/* gemnotes — website
   Nền TRẮNG, cam kết một chiều: không có bản tối. Chris chốt 01/09/2026 ("nền
   trắng cho sạch"). Nên mọi màu định nghĩa đúng một lần ở :root, không có khối
   prefers-color-scheme nào — thêm vào sau sẽ phải xem lại toàn bộ ảnh chụp màn
   hình, vì chúng có nền giấy ấm cố định. */
:root{
  --bg:#FFFFFF;
  --bg-2:#FAFAF9;        /* thẻ, bảng, khối nhấn */
  --bg-3:#F4F4F2;        /* nền ảnh chụp màn hình */
  --ink:#111114;
  --ink-2:#54575D;
  --muted:#8B8E94;
  --rule:#E4E4E1;
  --rule-2:#EFEFEC;
  --pos:#B0392A;         /* đúng màu nhấn của bộ nhận diện */
  --mono:ui-monospace,"SF Mono",SFMono-Regular,Menlo,Consolas,monospace;
  --text:Charter,"Bitstream Charter","Iowan Old Style",Georgia,serif;
  --pad:clamp(1.1rem,4vw,2rem);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--text);
  font-size:17.5px;line-height:1.65;-webkit-font-smoothing:antialiased;
  overflow-x:hidden;               /* chốt chặn cuối: không cho trang cuộn ngang */
  touch-action:manipulation;       /* bỏ double-tap-zoom + độ trễ 300ms, GIỮ pinch-zoom */
  text-size-adjust:100%;-webkit-text-size-adjust:100%}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
.wrap{max-width:1120px;margin:0 auto;padding:0 var(--pad)}
.narrow{max-width:46rem}
.mono{font-family:var(--mono)}
.hand{font-family:'Kalam',cursive}
.dim{color:var(--ink-2)}
.acc{color:var(--pos)}

/* ── chữ ─────────────────────────────────────────────── */
h1,h2,h3{font-family:var(--mono);font-weight:700;letter-spacing:-.03em;line-height:1.08;
  margin:0;text-wrap:balance}
h1{font-size:clamp(2rem,5.6vw,3.6rem)}
h2{font-size:clamp(1.5rem,3.7vw,2.35rem);line-height:1.14}
h3{font-size:clamp(1rem,1.9vw,1.2rem);letter-spacing:-.02em;line-height:1.3}
p{margin:0 0 1.05em}
.lead{font-size:clamp(1.06rem,2vw,1.28rem);color:var(--ink-2);line-height:1.55}
.lbl{font-family:var(--mono);font-size:.7rem;letter-spacing:.18em;text-transform:uppercase;
  color:var(--muted);display:block;margin-bottom:1rem}
ul.bul,ol.num{color:var(--ink-2);font-size:1rem;padding-left:1.15rem;margin:0 0 1.05em}
ul.bul li,ol.num li{margin-bottom:.45em}

/* ── nav ─────────────────────────────────────────────── */
nav{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.9);
  backdrop-filter:blur(12px);border-bottom:1px solid var(--rule-2)}
nav .wrap{display:flex;align-items:center;gap:1.4rem;height:60px}
.brand{display:flex;align-items:center;gap:.5rem;text-decoration:none;flex:0 0 auto;line-height:1}
.brand svg{width:20px;height:20px;flex:none;display:block}
.brand b{font-family:var(--mono);font-size:.98rem;letter-spacing:-.03em;font-weight:700;
  line-height:1;display:block}
nav ul{display:flex;align-items:center;gap:1.3rem;list-style:none;margin:0;padding:0;flex:1 1 auto}
nav ul a{display:inline-flex;align-items:center;line-height:1}
nav a{font-family:var(--mono);font-size:.76rem;letter-spacing:.03em;color:var(--ink-2);
  text-decoration:none;white-space:nowrap;padding:.2rem 0;border-bottom:1px solid transparent}
nav a:hover{color:var(--ink);border-bottom-color:var(--pos)}
nav a.on{color:var(--ink);border-bottom-color:var(--ink)}
.navcta{flex:0 0 auto;display:flex;align-items:center;gap:.9rem}
.navcta a{border-bottom:0}
.navlink{font-family:var(--mono);font-size:.76rem;letter-spacing:.03em;color:var(--ink-2);
  text-decoration:none;white-space:nowrap;border-bottom:1px solid transparent;padding:.1rem 0}
.navlink:hover{color:var(--ink);border-bottom-color:var(--pos)}
.m-cta{display:none}
.burger{display:none;background:none;border:0;color:var(--ink);cursor:pointer;
  padding:.35rem;margin-left:auto;margin-right:-.35rem;z-index:60;align-items:center;justify-content:center}
.burger svg{display:block;transition:transform .2s}
.burger[aria-expanded=true] svg{transform:rotate(90deg)}
@media (max-width:900px){
  nav ul{position:absolute;top:60px;left:0;right:0;background:var(--bg);flex-direction:column;
    align-items:stretch;gap:0;padding:.4rem var(--pad) 1.2rem;
    border-bottom:1px solid var(--rule);box-shadow:0 12px 24px rgba(0,0,0,.06);display:none}
  nav ul.open{display:flex}
  nav ul li:not(.m-cta){display:block}
  nav ul a{padding:.7rem 0;border-bottom:1px solid var(--rule-2);width:100%;font-size:.92rem;color:var(--ink)}
  .navcta{display:none}
  /* CTA đôi ở cuối menu: wishlist là chính (phải), download phụ (trái) */
  .m-cta{display:flex;gap:.6rem;margin-top:1rem;border-bottom:0}
  .m-cta a{flex:1;text-align:center;border-bottom:0;padding:.8rem 1rem}
  .burger{display:flex}
}

