/* CSS dùng chung cho cổng và mọi web con. Màu lấy từ logo chú Rùa:
   xanh mạ (đầu) · xanh trời (mai) · vàng (yếm) · xanh đậm (viền). Web con chỉ đổi biến --mau. */
:root {
  --dam: #1f2d5c;           /* xanh đậm — viền logo: chữ chính, chân trang */
  --ma: #a3d61c;            /* xanh mạ — đầu rùa */
  --ma-nhat: #f2fadc;
  --troi: #1e9bf0;          /* xanh trời — mai rùa */
  --troi-nhat: #e3f3fe;
  --vang: #fcd34d;          /* yếm rùa */
  --mau: var(--troi);       /* màu nhấn; web con ghi đè */
  --nen: #fbfdf7;
  --nen-the: #ffffff;
  --chu: #1f2d5c;
  --chu-phu: #55607f;
  --vien: #e3e8d8;
  --bo-goc: 18px;
  --bong: 0 1px 2px rgb(31 45 92 / .06), 0 8px 24px rgb(31 45 92 / .07);
  --rong: 1160px;
  font-family: 'Be Vietnam Pro', system-ui, -apple-system, 'Segoe UI', Roboto, Arial, sans-serif;
  color: var(--chu);
  background: var(--nen);
  line-height: 1.65;
}

*, *::before, *::after { box-sizing: border-box; }
body { margin: 0; background: var(--nen); -webkit-font-smoothing: antialiased; }
img { max-width: 100%; height: auto; display: block; }
a { color: var(--mau); }
h1, h2, h3 { line-height: 1.22; margin: 0 0 .5em; font-weight: 800; letter-spacing: -.01em; }

.khung { max-width: var(--rong); margin: 0 auto; padding-inline: 16px; }

/* ── Thanh trên ── */
.thanh-tren { background: rgb(255 255 255 / .9); backdrop-filter: blur(8px); border-bottom: 1px solid var(--vien); position: sticky; top: 0; z-index: 10; }
.thanh-tren .khung { display: flex; align-items: center; gap: 28px; min-height: 68px; flex-wrap: wrap; }
.logo { font-weight: 800; font-size: 1.25rem; color: var(--dam); text-decoration: none; display: flex; align-items: center; gap: 10px; }
.logo img { width: 44px; height: auto; }
.logo .chu-tat { width: 40px; height: 40px; border-radius: 12px; overflow: hidden; display: grid; place-items: center; background: var(--mau); color: #fff; font-size: 1.2rem; }
.thanh-tren nav { min-width: 0; } /* cho menu co lại trong hàng flex — thiếu dòng này menu dài làm tràn cả trang (111 báo 12/10) */
.menu { display: flex; gap: 6px; flex-wrap: wrap; list-style: none; margin: 0; padding: 0; }
.menu a { color: var(--chu-phu); text-decoration: none; font-weight: 600; padding: 6px 12px; border-radius: 999px; }
.menu a:hover, .menu a[aria-current='page'] { color: var(--dam); background: var(--ma-nhat); }
.ve-cong { margin-left: auto; display: flex; align-items: center; gap: 6px; font-size: .85rem; font-weight: 600; color: var(--chu-phu); text-decoration: none; padding: 6px 12px 6px 6px; border: 1px solid var(--vien); border-radius: 999px; }
.ve-cong img { width: 26px; }
.ve-cong:hover { border-color: var(--ma); color: var(--dam); }

/* ── Đầu trang chủ ── */
.hero { background: radial-gradient(1200px 400px at 85% 0%, var(--troi-nhat), transparent 60%), linear-gradient(180deg, var(--ma-nhat), var(--nen)); border-bottom: 1px solid var(--vien); }
.hero .khung { display: grid; grid-template-columns: 1.2fr 1fr; gap: 32px; align-items: center; padding-block: 56px; }
.hero h1 { font-size: clamp(2rem, 4.6vw, 3.4rem); }
.hero h1 .nhan { background: linear-gradient(transparent 62%, var(--vang) 62%); }
.hero p { color: var(--chu-phu); font-size: 1.15rem; max-width: 560px; margin: 0 0 24px; }
.hero .linh-vat { justify-self: center; width: min(100%, 420px); filter: drop-shadow(0 18px 30px rgb(31 45 92 / .18)); }
@media (max-width: 760px) {
  .hero .khung { grid-template-columns: 1fr; padding-block: 32px; }
  .hero .linh-vat { width: 220px; grid-row: 1; }
}

.mo-dau { padding-block: 48px 24px; }
.mo-dau h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
.mo-dau p { color: var(--chu-phu); font-size: 1.1rem; max-width: 640px; margin: 0; }

/* ── Nút ── */
.nut { display: inline-flex; align-items: center; gap: 8px; background: var(--ngach-mau, var(--dam)); color: #fff; font-weight: 700; padding: 13px 24px; border-radius: 14px; text-decoration: none; box-shadow: var(--bong); transition: transform .15s, filter .15s; }
.nut:hover { transform: translateY(-1px); filter: brightness(1.1); }
.nut.phu { background: #fff; color: var(--dam); border: 2px solid var(--dam); box-shadow: none; }

