/* Trang chi tiết tài liệu — bố cục theo mẫu linhlinh17745, token DESIGN.md */

/* HERO: bìa tài liệu + thông tin */
.b4t-phero{display:grid;grid-template-columns:minmax(340px,.84fr) 1.16fr;gap:48px;align-items:center;margin-top:var(--b4t-space-md);padding:34px;background:var(--b4t-color-paper);border:1px solid var(--b4t-color-line);border-radius:var(--b4t-radius-xl);box-shadow:var(--b4t-shadow-rest)}
.b4t-docstage{min-height:460px;display:grid;place-items:center;background:linear-gradient(145deg,#dcecf8,#f2f7fb 65%);border-radius:20px;padding:26px}
.b4t-docsheet{width:74%;aspect-ratio:1/1.32;background:var(--b4t-color-paper);padding:38px 26px;box-shadow:0 18px 40px rgba(20,48,74,.16);transform:rotate(-1.3deg);border-top:4px solid var(--b4t-color-primary);display:flex;flex-direction:column;gap:10px;text-align:center;overflow:hidden}
.b4t-docsheet--img{padding:0;transform:rotate(-1.3deg)}
.b4t-docsheet--img img{width:100%;height:100%;object-fit:cover;object-position:top}
.b4t-docsheet__kicker{font:800 10px/1.2 var(--b4t-font-sans);letter-spacing:.18em;color:var(--b4t-color-primary)}
.b4t-docsheet__title{font:700 15px/1.35 var(--b4t-font-serif);color:var(--b4t-color-ink)}
.b4t-docsheet__sub{font-size:11px;color:var(--b4t-color-muted)}

.b4t-phero__title{font-size:clamp(23px,2.5vw,31px);line-height:1.22;margin:6px 0 0}
.b4t-fcode{display:inline-flex;align-items:center;gap:6px;margin:14px 0 2px;padding:7px 14px;border-radius:var(--b4t-radius-full);background:linear-gradient(105deg,var(--b4t-color-ink),#1f5d8c);color:#fff;font-size:12px}
.b4t-fcode b{font-weight:700}
.b4t-facts{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;margin:18px 0}
.b4t-facts div{border:1px solid var(--b4t-color-line);border-radius:var(--b4t-radius-sm);padding:10px 12px;background:#fbfcfd}
.b4t-facts span{display:block;color:#83919e;font-size:10.5px}
.b4t-facts strong{display:block;color:var(--b4t-color-ink);font-size:12.5px;margin-top:2px;font-weight:600}
.b4t-phero__price{font:800 26px/1.1 var(--b4t-font-sans);color:var(--b4t-color-ink);margin:4px 0 14px}
.b4t-phero__price .woocommerce-Price-currencySymbol{font-weight:600}
.b4t-phero__actions{display:grid;grid-template-columns:1.2fr .8fr;gap:10px}

/* LAYOUT thân: nội dung + thẻ mua */
.b4t-player{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:24px;align-items:start;margin-top:26px}
.b4t-player__main{min-width:0}
.b4t-panel{background:var(--b4t-color-paper);border:1px solid var(--b4t-color-line);border-radius:var(--b4t-radius-xl);padding:30px 34px;scroll-margin-top:90px}
.b4t-single-desc h2{font-size:22px;margin:0 0 var(--b4t-space-md)}
/* Mô tả sản phẩm: chữ đen (team 2026-10-06); link trong khối giữ màu thương hiệu */
.b4t-single-desc,.b4t-single-desc h2,.b4t-single-desc p,.b4t-single-desc li{color:#000}
.b4t-fitcheck{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:18px;padding-top:16px;border-top:1px solid #cfe6d7;color:#23714d;font-size:13px}
.b4t-fitcheck a{color:var(--b4t-color-primary);font-weight:600}

/* Xem thử Drive */
.b4t-preview{margin-top:24px;background:#fff8f3;border:1px solid #f1d6c4;border-radius:var(--b4t-radius-xl);padding:26px;scroll-margin-top:90px}
.b4t-preview__head h2{font-size:20px;margin:0 0 4px}
.b4t-preview__head p{margin:0;color:var(--b4t-color-muted);font-size:13px}
.b4t-driveframe{margin-top:18px;border-radius:var(--b4t-radius-md);overflow:hidden;background:#304a62;box-shadow:0 12px 30px rgba(20,48,74,.14)}
.b4t-driveframe__bar{height:44px;background:#20384e;color:#fff;display:flex;align-items:center;justify-content:space-between;padding:0 16px;font-size:11px}
.b4t-driveframe iframe{display:block;width:100%;height:680px;border:0;background:#304a62}
.b4t-preview__cta{display:flex;width:max-content;min-width:200px;margin:18px auto 0}

