/* APTA EDU – màu theo logo: đỏ #E8202A, đen #16181D, nền trắng ấm; vàng chỉ làm điểm nhấn nhỏ */
:root{--red:#E8202A;--red-d:#C21118;--ink:#16181D;--muted:#5A5F6B;--line:#ECE6E3;--bg:#FFFFFF;--soft:#FFF5F3;--sand:#FAF7F2;--gold:#FFC93C;
  --f-h:"Nunito","Be Vietnam Pro",system-ui,sans-serif;--f-b:"Be Vietnam Pro",system-ui,sans-serif;--r:18px;--sh:0 10px 30px rgba(22,24,29,.08)}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:90px}
body{margin:0;font:16px/1.65 var(--f-b);color:var(--ink);background:var(--bg)}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
h1,h2,h3{font-family:var(--f-h);font-weight:900;line-height:1.18;margin:0 0 .5em;text-wrap:balance}
h1{font-size:clamp(30px,5vw,50px)} h2{font-size:clamp(25px,3.4vw,36px)} h3{font-size:20px}
p{margin:0 0 1em}
.wrap{max-width:1180px;margin:0 auto;padding:0 16px}
.small{font-size:14px}
.muted{color:var(--muted)}
.eyebrow{display:inline-block;font-weight:800;font-size:13px;letter-spacing:.12em;text-transform:uppercase;color:var(--red);margin-bottom:10px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 22px;border-radius:999px;font-weight:700;text-decoration:none;border:2px solid transparent;cursor:pointer;font-size:16px;white-space:nowrap;transition:.15s}
.btn-red{background:var(--red);color:#fff;box-shadow:0 6px 16px rgba(232,32,42,.28)}
.btn-red:hover{background:var(--red-d)}
.btn-ghost{border-color:var(--ink);color:var(--ink);background:#fff}
.btn-ghost:hover{background:var(--ink);color:#fff}
.btns{display:flex;gap:12px;flex-wrap:wrap}

/* Đầu trang */
header.site{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.96);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.hrow{display:flex;align-items:center;gap:18px;min-height:74px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;flex:none}
.brand img{width:54px;height:auto}
.brand span{text-align:center}
.brand b{font:900 22px var(--f-h);letter-spacing:.03em;display:block;line-height:1}
.brand b em{font-style:normal;color:var(--red)}
.brand small{display:block;font-size:12px;color:var(--muted);margin-top:3px}
nav.main{display:flex;gap:4px;margin-left:auto}
nav.main a{text-decoration:none;font-weight:600;padding:8px 12px;border-radius:10px}
nav.main a:hover{background:var(--soft)}
nav.main a.on{color:var(--red);background:var(--soft)}
.hact{display:flex;align-items:center;gap:10px}
.hotline{text-decoration:none;line-height:1.1;text-align:right}
.hotline small{display:block;font-size:11px;color:var(--muted)} .hotline b{color:var(--red);font-size:16px}
.hcta{padding:10px 16px;font-size:15px}
.login{font-size:13px;color:var(--muted);text-decoration:none;border:1px solid var(--line);padding:6px 10px;border-radius:999px}
.login:hover{color:var(--ink);border-color:var(--ink)}
.burger{display:none;border:0;background:var(--soft);font-size:22px;width:44px;height:44px;border-radius:12px;cursor:pointer}
nav.main a,.hotline b,.brand b,.login{white-space:nowrap}
@media (max-width:1700px){.hotline{display:none}}
nav.main a.m-only{display:none} /* Liên hệ trùng nút Đăng ký học thử → chỉ hiện trong menu điện thoại */
@media (max-width:1400px){.login{display:none}}
@media (max-width:1100px){nav.main a{padding:8px 9px}}
@media (max-width:1140px){.brand small{display:none}}
/* Menu xổ xuống Tài liệu: Lớp → Môn */
.dd{position:relative;display:flex}
.dd-mui{font-size:11px;margin-left:2px}
.dd-menu,.dd-menu2{display:none;position:absolute;background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:var(--sh);padding:6px;min-width:190px;z-index:30}
.dd-menu{top:100%;right:0;margin-top:4px} .dd-menu::before{content:"";position:absolute;left:0;right:0;top:-10px;height:10px}
.dd-menu2{top:-7px;right:100%;margin-right:4px} .dd-menu2::before{content:"";position:absolute;top:0;bottom:0;right:-10px;width:10px} /* mở sang trái vì Tài liệu nằm sát mép phải */