/* ── Lưới thẻ ── */
.luoi { display: grid; gap: 18px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.the { background: var(--nen-the); border: 1px solid var(--vien); border-radius: var(--bo-goc); padding: 20px; box-shadow: var(--bong); }
.the h2, .the h3 { font-size: 1.1rem; }
.the p { color: var(--chu-phu); margin: 0; font-size: .95rem; }
a.the { display: block; text-decoration: none; color: inherit; transition: border-color .15s, transform .15s; }
a.the:hover { border-color: var(--ngach-mau, var(--mau)); transform: translateY(-3px); }

.muc { padding-block: 32px 40px; }
.muc > h2, .tieu-de-muc { font-size: 1.55rem; margin-bottom: 18px; display: flex; align-items: center; gap: 10px; }

/* Thẻ bài có ảnh video */
.the-bai { padding: 0; overflow: hidden; display: flex; flex-direction: column; }
.the-bai .anh { aspect-ratio: 16 / 9; background: var(--troi-nhat); overflow: hidden; }
.the-bai .anh img { width: 100%; height: 100%; object-fit: cover; }
.the-bai .than { padding: 16px 18px 20px; }
.the-bai .nhan-ngach { display: inline-block; font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .04em; color: var(--ngach-mau); margin-bottom: 6px; }

/* Thẻ nhóm ở cổng */
.the-nhom { padding: 0; overflow: hidden; }
.the-nhom .dau { background: var(--nhom-mau); color: #fff; padding: 18px 20px; display: flex; align-items: center; gap: 12px; }
.the-nhom .dau .bt { width: 48px; height: 48px; border-radius: 14px; background: rgb(255 255 255 / .22); display: grid; place-items: center; font-size: 1.6rem; flex: none; }
.the-nhom .dau h2 { margin: 0; font-size: 1.3rem; }
.the-nhom .dau p { margin: 0; color: rgb(255 255 255 / .9); font-size: .88rem; }
.ds-ngach { list-style: none; padding: 12px; margin: 0; display: grid; gap: 4px; }
.ds-ngach a { display: flex; align-items: center; gap: 12px; text-decoration: none; color: var(--chu); font-weight: 700; padding: 10px; border-radius: 12px; }
.ds-ngach a:hover { background: var(--ma-nhat); }
.ds-ngach .mo { font-weight: 400; font-size: .85rem; color: var(--chu-phu); display: block; line-height: 1.4; }
.chip-ngach { width: 40px; height: 40px; border-radius: 12px; flex: none; display: grid; place-items: center; background: var(--ngach-mau); color: #fff; font-weight: 800; overflow: hidden; }
.chip-ngach img { width: 100%; height: 100%; object-fit: cover; }
.nhan-thu { font-size: .68rem; font-weight: 700; background: var(--vang); color: #713f12; padding: 1px 7px; border-radius: 6px; margin-left: 4px; }

/* ── Khối nổi bật ngách (trang chủ giai đoạn đầu) ── */
.noi-bat { background: var(--nen-the); border: 1px solid var(--vien); border-radius: 24px; overflow: hidden; box-shadow: var(--bong); }
.noi-bat-dau { display: flex; gap: 28px; align-items: center; flex-wrap: wrap; padding: 32px; background: linear-gradient(135deg, color-mix(in srgb, var(--ngach-mau) 14%, #fff), #fff 70%); }
.noi-bat-dau > div:last-child { flex: 1 1 280px; }
.noi-bat-logo { width: 128px; height: 128px; border-radius: 28px; object-fit: cover; flex: none; box-shadow: var(--bong); }
.noi-bat-logo.chu { display: grid; place-items: center; background: var(--ngach-mau); color: #fff; font-size: 3.6rem; font-weight: 800; }
.noi-bat-nhom { font-size: .8rem; font-weight: 700; color: var(--ngach-mau); text-transform: uppercase; letter-spacing: .06em; }
.noi-bat h2 { font-size: clamp(1.7rem, 3.5vw, 2.4rem); margin: 4px 0 8px; }
.noi-bat-dau p { color: var(--chu-phu); margin: 0 0 18px; font-size: 1.05rem; }
.noi-bat-bai { padding: 0 32px 32px; }
@media (max-width: 560px) { .noi-bat-dau { padding: 22px; } .noi-bat-bai { padding: 0 22px 22px; } }

/* ── Đầu trang web con ── */
.dau-ngach { background: linear-gradient(135deg, var(--mau), color-mix(in srgb, var(--mau) 65%, #000)); color: #fff; }
.dau-ngach .khung { padding-block: 44px; }
.dau-ngach h1 { font-size: clamp(1.9rem, 4vw, 2.8rem); margin-bottom: 8px; }
.dau-ngach p { margin: 0; font-size: 1.1rem; color: rgb(255 255 255 / .9); max-width: 640px; }
.dau-ngach .duong-dan, .dau-ngach .duong-dan a { color: rgb(255 255 255 / .8); padding-top: 0; margin-bottom: 12px; }

/* ── Bài viết ── */
.bai { max-width: 780px; margin: 0 auto; padding: 32px 16px 56px; }
.bai h1 { font-size: clamp(1.7rem, 3.6vw, 2.4rem); }
.bai .thong-tin { color: var(--chu-phu); font-size: .9rem; margin-bottom: 24px; }
.bai .noi-dung { font-size: 1.08rem; }
.bai .noi-dung h2 { margin-top: 1.8em; font-size: 1.45rem; }

