/* ChangeAI — sales page dài, nền đen, tiêu đề in hoa đậm, màu nhấn vàng. */
:root{--bg:#090909;--card:#121212;--card2:#1A1712;--line:rgba(229,193,88,.22);--text:#FFFFFF;--muted:#A3A8B0;--gold:#E5C158;--gold-g:linear-gradient(#F0D581,#D7B345);--ink:#090909;--ease:cubic-bezier(.2,.7,.2,1)}
*{box-sizing:border-box;margin:0}
[hidden]{display:none!important}
html{scroll-behavior:smooth;scroll-padding-top:76px}
body{font:400 17px/1.6 'Be Vietnam Pro',system-ui,sans-serif;color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;overflow-x:hidden}
img{display:block;max-width:100%;height:auto}
a{color:inherit}
h1,h2{font-weight:800;text-transform:uppercase;letter-spacing:-.015em;line-height:1.36;text-wrap:balance}
h2{font-size:clamp(28px,3.6vw,44px);max-width:22ch}
h3{font-size:21px;font-weight:700;line-height:1.3}
:focus-visible{outline:3px solid var(--gold);outline-offset:3px;border-radius:6px}

.cta{display:inline-flex;align-items:center;justify-content:center;min-height:54px;padding:0 30px;border-radius:12px;border:0;background:var(--gold-g);color:var(--ink);font:inherit;font-weight:700;text-decoration:none;cursor:pointer;transition:background .2s,transform .15s}
.cta:hover{filter:brightness(1.08)}.cta:active{transform:scale(.98)}
.cta.sm{min-height:42px;padding:0 18px;font-size:15px;border-radius:10px}
.cta.wide{width:100%}

.nav{position:sticky;top:0;z-index:30;display:flex;justify-content:space-between;align-items:center;padding:12px clamp(16px,4vw,48px);background:rgba(10,15,14,.9);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px)}
.brand img{height:34px;width:auto;border-radius:6px}

.hero{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:clamp(24px,4vw,64px);align-items:center;max-width:1280px;margin:0 auto;padding:clamp(40px,6vw,88px) clamp(16px,4vw,48px)}
h1{font-size:clamp(36px,5vw,64px);max-width:7.6em}
h1 span{display:block;padding-block:.2em;margin-block:-.2em;background:linear-gradient(#F5DE98,#D7B345);-webkit-background-clip:text;background-clip:text;color:transparent}
.lead{color:var(--muted);margin:20px 0 28px;max-width:46ch;font-size:18px}
.facts{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:12px 32px;margin-top:32px;color:var(--muted);font-size:14px}
.facts b{display:block;color:var(--text);font-size:17px;font-weight:700}
.hero-img{border-radius:20px;width:100%}

.sec{max-width:1120px;margin:0 auto;padding:clamp(56px,7vw,96px) clamp(16px,4vw,48px)}
.sub{color:var(--muted);margin-top:14px;max-width:58ch}
.fine{color:var(--muted);font-size:13px;margin-top:14px}

.pains{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin-top:36px}
.pains article{background:var(--card);border-radius:16px;padding:24px}
.pains p{color:var(--muted);margin-top:8px;font-size:16px}

.steps{list-style:none;padding:0;margin-top:40px;display:grid;gap:18px;counter-reset:s}
.steps li{counter-increment:s;display:grid;grid-template-columns:minmax(0,5fr) minmax(0,6fr);gap:clamp(20px,4vw,48px);align-items:center;background:var(--card);border-radius:20px;padding:clamp(16px,2vw,24px)}
.steps li:nth-child(even) img{order:2}
.steps img{border-radius:14px;width:100%}
.steps h3{font-size:clamp(24px,2.6vw,32px);font-weight:800}
.steps h3::before{content:counter(s);display:grid;place-items:center;width:40px;height:40px;border-radius:50%;background:var(--gold);color:var(--ink);font-size:18px;margin-bottom:14px}
.steps p{color:var(--muted);margin-top:10px;max-width:44ch}

.versus{display:grid;grid-template-columns:1fr 1fr;margin-top:18px;border-radius:20px;overflow:hidden}
.versus>div{padding:32px;text-align:center;background:var(--card2);color:var(--muted)}
.versus .on{background:var(--gold-g);color:var(--ink)}
.versus p{font-weight:600}
.versus b{display:block;font-size:clamp(32px,4.4vw,52px);font-weight:800;line-height:1.36;margin:6px 0;color:var(--text);text-transform:uppercase}
.versus .on b{color:var(--ink)}

