/* ai.arcpoly.com - giao diện đồng bộ hệ sinh thái Arcpoly (25-10-2026).
   Nền trắng, tối giản, màu chủ đạo #f54d2d, chữ Be Vietnam Pro, nút bo tròn - giống arcpoly.com. */
:root{
  --brand:#f54d2d; --brand-dark:#d8401f; --soft:#fff1ed;
  --ink:#141414; --slate:#4a4a4a; --muted:#6b6b6b; --muted-2:#8a8a8a; --line:#ececec;
  --surface:#fafafa; --surface-3:#f4f4f4; --bg:#ffffff;
  --r:20px; --shadow:0 2px 4px rgba(0,0,0,.04),0 24px 48px -24px rgba(0,0,0,.14);
  --gutter:clamp(16px,4vw,40px); --wrap:1180px;
  --sans:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:16.5px;line-height:1.65}
img{display:block;max-width:100%}
a{color:var(--brand);text-underline-offset:3px}
h1,h2,h3{letter-spacing:-.03em;line-height:1.15;margin:0}
p{margin:0}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 var(--gutter)}
.wrap-narrow{max-width:860px;margin:0 auto;padding:0 var(--gutter)}
html.lang-wait body{visibility:hidden}

/* ---------- Nút ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border-radius:999px;padding:12px 22px;
  font:600 15px/1.2 var(--sans);text-decoration:none;border:1.5px solid transparent;cursor:pointer;
  transition:background .15s,border-color .15s,transform .15s;white-space:nowrap}
.btn--brand{background:var(--brand);color:#fff}
.btn--brand:hover{background:var(--brand-dark);transform:translateY(-1px)}
.btn--ghost{background:#fff;color:var(--ink);border-color:var(--line)}
.btn--ghost:hover{border-color:var(--ink)}
.btn--sm{padding:9px 16px;font-size:14px}
.btn--block{display:flex;width:100%}

/* ---------- Đầu trang ---------- */
.head{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.9);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.head .wrap{display:flex;align-items:center;gap:20px;height:68px}
.logo{display:flex;align-items:center;gap:10px;color:var(--ink);text-decoration:none;font-weight:700;font-size:18px;letter-spacing:-.01em}
.logo img{width:34px;height:34px}
.logo b{color:var(--brand)}
.nav{display:flex;gap:2px;margin-left:12px;margin-right:auto}
.nav a{color:var(--slate);text-decoration:none;font-size:15px;padding:8px 14px;border-radius:999px}
.nav a:hover{background:var(--surface-3);color:var(--ink)}
.nav a.is-on{color:var(--brand);font-weight:600}
.tools{display:flex;align-items:center;gap:8px}
.eco{color:var(--slate);text-decoration:none;font-size:14px;font-weight:500;padding:8px 14px;border:1px solid var(--line);border-radius:999px;display:inline-flex;align-items:center;gap:6px}
.eco svg{width:16px;height:16px}
.eco:hover{border-color:var(--ink);color:var(--ink)}
.lang{display:inline-flex;border:1px solid var(--line);border-radius:999px;padding:3px}
.lang button{border:0;background:none;padding:4px 10px;border-radius:999px;font:600 12px/1.4 var(--sans);color:var(--muted);cursor:pointer}
.lang button.is-on{background:var(--ink);color:#fff}
.burger{display:none;width:40px;height:40px;border:1px solid var(--line);border-radius:999px;background:#fff;cursor:pointer}
.burger span{display:block;width:17px;height:1.5px;background:var(--ink);margin:3.5px auto}
@media (max-width:920px){
  .head .wrap{flex-wrap:wrap;height:auto;min-height:64px;padding-top:12px;padding-bottom:12px}
  .nav,.tools .eco,.tools .btn{display:none}
  .burger{display:block}
  .tools{margin-left:auto;order:2}
  .logo{order:1}
  .nav{order:3}
  .mob-cta{order:4}
  .head.is-open .nav{display:flex;flex-direction:column;flex-basis:100%;margin:6px 0 0;border-top:1px solid var(--line);padding-top:8px}
  .head.is-open .nav a{padding:12px 6px;font-size:16px;color:var(--ink)}
  .head.is-open .mob-cta{display:flex}
}
.mob-cta{display:none;flex-basis:100%;gap:8px;padding:6px 0 4px}
.mob-cta .btn{flex:1}