.duong-dan { font-size: .85rem; color: var(--chu-phu); padding-top: 20px; }
.duong-dan ol { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: 0; }
.duong-dan li + li::before { content: '›'; margin-right: 6px; }
.duong-dan a { color: var(--chu-phu); text-decoration: none; }
.duong-dan a:hover { color: var(--mau); }

/* Video YouTube nhẹ: chỉ tải iframe khi bấm */
.yt { position: relative; aspect-ratio: 16 / 9; border-radius: var(--bo-goc); overflow: hidden; background: var(--dam); margin-bottom: 24px; box-shadow: var(--bong); }
.yt img, .yt iframe { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; border: 0; }
.yt button { position: absolute; inset: 0; margin: auto; width: 76px; height: 54px; border: 0; border-radius: 14px; background: #e00; cursor: pointer; box-shadow: 0 6px 20px rgb(0 0 0 / .35); }
.yt button::after { content: ''; position: absolute; left: 31px; top: 17px; border-style: solid; border-width: 10px 0 10px 17px; border-color: transparent transparent transparent #fff; }

/* Giới thiệu ngắn trang chủ */
.gioi-thieu-ngan { display: grid; grid-template-columns: 160px 1fr; gap: 28px; align-items: center; background: var(--ma-nhat); border-radius: 24px; padding: 32px; }
.gioi-thieu-ngan img { width: 160px; }
.gioi-thieu-ngan h2 { font-size: 1.5rem; }
.gioi-thieu-ngan p { color: var(--chu-phu); margin: 0 0 10px; }
@media (max-width: 640px) { .gioi-thieu-ngan { grid-template-columns: 1fr; padding: 22px; } .gioi-thieu-ngan img { width: 120px; } }

/* ── Chân trang ── */
.chan-trang { background: var(--dam); color: rgb(255 255 255 / .75); padding: 44px 0 28px; margin-top: 0; border-top: 1px solid rgb(255 255 255 / .08); font-size: .9rem; }
.chan-trang .cot { display: grid; gap: 28px; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); }
.chan-trang .logo-chan { width: 110px; margin-bottom: 10px; }
.chan-trang h3 { font-size: .95rem; color: #fff; }
.chan-trang ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 6px; }
.chan-trang a { color: rgb(255 255 255 / .75); text-decoration: none; }
.chan-trang a:hover { color: var(--ma); }
.chan-trang .ban-quyen { border-top: 1px solid rgb(255 255 255 / .12); margin-top: 28px; padding-top: 18px; font-size: .82rem; }

.trong { color: var(--chu-phu); padding: 24px; text-align: center; border: 1px dashed var(--vien); border-radius: var(--bo-goc); }
.logo .chu-tat img { width: 100%; height: 100%; object-fit: cover; }

/* Điện thoại: thanh trên gọn 2 dòng — logo + nút về cổng, menu vuốt ngang bên dưới */
@media (max-width: 640px) {
  .thanh-tren .khung { gap: 4px 12px; padding-block: 8px; min-height: 0; }
  .thanh-tren nav { order: 3; flex-basis: 100%; min-width: 0; max-width: 100%; }
  .menu { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; margin-inline: -4px; }
  .menu a { white-space: nowrap; padding: 4px 10px; }
}
.luoi-nhom { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* ═══ Trang chủ: 4 phần ═══ */
.nhan-tren { display: inline-block; font-size: .85rem; font-weight: 700; color: var(--dam); background: #fff; border: 1px solid var(--vien); padding: 6px 14px; border-radius: 999px; margin: 0 0 18px; }
.hero { padding-bottom: 72px; border-bottom: 0; }
.phan-tim { margin-top: -64px; position: relative; z-index: 2; padding-bottom: 24px; }

.phan { padding-block: 80px; }
.phan-nhat { background: #fff; border-block: 1px solid var(--vien); }
.phan-dam { background: var(--dam); color: rgb(255 255 255 / .8); }
.nhan-muc { font-size: .8rem; font-weight: 800; text-transform: uppercase; letter-spacing: .14em; color: var(--troi); margin: 0 0 10px; }
.phan-dam .nhan-muc { color: var(--ma); }
.tieu-de-lon { font-size: clamp(1.7rem, 3.6vw, 2.6rem); margin-bottom: 18px; }
.phan-dam .tieu-de-lon, .phan-dam h3, .phan-dam h2 { color: #fff; }
.giua { text-align: center; margin-inline: auto; max-width: 760px; }
.doan { color: var(--chu-phu); font-size: 1.08rem; }
.tieu-de-nho { font-size: 1.25rem; margin: 56px 0 24px; text-align: center; }

/* 2. SEO Rùa là ai */
.la-ai { display: grid; grid-template-columns: 1fr 1.1fr; gap: 56px; align-items: center; }
.la-ai-anh { position: relative; }
.la-ai-anh img { border-radius: 24px; box-shadow: var(--bong); width: 100%; }
.la-ai-nam { position: absolute; left: -12px; bottom: -20px; background: var(--ma); color: var(--dam); border-radius: 18px; padding: 14px 20px; box-shadow: var(--bong); display: grid; }
.la-ai-nam strong { font-size: 2rem; line-height: 1; }
.la-ai-nam span { font-size: .8rem; font-weight: 700; }
.loi-nhan { display: flex; gap: 18px; align-items: flex-start; margin: 28px 0 0; padding: 22px; background: var(--ma-nhat); border-radius: 20px; }
.loi-nhan img { width: 64px; height: 64px; border-radius: 50%; flex: none; }
.loi-nhan blockquote { margin: 0 0 8px; font-style: italic; color: var(--chu); }
.loi-nhan figcaption { font-size: .9rem; color: var(--chu-phu); }
@media (max-width: 860px) { .la-ai { grid-template-columns: 1fr; gap: 40px; } .la-ai-nam { left: 12px; } }

