/* HAI VU PIANO ACADEMY — TÁC PHẨM & PHONG CÁCH V19
   Institutional – Academic – Premium
   One active section at a time
*/

.hv19-main{
  --ink:#18384f;
  --muted:#647681;
  --line:rgba(24,56,79,.12);
  --gold:#9a7040;
  --paper:#fbfaf7;
  color:var(--ink);
  background:#fff;
}
.hv19-wrap{width:min(1220px,calc(100% - 48px));margin-inline:auto}

.hv19-hero{
  padding:74px 0 58px;
  background:linear-gradient(90deg,#fbfaf6 0%,#f7fafb 100%);
  border-bottom:1px solid rgba(24,56,79,.07)
}
.hv19-eyebrow{
  display:block;margin-bottom:12px;color:var(--gold);
  font-size:12px;font-weight:650;letter-spacing:.055em
}
.hv19-hero-grid{
  display:grid;grid-template-columns:minmax(0,1.08fr) minmax(280px,.62fr);
  gap:72px;align-items:end
}
.hv19-hero h1{
  margin:0 0 18px;max-width:760px;
  font-size:clamp(44px,4.1vw,54px);line-height:1.08;
  letter-spacing:-.035em;font-weight:610
}
.hv19-hero p{
  max-width:790px;margin:0;color:var(--muted);
  font-size:17px;line-height:1.72
}
.hv19-summary{padding-left:26px;border-left:1px solid var(--line)}
.hv19-summary strong{
  display:block;margin-bottom:10px;font-size:28px;
  line-height:1.15;font-weight:600;letter-spacing:-.02em
}
.hv19-summary span{
  display:block;color:var(--muted);font-size:14px;line-height:1.68
}

/* Controls */
.hv19-controls{border-bottom:1px solid rgba(24,56,79,.08);background:#fff}
.hv19-controls-inner{width:min(1220px,calc(100% - 48px));margin-inline:auto;padding:22px 0 20px}
.hv19-control-top{
  display:grid;grid-template-columns:minmax(0,1fr) minmax(290px,360px);
  gap:16px;align-items:end
}
.hv19-field label{
  display:block;margin-bottom:7px;color:#758690;
  font-size:11px;font-weight:650;letter-spacing:.055em
}
.hv19-search,.hv19-select{
  width:100%;min-height:48px;padding:0 14px;
  border:1px solid rgba(24,56,79,.16);border-radius:9px;
  background:#fff;color:var(--ink);font:inherit;font-size:15px;outline:none
}
.hv19-search:focus,.hv19-select:focus{
  border-color:rgba(18,63,91,.42);box-shadow:0 0 0 3px rgba(18,63,91,.05)
}
.hv19-partbar{
  display:flex;justify-content:space-between;align-items:center;
  gap:18px;margin-top:14px;padding-top:14px;border-top:1px solid rgba(24,56,79,.08)
}
.hv19-current{min-width:0}
.hv19-current small{
  display:block;margin-bottom:3px;color:var(--gold);
  font-size:11px;font-weight:650;letter-spacing:.05em
}
.hv19-current strong{
  display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;
  color:var(--ink);font-size:15px;font-weight:600
}
.hv19-part-actions{display:flex;gap:8px;flex:0 0 auto}
.hv19-part-btn{
  min-height:38px;padding:0 13px;border:1px solid rgba(24,56,79,.15);
  border-radius:999px;background:#fff;color:var(--ink);
  font:inherit;font-size:12px;font-weight:600;cursor:pointer
}
.hv19-part-btn:disabled{opacity:.38;cursor:not-allowed}

/* Index */
.hv19-index{padding:60px 0 102px}
.hv19-part{
  display:grid;grid-template-columns:300px minmax(0,1fr);
  gap:66px;padding:0 0 72px
}
.hv19-part[hidden]{display:none!important}
.hv19-part.hv19-active{display:grid!important}
.hv19-part-meta{align-self:start}
.hv19-part-no{
  display:block;margin-bottom:10px;color:var(--gold);
  font-size:12px;font-weight:650;letter-spacing:.05em
}
.hv19-part h2{
  margin:0 0 12px;font-size:32px;line-height:1.22;
  letter-spacing:-.022em;font-weight:610
}
.hv19-part-count{margin:0;color:var(--muted);font-size:16px;line-height:1.7}
.hv19-list{display:grid;grid-template-columns:1fr 1fr;column-gap:36px}
.hv19-item{border-bottom:1px solid rgba(24,56,79,.1)}
.hv19-item a{
  display:grid;grid-template-columns:42px 1fr 18px;gap:12px;align-items:center;
  min-height:80px;padding:12px 0;color:var(--ink);text-decoration:none
}
.hv19-item a:hover .hv19-item-title{color:#0d547e}
.hv19-num{color:var(--gold);font-size:13px;font-weight:650;font-variant-numeric:tabular-nums}
.hv19-item-title{font-size:17px;line-height:1.48;font-weight:560}
.hv19-arrow{color:#8da0aa}
.hv19-empty{display:none;padding:34px 0;color:var(--muted);font-size:16px;line-height:1.65}

