/* ── Variables ──────────────────────────────────────────── */
:root{
  --navy:#0d2d52;--navy-d:#0a2440;--navy-mid:#2176b8;
  --blue:#378add;--green:#1a8a6e;--green-bg:#e8f8f0;
  --orange:#c0631a;--orange-bg:#fff3e0;
  --text:#1a1a2e;--text-b:#4a4a68;--text-m:#888;
  --bg:#fff;--bg-alt:#f8f9fa;--border:#e0e0e0;
  --danger:#e74c3c;--r:8px;--rl:12px;
  --sh:0 2px 12px rgba(13,45,82,.08);
  --shm:0 4px 24px rgba(13,45,82,.13);
  --mw:1100px;--gap:4.5rem
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:'Inter',system-ui,-apple-system,sans-serif;font-size:14px;color:var(--text);background:var(--bg);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.container{max-width:var(--mw);margin:0 auto;padding:0 1.5rem}

/* ════════════════════════════════
   NAV — đồng bộ timbanhocchung
════════════════════════════════ */
.site-nav{background:#0d2d52;position:sticky;top:0;z-index:100;box-shadow:0 1px 0 rgba(255,255,255,.05)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:52px}
.nav-left{display:flex;align-items:center;gap:0;flex-shrink:0}
.nav-brand-link{font-family:'Lora',serif;font-size:15px;font-weight:500;color:#F1EFE8;letter-spacing:.02em;white-space:nowrap;text-decoration:none}
.nav-brand-link span{color:#F1EFE8}
.nav-divider{width:1px;height:16px;background:rgba(255,255,255,.2);margin:0 12px;flex-shrink:0}
.nav-cobrand{display:flex;align-items:center;gap:6px}
.nav-cobrand-text{font-family:'Inter',sans-serif;font-size:11px;font-weight:400;color:rgba(255,255,255,.6);letter-spacing:.08em;white-space:nowrap}
.nav-links{display:flex;gap:1.75rem}
.nav-link{color:rgba(255,255,255,.55);font-size:13px;font-weight:500;padding:.25rem 0;border-bottom:2px solid transparent;transition:color .2s,border-color .2s;text-decoration:none;white-space:nowrap}
.nav-link:hover,.nav-link.active{color:#F1EFE8;border-bottom-color:#F5A623}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:4px}
.nav-toggle span{display:block;width:22px;height:2px;background:rgba(255,255,255,.65);border-radius:2px}
@media(max-width:680px){
  .nav-toggle{display:flex}
  .nav-cobrand{display:none}
  .nav-divider{display:none}
  .nav-links{display:none;position:absolute;top:52px;left:0;right:0;background:#0a2440;flex-direction:column;gap:0;padding:.5rem 0}
  .nav-links.open{display:flex;background:#0a2440}
  .nav-link{padding:.7rem 1.5rem;border-bottom:none;border-left:3px solid transparent}
  .nav-link.active{border-left-color:#F5A623}
}

/* ════════════════════════════════
   HERO
════════════════════════════════ */
.hero{background:var(--navy);padding:4rem 0 3.5rem;min-height:320px}
/* ════════════════════════════════
   HERO — với ảnh style C
════════════════════════════════ */
.hero{position:relative;overflow:hidden}
.hero-photo-wrap{
  position:absolute;
  right:0;top:0;bottom:0;
  width:45%;
  pointer-events:none;
}
.hero-photo-wrap::before{
  content:'';
  position:absolute;
  inset:0;
  background:linear-gradient(to right, #0d2d52 0%, #0d2d52 15%, transparent 60%);
  z-index:1;
}
.hero-photo-wrap::after{
  content:'';
  position:absolute;
  bottom:0;left:0;right:0;
  height:40%;
  background:linear-gradient(to top, #0d2d52, transparent);
  z-index:1;
}
.hero-photo{
  width:100%;height:100%;
  object-fit:cover;
  object-position:center 20%;
  opacity:0;
  animation:heroFadeIn 1.2s ease 0.3s forwards;
  filter:saturate(0.85) brightness(0.9);
}
@keyframes heroFadeIn{
  from{opacity:0;transform:scale(1.04)}
  to{opacity:0.65;transform:scale(1)}
}
.hero-content{position:relative;z-index:2;max-width:580px}