/* ---------- Chữ dùng chung ---------- */
.eyebrow{display:inline-flex;align-items:center;gap:10px;font-size:12.5px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--brand)}
.eyebrow::before{content:"";width:22px;height:2px;border-radius:2px;background:var(--brand)}
.lead{color:var(--muted);font-size:clamp(16.5px,1.6vw,19px)}
section{padding:clamp(56px,8vw,96px) 0}
.alt{background:var(--surface);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.sec-head{max-width:760px;margin-bottom:36px}
.sec-head h2{margin:10px 0 12px;font-size:clamp(28px,3.6vw,42px)}
.center{text-align:center;margin-left:auto;margin-right:auto}

/* ---------- Hero ---------- */
.hero{padding:clamp(52px,8vw,96px) 0 clamp(40px,6vw,72px);background:radial-gradient(60% 70% at 85% 0%,#fff3ef 0%,rgba(255,243,239,0) 70%)}
.hero .wrap{display:grid;gap:40px;align-items:center}
@media (min-width:980px){.hero .wrap{grid-template-columns:1.05fr 1fr}}
.hero h1{margin:14px 0 18px;font-size:clamp(34px,4.2vw,54px);text-wrap:balance;line-height:1.06;letter-spacing:-.04em;font-weight:800}
.hero h1 em{font-style:normal;color:var(--brand)}
.hero .cta{display:flex;flex-wrap:wrap;gap:10px;margin-top:28px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:22px}
.chip{font-size:13.5px;font-weight:500;color:var(--slate);background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 12px}
.hero-art{display:grid;grid-template-columns:1.2fr 1fr;grid-template-rows:1fr 1fr;gap:12px;aspect-ratio:1/0.9}
.hero-art figure{margin:0;border-radius:22px;overflow:hidden;box-shadow:var(--shadow)}
.hero-art figure:first-child{grid-row:1/3}
.hero-art img{width:100%;height:100%;object-fit:cover}

/* ---------- Số liệu ---------- */
.stats{display:grid;grid-template-columns:repeat(2,1fr);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;background:var(--line);gap:1px}
@media (min-width:760px){.stats{grid-template-columns:repeat(4,1fr)}}
.stat{background:#fff;padding:24px 22px}
.stat b{display:block;font-size:clamp(28px,3.4vw,38px);letter-spacing:-.03em;line-height:1.1}
.stat span{color:var(--muted);font-size:14.5px}

/* ---------- Thẻ ---------- */
.grid{display:grid;gap:18px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:26px}
.card h3{font-size:20px;margin:12px 0 8px}
.card p{color:var(--muted);font-size:15.5px}
.ico{width:44px;height:44px;border-radius:12px;background:var(--soft);color:var(--brand);display:grid;place-items:center}
.ico svg{width:22px;height:22px}

/* ---------- Công cụ ---------- */
.group-title{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin:44px 0 16px;font-size:22px}
.group-title:first-of-type{margin-top:0}
.group-title .n{font-size:14px;font-weight:500;color:var(--muted)}
.tools-grid{display:grid;gap:16px;grid-template-columns:repeat(auto-fill,minmax(250px,1fr))}
.tool{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:var(--r);overflow:hidden;scroll-margin-top:90px;transition:box-shadow .15s,border-color .15s}
.tool:hover{box-shadow:var(--shadow);border-color:transparent}
.tool-img{aspect-ratio:4/3;background:var(--surface-3);overflow:hidden}
.tool-img img{width:100%;height:100%;object-fit:cover}
.tool-img.is-icon{display:grid;place-items:center;background:linear-gradient(135deg,#1c1c1c,#2b2b2b)}
.tool-img.is-icon span{font-weight:800;font-size:22px;letter-spacing:.06em;text-transform:uppercase;color:var(--brand);text-align:center;padding:0 18px}
.tool-body{padding:18px 20px 20px}
.tool-k{font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--brand)}
.tool h3{font-size:18px;margin:6px 0 6px}
.tool p{color:var(--muted);font-size:14.5px;line-height:1.55}
.tool-new{display:inline-block;margin-left:6px;font-size:10.5px;font-weight:700;letter-spacing:.06em;color:#fff;background:var(--brand);border-radius:6px;padding:2px 6px;vertical-align:2px}

