/* Trang chủ doanhoi.lhu.edu.vn (LHUVNTW/DoanHoiSV) — CSS thuần, mọi quy tắc nằm dưới #yh.
   Thanh lịch có điểm nhấn: xanh đêm + xanh LHU + vàng; bo góc 2-4px; tiêu đề Playfair Display, nội dung Be Vietnam Pro.
   Điểm nhấn: khung Khám phá nổi đè hero, chữ nghiêng màu trong tiêu đề, nhãn "Tiêu điểm", băng xanh chữ chạy, băng vàng cuối trang. */
#yh {
    --ink: #0e1a33;
    --ink-2: #17264a;
    --brand: #284f9e;
    --brand-deep: #1f3f80;
    --gold: #c9a24a;
    --gold-soft: #e8d6a6;
    --gold-bg: #e2bd5f;
    --gold-text: #8a6d25; /* vàng cho chữ trên nền sáng (tương phản ≥ 4.5:1) */
    --paper: #f7f6f2;
    --line: #e4e2db;
    --muted: #6b7280;
    --serif: "Playfair Display", Georgia, "Times New Roman", serif;
    --sans: "Be Vietnam Pro", "Segoe UI", system-ui, sans-serif;
    --r: 4px;
    --shadow: 0 1px 2px rgba(14,26,51,.06), 0 12px 32px -16px rgba(14,26,51,.28);
    font-family: var(--sans);
    color: #2f3542;
    font-size: 1rem;
    line-height: 1.7;
    overflow-x: clip;
    background: #fff;
}
#yh a { color: inherit; text-decoration: none; }
#yh :focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }

/* ===== chung ===== */
#yh .yh-sec { padding: 4.5rem 0; }
#yh .yh-sec-paper { background: var(--paper); }
#yh .yh-sec-ink { background: var(--ink); color: #c9d1e3; }
#yh .yh-head { margin-bottom: 2.5rem; }
#yh .yh-eyebrow { display: flex; align-items: center; gap: .75rem; margin-bottom: .6rem; font-size: .75rem; font-weight: 600; letter-spacing: .22em; text-transform: uppercase; color: var(--gold-text); }
#yh .yh-eyebrow::before { content: ""; width: 2rem; height: 2px; background: var(--gold); }
#yh .yh-sec-ink .yh-eyebrow { color: var(--gold-soft); }
#yh .yh-h2 { font-family: var(--serif); font-size: clamp(1.9rem, 3.8vw, 3rem); line-height: 1.12; font-weight: 500; letter-spacing: -.01em; color: var(--ink); text-wrap: balance; }
#yh .yh-h2 em { font-style: italic; color: var(--brand); }
#yh .yh-sec-ink .yh-h2 { color: #fff; }
#yh .yh-sec-ink .yh-h2 em { color: var(--gold-soft); }

#yh .yh-btn {
    display: inline-flex; align-items: center; gap: .6rem; min-height: 3rem; padding: .75rem 1.5rem; border-radius: 2px;
    font-size: .85rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; transition: background-color .25s, color .25s, border-color .25s;
}
#yh .yh-btn .svtl-i { transition: transform .25s; }
#yh .yh-btn:hover .svtl-i { transform: translateX(4px); }
#yh .yh-btn-gold { background: var(--gold-bg); color: var(--ink); }
#yh .yh-btn-gold:hover { background: var(--gold-soft); }
#yh .yh-btn-ghost { border: 1px solid rgba(255,255,255,.45); color: #fff; }
#yh .yh-btn-ghost:hover { border-color: #fff; background: rgba(255,255,255,.06); }
#yh .yh-btn-ink { background: var(--ink); color: #fff; }
#yh .yh-btn-ink:hover { background: var(--brand); }

#yh .yh-more:not(:empty) { margin-top: 2rem; }
/* Location có nhiều thư mục con: mỗi thư mục một khối, cách nhau */
#yh .yh-more + .yh-bento, #yh .yh-bento + .yh-bento, #yh .yh-gallery + .yh-head { margin-top: 3.5rem; }
#yh .yh-more a { display: inline-flex; align-items: center; gap: .5rem; font-size: .85rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--ink); border-bottom: 2px solid var(--gold); padding-bottom: .2rem; }
#yh .yh-more a::after { content: "→"; transition: transform .25s; }
#yh .yh-more a:hover::after { transform: translateX(4px); }