@media(max-width:700px){
  .hero-photo-wrap{width:100%;opacity:.3}
  .hero-photo-wrap::before{background:linear-gradient(to right,#0d2d52 0%,rgba(13,45,82,.8) 100%)}
  .hero-content{max-width:100%}
}

.hero-eyebrow{font-size:11px;font-weight:600;letter-spacing:.12em;text-transform:uppercase;color:var(--blue);margin-bottom:1rem}
.hero-title{font-size:clamp(1.6rem,4vw,2.2rem);font-weight:600;color:#fff;line-height:1.2;margin-bottom:.4rem}
.hero-role{font-size:clamp(.95rem,2vw,1.1rem);font-weight:400;color:rgba(255,255,255,.65);margin-bottom:2rem}
.hero-btns{display:flex;gap:.75rem;flex-wrap:wrap}
.btn-hero{padding:.65rem 1.4rem;border-radius:var(--r);font-size:13px;font-weight:500;font-family:inherit;border:1.5px solid rgba(255,255,255,.22);background:transparent;color:rgba(255,255,255,.38);cursor:pointer;transition:color .18s,border-color .18s,background .18s;text-decoration:none;display:inline-flex;align-items:center;-webkit-appearance:none;appearance:none}
.btn-hero:hover{color:rgba(255,255,255,.82);border-color:rgba(255,255,255,.55);background:rgba(255,255,255,.08)}

/* ════════════════════════════════
   BUTTONS
════════════════════════════════ */
.btn{display:inline-flex;align-items:center;padding:.65rem 1.4rem;border-radius:var(--r);font-size:13px;font-weight:500;font-family:inherit;transition:all .2s;cursor:pointer;border:none;text-decoration:none;white-space:nowrap}
.btn-navy{background:var(--navy);color:#fff}.btn-navy:hover{background:var(--navy-d)}
.btn-sm{padding:.4rem .9rem;font-size:12px;background:var(--navy);color:#fff;border-radius:var(--r);border:none;cursor:pointer;font-family:inherit;text-decoration:none;display:inline-flex;align-items:center}.btn-sm:hover{background:var(--navy-d)}
.btn-zalo{display:inline-flex;align-items:center;gap:6px;padding:.6rem 1.1rem;border-radius:var(--r);font-size:13px;font-weight:500;font-family:inherit;background:transparent;color:var(--navy);border:1.5px solid rgba(13,45,82,.28);cursor:pointer;text-decoration:none;transition:all .15s}.btn-zalo:hover{background:rgba(13,45,82,.06);border-color:rgba(13,45,82,.5)}
.btn-register{display:inline-flex;align-items:center;gap:6px;padding:.6rem 1.1rem;border-radius:var(--r);font-size:13px;font-weight:500;font-family:inherit;background:var(--navy);color:#fff;border:none;cursor:pointer;text-decoration:none;transition:background .15s}.btn-register:hover{background:var(--navy-d)}
.btn-detail{display:inline-flex;align-items:center;gap:6px;padding:.6rem 1.1rem;border-radius:var(--r);font-size:13px;font-weight:500;font-family:inherit;background:#f0f2f4;color:#444;border:.5px solid #dde0e4;cursor:pointer;text-decoration:none;transition:all .15s}.btn-detail:hover{background:#e4e7ea;border-color:#ccd0d5}
.btn-more{display:inline-flex;align-items:center;gap:6px;padding:.7rem 1.6rem;border-radius:var(--r);font-size:13px;font-weight:600;font-family:inherit;background:var(--navy);color:#fff;border:none;cursor:pointer;text-decoration:none;transition:background .15s}.btn-more:hover{background:var(--navy-d)}

