/* HỆ THỐNG NGẦM — giao diện chung: đen ánh kim, vàng mạ, giấy ngà. */
:root{--bg:#0B0A08;--bg2:#12100C;--surface:#17140F;--surface2:#1F1A12;--ink:#F2EBDD;--muted:#B3A68C;--dim:#857A64;
  --gold:#D4AF5F;--gold2:#F0D89A;--gold3:#A87F35;--line:#332B1E;--paper:#F5EFE3;--paper2:#FBF8F1;--pink:#1C1812;--pmuted:#5A4E3C;--bronze:#8A6420;--bad:#E3926F;
  --fd:"Playfair Display",Georgia,"Times New Roman",serif;--fb:"Be Vietnam Pro","Segoe UI",system-ui,sans-serif;
  --foil:linear-gradient(180deg,#F7E7B4 0%,#D9B566 52%,#A87F35 100%);color-scheme:dark}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:400 17px/1.7 var(--fb);overflow-x:hidden}
img{max-width:100%;display:block;height:auto}
a{color:var(--gold2)}
a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:2px solid var(--gold);outline-offset:3px}
h1,h2,h3{margin:0;text-wrap:balance}
p{margin:0 0 14px}
.w{max-width:1160px;margin:0 auto;padding-inline:20px}
.k{font:700 12px/1.4 var(--fb);letter-spacing:.26em;text-transform:uppercase;color:var(--gold)}
.k::before{content:"";display:inline-block;width:26px;height:1px;background:var(--gold);vertical-align:middle;margin-right:12px}
section{padding-block:clamp(64px,9vw,120px);position:relative}
h2{font:700 clamp(30px,4.6vw,52px)/1.1 var(--fd);letter-spacing:-.01em;margin:14px 0 22px;max-width:22ch}
h2 em,h1 em{font-style:italic;color:var(--gold2)}
.lead{font-size:clamp(17px,2vw,20px);color:var(--muted);max-width:62ch}
strong{color:var(--gold2);font-weight:600}
.foil{background:var(--foil);-webkit-background-clip:text;background-clip:text;color:transparent;-webkit-text-fill-color:transparent;padding-block:.22em;-webkit-box-decoration-break:clone;box-decoration-break:clone}
.alt{background:var(--bg2)}
.paper{background:var(--paper);color:var(--pink)}
.paper .k{color:var(--bronze)}.paper .k::before{background:var(--bronze)}
.paper .lead{color:var(--pmuted)}.paper strong{color:var(--bronze)}
.paper h2 em{color:var(--bronze)}
.center{text-align:center}.center h2,.center .lead{margin-inline:auto}
.center .k::after{content:"";display:inline-block;width:26px;height:1px;background:currentColor;vertical-align:middle;margin-left:12px}
.orn{display:flex;align-items:center;justify-content:center;gap:12px;color:var(--gold);margin:6px 0 0}
.orn::before,.orn::after{content:"";width:60px;height:1px;background:linear-gradient(90deg,transparent,var(--gold))}
.orn::after{transform:scaleX(-1)}

/* nút */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;background:var(--foil);color:#14100A;font:800 16px/1.2 var(--fb);letter-spacing:.02em;border:0;border-radius:3px;padding:17px 28px;cursor:pointer;text-decoration:none;box-shadow:0 10px 30px -10px rgba(212,175,95,.55),inset 0 1px 0 rgba(255,255,255,.4);transition:transform .2s,box-shadow .2s}
.btn:hover{transform:translateY(-1px);box-shadow:0 16px 40px -12px rgba(212,175,95,.7),inset 0 1px 0 rgba(255,255,255,.4)}
.btn[disabled]{opacity:.6;cursor:wait;transform:none}
.btn.ghost{background:transparent;color:var(--gold2);border:1px solid var(--gold);box-shadow:none}
.btn.ghost:hover{background:rgba(212,175,95,.08)}
.btn.full{width:100%}

/* form */
.f{display:grid;gap:12px}
.f label{display:block;font:700 11.5px var(--fb);letter-spacing:.14em;text-transform:uppercase;color:var(--gold);margin-bottom:6px}
.f input,.f select,.f textarea{width:100%;font:400 16.5px var(--fb);color:var(--ink);background:rgba(11,10,8,.85);border:1px solid var(--line);border-radius:3px;padding:14px 15px}
.f input::placeholder,.f textarea::placeholder{color:#6f6657}
.f input:focus,.f select:focus,.f textarea:focus{border-color:var(--gold);outline:0}
.f .err{display:none;color:var(--bad);font-size:13px;margin-top:5px}
.f .bad input{border-color:var(--bad)}.f .bad .err{display:block}
.f small{font-size:12.5px;line-height:1.55;color:var(--dim)}
.hp{position:absolute!important;left:-9999px;width:1px;height:1px;opacity:0}

/* thẻ */
.card{background:linear-gradient(180deg,var(--surface2),var(--surface));border:1px solid var(--line);border-radius:6px;padding:26px;min-width:0}
.paper .card{background:var(--paper2);border-color:#D9C9A3}