/* ===== HERO ===== */
#yh .yh-hero { position: relative; overflow: hidden; background: radial-gradient(120% 90% at 85% 10%, var(--brand-deep) 0%, var(--ink) 55%); color: #fff; padding: 4rem 0 7rem; }
/* chữ "Youth" rất lớn, mờ, làm nền */
#yh .yh-hero-mark { position: absolute; right: -2rem; bottom: -3.5rem; font-family: var(--serif); font-style: italic; font-size: clamp(8rem, 22vw, 20rem); line-height: 1; color: transparent; -webkit-text-stroke: 1px rgba(232,214,166,.14); pointer-events: none; user-select: none; }
#yh .yh-hero-grid { position: relative; display: grid; gap: 3rem; align-items: center; }
#yh .yh-kicker { display: inline-block; margin-bottom: 1.5rem; padding-bottom: .9rem; border-bottom: 2px solid var(--gold); font-size: .8rem; line-height: 1.6; font-weight: 500; letter-spacing: .2em; text-transform: uppercase; color: var(--gold-soft); }
#yh .yh-display { display: block; font-family: var(--serif); font-size: clamp(2.7rem, 6.4vw, 5rem); line-height: 1.05; font-weight: 500; letter-spacing: -.015em; }
#yh .yh-display em { font-style: italic; color: var(--gold-bg); }
#yh .yh-nowrap { white-space: nowrap; }
#yh .yh-lead-wrap { margin-top: 1.75rem; max-width: 34rem; }
#yh .yh-lead { color: #b9c3d9; font-size: 1rem; line-height: 1.8; }
#yh .yh-cta { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2rem; }

/* ảnh banner: ul.Carousel > li > img; khối vàng đặc lệch phía sau làm điểm nhấn */
#yh .yh-frame { position: relative; padding: 1.25rem 1.25rem 0 0; }
#yh .yh-frame::before { content: ""; position: absolute; right: 0; top: 0; width: 55%; height: 60%; background: var(--gold-bg); border-radius: 2px; }
#yh .yh-deck { position: relative; }
#yh .yh-deck .Carousel { display: grid; aspect-ratio: 4 / 3; cursor: pointer; }
#yh .yh-deck .Carousel > li { grid-area: 1 / 1; overflow: hidden; border-radius: 2px; background: var(--ink-2); box-shadow: 0 30px 60px -28px rgba(0,0,0,.7); transition: opacity .9s ease; }
#yh .yh-deck .Carousel > li:nth-child(1) { z-index: 2; }
#yh .yh-deck .Carousel > li:not(:first-child) { opacity: 0; }
#yh .yh-deck .Carousel img { display: block; width: 100%; height: 100%; object-fit: cover; }
#yh .yh-frame-tag { position: relative; margin-top: 1rem; padding-left: .25rem; font-size: .72rem; letter-spacing: .2em; text-transform: uppercase; color: #9fabc6; }
#yh .yh-frame-tag i { display: inline-block; width: 4px; height: 4px; margin: 0 .6rem; border-radius: 50%; background: var(--gold); vertical-align: middle; }

/* ===== KHÁM PHÁ: khung trắng nổi đè hero; ul.yh-explore > li > a + ul.CSub ===== */
#yh .yh-explore-wrap { position: relative; z-index: 2; margin-top: -4rem; }
#yh .yh-explore { display: grid; background: #fff; border-top: 3px solid var(--gold); border-radius: 0 0 var(--r) var(--r); box-shadow: var(--shadow); counter-reset: yh; }
#yh .yh-explore > li { counter-increment: yh; position: relative; display: flex; flex-direction: column; padding: 1.5rem 1.5rem 1.6rem; border-bottom: 1px solid var(--line); transition: background-color .25s; }
#yh .yh-explore > li:last-child { border-bottom: 0; }
#yh .yh-explore > li::before { content: counter(yh, decimal-leading-zero); font-family: var(--serif); font-style: italic; font-size: 1.6rem; line-height: 1; color: var(--brand); }
#yh .yh-explore > li > a { margin-top: .6rem; font-family: var(--serif); font-size: 1.35rem; line-height: 1.25; font-weight: 500; color: var(--ink); }
#yh .yh-explore > li > a::after { content: ""; position: absolute; inset: 0; } /* cả ô bấm được */
#yh .yh-explore > li > a::before { content: "→"; float: right; margin-left: .5rem; font-family: var(--sans); font-size: 1.05rem; color: var(--gold); transition: transform .25s; }
#yh .yh-explore > li:hover { background: var(--paper); }
#yh .yh-explore > li:hover > a { color: var(--brand); }
#yh .yh-explore > li:hover > a::before { transform: translateX(4px); }
#yh .yh-explore .CSub { position: relative; z-index: 1; display: flex; flex-wrap: wrap; gap: .2rem 1rem; margin-top: .6rem; }
#yh .yh-explore .CSub a { font-size: .875rem; color: var(--muted); border-bottom: 1px solid transparent; transition: color .2s, border-color .2s; }
#yh .yh-explore .CSub a:hover { color: var(--ink); border-color: var(--gold); }