/* ---------- Quy trình ---------- */
.steps{display:grid;gap:18px;counter-reset:s}
@media (min-width:860px){.steps{grid-template-columns:repeat(3,1fr)}}
.step{position:relative;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:28px 26px 26px}
.step::before{counter-increment:s;content:"0" counter(s);display:inline-grid;place-items:center;width:42px;height:42px;border-radius:12px;background:var(--soft);color:var(--brand);font-weight:800;margin-bottom:14px}
.step h3{font-size:19px;margin-bottom:8px}
.step p{color:var(--muted);font-size:15px}

/* ---------- Giá ---------- */
.plans{display:grid;gap:16px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));padding-top:12px}
.plan{position:relative;display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:20px;padding:26px 22px 22px}
.plan.is-hot{border:2px solid var(--brand);box-shadow:0 24px 48px -28px rgba(245,77,45,.55)}
.plan-badge{position:absolute;top:0;left:50%;transform:translate(-50%,-55%);background:var(--brand);color:#fff;font-size:12.5px;font-weight:700;border-radius:999px;padding:5px 12px;white-space:nowrap}
.plan-name{font-weight:600;font-size:17px}
.plan-old{margin-top:12px;color:var(--muted-2);font-size:14px;text-decoration:line-through}
.plan-price{font-size:clamp(28px,2.6vw,34px);font-weight:800;letter-spacing:-.03em;line-height:1.1;white-space:nowrap}
.plan-per{color:var(--muted);font-size:14px;margin-top:2px}
.plan-month{margin-top:6px;font-size:14px;font-weight:600;color:var(--slate)}
.plan-save{display:inline-block;margin-top:10px;font-size:12.5px;font-weight:700;color:var(--brand);background:var(--soft);border-radius:6px;padding:3px 8px}
.plan ul{list-style:none;margin:16px 0 20px;padding:16px 0 0;border-top:1px solid var(--line);display:grid;gap:9px;flex:1}
.plan li{position:relative;padding-left:24px;font-size:14.5px;color:var(--slate)}
.plan li::before{content:"✓";position:absolute;left:0;color:var(--brand);font-weight:700}
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--r);background:#fff}
table{width:100%;border-collapse:collapse;font-size:15px;min-width:620px}
th,td{padding:14px 16px;text-align:left;border-bottom:1px solid var(--line)}
th{font-size:12.5px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);font-weight:700;background:var(--surface)}
tr:last-child td{border-bottom:0}
td b{white-space:nowrap}
.note{margin-top:12px;color:var(--muted);font-size:14px}

/* ---------- Hỏi đáp ---------- */
.faq{display:grid;gap:10px}
.faq details{background:#fff;border:1px solid var(--line);border-radius:16px;padding:16px 20px}
.faq summary{cursor:pointer;font-weight:600;list-style:none;display:flex;justify-content:space-between;gap:16px}
.faq summary::after{content:"+";color:var(--brand);font-weight:700;font-size:20px;line-height:1}
.faq details[open] summary::after{content:"-"}
.faq details p{margin-top:10px;color:var(--slate);font-size:15px}

/* ---------- Cấu hình máy ---------- */
.reqs{display:grid;gap:14px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.req{background:#fff;border:1px solid var(--line);border-radius:18px;padding:20px}
.req b{display:block;font-size:17px;margin:10px 0 4px}
.req span{color:var(--muted);font-size:14.5px}
.warn{margin-top:16px;border-left:3px solid var(--brand);background:var(--soft);border-radius:12px;padding:14px 18px;color:var(--slate);font-size:15px}