/* ════════════════════════════════
   SECTIONS
════════════════════════════════ */
.section{padding:var(--gap) 0}
.section.alt{background:var(--bg-alt)}
.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:1rem;margin-bottom:2rem;flex-wrap:wrap}
.section-head h2{font-size:20px;font-weight:600;color:var(--text)}
.de-label{font-size:11px;font-weight:400;color:var(--text-m);margin-left:.4rem}

/* ════════════════════════════════
   CARDS
════════════════════════════════ */
.cards-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1.25rem}
.card{display:flex;flex-direction:column;border:.5px solid var(--border);border-radius:var(--rl);overflow:hidden;background:var(--bg);transition:box-shadow .25s,transform .25s;text-decoration:none;color:inherit}
.card:hover{box-shadow:var(--shm);transform:translateY(-3px)}
.card.pinned{border-left:3px solid var(--navy)}
.card-cover{width:100%;height:160px;background:linear-gradient(135deg,var(--navy),var(--navy-mid));display:flex;align-items:center;justify-content:center;flex-shrink:0}
.card-cover img{width:100%;height:100%;object-fit:cover}
.no-img{font-size:2.5rem;font-weight:700;color:rgba(255,255,255,.12)}
.card-body{padding:1.1rem 1.25rem;display:flex;flex-direction:column;flex:1}
.card-tag{display:inline-block;background:var(--bg-alt);color:var(--text-m);font-size:10px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;padding:2px 8px;border-radius:20px;margin-bottom:.6rem;align-self:flex-start;border:.5px solid var(--border)}
.card-body h3{font-size:14px;font-weight:600;color:var(--text);line-height:1.4;margin-bottom:.4rem}
.card-body p{font-size:12px;color:var(--text-b);line-height:1.6;flex:1;margin-bottom:.75rem}
.card-date{font-size:11px;color:var(--text-m);margin-top:auto}

/* ════════════════════════════════
   COURSES HOME LIST
════════════════════════════════ */
.courses-list{display:flex;flex-direction:column;gap:.6rem}
.course-row{display:grid;grid-template-columns:52px 1fr auto;align-items:center;gap:1rem;padding:1rem 1.25rem;background:var(--bg);border:.5px solid var(--border);border-radius:var(--r);transition:box-shadow .2s}
.course-row:hover{box-shadow:var(--sh)}
.course-level{font-size:13px;font-weight:700;text-align:center;padding:4px 8px;border-radius:6px}
.level-ab{background:var(--green-bg);color:var(--green)}
.level-bc{background:var(--orange-bg);color:var(--orange)}
.level-cd{background:#eaf0f7;color:var(--navy)}
.course-info strong{display:block;font-size:13px;font-weight:600;color:var(--text)}
.de-name{font-size:11px;font-style:italic;color:var(--text-m);display:block}
.course-schedule{font-size:11px;color:var(--text-b);display:block}
@media(max-width:600px){.course-row{grid-template-columns:1fr}}

/* ════════════════════════════════
   BADGES
════════════════════════════════ */
.badge{display:inline-block;font-size:10px;font-weight:700;padding:2px 9px;border-radius:20px}
.badge-open{background:var(--green-bg);color:var(--green)}
.badge-soon{background:#eaf0f7;color:var(--navy)}
.badge-full{background:#fdecea;color:var(--danger)}