/* 3. Hệ thống */
.luoi-4 { grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); margin-top: 32px; }
.hoat-dong .hd-bt { width: 52px; height: 52px; border-radius: 16px; background: var(--troi-nhat); display: grid; place-items: center; font-size: 1.6rem; margin-bottom: 14px; }
.quy-trinh { list-style: none; padding: 0; margin: 0; display: grid; gap: 24px; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.quy-trinh li { border-top: 3px solid var(--ma); padding-top: 22px; position: relative; }
.quy-trinh .so-buoc { position: absolute; top: -15px; left: 0; background: var(--dam); color: #fff; font-size: .78rem; font-weight: 800; padding: 3px 10px; border-radius: 999px; }
.quy-trinh h4 { margin: 0 0 6px; font-size: 1.05rem; }
.quy-trinh p { margin: 0; color: var(--chu-phu); font-size: .95rem; }

/* 4. Sức mạnh */
.dai-so { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin: 40px 0; }
.dai-so div { background: rgb(255 255 255 / .06); border: 1px solid rgb(255 255 255 / .1); border-radius: 18px; padding: 22px; display: flex; flex-direction: column-reverse; }
.dai-so dd { margin: 0; font-size: clamp(1.8rem, 3.4vw, 2.4rem); font-weight: 800; color: var(--ma); line-height: 1.1; }
.dai-so dt { font-size: .9rem; margin-top: 6px; }
.luoi-studio { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 28px; justify-items: center; }
.luoi-studio figure { margin: 0; text-align: center; max-width: 280px; }
.khung-dt { border: 8px solid #0d1530; border-radius: 28px; overflow: hidden; background: #fff; box-shadow: 0 20px 40px rgb(0 0 0 / .35); }
.luoi-studio figcaption { margin-top: 16px; display: grid; }
.luoi-studio figcaption strong { color: #fff; font-size: 1.5rem; }
.luoi-studio figcaption span { font-size: .9rem; }
.chu-thich { text-align: center; font-size: .85rem; opacity: .7; margin: 24px 0 56px; }
.thu-vien { display: grid; grid-template-columns: repeat(4, 1fr); grid-auto-rows: 200px; gap: 14px; }
.thu-vien figure { margin: 0; position: relative; border-radius: 18px; overflow: hidden; }
.thu-vien figure.lon { grid-column: span 2; grid-row: span 2; }
.thu-vien figure.doc { grid-row: span 2; }
.thu-vien img { width: 100%; height: 100%; object-fit: cover; }
.thu-vien figcaption { position: absolute; inset: auto 0 0 0; padding: 28px 14px 10px; font-size: .82rem; color: #fff; background: linear-gradient(transparent, rgb(0 0 0 / .65)); }
@media (max-width: 760px) { .thu-vien { grid-template-columns: 1fr 1fr; grid-auto-rows: 150px; } }
.tuan-thu { margin-top: 56px; }
.the-toi { background: rgb(255 255 255 / .06); border: 1px solid rgb(255 255 255 / .1); border-radius: 18px; padding: 22px; }
.the-toi span { color: var(--ma); font-weight: 800; font-size: .9rem; }
.the-toi h3 { font-size: 1.05rem; margin: 6px 0; }
.the-toi p { margin: 0; font-size: .92rem; }
.cta-hop-tac { margin-top: 56px; background: linear-gradient(135deg, var(--ma), #c7ea5a); color: var(--dam); border-radius: 24px; padding: 36px; display: flex; gap: 24px; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.phan-dam .cta-hop-tac h2 { color: var(--dam); margin: 0 0 6px; font-size: 1.7rem; }
.cta-hop-tac p { margin: 0; color: var(--dam); }
.cta-nut { display: flex; gap: 12px; flex-wrap: wrap; }
.nut-ma { --ngach-mau: var(--dam); }
.nut-vien { background: transparent; color: var(--dam); border: 2px solid var(--dam); box-shadow: none; }

/* Trang chủ: chân trang liền khối tối, không hở */
.phan-dam + * { margin-top: 0; }

/* ═══════════ CHUẨN CHUNG 1.0 — linh kiện (xem bo-giao-dien-ngach/CHUAN-CHUNG.md) ═══════════ */

/* Nút tìm 🔍 trên thanh trên */
.nut-tim { margin-left: auto; width: 40px; height: 40px; border-radius: 12px; border: 1px solid var(--vien); background: #fff; color: var(--dam); display: grid; place-items: center; cursor: pointer; flex: none; }
.nut-tim:hover { border-color: var(--ma); }
.nut-tim svg { width: 18px; height: 18px; }
.nut-tim + .ve-cong { margin-left: 0; }