/* ===== TIN: li > .NImg > a(background) + .yh-card-body > .NTime + .NTitle > a ===== */
#yh .yh-news-sec { padding-top: 4rem; }
#yh .yh-bento { display: grid; gap: 1.5rem; }
#yh .yh-bento > li { position: relative; display: flex; flex-direction: column; overflow: hidden; border-radius: var(--r); background: #fff; box-shadow: var(--shadow); }
#yh .yh-bento > li::before { content: ""; position: absolute; z-index: 2; left: 0; right: 0; bottom: 0; height: 3px; background: var(--gold); transform: scaleX(0); transform-origin: left; transition: transform .35s ease; }
#yh .yh-bento > li:hover::before { transform: scaleX(1); }
#yh .yh-bento .NImg { overflow: hidden; background: #e6e8ee; }
#yh .yh-bento .NImg a { display: block; aspect-ratio: 16 / 10; background-size: cover; background-position: center; transition: transform .8s ease; }
#yh .yh-bento > li:hover .NImg a { transform: scale(1.04); }
#yh .yh-card-body { display: flex; flex-direction: column; gap: .5rem; padding: 1.1rem 1.25rem 1.35rem; }
#yh .yh-bento .NTime { font-size: .72rem; font-weight: 600; letter-spacing: .16em; color: var(--gold-text); }
#yh .yh-bento .NTitle { font-weight: 500; font-size: 1rem; line-height: 1.5; color: var(--ink); display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
#yh .yh-bento .NTitle a::after { content: ""; position: absolute; inset: 0; } /* cả thẻ bấm được */
#yh .yh-bento > li:hover .NTitle a { color: var(--brand); }
/* tin tiêu điểm: ảnh phủ kín, nhãn vàng, tiêu đề chữ có chân */
#yh .yh-bento > li:first-child { background: var(--ink); min-height: 22rem; }
#yh .yh-bento > li:first-child::after { content: "Tiêu điểm"; position: absolute; z-index: 2; left: 1.5rem; top: 1.5rem; padding: .3rem .75rem; background: var(--gold-bg); color: var(--ink); font-size: .7rem; font-weight: 600; letter-spacing: .18em; text-transform: uppercase; border-radius: 2px; }
#yh .yh-bento > li:first-child .NImg { position: absolute; inset: 0; }
#yh .yh-bento > li:first-child .NImg a { height: 100%; aspect-ratio: auto; }
#yh .yh-bento > li:first-child .yh-card-body { position: relative; margin-top: auto; padding: 6rem 1.75rem 1.75rem; background: linear-gradient(to top, rgba(14,26,51,.94) 35%, transparent); pointer-events: none; }
#yh .yh-bento > li:first-child .NTitle { font-family: var(--serif); font-size: clamp(1.4rem, 2.3vw, 2rem); line-height: 1.28; color: #fff; -webkit-line-clamp: 4; pointer-events: auto; }
#yh .yh-bento > li:first-child:hover .NTitle a { color: var(--gold-soft); }
#yh .yh-bento > li:first-child .NTime { color: var(--gold-soft); }

/* ===== băng xanh LHU chữ chạy ===== */
#yh .yh-marquee { overflow: hidden; background: var(--brand); color: #fff; }
#yh .yh-marquee-track { display: flex; width: max-content; animation: yh-marquee 60s linear infinite; }
#yh .yh-marquee p { flex-shrink: 0; padding: 1.4rem 0; white-space: nowrap; font-family: var(--serif); font-size: clamp(1.4rem, 3vw, 2.1rem); font-style: italic; line-height: 1.2; }
#yh .yh-marquee b { display: inline-block; width: 7px; height: 7px; margin: 0 2rem; border-radius: 50%; background: var(--gold-bg); vertical-align: middle; }
@keyframes yh-marquee { to { transform: translateX(-50%); } }