/* Thẻ mua (dark, dính) */
.b4t-buycard{position:sticky;top:88px;background:var(--b4t-color-ink);color:#fff;border-radius:var(--b4t-radius-xl);padding:24px;box-shadow:var(--b4t-shadow-pop);display:flex;flex-direction:column;gap:12px}
.b4t-buycard__head strong{display:block;font-size:16px}
.b4t-buycard__head span{display:block;margin-top:2px;font-size:12px;color:#b9c6d3}
.b4t-buycard__price{font:800 26px/1.1 var(--b4t-font-sans);color:#fff}
.b4t-buycard__price .woocommerce-Price-amount,.b4t-buycard__price .woocommerce-Price-currencySymbol{color:#fff}
.b4t-buycard .b4t-btn{width:100%}
.b4t-btn--ghost{background:transparent;border:1px solid rgba(255,255,255,.35);color:#fff}
.b4t-btn--ghost:hover{background:rgba(255,255,255,.1)}
.b4t-buycard__specs{margin:6px 0 0;display:flex;flex-direction:column;gap:1px;background:rgba(255,255,255,.08);border-radius:var(--b4t-radius-sm);overflow:hidden}
.b4t-buycard__specs div{display:flex;justify-content:space-between;gap:12px;padding:9px 12px}
.b4t-buycard__specs dt{margin:0;color:#b9c6d3;font-size:12px}
.b4t-buycard__specs dd{margin:0;color:#fff;font-size:12px;font-weight:600;text-align:right}
.b4t-buycard__zalo{display:flex;flex-direction:column;gap:2px;padding:12px 14px;border-radius:var(--b4t-radius-sm);background:var(--b4t-color-accent);color:var(--b4t-color-on-accent);text-decoration:none}
.b4t-buycard__zalo span{font-weight:700;font-size:14px}
.b4t-buycard__zalo b{font-size:12px;font-weight:600}
.b4t-single-trust{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:7px;font-size:12.5px;color:#b9c6d3}
.b4t-single-trust li{display:flex;gap:8px}
.b4t-single-trust li::before{content:"✓";color:var(--b4t-color-accent);font-weight:700;flex:none}

/* Có thể bạn quan tâm — slider; thẻ = .b4t-card y hệt trang danh mục (card.css) */
.b4t-related{margin-top:52px}
.b4t-related__head{display:flex;justify-content:space-between;align-items:center;gap:var(--b4t-space-md);border-bottom:1px solid var(--b4t-color-line);padding-bottom:12px;margin-bottom:18px}
.b4t-related__head h2{font-size:22px;margin:0}
.b4t-related__nav{display:flex;gap:8px}
.b4t-related__btn{display:grid;place-items:center;width:var(--b4t-touch-min);height:var(--b4t-touch-min);border:1px solid var(--b4t-color-line);border-radius:var(--b4t-radius-full);background:var(--b4t-color-paper);color:var(--b4t-color-primary);font-size:20px;line-height:1;cursor:pointer;transition:background-color .18s ease-out,color .18s ease-out}
.b4t-related__btn:hover:not(:disabled){background:var(--b4t-color-primary);border-color:var(--b4t-color-primary);color:#fff}
.b4t-related__btn:focus-visible{outline:3px solid var(--b4t-color-focus);outline-offset:2px}
.b4t-related__btn:disabled{opacity:.35;cursor:default}
.b4t-related__track{display:grid;grid-auto-flow:column;grid-auto-columns:calc((100% - 3*var(--b4t-space-md))/4);gap:var(--b4t-space-md);overflow-x:auto;scroll-snap-type:x mandatory;-webkit-overflow-scrolling:touch;scrollbar-width:none;padding-bottom:4px}
.b4t-related__track::-webkit-scrollbar{display:none}
.b4t-related__track:focus-visible{outline:3px solid var(--b4t-color-focus);outline-offset:-3px}
.b4t-related__track>.b4t-card{scroll-snap-align:start;min-width:0}
@media(max-width:1024px){.b4t-related__track{grid-auto-columns:calc((100% - 2*var(--b4t-space-md))/3)}}
@media(max-width:640px){
	.b4t-related__nav{display:none}
	.b4t-related__track{grid-auto-columns:82%}
}
@media(prefers-reduced-motion:reduce){.b4t-related__btn{transition:none}}

/* Responsive */
@media(max-width:1000px){
	.b4t-phero{grid-template-columns:1fr;gap:26px}
	.b4t-docstage{min-height:340px}
	.b4t-docsheet{width:56%}
	.b4t-player{grid-template-columns:1fr}
	.b4t-buycard{position:static}
}
@media(max-width:600px){
	.b4t-phero,.b4t-panel,.b4t-preview{padding:20px}
	/* Ảnh bìa lấp đầy khung (team 2026-10-01) */
	.b4t-docstage{min-height:0;padding:0;overflow:hidden}
	.b4t-docsheet--img{width:100%;transform:none;border-top:0;box-shadow:none}
	.b4t-facts{grid-template-columns:repeat(2,1fr)}
	.b4t-phero__actions{grid-template-columns:1fr}
	.b4t-driveframe iframe{height:520px}
}

/* Popup "Tải tài liệu" (yc17) */
.b4t-modal[hidden]{display:none}
.b4t-modal{position:fixed;inset:0;z-index:100;display:flex;align-items:center;justify-content:center;padding:20px}
.b4t-modal__backdrop{position:absolute;inset:0;background:rgba(20,48,74,.55)}
.b4t-modal__box{position:relative;z-index:1;width:min(560px,100%);background:var(--b4t-color-paper);border-radius:var(--b4t-radius-xl);box-shadow:var(--b4t-shadow-pop);padding:28px 30px;text-align:center}
.b4t-modal__x{position:absolute;top:10px;right:14px;background:none;border:0;font-size:26px;line-height:1;color:var(--b4t-color-muted);cursor:pointer}
.b4t-modal__x:hover{color:var(--b4t-color-ink)}
.b4t-modal__title{font-size:22px;color:var(--b4t-color-primary-strong);margin:0 0 var(--b4t-space-md);padding-bottom:var(--b4t-space-md);border-bottom:1px solid var(--b4t-color-line)}
.b4t-modal__box p{margin:0 0 var(--b4t-space-md);color:var(--b4t-color-ink);line-height:1.6}
.b4t-modal__box p b{color:var(--b4t-color-primary)}
.b4t-modal__cta{display:inline-flex;margin-top:4px}
@media(max-width:600px){.b4t-modal__box{padding:24px 18px}.b4t-modal__title{font-size:19px}}