/* ── section ─────────────────────────────────────────── */
section{padding:clamp(3.2rem,7vw,5.8rem) 0}
.rule-top{border-top:1px solid var(--rule)}
.tint{background:var(--bg-2)}
.head{max-width:44rem;margin-bottom:clamp(2rem,4vw,3rem)}
.head p{margin-top:1.05rem;font-size:1.05rem;color:var(--ink-2)}
.pagehead{padding:clamp(2.8rem,6vw,4.6rem) 0 clamp(1.6rem,3vw,2.4rem)}
.pagehead .lead{max-width:40rem;margin-top:1.2rem}
.crumb{font-family:var(--mono);font-size:.7rem;letter-spacing:.18em;text-transform:uppercase;
  color:var(--muted);display:block;margin-bottom:1.1rem}

/* ── nút ─────────────────────────────────────────────── */
.btns{display:flex;flex-wrap:wrap;gap:.7rem;margin-top:2rem}
.btn{display:inline-block;font-family:var(--mono);font-size:.86rem;padding:.82rem 1.35rem;
  text-decoration:none;border:1px solid var(--ink);background:var(--ink);color:#fff;
  transition:background .15s,border-color .15s;cursor:pointer}
.btn:hover{background:var(--pos);border-color:var(--pos)}
.btn.ghost{background:transparent;color:var(--ink)}
.btn.ghost:hover{background:var(--ink);color:#fff;border-color:var(--ink)}
.btn.sm{padding:.5rem .9rem;font-size:.76rem}
.arrow{display:inline-block;font-family:var(--mono);font-size:.82rem;color:var(--pos);
  text-decoration:none;border-bottom:1px solid transparent;margin-top:.5rem}
.arrow:hover{border-bottom-color:var(--pos)}

/* ── badge / tag ─────────────────────────────────────── */
.badge{display:inline-flex;align-items:center;gap:.5rem;border:1px solid var(--ink);
  padding:.42rem .8rem;font-family:var(--mono);font-size:.7rem;letter-spacing:.08em;
  margin-bottom:1.6rem}
.badge b{color:var(--pos);font-size:1.1em;line-height:0}
.tag{font-family:var(--mono);font-size:.66rem;letter-spacing:.1em;padding:.2rem .45rem;
  border:1px solid currentColor;white-space:nowrap;display:inline-block}
.live{color:var(--pos)}
.soon{color:var(--muted)}

/* ── ảnh ─────────────────────────────────────────────── */
figure{margin:0}
.shot{background:var(--bg-3);border:1px solid var(--rule);overflow:hidden}
.shot img{width:100%}
figcaption{font-family:var(--mono);font-size:.72rem;letter-spacing:.04em;color:var(--muted);
  padding:.7rem .9rem;border-top:1px solid var(--rule-2);line-height:1.5;background:var(--bg)}
figcaption b{color:var(--ink-2);font-weight:400}

/* ── hàng nội dung ───────────────────────────────────── */
.row{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.32fr);
  gap:clamp(1.6rem,4vw,3.4rem);align-items:center;margin-bottom:clamp(3rem,6vw,4.8rem)}
.row.flip{grid-template-columns:minmax(0,1.32fr) minmax(0,1fr)}
.row.flip .txt{order:2}
.row.even{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
.row:last-child{margin-bottom:0}
.row .txt h3{margin-bottom:.8rem}
.row .txt p{font-size:1rem;color:var(--ink-2)}
.row .txt p:last-child{margin-bottom:0}
.row .txt .k{color:var(--ink)}
@media (max-width:900px){
  .row,.row.flip,.row.even{grid-template-columns:1fr;gap:1.4rem}
  .row.flip .txt{order:0}
}

