/* Nen chung cho ca 3 mau: mot he thong, khong phai 3 trang roi rac.
   Moi mau ghi de --accent + font de ra dung chat nganh cua no. */
*,*::before,*::after{box-sizing:border-box}
:root{
  --bg:#ffffff; --bg-soft:#f6f7f9; --bg-card:#ffffff;
  --ink:#12161c; --ink-2:#3d4757; --ink-3:#6b7688;
  --line:#e4e8ee; --accent:#1a56db; --accent-ink:#ffffff;
  --radius:14px; --shadow:0 1px 2px rgba(16,24,40,.05),0 8px 24px -12px rgba(16,24,40,.18);
  --wrap:1200px;
}
@media (prefers-color-scheme:dark){
  :root{--bg:#0d1117;--bg-soft:#131922;--bg-card:#161d27;--ink:#eef2f7;--ink-2:#b6c0ce;
        --ink-3:#8592a3;--line:#242d3a;--shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.7)}
}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);
  font:16px/1.65 ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  -webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:inherit}
h1,h2,h3,h4{margin:0;line-height:1.18;letter-spacing:-.02em;font-weight:700}
p{margin:0}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 clamp(1rem,4vw,2rem)}

/* Bang bao "day la mau demo" — bat buoc: khong duoc de nguoi xem tuong
   day la san pham da giao cho khach that. */
.demo-bar{position:sticky;top:0;z-index:60;background:#12161c;color:#fff;font-size:.78rem;
  padding:.5rem 1rem;display:flex;gap:.9rem;align-items:center;justify-content:center;flex-wrap:wrap}
.demo-bar b{font-weight:600}
.demo-bar a{color:#ffd479;text-decoration:underline;text-underline-offset:2px}

.site-head{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--bg) 86%,transparent);
  backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.demo-bar+.site-head{top:2.1rem}
.nav{display:flex;align-items:center;gap:1.6rem;height:66px}
.logo{font-weight:800;font-size:1.12rem;letter-spacing:-.03em;display:flex;align-items:center;gap:.5rem;text-decoration:none}
.logo i{width:26px;height:26px;border-radius:7px;background:var(--accent);display:grid;place-items:center;
  color:var(--accent-ink);font-size:.8rem;font-style:normal;font-weight:800;flex-shrink:0}
.nav-links{display:flex;gap:1.35rem;margin-left:auto;font-size:.92rem;color:var(--ink-2)}
.nav-links a{text-decoration:none;padding:.3rem 0;border-bottom:2px solid transparent}
.nav-links a:hover,.nav-links a[aria-current]{color:var(--ink);border-bottom-color:var(--accent)}
.btn{display:inline-flex;align-items:center;gap:.45rem;border:0;cursor:pointer;font:inherit;font-size:.9rem;
  font-weight:600;padding:.62rem 1.1rem;border-radius:9px;background:var(--accent);color:var(--accent-ink);
  text-decoration:none;transition:transform .12s ease,filter .12s ease}
.btn:hover{filter:brightness(1.08);transform:translateY(-1px)}
.btn-ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn-ghost:hover{background:var(--bg-soft);filter:none}
:where(a,button,input,select):focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:6px}
.tag{display:inline-block;font-size:.68rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
  color:var(--accent);background:color-mix(in srgb,var(--accent) 12%,transparent);padding:.24rem .58rem;border-radius:5px}
.muted{color:var(--ink-3)}
.sec{padding:clamp(2.6rem,6vw,4.5rem) 0}
.sec-head{display:flex;align-items:flex-end;justify-content:space-between;gap:1rem;margin-bottom:1.6rem;flex-wrap:wrap}
.sec-head h2{font-size:clamp(1.35rem,3vw,1.85rem)}
.card{background:var(--bg-card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;
  transition:transform .16s ease,box-shadow .16s ease,border-color .16s ease}
.card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:color-mix(in srgb,var(--accent) 35%,var(--line))}
.grid{display:grid;gap:1.35rem}
.site-foot{border-top:1px solid var(--line);background:var(--bg-soft);padding:2.2rem 0;font-size:.88rem;color:var(--ink-3)}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}

/* ---- Dien thoai ----------------------------------------------------------
   Thanh dieu huong khong xuong dong lam CA TRANG cuon ngang (do that: 509px
   noi dung tren man 390px). Khong AN link di — an la mat duong vao chuyen muc;
   cho no thanh dai cuon ngang RIENG thi van bam duoc ma trang khong lech. */
@media (max-width:760px){
  .demo-bar{position:static;font-size:.72rem;padding:.45rem .8rem;text-align:center}
  .demo-bar+.site-head{top:0}
  .nav{height:auto;flex-wrap:wrap;gap:.6rem;padding-block:.7rem}
  .logo{font-size:1.02rem}
  .nav-links{order:3;flex-basis:100%;margin-left:0;gap:1.05rem;overflow-x:auto;
    scrollbar-width:none;padding-bottom:.15rem}
  .nav-links::-webkit-scrollbar{display:none}
  .nav-links a{white-space:nowrap}
  .nav>.btn,.nav>.cart{margin-left:auto!important}
  .nav>.btn+.btn{margin-left:.45rem!important}
}