/* ════════════════════════════════
   COURSES FULL PAGE
════════════════════════════════ */
.courses-full{display:flex;flex-direction:column;gap:1.25rem}
.course-card{border:.5px solid var(--border);border-radius:var(--rl);padding:1.75rem;background:var(--bg)}
.course-card-head{display:flex;justify-content:space-between;align-items:flex-start;gap:1rem;margin-bottom:1rem;flex-wrap:wrap}
.course-card-head h3{font-size:18px;font-weight:600;color:var(--text);margin:.25rem 0}
.course-level-badge{display:inline-block;font-size:11px;font-weight:700;padding:3px 9px;border-radius:6px;margin-bottom:4px}
.course-card-meta{display:flex;flex-wrap:wrap;gap:1rem;color:var(--text-b);font-size:12px;margin-bottom:1.25rem;padding-bottom:1.25rem;border-bottom:.5px solid var(--border)}
.course-card-meta span{display:flex;align-items:center;gap:4px}
.course-card-body{margin-bottom:1.5rem}
.course-btns{display:flex;gap:.6rem;flex-wrap:wrap;margin-top:1rem}

/* ════════════════════════════════
   CHANNELS
════════════════════════════════ */
.channels-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:1rem}
.channel-card{display:flex;flex-direction:column;gap:.35rem;padding:1.25rem;border:.5px solid var(--border);border-radius:var(--rl);background:var(--bg);transition:box-shadow .2s,transform .2s;text-decoration:none;color:inherit}
.channel-card:hover{box-shadow:var(--sh);transform:translateY(-2px)}
.ch-icon{width:36px;height:36px;background:#eaf0f7;border-radius:var(--r);display:flex;align-items:center;justify-content:center;font-size:16px;color:var(--navy);margin-bottom:.4rem}
.channel-card strong{font-size:13px;font-weight:600;color:var(--text)}
.channel-card p{font-size:12px;color:var(--text-b)}
.ch-link{font-size:11px;color:var(--navy);font-weight:500;margin-top:.2rem}


/* ════════════════════════════════
   PAGE HERO — sóng biển (tất cả trang)
════════════════════════════════ */
.page-hero-wave{
  position:relative;overflow:hidden;
  background:#0a2540;padding:2.75rem 0 3rem;
}
.page-hero-wave .hero-waves{
  position:absolute;inset:0;width:100%;height:100%;z-index:0;
}
.page-hero-wave::before{
  content:'';position:absolute;inset:0;
  background:linear-gradient(100deg,rgba(10,37,64,.97) 0%,rgba(10,37,64,.82) 45%,rgba(13,55,90,.35) 80%,transparent 100%);
  z-index:1;
}
.page-hero-content{position:relative;z-index:2}
.page-hero-content h1{
  font-size:clamp(1.5rem,3.5vw,2rem);
  font-weight:600;color:#fff;margin-bottom:.4rem;
}
.page-hero-content p{font-size:13px;color:rgba(255,255,255,.6)}
.page-hero-content .de-label{color:rgba(255,255,255,.35);font-size:11px}


/* ════════════════════════════════
   FILTER TABS
════════════════════════════════ */
.filter-tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:1.75rem}
.filter-tab{padding:5px 14px;border-radius:20px;font-size:12px;font-weight:500;border:.5px solid var(--border);background:var(--bg);color:var(--text-m);cursor:pointer;transition:all .15s;font-family:inherit}
.filter-tab:hover{border-color:var(--navy);color:var(--navy)}
.filter-tab.active{background:var(--navy);color:#fff;border-color:var(--navy)}