/* ── lưới ────────────────────────────────────────────── */
.g2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:clamp(1.2rem,3vw,2.2rem)}
.g3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(1.2rem,3vw,2.4rem)}
.g4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:clamp(.9rem,2vw,1.4rem)}
@media (max-width:900px){.g3,.g4{grid-template-columns:1fr 1fr}}
@media (max-width:620px){.g2,.g3,.g4{grid-template-columns:1fr}}
.pillar h3{margin-bottom:.7rem}
.pillar p{font-size:.98rem;color:var(--ink-2);margin:0}
.pillar .num{font-family:var(--mono);font-size:.7rem;letter-spacing:.18em;color:var(--pos);
  display:block;margin-bottom:.9rem}

/* ── dải số ──────────────────────────────────────────── */
.facts{display:grid;grid-template-columns:repeat(4,1fr);
  border-top:1px solid var(--rule);border-bottom:1px solid var(--rule)}
.facts div{padding:1.5rem 1.3rem 1.5rem 0}
.facts div+div{border-left:1px solid var(--rule-2);padding-left:1.3rem}
.facts .n{font-family:var(--mono);font-size:clamp(1.15rem,2.5vw,1.6rem);font-weight:700;
  letter-spacing:-.03em;display:block;margin-bottom:.35rem}
.facts .t{font-size:.85rem;color:var(--ink-2);line-height:1.45}
@media (max-width:760px){
  .facts{grid-template-columns:1fr 1fr}
  .facts div:nth-child(odd){padding-left:0;border-left:0}
  .facts div:nth-child(n+3){border-top:1px solid var(--rule-2)}
}

/* ── bảng ────────────────────────────────────────────── */
.tw{overflow-x:auto;-webkit-overflow-scrolling:touch}
table{border-collapse:collapse;width:100%;min-width:32rem;font-size:.95rem}
th,td{text-align:left;padding:.85rem 1rem .85rem 0;border-bottom:1px solid var(--rule-2);
  vertical-align:top}
th{font-family:var(--mono);font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;
  color:var(--muted);border-bottom:1px solid var(--ink);font-weight:400}
td{color:var(--ink-2)}
td:first-child{color:var(--ink);font-family:var(--mono);font-size:.86rem}

/* ── khối nhấn ───────────────────────────────────────── */
.note{border-left:2px solid var(--pos);padding:.15rem 0 .15rem 1.15rem;color:var(--ink-2);
  font-size:.97rem;margin:1.6rem 0}
.note b{color:var(--ink)}
blockquote{margin:1.8rem 0;padding-left:1.3rem;border-left:2px solid var(--rule);
  font-size:1.1rem;line-height:1.5;color:var(--ink-2)}
blockquote cite{display:block;margin-top:.6rem;font-style:normal;font-family:var(--mono);
  font-size:.72rem;letter-spacing:.06em;color:var(--muted)}
.panel{border:1px solid var(--rule);padding:clamp(1.2rem,3vw,2rem);background:var(--bg-2)}
.panel.warn{border-color:var(--pos)}
.panel h3{margin-bottom:.8rem}
.panel p{font-size:.98rem;color:var(--ink-2)}
.panel p:last-child{margin-bottom:0}
pre{max-width:100%;font-family:var(--mono);font-size:.82rem;line-height:1.75;background:var(--bg-2);
  border:1px solid var(--rule);padding:1rem 1.1rem;overflow-x:auto;margin:0 0 1.1rem}
code{font-family:var(--mono);font-size:.88em}
.diagram{border:1px solid var(--rule);background:var(--bg-2);padding:clamp(1.2rem,3vw,2.2rem)}
.diagram svg{width:100%;height:auto;display:block}

/* ── các bước ────────────────────────────────────────── */
.steps{list-style:none;margin:0;padding:0;counter-reset:s}
.steps>li{counter-increment:s;display:grid;grid-template-columns:3.2rem minmax(0,1fr);gap:1.4rem;
  padding:1.8rem 0;border-top:1px solid var(--rule)}
.steps>li::before{content:counter(s,decimal-leading-zero);font-family:var(--mono);
  font-size:.95rem;font-weight:700;color:var(--pos);padding-top:.15rem}
.steps h3{margin-bottom:.7rem}
.steps p{font-size:1rem;color:var(--ink-2)}
.steps p:last-child,.steps pre:last-child{margin-bottom:0}
@media (max-width:620px){.steps>li{grid-template-columns:minmax(0,1fr);gap:.6rem}}

/* ── danh sách trạng thái ────────────────────────────── */
.status{list-style:none;margin:0;padding:0}
.status li{display:grid;grid-template-columns:6.4rem minmax(0,1fr);gap:1rem;padding:.9rem 0;
  border-bottom:1px solid var(--rule-2);font-size:.98rem;color:var(--ink-2)}
.status li span:first-child{font-family:var(--mono);font-size:.68rem;letter-spacing:.1em;
  padding-top:.28rem}
.status .ok span:first-child{color:var(--pos)}
.status b{color:var(--ink);font-weight:400}
@media (max-width:620px){.status li{grid-template-columns:1fr;gap:.2rem}}