.dd:hover>.dd-menu,.dd:focus-within>.dd-menu,.dd-sub:hover>.dd-menu2,.dd-sub:focus-within>.dd-menu2{display:block}
nav.main .dd-menu a{display:block;padding:9px 14px;border-radius:9px;font-weight:600}
.dd-sub{position:relative} .dd-sub>a::before{content:"‹";float:left;margin-right:12px;color:var(--muted)}
nav.main .dd-menu a:hover{background:var(--soft);color:var(--red)}
@media (max-width:1000px){
  nav.main{display:none;position:absolute;left:0;right:0;top:100%;background:#fff;flex-direction:column;padding:10px 16px 16px;border-bottom:1px solid var(--line);box-shadow:var(--sh)}
  nav.main.open{display:flex} nav.main a{padding:12px}
  .burger{display:block} .hcta,.login{display:none} .hact{margin-left:auto} nav.main a.m-only{display:block}
  .dd{display:block} .dd-mui{display:none} .dd-menu{display:block!important;position:static;border:0;box-shadow:none;padding:0 0 6px 12px;margin:0;min-width:0}
  .dd-menu::before,.dd-menu2::before,.dd-sub>a::before{display:none!important}
  .dd-sub{display:flex;flex-wrap:wrap;align-items:center;gap:6px;padding:4px 0} .dd-sub>a{width:60px;padding:6px 0!important;font-weight:800!important}
  .dd-menu2{display:flex!important;flex-wrap:wrap;gap:6px;position:static;border:0;box-shadow:none;padding:0;margin:0;min-width:0}
  nav.main .dd-menu2 a{padding:6px 10px;background:var(--soft);font-size:13px}
}

/* Khối trang */
section{padding:64px 0}
section.alt{background:var(--sand)}
.hero{padding:44px 0 56px;background:linear-gradient(180deg,var(--soft),#fff)}
.hero .grid{display:grid;grid-template-columns:1.05fr 1fr;gap:40px;align-items:center}
.hero h1 em{font-style:normal;color:var(--red)}
.hero h1{font-size:clamp(22px,3.2vw,36px);text-align:center} .hero h1 span,.hero h1 em{display:block;white-space:nowrap} /* mỗi nửa khẩu hiệu một dòng */
.hero .chips{justify-content:center}
.hero .lead{font-size:18px;color:var(--muted);max-width:560px}
.hero .ph{border-radius:24px;overflow:hidden;box-shadow:var(--sh);aspect-ratio:4/3}
.hero .ph img{width:100%;height:100%;object-fit:cover}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0 24px}
.chip{background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 14px;font-weight:600;font-size:14px}
@media (max-width:860px){.hero .grid{grid-template-columns:1fr}.hero .ph{order:-1}}
.sec-head{max-width:720px;margin-bottom:28px}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:18px}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--r);overflow:hidden;box-shadow:var(--sh);display:flex;flex-direction:column}
.card img{aspect-ratio:3/2;object-fit:cover;width:100%}
.card .in{padding:18px 20px 20px;display:flex;flex-direction:column;gap:6px;flex:1}
.card .in p{color:var(--muted);font-size:15px;margin:0}
.card .more{margin-top:auto;padding-top:8px;font-weight:700;color:var(--red);text-decoration:none}
a.card{text-decoration:none}
a.card:hover{transform:translateY(-2px);transition:.15s}
.feat{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:16px}
.feat div{background:#fff;border-radius:var(--r);padding:20px;border:1px solid var(--line)}
.feat b{display:block;font:800 18px var(--f-h);margin:6px 0 4px}
.feat .ic{font-size:28px}
.feat p{color:var(--muted);font-size:15px;margin:0}
.split{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.split .ph{border-radius:var(--r);overflow:hidden;box-shadow:var(--sh)}
@media (max-width:860px){.split{grid-template-columns:1fr}}
ul.tick{list-style:none;padding:0;margin:0 0 1em}
ul.tick li{padding-left:30px;position:relative;margin:8px 0}
ul.tick li:before{content:"✓";position:absolute;left:0;top:0;width:22px;height:22px;border-radius:50%;background:var(--red);color:#fff;font-size:13px;font-weight:800;display:grid;place-items:center;margin-top:2px}
.shifts{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:16px 0}
.shifts div{background:#fff;border:1px solid var(--line);border-radius:14px;padding:14px;text-align:center}