/* Article */
.hv19-article-hero{
  padding:64px 0 44px;background:#fbfaf7;
  border-bottom:1px solid rgba(24,56,79,.08)
}
.hv19-breadcrumb{
  display:flex;gap:8px;flex-wrap:wrap;margin-bottom:23px;
  color:#788993;font-size:12px
}
.hv19-breadcrumb a{color:inherit;text-decoration:none}
.hv19-article-grid{
  display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:72px;align-items:end
}
.hv19-article-no{
  display:block;margin-bottom:11px;color:var(--gold);
  font-size:12px;font-weight:650;letter-spacing:.05em
}
.hv19-article-hero h1{
  max-width:830px;margin:0;
  font-size:clamp(42px,4vw,52px);line-height:1.09;
  letter-spacing:-.035em;font-weight:610
}
.hv19-context{
  padding-left:24px;border-left:1px solid var(--line);
  color:var(--muted);font-size:14px;line-height:1.72
}
.hv19-context strong{
  display:block;margin-bottom:8px;color:var(--ink);
  font-size:14px;font-weight:620
}
.hv19-article-layout{
  display:grid;grid-template-columns:minmax(0,770px) 300px;
  gap:76px;justify-content:space-between;padding:62px 0 104px
}
.hv19-copy{min-width:0}
.hv19-copy p{
  margin:0 0 26px;color:#2f4a5b;
  font-size:18.5px;line-height:1.82
}
.hv19-copy p:last-child{margin-bottom:0}
.hv19-copy::before{
  content:"";display:block;width:56px;height:1px;
  background:#b89161;margin-bottom:28px
}
.hv19-aside{align-self:start;position:sticky;top:104px}
.hv19-aside-title{
  margin-bottom:14px;color:var(--gold);
  font-size:11px;font-weight:650;letter-spacing:.06em
}
.hv19-aside a{
  display:grid;grid-template-columns:28px 1fr;gap:9px;
  padding:10px 0;border-bottom:1px solid rgba(24,56,79,.08);
  color:#6e7e87;text-decoration:none;font-size:13.5px;line-height:1.48
}
.hv19-aside a.current{color:var(--ink);font-weight:620}
.hv19-aside a span:first-child{color:#a17a4c;font-variant-numeric:tabular-nums}
.hv19-prevnext{
  display:grid;grid-template-columns:1fr 1fr;gap:18px;
  margin-top:52px;padding-top:24px;border-top:1px solid var(--line)
}
.hv19-prevnext a{padding:16px 0;color:var(--ink);text-decoration:none}
.hv19-prevnext a:last-child{text-align:right}
.hv19-prevnext small{display:block;margin-bottom:5px;color:#83929b;font-size:11px}
.hv19-prevnext strong{font-size:15px;line-height:1.5;font-weight:600}

@media(max-width:960px){
  .hv19-hero-grid,.hv19-article-grid{grid-template-columns:1fr;gap:28px}
  .hv19-summary,.hv19-context{padding-left:0;padding-top:20px;border-left:0;border-top:1px solid var(--line)}
  .hv19-control-top{grid-template-columns:1fr}
  .hv19-part.hv19-active{display:block!important}
  .hv19-part-meta{margin-bottom:24px}
  .hv19-article-layout{grid-template-columns:1fr;gap:52px}
  .hv19-aside{position:static}
}
@media(max-width:720px){
  .hv19-wrap,.hv19-controls-inner{width:min(100% - 32px,1220px)}
  .hv19-hero{padding:54px 0 44px}
  .hv19-hero h1,.hv19-article-hero h1{font-size:clamp(36px,10vw,42px)}
  .hv19-partbar{align-items:flex-start;flex-direction:column}
  .hv19-current strong{white-space:normal}
  .hv19-index{padding:48px 0 76px}
  .hv19-part h2{font-size:29px}
  .hv19-list{grid-template-columns:1fr}
  .hv19-item-title{font-size:16.5px}
  .hv19-article-hero{padding:48px 0 38px}
  .hv19-article-layout{padding:48px 0 76px}
  .hv19-copy p{font-size:17.5px;line-height:1.78}
  .hv19-prevnext{grid-template-columns:1fr}
  .hv19-prevnext a:last-child{text-align:left}
}