/* ── thư viện ảnh thiết bị ───────────────────────────── */
.gal{display:grid;grid-template-columns:repeat(6,1fr);gap:clamp(.7rem,1.6vw,1.1rem);
  align-items:start}
.gal figure{grid-column:span 2}
.gal figure.wide{grid-column:span 3}
.gal figure.big{grid-column:span 6}
@media (max-width:820px){
  .gal{grid-template-columns:repeat(2,1fr)}
  .gal figure,.gal figure.wide{grid-column:span 1}
  .gal figure.big{grid-column:span 2}
}

/* ── giá ─────────────────────────────────────────────── */
.price{display:flex;align-items:baseline;gap:.9rem;flex-wrap:wrap;margin:.4rem 0 .3rem}
.price .now{font-family:var(--mono);font-size:clamp(2rem,5vw,3rem);font-weight:700;
  letter-spacing:-.04em}
.price .was{font-family:var(--mono);font-size:1.1rem;color:var(--muted);
  text-decoration:line-through}
.price .off{font-family:var(--mono);font-size:.7rem;letter-spacing:.1em;color:#fff;
  background:var(--pos);padding:.28rem .5rem}
.spec{list-style:none;margin:0;padding:0;font-size:.95rem}
.spec li{display:flex;justify-content:space-between;gap:1rem;padding:.6rem 0;
  border-bottom:1px solid var(--rule-2)}
.spec b{font-family:var(--mono);font-size:.82rem;font-weight:400;color:var(--muted);
  flex:0 0 auto}
.spec span{color:var(--ink-2);text-align:right}

/* ── form ────────────────────────────────────────────── */
form{display:flex;flex-direction:column;gap:1.5rem;max-width:34rem}
label{display:block;font-family:var(--mono);font-size:.68rem;letter-spacing:.12em;
  text-transform:uppercase;color:var(--muted);margin-bottom:.55rem}
label .n{text-transform:none;letter-spacing:0}
input[type=email],input[type=text],textarea{width:100%;font-family:var(--text);font-size:1rem;
  color:var(--ink);background:var(--bg);border:1px solid var(--rule);padding:.75rem .85rem;
  min-height:2.9rem;border-radius:0;line-height:1.55}
textarea{resize:vertical;display:block}
input:focus,textarea:focus{outline:2px solid var(--pos);outline-offset:1px;border-color:var(--ink)}
.chips{display:flex;flex-wrap:wrap;gap:.45rem}
.chip{position:relative}
.chip input{position:absolute;opacity:0;width:100%;height:100%;margin:0;cursor:pointer}
.chip span{display:flex;align-items:center;font-family:var(--mono);font-size:.8rem;
  border:1px solid var(--rule);padding:.5rem .8rem;min-height:2.5rem;cursor:pointer}
.chip input:checked+span{background:var(--ink);color:#fff;border-color:var(--ink)}
.chip input:focus-visible+span{outline:2px solid var(--pos);outline-offset:2px}
form button{align-self:flex-start}
button:disabled,.btn:disabled{opacity:1;cursor:default;background:transparent;color:var(--muted);
  border-color:var(--rule);border-style:dashed}
button:disabled:hover,.btn:disabled:hover{background:transparent;border-color:var(--rule)}
.msg{font-family:var(--mono);font-size:.84rem;line-height:1.6;padding:.95rem 1.05rem;
  border:1px solid var(--rule);background:var(--bg-2)}
.msg.err{border-color:var(--pos);color:var(--pos)}
.hide{display:none}
.hp{position:absolute;left:-9999px}

/* ── chân trang ──────────────────────────────────────── */
footer{border-top:1px solid var(--rule);padding:3.2rem 0 4rem;font-family:var(--mono);
  font-size:.75rem;color:var(--muted);line-height:1.95;margin-top:0}
footer a{color:var(--ink-2);text-decoration:none}
footer a:hover{color:var(--pos)}
.fcols{display:grid;grid-template-columns:1.5fr 1fr 1fr 1.2fr;gap:2rem}
.fcols p{margin:.7rem 0 0;font-family:var(--mono);font-size:.75rem;line-height:1.95}
.fbrand{margin-bottom:.2rem}
.flbl{display:block;color:var(--ink);letter-spacing:.14em;text-transform:uppercase;
  font-size:.66rem;margin-bottom:.5rem}
@media (max-width:820px){.fcols{grid-template-columns:1fr 1fr}}
@media (max-width:520px){.fcols{grid-template-columns:1fr}}