/* ════════════════════════════════
   POST / PROSE
════════════════════════════════ */
.post-article{padding:3rem 0 5rem}
.post-container{max-width:720px}
.post-header{margin-bottom:2.5rem;padding-bottom:1.75rem;border-bottom:.5px solid var(--border)}
.post-header h1{font-size:clamp(1.5rem,3.5vw,2.2rem);font-weight:600;color:var(--text);line-height:1.25;margin:.6rem 0}
.post-lead{font-size:15px;color:var(--text-b);margin-top:.6rem;line-height:1.7}
.post-meta{color:var(--text-m);font-size:12px;margin-top:.6rem}
.post-tags{display:flex;gap:.4rem;flex-wrap:wrap}
.post-cover{width:100%;max-height:420px;height:auto;object-fit:contain;object-position:top center;border-radius:var(--rl);margin-bottom:2rem;display:block;background:#f8f9fa}
.prose h2{font-size:20px;font-weight:600;color:var(--text);margin:2rem 0 .6rem}
.prose h3{font-size:16px;font-weight:600;color:var(--text);margin:1.5rem 0 .5rem}
.prose p{font-size:14px;color:var(--text-b);margin-bottom:1.1rem;line-height:1.8}
.prose ul,.prose ol{padding-left:1.4rem;margin-bottom:1.1rem;color:var(--text-b);font-size:14px}
.prose li{margin-bottom:.35rem}
.prose strong{color:var(--text);font-weight:600}
.prose a{color:var(--navy);border-bottom:1px solid #b5d4f4}
.prose blockquote{border-left:3px solid var(--navy);margin:1.5rem 0;padding:.75rem 1.25rem;background:#eaf0f7;border-radius:0 var(--r) var(--r) 0;color:var(--navy-d);font-style:italic;font-size:14px}
.prose code{background:var(--bg-alt);padding:.15em .4em;border-radius:4px;font-size:.88em}
.prose img{border-radius:var(--rl);margin:1.5rem 0;max-width:100%;height:auto;display:block}
.post-back a{font-size:13px;color:var(--text-m);display:inline-flex;align-items:center;gap:4px}
.post-back a:hover{color:var(--navy)}

/* ════════════════════════════════
   CONTACT
════════════════════════════════ */
.contact-wrap{display:grid;grid-template-columns:1fr 1fr;gap:3.5rem;align-items:start}
.contact-wrap h2{font-size:18px;font-weight:600;color:var(--text);margin-bottom:1.25rem}
.contact-list{display:flex;flex-direction:column;gap:.6rem}
.contact-item{display:flex;align-items:center;gap:.9rem;padding:.9rem 1.1rem;border:.5px solid var(--border);border-radius:var(--r);transition:all .2s;text-decoration:none;color:inherit}
.contact-item:hover{border-color:var(--navy);box-shadow:var(--sh)}
.ci-icon{width:36px;height:36px;background:#eaf0f7;border-radius:var(--r);display:flex;align-items:center;justify-content:center;font-size:16px;color:var(--navy);flex-shrink:0}
.contact-item div{display:flex;flex-direction:column}
.contact-item strong{font-weight:600;color:var(--text);font-size:13px}
.contact-item span{color:var(--text-b);font-size:12px}
.faq-list{display:flex;flex-direction:column;gap:.4rem}
.faq-item{border:.5px solid var(--border);border-radius:var(--r);overflow:hidden}
.faq-item summary{padding:.9rem 1.1rem;font-weight:500;font-size:13px;cursor:pointer;color:var(--text);list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:'+';color:var(--navy);font-size:1.1rem}
.faq-item[open] summary::after{content:'−'}
.faq-item[open] summary{background:var(--bg-alt)}
.faq-item p{padding:0 1.1rem .9rem;color:var(--text-b);font-size:13px}
@media(max-width:680px){.contact-wrap{grid-template-columns:1fr;gap:2rem}}