/* Lớp tìm kiếm (Pagefind UI) */
.lop-tim { position: fixed; inset: 0; z-index: 50; background: rgb(31 45 92 / .45); display: none; padding: 72px 16px 16px; }
.lop-tim.mo { display: block; }
.hop-tim { max-width: 720px; margin: 0 auto; background: #fff; border-radius: 20px; box-shadow: 0 20px 60px rgb(0 0 0 / .25); padding: 16px; max-height: calc(100vh - 100px); overflow: auto; }
.hop-tim .dau-tim { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 8px; font-size: .85rem; color: var(--chu-phu); }
.hop-tim .dong-tim { border: 0; background: none; font-size: 1.4rem; cursor: pointer; color: var(--chu-phu); width: 44px; height: 44px; }
.hop-tim { --pagefind-ui-primary: var(--mau); --pagefind-ui-text: var(--dam); --pagefind-ui-border: var(--vien); --pagefind-ui-border-radius: 12px; --pagefind-ui-font: 'Be Vietnam Pro', system-ui, sans-serif; }
@media (max-width: 640px) { .lop-tim { padding: 0; } .hop-tim { border-radius: 0; height: 100%; max-height: none; } }

/* Trang bài: 2 cột trên máy tính (bài + mục lục phải chạy theo) */
.bai-khung { max-width: var(--rong); margin: 0 auto; padding: 24px 16px 56px; display: grid; grid-template-columns: minmax(0, 760px) 280px; gap: 48px; justify-content: center; align-items: start; }
.bai-khung > article { min-width: 0; }
.bai-khung .bai { max-width: none; margin: 0; padding: 0; }
.noi-dung h2, .noi-dung h3 { scroll-margin-top: 96px; }
@media (max-width: 1024px) { .bai-khung { grid-template-columns: minmax(0, 1fr); max-width: 808px; gap: 0; } .muc-luc-ben { display: none; } }

/* Mục lục — máy tính: cột phải dính theo, thu/mở được */
.muc-luc-ben { position: sticky; top: 92px; max-height: calc(100vh - 110px); overflow: auto; background: #fff; border: 1px solid var(--vien); border-radius: 18px; padding: 14px 16px; font-size: .9rem; }
.muc-luc-ben .dau-ml { display: flex; justify-content: space-between; align-items: center; font-weight: 800; color: var(--dam); }
.muc-luc-ben .thu-ml { border: 1px solid var(--vien); background: #fff; border-radius: 8px; width: 30px; height: 30px; cursor: pointer; color: var(--chu-phu); font-size: 1rem; line-height: 1; }
.muc-luc-ben.thu .ds-ml { display: none; }
.ds-ml { list-style: none; margin: 10px 0 0; padding: 0; display: grid; gap: 2px; }
.ds-ml a { display: block; padding: 6px 10px; border-left: 3px solid transparent; border-radius: 0 8px 8px 0; color: var(--chu-phu); text-decoration: none; line-height: 1.4; }
.ds-ml a:hover { color: var(--dam); background: var(--ma-nhat); }
.ds-ml a.dang-doc { color: var(--dam); font-weight: 700; border-left-color: var(--mau); background: var(--ma-nhat); }
.ds-ml .cap-3 a { padding-left: 24px; font-size: .85rem; }

/* Mục lục — máy tính bảng / điện thoại: khối gập trong bài */
.muc-luc-gap { display: none; margin: 0 0 24px; border: 1px solid var(--vien); border-radius: 16px; background: #fff; }
.muc-luc-gap summary { cursor: pointer; padding: 12px 16px; font-weight: 800; color: var(--dam); min-height: 44px; list-style: none; display: flex; justify-content: space-between; align-items: center; }
.muc-luc-gap summary::-webkit-details-marker { display: none; }
.muc-luc-gap summary::after { content: '▸'; transition: transform .15s; }
.muc-luc-gap[open] summary::after { transform: rotate(90deg); }
.muc-luc-gap .ds-ml { margin: 0; padding: 0 8px 12px; }
@media (max-width: 1024px) { .muc-luc-gap { display: block; } }

/* Bài liên quan */
.lien-quan { margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--vien); }

/* Điện thoại: chữ nội dung 17px, nút đủ lớn cho ngón tay */
@media (max-width: 640px) {
  .bai .noi-dung { font-size: 1.0625rem; }
  .nut { min-height: 44px; }
  .nut-tim { margin-left: auto; }
}

/* Điện thoại: nút về cổng chỉ còn icon rùa để dòng 1 vừa (logo · 🔍 · 🐢) */
@media (max-width: 640px) {
  .thanh-tren .khung { flex-wrap: wrap; }
  .logo { min-width: 0; font-size: 1.1rem; }
  .ve-cong { font-size: 0; gap: 0; padding: 6px; width: 40px; height: 40px; justify-content: center; }
  .ve-cong img { width: 26px; }
}

/* ═══════════ CHUẨN CHUNG 2.0 — menu chính, trang Lớp, thanh đổi môn ═══════════ */

