:root{--ar-bg:#070a12;--ar-bg2:#0c1120;--ar-panel:#111829;--ar-line:#1f2a44;--ar-tx:#e7ecf7;--ar-mt:#8c97b2;--ar-pr:#d4ff5c;--ar-cy:#3de0ff;--ar-mg:#ff4fd8;--ar-w:1240px;--cut:14px}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:radial-gradient(1200px 600px at 85% -10%,rgba(61,224,255,.10),transparent 60%),radial-gradient(900px 500px at -10% 10%,rgba(212,255,92,.07),transparent 60%),var(--ar-bg);color:var(--ar-tx);font:16.5px/1.75 'Be Vietnam Pro',system-ui,sans-serif;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}img{max-width:100%;height:auto;display:block}
h1,h2,h3,h4{font-family:'Chakra Petch','Be Vietnam Pro',sans-serif;font-weight:700;line-height:1.2;margin:0;letter-spacing:-.005em}
.wrap{max-width:var(--ar-w);margin:0 auto;padding:0 24px}
.ar-cut{clip-path:polygon(0 0,calc(100% - var(--cut)) 0,100% var(--cut),100% 100%,var(--cut) 100%,0 calc(100% - var(--cut)))}
.ar-tag{display:inline-flex;align-items:center;gap:7px;font:700 11.5px/1 'Chakra Petch',sans-serif;letter-spacing:.14em;text-transform:uppercase;color:var(--c,var(--ar-pr))}
.ar-tag:before{content:"";width:8px;height:8px;background:var(--c,var(--ar-pr));box-shadow:0 0 10px var(--c,var(--ar-pr));transform:rotate(45deg)}
/* Header */
.ar-tick{background:var(--ar-pr);color:#0a0f02;font:700 12px/1 'Chakra Petch',sans-serif;letter-spacing:.12em;text-transform:uppercase;overflow:hidden;white-space:nowrap}
.ar-tick .wrap{display:flex;gap:28px;padding-top:8px;padding-bottom:8px}.ar-tick b{background:#0a0f02;color:var(--ar-pr);padding:3px 8px;margin-right:4px}
.ar-tick span{opacity:.85}
.ar-hd{position:sticky;top:0;z-index:20;background:rgba(7,10,18,.86);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--ar-line)}
.ar-hd .row{display:flex;align-items:center;justify-content:space-between;gap:24px;min-height:72px}
.ar-hd .ar-nav{border-top:1px solid var(--ar-line);padding:8px 0}
.ar-search{font:600 12px/1 'Chakra Petch',sans-serif;letter-spacing:.14em;text-transform:uppercase;color:var(--ar-mt);display:flex;gap:18px}.ar-search a:hover{color:var(--ar-pr)}
.ar-brand{display:flex;align-items:center;gap:12px;white-space:nowrap}
.ar-brand img{width:44px;height:44px;filter:drop-shadow(0 0 10px rgba(212,255,92,.35))}
.ar-brand b{font:700 23px/1 'Chakra Petch',sans-serif;letter-spacing:.04em;text-transform:uppercase}
.ar-brand b i{font-style:normal;color:var(--ar-pr);text-shadow:0 0 18px rgba(212,255,92,.45)}
.ar-brand small{display:block;font:500 11px/1 'Be Vietnam Pro',sans-serif;letter-spacing:.16em;text-transform:uppercase;color:var(--ar-mt);margin-top:6px}
.ar-nav{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none}
.ar-nav a{font:600 13.5px/1 'Chakra Petch',sans-serif;letter-spacing:.06em;text-transform:uppercase;color:#c3cbe0;padding:11px 14px;border:1px solid transparent;white-space:nowrap;transition:.2s}
.ar-nav a:hover,.ar-nav a[aria-current]{color:var(--c,var(--ar-pr));border-color:var(--ar-line);background:var(--ar-panel)}
/* Ảnh bìa vẽ bằng CSS */