/* ════════════════════════════════
   MODAL
════════════════════════════════ */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.5);display:flex;align-items:center;justify-content:center;z-index:200;padding:1rem}
.modal-overlay.hidden{display:none}
.modal-box{background:#fff;border-radius:var(--rl);padding:2rem;max-width:520px;width:100%;max-height:90vh;overflow-y:auto;position:relative}
.modal-close{position:absolute;top:1rem;right:1rem;background:none;border:none;font-size:1.25rem;cursor:pointer;color:var(--text-m);line-height:1}
.modal-close:hover{color:var(--text)}
.modal-title{font-size:17px;font-weight:600;color:var(--text);margin-bottom:1.25rem;padding-right:2rem}
.modal-form-group{margin-bottom:.9rem}
.modal-form-group label{display:block;font-size:12px;font-weight:500;color:var(--text-m);text-transform:uppercase;letter-spacing:.04em;margin-bottom:4px}
.modal-form-group input,.modal-form-group textarea,.modal-form-group select{width:100%;border:.5px solid var(--border);border-radius:var(--r);padding:.6rem .85rem;font-size:13px;font-family:inherit;outline:none;color:var(--text)}
.modal-form-group input:focus,.modal-form-group textarea:focus{border-color:var(--navy)}
.modal-form-group textarea{min-height:80px;resize:vertical}
.modal-note{font-size:12px;color:var(--text-m);line-height:1.65;background:var(--bg-alt);padding:.75rem 1rem;border-radius:var(--r);margin-bottom:1rem}
.modal-actions{display:flex;gap:.6rem;margin-top:1.25rem;flex-wrap:wrap}

/* ════════════════════════════════
   FOOTER
════════════════════════════════ */
.site-footer{background:var(--navy);padding:2.5rem 0 2rem}
.footer-inner{display:grid;grid-template-columns:1fr auto;gap:1.5rem 3rem;align-items:start}
.footer-brand strong{display:block;font-size:14px;color:#fff;margin-bottom:.25rem}
.footer-brand em{font-style:italic;font-size:12px;color:rgba(255,255,255,.55)}
.footer-nav{display:flex;flex-direction:column;gap:.4rem;text-align:right}
.footer-nav a{color:rgba(255,255,255,.55);font-size:12px;transition:color .2s}
.footer-nav a:hover{color:#fff}
.footer-copy{grid-column:1/-1;font-size:11px;color:rgba(255,255,255,.35);border-top:.5px solid rgba(255,255,255,.08);padding-top:1.25rem}
@media(max-width:600px){.footer-inner{grid-template-columns:1fr}.footer-nav{text-align:left;flex-direction:row;flex-wrap:wrap;gap:.6rem 1.25rem}}
.empty-state{color:var(--text-m);font-style:italic;padding:3rem;text-align:center;border:.5px dashed var(--border);border-radius:var(--rl);font-size:13px}

/* Slim wave bar for post pages */
.post-hero-wave{
  position:relative;overflow:hidden;
  background:#0a2540;height:80px;
}

/* Home hero — cao hơn các trang khác */
.home-hero{padding:4rem 0 5rem !important;min-height:340px !important}
.home-hero .hero-eyebrow{font-size:11px;font-weight:600;letter-spacing:.12em;text-transform:uppercase;color:#7EB8E8;margin-bottom:1rem}
.home-hero .hero-title{font-size:clamp(1.8rem,4.5vw,2.6rem);font-weight:600;color:#fff;line-height:1.15;margin-bottom:.5rem}
.home-hero .hero-role{font-size:clamp(.95rem,2vw,1.05rem);font-weight:400;color:rgba(255,255,255,.6);margin-bottom:2rem}
.hero-btns{display:flex;gap:.75rem;flex-wrap:wrap}

/* ── Contact 3 cột ──────────────────────────────────────── */
.contact-3col {
  display: grid;
  grid-template-columns: 1fr 1.2fr 1fr;
  gap: 3rem;
  align-items: start;
}
.contact-col-title {
  font-size: 16px; font-weight: 600;
  color: var(--text); margin-bottom: 1.25rem;
  padding-bottom: 0.6rem;
  border-bottom: 0.5px solid var(--border);
}
/* Icon màu riêng cho kênh */
.ci-yt { background: #fff0f0 !important; color: #cc0000 !important; }
.ci-fb { background: #eef2ff !important; color: #1877f2 !important; }
.ci-tbh { background: var(--green-bg) !important; color: var(--green) !important; }

@media (max-width: 900px) {
  .contact-3col { grid-template-columns: 1fr 1fr; gap: 2rem; }
}
@media (max-width: 580px) {
  .contact-3col { grid-template-columns: 1fr; gap: 2rem; }
}