/* ===== VIDEO: 1 lớn + 4 nhỏ ===== */
#yh .yh-videos { display: grid; gap: 1.5rem; }
#yh .yh-video { display: block; }
#yh .yh-video-img { position: relative; display: block; overflow: hidden; aspect-ratio: 16 / 9; border-radius: var(--r); background: var(--ink-2); }
#yh .yh-video-img img { width: 100%; height: 100%; object-fit: cover; transition: transform .8s ease, opacity .3s; opacity: .88; }
#yh .yh-video:hover .yh-video-img img { transform: scale(1.04); opacity: 1; }
#yh .yh-play { position: absolute; left: 1rem; bottom: 1rem; display: grid; place-items: center; width: 2.75rem; height: 2.75rem; border-radius: 50%; background: var(--gold-bg); color: var(--ink); font-size: .95rem; box-shadow: 0 0 0 6px rgba(226,189,95,.22); transition: transform .25s; }
#yh .yh-video:hover .yh-play { transform: scale(1.1); }
#yh .yh-video-t { display: block; margin-top: .8rem; font-size: .92rem; line-height: 1.5; color: #e3e8f2; transition: color .2s; }
#yh .yh-video:hover .yh-video-t { color: var(--gold-soft); }
#yh .yh-video-main { position: relative; }
#yh .yh-video-main .yh-video-t { position: absolute; left: 0; right: 0; bottom: 0; margin: 0; padding: 5rem 1.5rem 1.5rem 5.5rem; background: linear-gradient(to top, rgba(14,26,51,.92) 30%, transparent); border-radius: 0 0 var(--r) var(--r); font-family: var(--serif); font-size: clamp(1.15rem, 2vw, 1.5rem); line-height: 1.3; color: #fff; }
#yh .yh-video-main .yh-play { z-index: 1; left: 1.5rem; bottom: 1.5rem; width: 3.25rem; height: 3.25rem; font-size: 1.1rem; }
#yh .yh-player { width: min(64rem, 94vw); max-width: none; padding: 0; border: 0; border-radius: var(--r); overflow: visible; background: #000; }
#yh .yh-player::backdrop { background: rgba(14,26,51,.9); }
#yh .yh-player > div { aspect-ratio: 16 / 9; }
#yh .yh-player iframe { display: block; width: 100%; height: 100%; border: 0; }
#yh .yh-player-close { position: absolute; right: 0; top: -3rem; width: 2.5rem; height: 2.5rem; border-radius: 2px; background: var(--gold-bg); color: var(--ink); font-size: 1.5rem; line-height: 1; }

/* ===== THƯ VIỆN ẢNH ===== */
#yh .yh-gallery-sec:not(:has(li)) { display: none; }
#yh .yh-gallery { display: grid; grid-template-columns: repeat(2, 1fr); gap: .75rem; }
#yh .yh-gallery li { position: relative; overflow: hidden; border-radius: var(--r); }
#yh .yh-gallery .NImg a { display: block; aspect-ratio: 1; background-size: cover; background-position: center; transition: transform .8s ease; }
#yh .yh-gallery li:hover .NImg a { transform: scale(1.05); }
#yh .yh-gallery .NTitle { position: absolute; inset: auto 0 0; padding: 2.5rem .9rem .8rem; background: linear-gradient(to top, rgba(14,26,51,.88), transparent); font-size: .85rem; line-height: 1.4; color: #fff; pointer-events: none; }
#yh .yh-gallery .NTitle a { pointer-events: auto; }

/* ===== VĂN BẢN: div.yh-doc > h3.yh-doc-h > a + ul.yh-list > li > .NTitle > a ===== */
#yh .yh-docs { display: grid; gap: 1.5rem; }
#yh .yh-doc { height: 100%; padding: 1.75rem 1.75rem 1.5rem; background: #fff; border-top: 3px solid var(--brand); border-radius: 0 0 var(--r) var(--r); box-shadow: var(--shadow); }
#yh .yh-doc-h { margin-bottom: .5rem; font-family: var(--serif); font-size: 1.4rem; line-height: 1.3; font-weight: 500; color: var(--ink); }
#yh .yh-doc-h a:hover { color: var(--brand); }
#yh .yh-list li { position: relative; padding: .8rem 0 .8rem 1.1rem; border-bottom: 1px solid var(--line); font-size: .93rem; line-height: 1.5; }
#yh .yh-list li:last-child { border-bottom: 0; }
#yh .yh-list li::before { content: ""; position: absolute; left: 0; top: 1.45rem; width: 5px; height: 5px; border-radius: 50%; background: var(--gold); }
#yh .yh-list a { transition: color .2s; }
#yh .yh-list a:hover { color: var(--brand); }
#yh .yh-doc .yh-more:not(:empty) { margin-top: 1rem; }