.shifts b{display:block;font:900 24px var(--f-h);color:var(--red)}
.shifts small{color:var(--muted)}
@media (max-width:520px){.shifts{grid-template-columns:1fr}}
.steps{counter-reset:s;display:grid;gap:14px}
.steps li{list-style:none;background:#fff;border:1px solid var(--line);border-radius:14px;padding:14px 16px 14px 62px;position:relative}
.steps li:before{counter-increment:s;content:counter(s);position:absolute;left:16px;top:14px;width:32px;height:32px;border-radius:50%;background:var(--ink);color:#fff;font-weight:800;display:grid;place-items:center}
.steps{padding:0;margin:0}
.gallery{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:12px}
.gallery figure{margin:0;border-radius:14px;overflow:hidden;background:#eee}
.gallery img{aspect-ratio:4/3;object-fit:cover;width:100%}
.gallery figcaption{font-size:14px;padding:8px 10px;background:#fff;color:var(--muted)}
.cta-band{background:var(--ink);color:#fff;border-radius:24px;padding:36px;display:flex;gap:24px;align-items:center;justify-content:space-between;flex-wrap:wrap}
.cta-band h2{color:#fff;margin:0 0 6px}
.cta-band p{color:#cfd2d8;margin:0}
.crumb{font-size:14px;color:var(--muted);margin-bottom:10px}
.crumb a{text-decoration:none}
.page-head{padding:40px 0 28px;background:linear-gradient(180deg,var(--soft),#fff)}
.page-head .lead{font-size:18px;color:var(--muted);max-width:760px}
.prose{max-width:780px}
.prose h2{font-size:26px;margin-top:1.4em}
.faq details{background:#fff;border:1px solid var(--line);border-radius:14px;padding:14px 18px;margin-bottom:10px}
.faq summary{font-weight:700;cursor:pointer}
.faq details p{margin:10px 0 0;color:var(--muted)}

/* Form đăng ký */
.form-card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:24px;box-shadow:var(--sh)}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px 14px}
.form-grid .full{grid-column:1/-1}
@media (max-width:600px){.form-grid{grid-template-columns:1fr}}
label.f{display:grid;gap:5px;font-size:14px;font-weight:600}
label.f input,label.f select,label.f textarea{font:inherit;font-weight:400;border:1.5px solid var(--line);border-radius:12px;padding:11px 12px;background:#fff;width:100%}
label.f input:focus,label.f select:focus,label.f textarea:focus{outline:none;border-color:var(--red)}
.consent{display:flex;gap:8px;font-size:13px;color:var(--muted);align-items:flex-start}
.form-msg{margin-top:12px;font-weight:600}
.form-msg.ok{color:#0A7A4E} .form-msg.err{color:var(--red-d)}
.map{border:0;width:100%;height:340px;border-radius:var(--r)}

/* Chân trang */
footer.site{background:var(--ink);color:#C9CCD3;padding:48px 0 90px;margin-top:20px;font-size:15px}
footer.site a{text-decoration:none} footer.site a:hover{color:#fff}
.fgrid{display:grid;grid-template-columns:1.3fr 1fr 1fr 1.2fr;gap:28px}
.fbrand img{background:#fff;border-radius:14px;padding:6px;margin-bottom:10px}
.fbrand b{color:#fff}
footer h4{color:#fff;margin:0 0 10px;font-size:16px}
footer ul{list-style:none;padding:0;margin:0} footer li{margin:7px 0}
.legal{border-top:1px solid #2A2D35;margin-top:28px;padding-top:16px;font-size:13px}
@media (max-width:860px){.fgrid{grid-template-columns:1fr 1fr}}
@media (max-width:520px){.fgrid{grid-template-columns:1fr}}
.mbar{display:none}
@media (max-width:720px){
  .mbar{display:grid;grid-template-columns:1fr 1fr 1.4fr;position:fixed;left:0;right:0;bottom:0;z-index:30;background:#fff;border-top:1px solid var(--line);box-shadow:0 -4px 14px rgba(0,0,0,.08);padding-bottom:env(safe-area-inset-bottom,0)}
  .mbar a{text-align:center;padding:13px 4px;font-weight:700;text-decoration:none;font-size:15px}
  .mbar a.go{background:var(--red);color:#fff}
  section{padding:48px 0}
}
/* Thư viện tài liệu: Lớp → Môn → Thời điểm */
.tl-chon{background:var(--sand);border:1px solid var(--line);border-radius:18px;padding:14px 16px;margin:0 0 22px}