.ar-cover{position:relative;overflow:hidden;aspect-ratio:16/9;background:radial-gradient(circle at var(--x) 38%,color-mix(in srgb,var(--c) 45%,transparent),transparent 45%),linear-gradient(180deg,#0d1326 0%,#141a3a 55%,#0a0d18 56%,#070a12 100%)}
.ar-cover:before{content:"";position:absolute;left:-50%;right:-50%;bottom:0;height:44%;background:linear-gradient(transparent 0 calc(100% - 1px),color-mix(in srgb,var(--c) 70%,transparent) 0) 0 0/100% 18px,linear-gradient(90deg,transparent 0 calc(100% - 1px),color-mix(in srgb,var(--c) 70%,transparent) 0) 0 0/36px 100%;transform:perspective(220px) rotateX(58deg);transform-origin:50% 100%;opacity:.55}
.ar-cover:after{content:"";position:absolute;inset:0;background:repeating-linear-gradient(0deg,rgba(255,255,255,.035) 0 1px,transparent 1px 3px);pointer-events:none}
.ar-cover svg{position:absolute;left:50%;top:40%;width:22%;max-width:96px;transform:translate(-50%,-50%) rotate(var(--r));fill:var(--c);filter:drop-shadow(0 0 14px var(--c));opacity:.92}
.ar-cover .lv{position:absolute;right:12px;top:12px;font:700 11px/1 'Chakra Petch',sans-serif;letter-spacing:.12em;color:#0a0f02;background:var(--c);padding:5px 8px;z-index:1}
/* Hero */
.ar-hero{display:grid;grid-template-columns:minmax(0,1.55fr) minmax(0,1fr);gap:22px;margin:34px auto 10px}
.ar-big{position:relative;background:var(--ar-panel);border:1px solid var(--ar-line)}
.ar-big .ar-cover{aspect-ratio:16/8}
.ar-big .in{padding:26px 28px 30px}
.ar-big h2{font-size:clamp(26px,3.2vw,38px);margin:14px 0 12px}
.ar-big h2 a:hover,.ar-mini h3 a:hover,.ar-card h3 a:hover,.ar-row h3 a:hover{color:var(--c,var(--ar-pr))}
.ar-big p{color:#b4bdd3;margin:0 0 18px}
.ar-stack{display:grid;gap:22px;grid-template-rows:repeat(3,1fr)}
.ar-mini{display:grid;grid-template-columns:140px minmax(0,1fr);gap:16px;align-items:center;background:var(--ar-panel);border:1px solid var(--ar-line);padding:12px}
.ar-mini .ar-cover{aspect-ratio:4/3}.ar-mini h3{font-size:17px;margin:8px 0 6px;line-height:1.3}
.ar-meta{font-size:12.5px;color:var(--ar-mt);display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.ar-meta .xp{font:700 11px/1 'Chakra Petch',sans-serif;letter-spacing:.1em;color:var(--ar-cy);border:1px solid rgba(61,224,255,.35);padding:4px 7px}
.ar-btn{display:inline-flex;align-items:center;gap:10px;font:700 13px/1 'Chakra Petch',sans-serif;letter-spacing:.12em;text-transform:uppercase;padding:13px 22px;background:var(--ar-pr);color:#0a0f02;transition:.2s}
.ar-btn:hover{box-shadow:0 0 0 2px var(--ar-bg),0 0 0 3px var(--ar-pr),0 0 24px rgba(212,255,92,.45)}
/* Section */
.ar-sec{display:flex;align-items:center;justify-content:space-between;gap:16px;margin:56px 0 22px}
.ar-sec h2{font-size:26px;text-transform:uppercase;letter-spacing:.04em;display:flex;align-items:center;gap:12px}
.ar-sec h2:before{content:"";width:6px;height:26px;background:var(--c,var(--ar-pr));box-shadow:0 0 14px var(--c,var(--ar-pr))}
.ar-sec a{font:600 13px/1 'Chakra Petch',sans-serif;letter-spacing:.1em;text-transform:uppercase;color:var(--c,var(--ar-pr))}
.ar-sec:after{content:"";flex:1;height:1px;background:linear-gradient(90deg,var(--ar-line),transparent);order:1}
.ar-sec a{order:2}