.split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:clamp(24px,4vw,56px);align-items:start}
.split-img{border-radius:16px;margin-top:24px;width:100%}
.cost{background:var(--card);border-radius:20px;padding:clamp(20px,3vw,32px)}
table{width:100%;border-collapse:collapse}
th,td{text-align:left;padding:12px 0;border-bottom:1px solid var(--line)}
th{color:var(--muted);font-size:14px;font-weight:600}
th:last-child,td:last-child{text-align:right}
tfoot td{font-weight:800;font-size:20px;border-bottom:0}
.cost-ai{background:var(--gold-g);color:var(--ink);border-radius:14px;padding:20px;margin-top:12px}
.cost-ai p{font-weight:600}
.cost-ai b{display:block;font-size:30px;font-weight:800;line-height:1.2}
.cost-ai span{font-size:15px}

.agenda{list-style:none;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-top:36px}
.agenda li{background:var(--card);border-radius:16px;padding:24px}
.agenda p{color:var(--muted);margin-top:8px;font-size:16px}
.pick{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:14px}
.pick>div{background:var(--card);border-radius:16px;padding:24px}
.pick .gift{background:var(--card2);box-shadow:inset 0 0 0 1.5px var(--gold)}
.pick ul{list-style:none;padding:0;display:grid;gap:10px;margin-top:14px;color:var(--muted)}
.pick li{padding-left:26px;position:relative}
.pick li::before{content:"";position:absolute;left:2px;top:9px;width:13px;height:7px;border-left:2px solid var(--gold);border-bottom:2px solid var(--gold);transform:rotate(-45deg)}

.reg{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:clamp(24px,4vw,56px);align-items:center}
.sub b{color:var(--text)}
.regbox{background:var(--card);border-radius:20px;padding:clamp(20px,3vw,32px);box-shadow:inset 0 0 0 1.5px var(--line)}
form{display:grid;gap:14px}
label{display:grid;gap:6px;font-size:14px;font-weight:600}
input,select,textarea{font:inherit;font-size:16px;font-weight:400;padding:13px 14px;border:1px solid #2E2A20;border-radius:10px;background:var(--bg);color:var(--text);width:100%}
input::placeholder{color:#777}
input:focus,select:focus{outline:none;border-color:var(--gold)}
[aria-invalid=true]{border-color:#FF7A6B!important}
.err{color:#FF9C90;font-size:13px;font-weight:500}
.check{display:flex;gap:10px;align-items:flex-start;font-weight:400;color:var(--muted)}
.check input{width:20px;height:20px;margin-top:2px;flex:none;accent-color:var(--gold)}
.hp{position:absolute;left:-9999px}
.done{display:grid;gap:12px;text-align:center;justify-items:center;padding:20px 0}
.done h3{font-size:26px;color:var(--gold)}
.done p{color:var(--muted);max-width:40ch}

.faq{margin-top:28px;max-width:820px}
details{border-bottom:1px solid var(--line)}
summary{list-style:none;cursor:pointer;padding:20px 40px 20px 0;font-weight:600;font-size:18px;position:relative}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";position:absolute;right:4px;top:14px;font-size:26px;font-weight:400;color:var(--gold);transition:transform .25s var(--ease)}
details[open] summary::after{transform:rotate(45deg)}
details p{padding:0 0 20px;color:var(--muted);max-width:62ch}

.foot{display:flex;flex-wrap:wrap;gap:14px;justify-content:space-between;align-items:center;padding:28px clamp(16px,4vw,48px);color:var(--muted);font-size:13px;background:var(--card)}
.foot img{height:28px;width:auto;border-radius:5px}

.dock{position:fixed;left:16px;right:16px;bottom:max(14px,env(safe-area-inset-bottom));z-index:30;transition:transform .3s var(--ease),opacity .3s}
.dock.hide{transform:translateY(160%);opacity:0;pointer-events:none}

.js .reveal{opacity:0;transform:translateY(22px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.js .reveal.in{opacity:1;transform:none}

@media (min-width:834px){.dock{display:none}}
@media (max-width:833px){
  .hero,.split,.reg,.steps li,.pick,.agenda{grid-template-columns:minmax(0,1fr)}
  .pains{grid-template-columns:repeat(2,minmax(0,1fr))}
  .steps li:nth-child(even) img{order:0}
  .versus>div{padding:24px 12px}
  .versus b{font-size:26px}
  .foot{padding-bottom:88px}
}