.tl-hang{display:flex;gap:12px;align-items:flex-start;padding:6px 0} .tl-hang+.tl-hang{border-top:1px dashed var(--line)}
.tl-hang>b{flex:none;width:84px;padding-top:7px;font-size:14px;color:var(--muted)}
.tl-chon .chips{margin:0;gap:6px} .tl-chon .chip{cursor:pointer;font-family:inherit;color:var(--ink)}
.tl-chon .chip.on{background:var(--red);border-color:var(--red);color:#fff} .tl-chon .chip span{font-size:11px;opacity:.75}
#tl-tieu-de{font-size:22px;margin:0 0 12px}
.tl-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:12px}
.tl-item{display:flex;flex-wrap:wrap;align-items:center;gap:10px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:12px 14px;box-shadow:var(--sh)}
.tl-item[hidden]{display:none}
.tl-ic{flex:none;width:46px;height:46px;border-radius:10px;background:var(--soft);color:var(--red);font-weight:800;font-size:11px;display:flex;align-items:center;justify-content:center}
.tl-tx{flex:1;min-width:0} .tl-tx h4{margin:0 0 2px;font-size:16px} .tl-tx p{margin:0 0 2px;color:var(--muted);font-size:13px} .tl-tx small{color:var(--muted);font-size:12px}
.tl-bt{display:flex;gap:8px;width:100%} .tl-bt .btn{flex:1;padding:7px 12px;font-size:14px}
.tl-empty{background:#fff;border:1px dashed var(--line);border-radius:16px;padding:28px;text-align:center;color:var(--muted)}
.tl-empty[hidden]{display:none}
@media (max-width:640px){.tl-hang{flex-direction:column;gap:4px}.tl-hang>b{padding:0}}
/* Mục lục tài liệu + trang riêng từng môn */
.tl-muc-luc{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px;margin-bottom:30px}
.tl-lop-the{background:var(--sand);border:1px solid var(--line);border-radius:18px;padding:16px;scroll-margin-top:100px}
.tl-lop-the h2{margin:0 0 10px;font-size:22px} .tl-lop-the h2 small{font-size:13px;color:var(--muted);font-weight:600}
.tl-mon-link{display:grid;gap:6px}
.tl-mon-link a{display:flex;justify-content:space-between;align-items:center;background:#fff;border:1px solid var(--line);border-radius:12px;padding:10px 14px;font-weight:700;text-decoration:none;color:var(--ink)}
.tl-mon-link a:hover{border-color:var(--red);color:var(--red)} .tl-mon-link span{font-size:12px;color:var(--muted);font-weight:600}
.tl-moi-h{margin:10px 0 12px}
.tl-chon .chips a.chip{text-decoration:none;color:var(--muted)} .tl-chon .chips a.chip.co{color:var(--ink);border-color:var(--red)}
.tl-chon .chip span{font-size:11px;color:var(--red)}
.tl-dot{padding:0;margin:0 0 22px;scroll-margin-top:100px} .tl-dot h2{font-size:20px;margin:0 0 10px}
.tl-lien-quan{border-top:1px solid var(--line);padding-top:16px;margin-top:10px} .tl-lien-quan h3{font-size:16px;margin:12px 0 6px}
.tl-lien-quan .chips{margin:0} .tl-lien-quan a.chip{text-decoration:none;color:var(--ink)} .tl-lien-quan a.chip:hover{border-color:var(--red);color:var(--red)}
/* Trang Tài liệu: chỉ ảnh giới thiệu; nội dung chọn qua menu */
.tl-gioi-thieu{padding:24px 0 10px}
.tl-anh{display:grid;grid-template-columns:1fr 1.35fr;gap:36px;align-items:center;margin:14px 0 0}
.tl-anh img{display:block;width:100%;aspect-ratio:4/3;object-fit:cover;border-radius:24px;box-shadow:var(--sh);order:2}
.tl-anh figcaption{order:1}
.tl-anh h1{margin:0 0 12px;font-size:clamp(30px,4vw,46px)} .tl-anh p{margin:0;font-size:17px;color:var(--muted)}
.tl-anh .tl-goi-y{margin-top:16px;display:inline-block;background:var(--soft);border-radius:999px;padding:8px 16px;font-size:14px;color:var(--ink)}
.tl-anh .tl-dt{display:none}
@media (max-width:1000px){.tl-anh{grid-template-columns:1fr;gap:18px}.tl-anh img{order:1}.tl-anh figcaption{order:2}.tl-anh .tl-goi-y{display:none}.tl-anh .tl-goi-y.tl-dt{display:inline-block}}
.tl-chon .chips a.chip.on{background:var(--red);border-color:var(--red);color:#fff} .tl-chon .chips a.chip.on span{color:#fff}
.tl-dot[hidden]{display:none}
.sec-head h2 em{font-style:normal;color:var(--red)}