/* Menu chính (cổng): mục xổ xuống */
.menu-chinh { min-width: 0; }
.mc-ds { list-style: none; margin: 0; padding: 0; display: flex; gap: 4px; flex-wrap: wrap; }
.mc-muc { position: relative; }
.mc-nut { display: inline-flex; align-items: center; gap: 4px; border: 0; background: none; font: inherit; font-weight: 600; color: var(--chu-phu); padding: 8px 12px; border-radius: 999px; cursor: pointer; text-decoration: none; }
button.mc-nut::after { content: '▾'; font-size: .75em; }
.mc-nut:hover, .mc-muc.mo > .mc-nut { color: var(--dam); background: var(--ma-nhat); }
.mc-xo { display: none; position: absolute; top: calc(100% + 6px); left: 0; z-index: 30; background: #fff; border: 1px solid var(--vien); border-radius: 18px; box-shadow: var(--bong); padding: 16px; gap: 20px; min-width: 220px; }
.mc-muc.mo > .mc-xo { display: flex; flex-wrap: wrap; }
@media (hover: hover) and (min-width: 901px) { .mc-muc:hover > .mc-xo { display: flex; flex-wrap: wrap; } }
.mc-cot { min-width: 150px; }
.mc-tieu { display: block; font-size: .78rem; font-weight: 800; text-transform: uppercase; letter-spacing: .05em; color: var(--chu-phu); margin-bottom: 6px; }
.mc-cot ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 2px; }
.mc-cot a { display: block; padding: 6px 10px; border-radius: 10px; color: var(--dam); text-decoration: none; font-weight: 600; }
.mc-cot a:hover { background: var(--ma-nhat); }
.mc-lop { grid-template-columns: repeat(3, auto); }
.nut-menu { display: none; width: 40px; height: 40px; border-radius: 12px; border: 1px solid var(--vien); background: #fff; color: var(--dam); place-items: center; cursor: pointer; }
.nut-menu svg { width: 20px; height: 20px; }

/* Điện thoại / máy tính bảng hẹp: menu gom vào ☰ */
@media (max-width: 900px) {
  .nut-menu { display: grid; order: 2; }
  .thanh-tren .nut-tim { order: 3; margin-left: auto; }
  .thanh-tren .logo { order: 1; }
  .menu-chinh { display: none; order: 9; flex-basis: 100%; padding: 8px 0 12px; }
  .menu-chinh.mo { display: block; }
  .mc-ds { flex-direction: column; gap: 2px; }
  .mc-nut { width: 100%; justify-content: space-between; padding: 12px; border-radius: 12px; min-height: 44px; }
  .mc-xo { position: static; box-shadow: none; border: 0; padding: 4px 8px 8px; background: var(--ma-nhat); border-radius: 12px; }
  .mc-cot { min-width: 0; flex: 1 1 140px; }
}

/* Trang Lớp: ô môn */
.nhan-cap { display: inline-block; font-size: .8rem; font-weight: 800; letter-spacing: .06em; text-transform: uppercase; background: rgb(255 255 255 / .18); padding: 3px 10px; border-radius: 999px; margin: 0 0 8px; }
.luoi-mon { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.o-mon { display: flex !important; align-items: center; gap: 14px; padding: 18px; }
.chip-lon { width: 56px; height: 56px; border-radius: 16px; font-size: 1.4rem; }
.o-mon-chu { display: grid; }
.o-mon-chu strong { font-size: 1.15rem; color: var(--dam); }
.o-mon-chu span { font-size: .88rem; color: var(--chu-phu); }
.ds-lop { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.ds-lop a { display: inline-block; padding: 8px 16px; border-radius: 999px; border: 1px solid var(--vien); background: #fff; color: var(--dam); font-weight: 700; text-decoration: none; min-height: 40px; }
.ds-lop a:hover, .ds-lop a[aria-current='page'] { border-color: var(--ma); background: var(--ma-nhat); }

/* Thanh đổi môn (trang môn của một lớp) */
.thanh-doi-mon { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; max-width: var(--rong); margin: 16px auto 0; padding: 10px 16px; }
.thanh-doi-mon .ve-lop { font-weight: 700; color: var(--dam); text-decoration: none; padding: 6px 12px; border: 1px solid var(--vien); border-radius: 999px; background: #fff; }
.thanh-doi-mon .ve-lop:hover { border-color: var(--ma); }
.thanh-doi-mon .nhan-lop { font-weight: 700; color: var(--chu-phu); font-size: .9rem; }
.ds-doi-mon { list-style: none; margin: 0; padding: 0; display: flex; gap: 6px; flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; min-width: 0; flex: 1 1 200px; }
.ds-doi-mon a { display: inline-block; white-space: nowrap; padding: 6px 14px; border-radius: 999px; color: var(--chu-phu); text-decoration: none; font-weight: 600; background: #fff; border: 1px solid var(--vien); }
.ds-doi-mon a[aria-current='page'] { background: var(--mau); border-color: var(--mau); color: #fff; }
.mc-lop a { white-space: nowrap; }
.mc-lop { grid-template-columns: repeat(3, minmax(72px, auto)); }
@media (max-width: 900px) {
  .thanh-tren .khung { flex-wrap: wrap; }
  .thanh-tren .logo { order: 1; }
  .thanh-tren .nut-tim { order: 2; margin-left: auto; }
  .thanh-tren .nut-menu { order: 3; }
  .thanh-tren .menu-chinh { order: 9; flex-basis: 100%; }
}

/* Chân trang gọn (14/10) */
.chan-gon { padding: 28px 0 20px; }
.chan-hang { display: flex; align-items: center; justify-content: space-between; gap: 20px 32px; flex-wrap: wrap; }
.chan-logo img { width: 80px; height: auto; }
.chan-cot-link { display: grid; gap: 8px; }
.chan-link { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px 18px; }
.chan-link a { color: rgb(255 255 255 / .8); text-decoration: none; font-weight: 600; }
.chan-link a:hover { color: var(--ma); }
.chan-nhan { color: rgb(255 255 255 / .5); font-weight: 700; }
.chan-gon .ban-quyen { margin-top: 18px; padding-top: 14px; }
@media (max-width: 640px) { .chan-hang { flex-direction: column; align-items: flex-start; } .chan-link { gap: 6px 14px; } }