/* các phần dài thêm */
.band{display:flex;flex-wrap:wrap;gap:20px 40px;justify-content:space-between;align-items:center;max-width:1024px;margin:8px auto;padding:clamp(28px,4vw,44px);border-radius:20px;background:var(--card2);box-shadow:inset 0 0 0 1.5px var(--line)}
.band h2{font-size:clamp(22px,2.6vw,30px);max-width:24ch}
.band p{color:var(--muted);margin-top:6px}
.days{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:36px}
.days>div{background:var(--card);border-radius:18px;padding:clamp(20px,3vw,32px)}
.days .on{box-shadow:inset 0 0 0 1.5px var(--gold)}
.days h3{font-size:24px;font-weight:800;margin-bottom:16px}
.days ol{list-style:none;padding:0;display:grid;gap:14px}
.days li{display:grid;grid-template-columns:56px 1fr;gap:12px;color:var(--muted);font-size:16px}
.days b{color:var(--text)}.days .on b{color:var(--gold)}
.walk{list-style:none;padding:0;margin-top:36px;display:grid;gap:14px}
.walk li{display:grid;grid-template-columns:minmax(0,3fr) minmax(0,7fr);gap:24px;align-items:center;background:var(--card);border-radius:18px;padding:22px}
.walk span{font-weight:700;font-size:18px}
.ui{background:#1E1E1E;border-radius:12px;padding:16px;font-size:15px;color:#DDD;line-height:1.6}
.ui b{color:var(--gold)}
.ui.bubble{background:var(--card2);box-shadow:inset 0 0 0 1px var(--line)}
.ui.wave{display:flex;align-items:center;gap:3px;height:76px}
.ui.wave i{flex:1;height:var(--h);background:var(--gold);border-radius:2px}
.ui.tracks{display:flex;gap:4px;height:70px}
.ui.tracks i{width:var(--w);background:var(--gold);opacity:.75;border-radius:6px}
.ui.tracks i:nth-child(even){opacity:.4}
.ui.sched p{display:flex;gap:12px;align-items:center;padding:4px 0}
.ui.sched em{margin-left:auto;font-style:normal;font-size:13px;color:var(--gold)}
.week{list-style:none;padding:0;margin-top:36px;display:grid;grid-template-columns:repeat(7,minmax(0,1fr));gap:10px}
.week li{background:var(--card);border-radius:14px;padding:18px 14px;color:var(--muted);font-size:15px;line-height:1.4}
.week b{display:block;color:var(--gold);margin-bottom:8px;font-size:15px}
.tools{margin-top:32px;background:var(--card);border-radius:18px;overflow:hidden}
.tools th,.tools td{padding:16px 20px}
.tools th:last-child,.tools td:last-child{text-align:left}
.tools tr:last-child td{border-bottom:0}
.kinds{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-top:36px}
.kinds article{background:var(--card);border-radius:16px;padding:24px}
.kinds p{color:var(--muted);margin-top:8px;font-size:16px}
.fixes{list-style:none;padding:0;margin-top:36px;display:grid;gap:12px}
.fixes li{display:grid;grid-template-columns:1fr 1fr;border-radius:16px;overflow:hidden}
.fixes li>div{padding:22px;background:var(--card)}
.fixes .on{background:var(--card2);box-shadow:inset 0 0 0 1.5px var(--line)}
.fixes b{display:block;font-size:18px;margin-bottom:4px}.fixes .on b{color:var(--gold)}
.fixes span{color:var(--muted);font-size:16px}
.agenda{grid-template-columns:repeat(4,minmax(0,1fr))!important}
.agenda b{display:block;color:var(--gold);font-size:14px;margin-bottom:8px}
.road{list-style:none;padding:0;margin-top:36px;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}
.road li{background:var(--card);border-radius:16px;padding:24px}
.road b{display:block;color:var(--gold);margin-bottom:8px}
.road p{color:var(--muted);margin-top:8px;font-size:16px}
.final{text-align:center;display:grid;justify-items:center;gap:8px}
.final h2{max-width:20ch}.final .cta{margin-top:20px}
@media (max-width:833px){
  .days,.fixes li,.walk li,.kinds,.road,.agenda{grid-template-columns:minmax(0,1fr)!important}
  .week{grid-template-columns:repeat(2,minmax(0,1fr))}
  .band{margin:8px 16px}
  .tools th,.tools td{padding:12px;font-size:14px}
}