.ar-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:22px}
.ar-card{background:var(--ar-panel);border:1px solid var(--ar-line);transition:transform .25s,border-color .25s,box-shadow .25s}
.ar-card:hover{transform:translateY(-4px);border-color:color-mix(in srgb,var(--c) 55%,transparent);box-shadow:0 14px 40px -18px var(--c)}
.ar-card .in{padding:16px 18px 20px}.ar-card h3{font-size:19px;margin:10px 0 8px;line-height:1.3}
.ar-card p{color:var(--ar-mt);font-size:14.5px;line-height:1.6;margin:0 0 12px;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden}
/* Thân trang + sidebar */
.ar-main{display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:40px;margin:0 auto 70px}
.ar-row{display:grid;grid-template-columns:230px minmax(0,1fr);gap:20px;padding:18px;background:var(--ar-panel);border:1px solid var(--ar-line);margin-bottom:16px}
.ar-row h3{font-size:21px;margin:10px 0 8px}.ar-row p{color:var(--ar-mt);font-size:15px;margin:0 0 10px}
.ar-side{display:flex;flex-direction:column;gap:22px}
.ar-box{background:var(--ar-panel);border:1px solid var(--ar-line);padding:22px}
.ar-box h3{font-size:16px;text-transform:uppercase;letter-spacing:.12em;margin:0 0 16px;color:var(--ar-pr)}
.ar-lb{list-style:none;margin:0;padding:0;counter-reset:r}
.ar-lb li{counter-increment:r;display:grid;grid-template-columns:38px 1fr;gap:10px;padding:11px 0;border-top:1px dashed var(--ar-line);font-size:14.5px;line-height:1.45}
.ar-lb li:first-child{border-top:0}
.ar-lb li:before{content:counter(r,decimal-leading-zero);font:700 18px/1.2 'Chakra Petch',sans-serif;color:var(--ar-mt)}
.ar-lb li:nth-child(1):before{color:#ffd23d;text-shadow:0 0 12px rgba(255,210,61,.6)}.ar-lb li:nth-child(2):before{color:#d7e0f0}.ar-lb li:nth-child(3):before{color:#ff9a5c}
.ar-lb a:hover{color:var(--ar-pr)}
.ar-cats{display:grid;gap:8px}
.ar-cats a{display:flex;justify-content:space-between;align-items:center;padding:12px 14px;background:var(--ar-bg2);border-left:3px solid var(--c);font:600 14px/1 'Chakra Petch',sans-serif;letter-spacing:.04em;text-transform:uppercase;transition:.2s}
.ar-cats a:hover{background:color-mix(in srgb,var(--c) 14%,var(--ar-bg2))}
.ar-cats span{color:var(--ar-mt);font:500 12px/1 'Be Vietnam Pro',sans-serif;text-transform:none}
.ar-gg{background:linear-gradient(135deg,rgba(212,255,92,.14),rgba(61,224,255,.08));border:1px solid rgba(212,255,92,.35);padding:22px;text-align:center}
.ar-gg b{display:block;font:700 30px/1 'Chakra Petch',sans-serif;color:var(--ar-pr);letter-spacing:.12em;text-shadow:0 0 18px rgba(212,255,92,.5)}
.ar-gg p{margin:10px 0 0;color:#c3cbe0;font-size:14.5px}
/* Trang chuyên mục */
.ar-band{position:relative;overflow:hidden;border-bottom:1px solid var(--ar-line);background:linear-gradient(120deg,color-mix(in srgb,var(--c) 18%,transparent),transparent 55%)}
.ar-band .wrap{padding-top:52px;padding-bottom:46px}
.ar-band h1{font-size:clamp(32px,5vw,52px);text-transform:uppercase;letter-spacing:.02em;margin:14px 0 10px}
.ar-band h1 em{font-style:normal;color:var(--c)}
.ar-band p{color:#b4bdd3;max-width:640px;margin:0}