/* video */
.yt{position:relative;aspect-ratio:16/9;width:100%;background:#000 center/cover no-repeat;border-radius:6px;overflow:hidden;border:1px solid var(--line);box-shadow:0 30px 60px -30px rgba(0,0,0,.8)}
.yt button{position:absolute;inset:0;width:100%;height:100%;border:0;background:linear-gradient(0deg,rgba(11,10,8,.9),rgba(11,10,8,.05) 62%);cursor:pointer;display:flex;flex-direction:column;justify-content:flex-end;align-items:flex-start;gap:6px;padding:18px;text-align:left;color:#fff;font:700 15.5px/1.35 var(--fb)}
.yt button::before{content:"";position:absolute;left:50%;top:44%;width:74px;height:74px;margin:-37px 0 0 -37px;border-radius:50%;background:var(--gold) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M8 5v14l11-7z' fill='%2314100A'/%3E%3C/svg%3E") 56% 50%/32px no-repeat;box-shadow:0 0 0 10px rgba(212,175,95,.18),0 8px 30px rgba(0,0,0,.6);transition:transform .2s}
.yt button:hover::before{transform:scale(1.08)}
.yt button small{font-weight:700;font-size:11px;color:var(--gold2);letter-spacing:.16em;text-transform:uppercase}
.yt iframe{position:absolute;inset:0;width:100%;height:100%;border:0}

/* thanh trên + Zalo nổi */
.bar{position:sticky;top:0;z-index:40;background:rgba(11,10,8,.86);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.bar .w{display:flex;align-items:center;gap:16px;min-height:60px}
.logo{font:700 15px var(--fd);letter-spacing:.18em;color:var(--ink);text-decoration:none;white-space:nowrap}
.logo b{color:var(--gold)}
.bar nav{display:flex;gap:22px;margin-left:auto;font-size:14px}
.bar nav a{color:var(--muted);text-decoration:none}.bar nav a:hover{color:var(--gold2)}
.bar .btn{padding:10px 18px;font-size:14px;gap:0}
.zalo{position:fixed;right:16px;bottom:calc(16px + env(safe-area-inset-bottom,0px));z-index:50;display:flex;align-items:center;gap:8px;background:#0B0A08;border:1px solid var(--gold);color:var(--gold2);border-radius:99px;padding:10px 16px 10px 12px;font:700 13.5px var(--fb);text-decoration:none;box-shadow:0 10px 30px rgba(0,0,0,.55)}
.zalo i{width:26px;height:26px;border-radius:50%;background:var(--foil);display:grid;place-items:center;font:800 11px var(--fb);color:#14100A;font-style:normal}
footer{padding:44px 0 calc(90px + env(safe-area-inset-bottom,0px));font-size:13.5px;color:var(--dim);border-top:1px solid var(--line);background:#080706}
footer a{color:var(--muted)}
footer .w{display:grid;gap:10px}

.rv{opacity:0;transform:translateY(22px);transition:opacity .8s ease,transform .8s ease}
.rv.in{opacity:1;transform:none}
@media (max-width:820px){.bar nav{display:none}.bar .btn{margin-left:auto}body{font-size:16.5px}}
@media (max-width:480px){.bar .btn{padding:9px 14px;font-size:13px}.bar .btn .dai{display:none}.logo{font-size:13px;letter-spacing:.14em}}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}.rv{opacity:1;transform:none;transition:none}.btn,.yt button::before{transition:none}}

/* khối link đại sứ */
.ds-ok{font-size:16px;color:var(--ink);margin:0 0 12px}.ds-ok b{color:var(--gold2)}
.ds-link{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:10px;margin-bottom:18px}
.ds-link input{width:100%;font:600 16px var(--fb);color:var(--gold2);background:#0B0A08;border:1px solid var(--gold);border-radius:3px;padding:14px}
.ds-grid{display:grid;grid-template-columns:200px minmax(0,1fr);gap:20px;align-items:start}
.ds-qr{background:#fff;padding:16px;border-radius:4px;width:200px}
.ds-qr img,.ds-qr canvas{width:168px!important;height:168px!important}
.ds-h{font:700 12px var(--fb);letter-spacing:.14em;text-transform:uppercase;color:var(--gold);margin:0 0 10px}
.ds-msg{background:var(--surface);border:1px solid var(--line);border-radius:4px;padding:14px;margin-bottom:10px}
.ds-msg p{font-size:14.5px;color:#DCD2BE;margin:0 0 10px;line-height:1.55}
.ds-msg .btn{padding:8px 14px;font-size:13px}
.ds-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:6px}.ds-row .btn{padding:12px 18px;font-size:14px}
.ds-note{font-size:13.5px;color:var(--muted);margin-top:16px}
.ds-err{color:var(--bad);font-size:14px;margin-top:10px}
@media (max-width:640px){.ds-grid{grid-template-columns:1fr}.ds-qr{margin-inline:auto}.ds-link{grid-template-columns:1fr}}