/* đếm ngược */
.count{margin:0 0 24px;max-width:420px}
.count-t{color:var(--gold);font-size:14px;font-weight:600;margin-bottom:10px}
.count ul{list-style:none;padding:0;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px}
.count li{background:var(--card2);box-shadow:inset 0 0 0 1px var(--line);border-radius:12px;padding:10px 4px;text-align:center;font-size:13px;color:var(--muted)}
.count b{display:block;font-size:30px;font-weight:800;line-height:1.2;color:var(--text);font-variant-numeric:tabular-nums}
.reg-copy .count{margin:24px 0 0}
/* video kết quả: bấm để phát, chỉ tải khi bấm */
.clips{list-style:none;padding:0;margin-top:36px;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:14px}
.clip{position:relative;aspect-ratio:9/16;border-radius:16px;overflow:hidden;background:var(--card)}
.clip video{display:block;width:100%;height:100%;object-fit:cover}
.play{position:absolute;inset:0;width:100%;border:0;background:none;cursor:pointer}
.play::before{content:"";position:absolute;right:10px;bottom:10px;width:44px;height:44px;border-radius:50%;background:var(--gold-g);box-shadow:0 2px 10px rgba(0,0,0,.45)}
.play::after{content:"";position:absolute;right:24px;bottom:22px;border-style:solid;border-width:10px 0 10px 16px;border-color:transparent transparent transparent var(--ink)}
.clips p{font-weight:600;font-size:16px;line-height:1.4;margin-top:12px}
.clips .how{display:block;color:var(--gold);font-weight:600;font-size:14px;line-height:1.4;margin-top:4px}
.clips .how+small{display:block;margin-top:2px}
.tools-end{margin-top:18px}
h1 i{display:block;width:10.4em;text-align:center;font-style:normal;color:var(--gold);font-size:.7em;line-height:1.2;margin:6px 0}
h1 em{display:block;font-style:normal;font-size:.62em;line-height:1.3}
.h1-note{color:var(--muted);font-size:clamp(15px,1.4vw,17px);line-height:1.5;margin-top:14px}
.tools td:last-child,.tools th:last-child{white-space:nowrap}
.clips small{color:var(--muted);font-size:14px}
@media (max-width:833px){
  .clips{grid-template-columns:none;grid-auto-flow:column;grid-auto-columns:68%;overflow-x:auto;scroll-snap-type:x mandatory;margin-inline:-16px;padding-inline:16px;scroll-padding-inline:16px}
  .clips li{scroll-snap-align:start;min-width:0}
}
/* phần lớn khách xem trên điện thoại: chữ căn giữa; bảng, form, hỏi đáp và mốc giờ vẫn căn trái cho dễ đọc */
@media (max-width:833px){
  .hero-copy,.sec,.band,.foot{text-align:center}
  h1,h2,.sub,.lead,.h1-note,.fine,.steps p,.band h2{margin-inline:auto}
  h1 i{width:auto}
  .count ul,.facts,.band{justify-content:center}
  .week li:last-child{grid-column:1/-1}
  .steps h3::before{margin-inline:auto}
  table,form,details,.days li,.ui,.pick ul,.pick li,#done{text-align:left}
}
/* nút chuyển video: vuốt có thể bị điều khiển của video chặn, và máy tính không vuốt được */
.clip-nav{display:none;align-items:center;justify-content:center;gap:18px;margin-top:18px;color:var(--muted);font-size:16px}
.clip-nav b{color:var(--text)}
.clip-nav button{width:52px;height:52px;border:0;border-radius:50%;background:var(--gold-g);color:var(--ink);font-size:30px;font-weight:800;line-height:1;cursor:pointer}
.clip-nav button:disabled{opacity:.3;cursor:default}
.clip,.clip video,.play{touch-action:pan-x pan-y}
@media (max-width:833px){.clip-nav{display:flex}}
/* đầu trang bản máy tính: chữ và ảnh trong một khung giữa màn hình, ảnh luôn hiện đủ */
@media (min-width:834px){
  .hero{max-width:1200px;min-height:calc(100vh - 72px);grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:clamp(32px,4vw,64px);padding-block:32px}
  .hero-copy{justify-self:end;width:100%;max-width:560px}
  h1{max-width:11.5em;font-size:clamp(30px,3.3vw,44px)}
  h1 i{width:auto;text-align:center;margin:2px 0}
  h1 em{font-size:.72em}
  .h1-note{margin-top:10px}
  .lead{margin:14px 0 18px;font-size:17px}
  .hero .facts{margin-top:20px}
  .hero-img{justify-self:start;width:auto;height:auto;max-width:100%;max-height:calc(100vh - 136px);aspect-ratio:1}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .js .reveal{opacity:1;transform:none}
}