.ar-crumb{font:600 12px/1 'Chakra Petch',sans-serif;letter-spacing:.14em;text-transform:uppercase;color:var(--ar-mt)}.ar-crumb a:hover{color:var(--ar-pr)}
.ar-pg{display:flex;gap:8px;margin:28px 0 0}.ar-pg a,.ar-pg span{min-width:42px;height:42px;display:grid;place-items:center;border:1px solid var(--ar-line);background:var(--ar-panel);font:700 14px/1 'Chakra Petch',sans-serif}.ar-pg span{background:var(--ar-pr);color:#0a0f02;border-color:var(--ar-pr)}
/* Bài viết */
.ar-prog{position:fixed;left:0;top:0;height:3px;width:0;background:linear-gradient(90deg,var(--ar-pr),var(--ar-cy));box-shadow:0 0 12px var(--ar-pr);z-index:30}
.ar-ahd{border-bottom:1px solid var(--ar-line);background:linear-gradient(180deg,color-mix(in srgb,var(--c) 10%,transparent),transparent)}
.ar-ahd .wrap{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);gap:40px;align-items:center;padding-top:40px;padding-bottom:44px}
.ar-ahd h1{font-size:clamp(30px,4vw,46px);margin:16px 0 16px}
.ar-dek{font-size:18px;color:#b4bdd3;margin:0 0 20px}
.ar-ahd .ar-cover{border:1px solid var(--ar-line)}
.ar-post{display:grid;grid-template-columns:250px minmax(0,740px);gap:56px;justify-content:center;margin:44px auto 70px}
.ar-toc{position:sticky;top:96px;align-self:start;background:var(--ar-panel);border:1px solid var(--ar-line);padding:18px 18px 14px}
.ar-toc b{display:block;font:700 12px/1 'Chakra Petch',sans-serif;letter-spacing:.14em;text-transform:uppercase;color:var(--ar-pr);margin-bottom:12px}
.ar-toc ol{list-style:none;margin:0;padding:0;counter-reset:q}
.ar-toc li{counter-increment:q;display:grid;grid-template-columns:28px 1fr;font-size:13.5px;line-height:1.45;padding:7px 0;border-top:1px dashed var(--ar-line)}
.ar-toc li:before{content:counter(q,decimal-leading-zero);font:700 12.5px/1.6 'Chakra Petch',sans-serif;color:var(--ar-mt)}
.ar-toc a{color:#c3cbe0}.ar-toc a:hover{color:var(--ar-pr)}
.ar-body{font-size:17.5px;line-height:1.85;color:#d5dbea}
.ar-body p{margin:0 0 1.2em}
.ar-body a{color:var(--ar-cy);border-bottom:1px solid rgba(61,224,255,.35)}.ar-body a:hover{color:var(--ar-pr);border-color:var(--ar-pr)}
.ar-body h2{font-size:28px;margin:1.9em 0 .7em;padding-left:16px;border-left:4px solid var(--c,var(--ar-pr));color:#fff}
.ar-body h3{font-size:21px;margin:1.5em 0 .5em;color:#fff}
.ar-body strong{color:#fff}
.ar-body ul,.ar-body ol{padding-left:1.3em;margin:0 0 1.2em}.ar-body li{margin:.35em 0}.ar-body li::marker{color:var(--ar-pr)}
.ar-body blockquote{margin:1.6em 0;padding:16px 20px;background:var(--ar-panel);border-left:3px solid var(--ar-mg);color:#e3d6f0}
.ar-body table{border-collapse:collapse;width:100%;margin:1.5em 0;font-size:15px;display:block;overflow-x:auto;background:var(--ar-panel)}
.ar-body th,.ar-body td{border:1px solid var(--ar-line);padding:11px 13px;text-align:left;vertical-align:top}
.ar-body th{font:700 12.5px/1.3 'Chakra Petch',sans-serif;letter-spacing:.1em;text-transform:uppercase;color:var(--ar-pr);background:var(--ar-bg2)}
.ar-faq{margin-top:2.6em}.ar-faq details{background:var(--ar-panel);border:1px solid var(--ar-line);margin-bottom:10px;padding:16px 18px}
