px;font-weight:600}.msg.ok{color:var(--acc2)}.msg.err{color:#f87171}
/* footer */
.foot{border-top:1px solid var(--line);background:#02050d;padding:48px 0 20px;margin-top:0}
.fcols{display:grid;grid-template-columns:repeat(5,1fr);gap:24px}
@media (max-width:900px){.fcols{grid-template-columns:repeat(2,1fr)}}
.fcols a{display:block;color:#cbd5e1;font-size:14.5px;padding:3px 0}.fcols p{font-size:14.5px}
.fbar{display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;border-top:1px solid var(--line);margin-top:28px;padding-top:16px;font-size:13.5px;color:var(--mute)}
.fbar a{color:var(--mute)}
/* portfolio */
.projs{grid-template-columns:repeat(auto-fill,minmax(min(320px,100%),1fr))}
.proj img{width:100%;aspect-ratio:16/10;object-fit:cover;border-radius:10px;margin-bottom:12px;background:#0b1220}
.proj .chips{margin:10px 0}.proj .chips li{font-size:12.5px;padding:4px 10px}
.proj details summary{cursor:pointer;color:var(--acc2);font-weight:600;margin-top:6px}
.facts{display:grid;grid-template-columns:auto 1fr;gap:4px 14px;font-size:14.5px;margin:12px 0}.facts dt{color:var(--mute)}.facts dd{margin:0;color:#e5e7eb}
.small{font-size:13px;margin:0 0 4px}
.card ul.chips{padding-left:0}
.eyebrow{color:var(--acc2);font-weight:700;letter-spacing:.08em;text-transform:uppercase;font-size:14px;margin-bottom:10px}
.hero.home h1{font-size:clamp(38px,6vw,68px)}.lead.big{font-size:clamp(19px,2.4vw,24px);color:var(--ink)}
.tag{color:var(--ink)}
/* homepage 2026: visual, short */
.hgrid{display:grid;grid-template-columns:1.15fr .85fr;gap:40px;align-items:center}
.demo{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:18px 18px 8px;box-shadow:0 20px 60px rgba(0,0,0,.45),0 0 0 1px rgba(35,167,153,.15)}
.demo-h{font-size:13px;color:var(--mute);margin:0 0 12px;display:flex;align-items:center;gap:6px}
.demo-h span{width:9px;height:9px;border-radius:50%;background:#374151;display:inline-block}
.dl{margin:0 0 10px;padding:10px 14px;border-radius:12px;font-size:15px;background:var(--bg2);border:1px solid var(--line);opacity:0;animation:dl 12s infinite;animation-delay:calc(var(--d) * 1.4s)}
.dl.in{border-color:#374151}.dl.bot{border-left:3px solid var(--acc)}.dl.ok{background:rgba(35,167,153,.14);border-color:var(--acc);color:#fff;font-weight:600}
.dl.bot::before{content:"🤖 ";}.dl.in::before{content:"✉️ ";}.dl.ok::before{content:"✅ ";}
@keyframes dl{0%{opacity:0;transform:translateY(8px)}5%,85%{opacity:1;transform:none}95%,100%{opacity:0}}
@media (prefers-reduced-motion:reduce){.dl{animation:none;opacity:1}}
.tiles{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:22px}
.tile{display:flex;flex-direction:column;gap:6px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px;color:var(--ink);transition:border-color .2s,transform .2s}
.tile:hover{border-color:var(--acc);transform:translateY(-3px);text-decoration:none}
.tile svg{color:var(--acc2);margin-bottom:6px}.tile b{font-size:18px}.tile span{color:var(--mute);font-size:15px}
.work{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:22px 0}
.wk{display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;color:var(--ink)}
.wk:hover{border-color:var(--acc);text-decoration:none}
.wk img{display:block;width:100%;aspect-ratio:16/9;object-fit:cover}
.wk b{display:block;padding:12px 16px 0}.wk span{display:block;padding:0 16px 14px;color:var(--mute);font-size:14px}
.steps{list-style:none;padding:0;margin:22px 0 0;display:grid;grid-template-columns:repeat(4,1fr);gap:16px;counter-reset:s}
.steps li{counter-increment:s;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.steps li::before{content:counter(s);display:inline-grid;place-items:center;width:32px;height:32px;border-radius:50%;background:var(--acc);color:#04130f;font-weight:800;margin-bottom:10px}
.steps b{display:block;font-size:18px}.steps span{color:var(--mute);font-size:15px}
@media (max-width:900px){.hgrid{grid-template-columns:1fr}.tiles,.work{grid-template-columns:1fr 1fr}.steps{grid-template-columns:1fr 1fr}}
@media (max-width:560px){.tiles,.work,.steps{grid-template-columns:1fr}}
.band{padding:28px 0;background:linear-gradient(90deg,rgba(35,167,153,.18),rgba(32,105,98,.08))}
.bandrow{display:flex;align-items:center;justify-content:space-between;gap:20px}.bandrow p{margin:0;font-size:18px;color:var(--ink)}
@media (max-width:700px){.bandrow{flex-direction:column;align-items:flex-start}}
/* iPhone Safari: no zoom when a form field is tapped (needs 16px), blurred header, no font jump in landscape */
.lead input,.lead select,.lead textarea{font-size:16px}
.top{-webkit-backdrop-filter:blur(8px)}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%}
.faq{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin:10px 0}
.faq summary{cursor:pointer;font-weight:700;list-style:none}.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";float:right;color:var(--acc2);font-weight:800}.faq[open] summary::after{content:"–"}.faq p{margin:10px 0 0}
.hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
/* Estatrail product band (5 Nov) */
.prod{background:linear-gradient(135deg,rgba(35,167,153,.16),rgba(32,105,98,.05));border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.prod h2{display:flex;align-items:center;gap:10px}.prod h2 svg{color:var(--acc2)}
.prod .ticks{margin:14px 0}
.aitag{display:inline-block;background:var(--acc);color:#0b1220;font-weight:700;font-size:11.5px;letter-spacing:.04em;border-radius:6px;padding:2px 7px;margin-right:6px}
.aiuse{border-left:3px solid var(--acc);padding:6px 0 6px 12px;margin:10px 0;font-size:15px}
.aiwork{padding-left:18px}.aiwork li{margin:8px 0}
/* WhatsApp chat button (same as blog, 5 Nov) */
.wa{position:fixed;right:18px;bottom:18px;z-index:999;display:flex;align-items:center;gap:8px;background:#25d366;color:#05210f;font:600 15px/1 system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;padding:12px 16px;border-radius:999px;box-shadow:0 8px 24px rgba(0,0,0,.25);text-decoration:none}
.wa:hover{background:#20bd5a;text-decoration:none}
@media (max-width:600px){.wa span{display:none}.wa{padding:14px}}
.fh{font-size:15px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;color:var(--ink);margin:0 0 .6em}
.narrow p a,.lead a{text-decoration:underline;text-underline-offset:2px}