/* Nút lên đầu trang (do /chung/chan-trang.js tạo) */
.ve-dau { position: fixed; right: 16px; bottom: 16px; z-index: 40; width: 46px; height: 46px; border-radius: 50%; border: 0; background: var(--dam); color: #fff; box-shadow: 0 6px 18px rgb(31 45 92 / .3); cursor: pointer; display: grid; place-items: center; opacity: 0; transform: translateY(12px); pointer-events: none; transition: opacity .2s, transform .2s; }
.ve-dau.hien { opacity: 1; transform: none; pointer-events: auto; }
.ve-dau:hover { background: var(--mau, var(--dam)); }
.ve-dau svg { width: 20px; height: 20px; }
@media print { .ve-dau { display: none; } }

/* Trang chủ: thư mục lớn — mục con dạng nút */
.luoi-thu-muc { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.ds-muc-con { list-style: none; margin: 0; padding: 14px; display: flex; flex-wrap: wrap; gap: 8px; }
.ds-muc-con a { display: inline-block; padding: 8px 16px; border-radius: 999px; border: 1px solid var(--vien); background: #fff; color: var(--dam); font-weight: 700; text-decoration: none; min-height: 40px; }
.ds-muc-con a:hover { border-color: var(--nhom-mau); background: color-mix(in srgb, var(--nhom-mau) 10%, #fff); }
.chan-trang .chan-link { display: flex; flex-wrap: wrap; gap: 6px 20px; }
.ve-dau { background: var(--ma); color: var(--dam); }
.ve-dau:hover { background: #b8e63a; }
@media (max-width: 640px) { .chan-gon { padding-bottom: 76px; } }

/* ═══ Chân trang chuyên nghiệp (14/10, thay bản gọn) ═══ */
.chan-pro { padding: 0; border-top: 3px solid var(--ma); }
.chan-pro > .khung { padding-block: 44px 32px; }
.chan-luoi { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.3fr; gap: 32px; }
.chan-thuong-hieu .chan-logo img { width: 96px; height: auto; }
.chan-thuong-hieu p { margin: 12px 0 0; max-width: 300px; line-height: 1.6; color: rgb(255 255 255 / .7); }
.chan-pro h3 { font-size: .78rem; font-weight: 800; text-transform: uppercase; letter-spacing: .1em; color: var(--ma); margin: 4px 0 14px; }
.chan-pro .chan-luoi ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 9px; }
.chan-pro .chan-luoi a { color: rgb(255 255 255 / .82); text-decoration: none; }
.chan-pro .chan-luoi a:hover { color: #fff; text-decoration: underline; text-underline-offset: 3px; }
.chan-lien-he li { color: rgb(255 255 255 / .82); overflow-wrap: anywhere; }
.chan-day { background: rgb(0 0 0 / .18); font-size: .82rem; color: rgb(255 255 255 / .6); }
.chan-day .khung { display: flex; justify-content: space-between; gap: 8px 24px; flex-wrap: wrap; padding-block: 14px; }
.chan-day a { color: rgb(255 255 255 / .8); }
@media (max-width: 900px) { .chan-luoi { grid-template-columns: 1fr 1fr; } .chan-thuong-hieu { grid-column: 1 / -1; } }
@media (max-width: 640px) { .chan-luoi { gap: 24px 16px; } .chan-pro > .khung { padding-block: 32px 24px; } .chan-day .khung { padding-bottom: 72px; } }
@media (max-width: 640px) { .chan-luoi > div:last-child { grid-column: 1 / -1; } .chan-lien-he li { overflow-wrap: normal; } }