/* ---------- Liên hệ ---------- */
.contact{display:grid;gap:28px;align-items:center;border-radius:28px;padding:clamp(28px,5vw,56px);
  background:linear-gradient(135deg,#fff1ed 0%,#ffffff 75%);border:2px solid var(--brand);box-shadow:0 30px 60px -36px rgba(245,77,45,.5)}
@media (min-width:880px){.contact{grid-template-columns:1.2fr 1fr}}
.contact h2{margin:10px 0 12px;font-size:clamp(26px,3.4vw,40px)}
.kenh-list{display:grid;gap:10px}
.kenh{display:flex;align-items:center;gap:14px;padding:14px 16px;background:#fff;border:1px solid var(--line);border-radius:16px;text-decoration:none;color:var(--ink);transition:border-color .15s}
.kenh:hover{border-color:var(--brand)}
.kenh .ico{flex:0 0 auto}
.kenh b{display:block;font-size:15.5px}
.kenh span{font-size:13.5px;color:var(--muted)}
.policy{display:grid;gap:14px}
.policy .card h3{font-size:18px;margin-top:0}
.policy ul{margin:10px 0 0;padding-left:20px;color:var(--slate);font-size:15px}

/* ---------- Đầu trang con ---------- */
.phead{padding:clamp(48px,7vw,80px) 0 clamp(32px,5vw,48px);border-bottom:1px solid var(--line);background:radial-gradient(60% 90% at 90% 0%,#fff3ef 0%,rgba(255,243,239,0) 70%)}
.phead h1{margin:12px 0 14px;font-size:clamp(32px,4.6vw,54px);letter-spacing:-.04em;font-weight:800}
.phead .lead{max-width:680px}

/* ---------- Chân trang ---------- */
.foot{border-top:1px solid var(--line);padding:48px 0 36px;color:var(--muted);font-size:14.5px}
.foot-in{display:grid;gap:28px}
@media (min-width:860px){.foot-in{grid-template-columns:1.4fr 1fr 1fr 1fr}}
.foot h4{margin:0 0 12px;font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted-2)}
.foot a{display:block;color:var(--slate);text-decoration:none;padding:3px 0}
.foot a:hover{color:var(--brand)}
.foot .logo{margin-bottom:12px}
.foot-bot{margin-top:32px;padding-top:20px;border-top:1px solid var(--line);display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;font-size:13.5px;color:var(--muted-2)}

/* Cấu hình tối thiểu / đề xuất (25-10-2026) */
.hero-spec{display:inline-flex;align-items:center;gap:8px;margin-top:18px;padding:10px 16px;border-radius:14px;background:var(--soft);
  border:1px solid #ffd2c5;color:var(--ink);text-decoration:none;font-size:15px}
.hero-spec b{color:var(--brand)}
.hero-spec:hover{border-color:var(--brand);color:var(--ink)}
.specs{display:grid;gap:20px}
@media (min-width:860px){.specs{grid-template-columns:1fr 1fr}}
.spec{position:relative;background:#fff;border:1px solid var(--line);border-radius:24px;padding:28px 28px 22px}
.spec.is-rec{border:2px solid var(--brand);box-shadow:0 30px 60px -36px rgba(245,77,45,.55);background:linear-gradient(160deg,#fff1ed 0%,#ffffff 55%)}
.spec-badge{position:absolute;top:0;left:28px;transform:translateY(-55%);background:var(--brand);color:#fff;font-size:12.5px;font-weight:700;border-radius:999px;padding:5px 12px}
.spec h3{font-size:24px}
.spec > p{color:var(--muted);margin-top:6px}
.spec ul{list-style:none;margin:18px 0 0;padding:0;display:grid}
.spec li{display:flex;align-items:center;gap:14px;padding:13px 0;border-top:1px solid var(--line)}
.spec li .ico{width:40px;height:40px;flex:0 0 auto}
.spec small{display:block;font-size:12.5px;color:var(--muted);font-weight:600;letter-spacing:.04em;text-transform:uppercase}
.spec li b{font-size:17px}
.spec.is-rec li b{color:var(--ink)}
.specs + .warn{margin-top:18px}