.ar-faq summary{cursor:pointer;list-style:none;font:700 17px/1.4 'Chakra Petch',sans-serif;display:flex;justify-content:space-between;gap:14px;color:#fff}
.ar-faq summary::-webkit-details-marker{display:none}.ar-faq summary:after{content:"+";color:var(--ar-pr);font-size:22px;line-height:1}
.ar-faq details[open]{border-color:rgba(212,255,92,.4)}.ar-faq details[open] summary:after{content:"–"}
.ar-faq details p{margin:12px 0 0;color:#b4bdd3;font-size:16px}
.ar-gg-end{margin-top:40px;display:flex;align-items:center;gap:16px;padding:20px;background:var(--ar-panel);border:1px solid var(--ar-line)}
.ar-gg-end img{width:46px;height:46px}.ar-gg-end b{display:block;font:700 16px/1.3 'Chakra Petch',sans-serif;color:#fff}.ar-gg-end span{color:var(--ar-mt);font-size:14px}
.ar-rel{border-top:1px solid var(--ar-line);padding:10px 0 70px;background:var(--ar-bg2)}
/* Trang tĩnh, 404, footer */
.ar-page{max-width:780px;margin:56px auto 80px;padding:0 24px}.ar-page h1{font-size:42px;margin:14px 0 24px;text-transform:uppercase}
.notfound{text-align:center;padding:110px 24px}.notfound h1{font-size:64px;color:var(--ar-pr);text-shadow:0 0 30px rgba(212,255,92,.5);margin-bottom:10px}.notfound .btn{display:inline-block;margin-top:16px;padding:13px 22px;background:var(--ar-pr);color:#0a0f02;font:700 13px/1 'Chakra Petch',sans-serif;letter-spacing:.12em;text-transform:uppercase}
.ar-ft{border-top:1px solid var(--ar-line);background:#05070d;padding:56px 0 26px;color:var(--ar-mt);font-size:14.5px}
.ar-ft .cols{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:40px;padding-bottom:36px;border-bottom:1px solid var(--ar-line)}
.ar-ft h4{font:700 13px/1 'Chakra Petch',sans-serif;letter-spacing:.14em;text-transform:uppercase;color:#fff;margin:0 0 16px}
.ar-ft ul{list-style:none;margin:0;padding:0}.ar-ft li{margin:0 0 10px}.ar-ft a:hover{color:var(--ar-pr)}
.ar-ft .about p{margin:14px 0 0;max-width:380px;line-height:1.7}
.ar-ft .bot{display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;padding-top:20px;font:600 12px/1 'Chakra Petch',sans-serif;letter-spacing:.1em;text-transform:uppercase}
.ar-ft .bot i{font-style:normal;color:var(--ar-pr)}
@media (max-width:1020px){.ar-hero{grid-template-columns:1fr}.ar-stack{grid-template-rows:none}.ar-main{grid-template-columns:minmax(0,1fr)}.ar-post{grid-template-columns:minmax(0,1fr);gap:24px}.ar-toc{position:static}.ar-ahd .wrap{grid-template-columns:1fr;gap:26px}.ar-ahd .ar-cover{order:-1}.ar-ft .cols{grid-template-columns:1fr 1fr}.ar-ft .about{grid-column:1/-1}}
@media (max-width:640px){body{font-size:16px}.wrap{padding:0 16px}.ar-tick span:nth-child(n+3){display:none}.ar-hd .row{min-height:64px}.ar-search{display:none}.ar-brand b{font-size:20px}.ar-brand img{width:38px;height:38px}.ar-nav a{padding:9px 10px;font-size:12.5px}
.ar-hd{position:static}.ar-big .in{padding:18px}.ar-mini{grid-template-columns:110px minmax(0,1fr)}.ar-row{grid-template-columns:1fr;padding:14px}.ar-sec h2{font-size:21px}.ar-body{font-size:16.5px}.ar-body h2{font-size:23px}.ar-ft .cols{grid-template-columns:1fr}}