/* ===== LỜI MỜI: băng vàng ===== */
#yh .yh-join { position: relative; overflow: hidden; background: var(--gold-bg); color: var(--ink); padding: 3.5rem 0; }
#yh .yh-join::after { content: "Youth"; position: absolute; right: -1rem; top: 50%; transform: translateY(-50%); font-family: var(--serif); font-style: italic; font-size: clamp(6rem, 14vw, 11rem); line-height: 1; color: transparent; -webkit-text-stroke: 1px rgba(14,26,51,.14); pointer-events: none; }
#yh .yh-join-in { position: relative; z-index: 1; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 1.5rem; }
#yh .yh-join h2 { max-width: 40rem; font-family: var(--serif); font-size: clamp(1.6rem, 3.2vw, 2.4rem); line-height: 1.25; font-weight: 500; }
#yh .yh-join h2 em { display: block; font-style: italic; color: var(--brand-deep); }

/* điện thoại: tin 2-5 dạng ngang gọn */
@media (max-width: 39.99rem) {
    #yh .yh-bento { gap: 1rem; }
    #yh .yh-bento > li:not(:first-child) { flex-direction: row; }
    #yh .yh-bento > li:not(:first-child) .NImg { flex: 0 0 36%; }
    #yh .yh-bento > li:not(:first-child) .NImg a { height: 100%; min-height: 6.5rem; aspect-ratio: auto; }
    #yh .yh-bento > li:not(:first-child) .yh-card-body { padding: .8rem .9rem; gap: .3rem; }
    #yh .yh-bento > li:not(:first-child) .NTitle { font-size: .92rem; }
    #yh .yh-explore-wrap { margin-top: -3rem; }
}

/* ===== màn hình lớn ===== */
@media (min-width: 40rem) {
    #yh .yh-explore { grid-template-columns: repeat(2, 1fr); }
    #yh .yh-explore > li { border-bottom: 1px solid var(--line); }
    #yh .yh-explore > li:nth-child(odd) { border-right: 1px solid var(--line); }
    #yh .yh-explore > li:nth-last-child(-n+2):nth-child(odd), #yh .yh-explore > li:last-child { border-bottom: 0; }
    #yh .yh-bento { grid-template-columns: repeat(2, 1fr); }
    #yh .yh-bento > li:first-child { grid-column: 1 / -1; }
    #yh .yh-videos { grid-template-columns: repeat(2, 1fr); }
    #yh .yh-video-main { grid-column: 1 / -1; }
    #yh .yh-gallery { grid-template-columns: repeat(3, 1fr); }
}
@media (min-width: 64rem) {
    #yh .yh-sec { padding: 6.5rem 0; }
    #yh .yh-news-sec { padding-top: 5rem; }
    #yh .yh-hero { padding: 5.5rem 0 10rem; }
    #yh .yh-hero-grid { grid-template-columns: 1.1fr 1fr; gap: 5rem; }
    #yh .yh-frame { padding: 1.75rem 1.75rem 0 0; }
    #yh .yh-explore-wrap { margin-top: -5.5rem; }
    #yh .yh-explore { grid-template-columns: repeat(4, 1fr); }
    #yh .yh-explore > li { padding: 1.75rem 1.75rem 2rem; border-bottom: 0; border-right: 1px solid var(--line); }
    #yh .yh-explore > li:last-child { border-right: 0; }
    #yh .yh-bento { grid-template-columns: repeat(4, 1fr); }
    #yh .yh-bento > li:first-child { grid-column: span 2; grid-row: span 2; min-height: 30rem; }
    #yh .yh-videos { grid-template-columns: repeat(4, 1fr); }
    #yh .yh-video-main { grid-column: span 2; grid-row: span 2; }
    #yh .yh-video-main .yh-video-img { aspect-ratio: auto; height: 100%; }
    #yh .yh-docs { grid-template-columns: repeat(3, 1fr); }
    #yh .yh-gallery { grid-template-columns: repeat(6, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
    #yh .yh-marquee-track { animation: none; }
    #yh * { transition: none !important; }
}