/* ═══ Trang chủ 4 phần (14/10) ═══ */
.hero-nut { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 10px; }
.hero-nut a { display: inline-flex; align-items: center; gap: 6px; padding: 10px 18px; border-radius: 999px; background: #fff; border: 1px solid var(--vien); color: var(--dam); font-weight: 700; text-decoration: none; box-shadow: var(--bong); min-height: 44px; }
.hero-nut a:hover { border-color: var(--ma); transform: translateY(-1px); }
.phan-tc { padding-block: 72px; scroll-margin-top: 70px; }
.phan-tc.phan-dam { background: var(--dam); color: rgb(255 255 255 / .8); }
.phan-tc .dau-phan { max-width: 720px; margin: 0 0 28px; }
.phan-dam .doan, .phan-dam .loi-nhan blockquote { color: rgb(255 255 255 / .85); }
.phan-dam .loi-nhan { background: rgb(255 255 255 / .06); }
.phan-dam .loi-nhan figcaption { color: rgb(255 255 255 / .7); }
.phan-dam .loi-nhan figcaption strong { color: #fff; }
.the-nhom h3 { margin: 0; font-size: 1.25rem; color: #fff; }
.the-nhom.sap-co { opacity: .75; }
.the-nhom.sap-co .dau { filter: saturate(.55); }
.sap-ra-mat { margin: 0; padding: 16px 20px; color: var(--chu-phu); font-weight: 600; font-size: .92rem; }
.nghe-gioi-thieu { margin: 24px 0 8px; }
.tieu-de-nho.trang, .quy-trinh.trang h4 { color: #fff; }
.quy-trinh.trang p { color: rgb(255 255 255 / .75); }
.quy-trinh.trang .so-buoc { background: var(--ma); color: var(--dam); }
.luoi-anh-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 48px; }
.luoi-anh-4 figure { margin: 0; position: relative; border-radius: 16px; overflow: hidden; aspect-ratio: 4 / 3; }
.luoi-anh-4 img { width: 100%; height: 100%; object-fit: cover; }
.luoi-anh-4 figcaption { position: absolute; inset: auto 0 0 0; padding: 24px 12px 10px; font-size: .8rem; color: #fff; background: linear-gradient(transparent, rgb(0 0 0 / .65)); }
@media (max-width: 760px) { .luoi-anh-4 { grid-template-columns: 1fr 1fr; } }
.dt-luoi { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 860px) { .dt-luoi { grid-template-columns: 1fr; } }
.dt-khoi { padding: 26px; }
.dt-khoi h3 { font-size: 1.15rem; margin: 0 0 14px; }
.dt-buoc { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; }
.dt-buoc li { display: flex; gap: 14px; align-items: flex-start; }
.dt-buoc li > span { flex: none; width: 34px; height: 34px; border-radius: 50%; background: var(--ma); color: var(--dam); font-weight: 800; display: grid; place-items: center; }
.dt-buoc strong { color: var(--dam); }
.dt-buoc p { margin: 2px 0 0; color: var(--chu-phu); font-size: .95rem; }
.dt-dau { margin: 0; padding-left: 20px; display: grid; gap: 8px; color: var(--chu); }
.dt-dau li::marker { color: var(--ma); }
.dt-chip { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.dt-chip li { padding: 8px 14px; border-radius: 999px; background: var(--ma-nhat); color: var(--dam); font-weight: 700; font-size: .92rem; }
#dao-tao .cta-hop-tac { margin-top: 32px; }
.hero { padding-bottom: 0; } .hero + .phan-tc { padding-top: 48px; }
.luoi-nang-luc { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); margin-bottom: 8px; }
.nang-luc .nl-bt { font-size: 1.7rem; display: block; margin-bottom: 8px; }
.nang-luc h4 { margin: 0 0 6px; color: #fff; font-size: 1.05rem; }
.nang-luc p { margin: 0; font-size: .9rem; color: rgb(255 255 255 / .75); }

/* ═══ Hiệu ứng (Chuẩn 2.1) — chỉ chạy khi người dùng KHÔNG bật giảm chuyển động ═══ */
@media (prefers-reduced-motion: no-preference) {
  /* 1. Hiện dần khi cuộn (class do /chung/hieu-ung.js gắn) */
  .hu-an { opacity: 0; transform: translateY(26px); }
  .hu-an.hu-hien { opacity: 1; transform: none; transition: opacity .6s ease var(--hu-tre, 0ms), transform .7s cubic-bezier(.2,.7,.2,1) var(--hu-tre, 0ms); }

  /* 3. Chú Rùa nhấp nhô */
  .hero .linh-vat { animation: rua-noi 5s ease-in-out infinite; }
  @keyframes rua-noi { 0%, 100% { transform: translateY(0) rotate(0); } 50% { transform: translateY(-12px) rotate(-1.2deg); } }
}

/* 4. Thẻ nhấc lên khi rê chuột (chỉ máy có chuột) */
@media (hover: hover) {
  .the, .the-nhom, .the-toi, .o-mon, .dt-khoi { transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease; }
  .the-nhom:hover, .o-mon:hover, a.the:hover, .dt-khoi:hover { transform: translateY(-5px); box-shadow: 0 2px 4px rgb(31 45 92 / .06), 0 18px 40px rgb(31 45 92 / .14); }
  .the-nhom:hover { border-color: var(--nhom-mau); }
  .the-toi:hover { transform: translateY(-5px); background: rgb(255 255 255 / .1); border-color: rgb(163 214 28 / .5); }
  .luoi-anh-4 figure img, .thu-vien figure img { transition: transform .6s ease; }
  .luoi-anh-4 figure:hover img, .thu-vien figure:hover img { transform: scale(1.05); }
}

/* ═══ Menu điện thoại thu vào ☰ cho MỌI KÊNH (14/10) — nút do /chung/chan-trang.js thêm ═══ */
@media (max-width: 900px) {
  .thanh-tren .khung { flex-wrap: wrap; }
  .thanh-tren nav:not(.menu-chinh) { display: none; order: 9; flex-basis: 100%; min-width: 0; padding: 4px 0 10px; }
  .thanh-tren nav:not(.menu-chinh).mo { display: block; }
  .thanh-tren nav:not(.menu-chinh) .menu { flex-direction: column; flex-wrap: nowrap; overflow: visible; gap: 2px; margin: 0; }
  .thanh-tren nav:not(.menu-chinh) .menu a { display: block; padding: 12px; border-radius: 12px; min-height: 44px; white-space: normal; }
  .thanh-tren .logo { order: 1; }
  .thanh-tren .nut-tim { order: 2; margin-left: auto; }
  .thanh-tren .ve-cong { order: 3; }
  .thanh-tren .nut-menu { order: 4; display: grid; }
}