/* ===== Kinh Nghiệm Bài Việt — professional theme ===== */
:root{
  --bg:#f6f7fb; --surface:#ffffff; --ink:#151a2d; --ink-soft:#4a5169; --muted:#7b8299;
  --line:#e7e9f2; --brand:#4f46e5; --brand-2:#7c3aed; --brand-ink:#3730a3;
  --accent:#059669; --accent-soft:#ecfdf5; --warn:#b45309; --warn-soft:#fffbeb;
  --shadow-sm:0 1px 2px rgba(20,26,45,.06),0 1px 3px rgba(20,26,45,.05);
  --shadow-md:0 6px 20px rgba(20,26,45,.08);
  --shadow-lg:0 18px 45px rgba(20,26,45,.14);
  --radius:16px; --radius-sm:10px; --wrap:1160px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);
  font-family:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  line-height:1.7;font-size:16.5px;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}
a:hover{color:var(--brand-ink)}
img{max-width:100%;display:block}
.container{max-width:var(--wrap);margin:0 auto;padding:0 22px}
.muted{color:var(--muted)}

/* ---------- Header ---------- */
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);
  backdrop-filter:saturate(160%) blur(12px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;gap:24px;height:70px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.18rem;color:var(--ink);letter-spacing:-.02em}
.logo .mark{width:36px;height:36px;border-radius:10px;display:grid;place-items:center;color:#fff;font-size:1.1rem;
  background:linear-gradient(135deg,var(--brand),var(--brand-2));box-shadow:var(--shadow-sm)}
.nav-links{display:flex;gap:6px;align-items:center;margin-left:auto}
.nav-links a{color:var(--ink-soft);font-weight:600;font-size:.95rem;padding:9px 14px;border-radius:9px;transition:.15s}
.nav-links a:hover{background:var(--bg);color:var(--ink)}
.nav-links a.cta{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;box-shadow:var(--shadow-sm)}
.nav-links a.cta:hover{filter:brightness(1.05)}
.cat-bar{border-top:1px solid var(--line);background:var(--surface)}
.cat-bar .inner{display:flex;gap:8px;overflow-x:auto;padding:11px 0}
.cat-bar a{white-space:nowrap;font-size:.9rem;font-weight:600;color:var(--ink-soft);
  padding:6px 14px;border:1px solid var(--line);border-radius:999px;background:var(--bg)}
.cat-bar a:hover{border-color:var(--brand);color:var(--brand)}

/* ---------- Hero ---------- */
.hero{position:relative;overflow:hidden;color:#fff;
  background:radial-gradient(1000px 420px at 15% -20%,#8b5cf6 0,transparent 55%),
             radial-gradient(900px 400px at 100% 0,#4338ca 0,transparent 50%),
             linear-gradient(135deg,#4f46e5,#6d28d9)}
.hero::after{content:"";position:absolute;inset:0;opacity:.12;
  background-image:radial-gradient(#fff 1px,transparent 1px);background-size:22px 22px}
.hero .container{position:relative;padding:74px 22px 66px;text-align:center}
.hero .eyebrow{display:inline-block;font-weight:600;font-size:.82rem;letter-spacing:.08em;text-transform:uppercase;
  background:rgba(255,255,255,.16);border:1px solid rgba(255,255,255,.28);padding:6px 14px;border-radius:999px;margin-bottom:18px}
.hero h1{margin:0 0 14px;font-size:2.7rem;line-height:1.15;font-weight:800;letter-spacing:-.02em}
.hero p{margin:0 auto 26px;max-width:640px;font-size:1.12rem;color:rgba(255,255,255,.92)}
.hero .chips{display:flex;gap:10px;flex-wrap:wrap;justify-content:center}
.hero .chip{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.28);
  color:#fff;padding:8px 16px;border-radius:999px;font-size:.92rem;font-weight:600;transition:.15s}
.hero .chip:hover{background:rgba(255,255,255,.24)}

/* ---------- Sections ---------- */
main{padding-bottom:20px}
.section{padding:46px 0}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:14px;margin-bottom:26px}
.section-head h2{margin:0;font-size:1.6rem;font-weight:800;letter-spacing:-.02em}
.section-head p{margin:4px 0 0;color:var(--muted);font-size:.98rem}

/* ---------- Card grid ---------- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:24px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;
  display:flex;flex-direction:column;box-shadow:var(--shadow-sm);transition:transform .18s,box-shadow .18s,border-color .18s}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow-lg);border-color:transparent}
.card .thumb{aspect-ratio:16/9;background:linear-gradient(135deg,#eef0fb,#e6e9fb);position:relative;overflow:hidden;
  display:grid;place-items:center;font-size:2.6rem}
.card .thumb img{width:100%;height:100%;object-fit:cover;transition:transform .3s}
.card:hover .thumb img{transform:scale(1.04)}
.card .thumb .tag{position:absolute;left:12px;top:12px;background:rgba(255,255,255,.94);color:var(--brand-ink);
  font-size:.74rem;font-weight:700;padding:4px 11px;border-radius:999px;box-shadow:var(--shadow-sm)}
.card .body{padding:18px 20px 20px;display:flex;flex-direction:column;gap:10px;flex:1}
.card h3{margin:0;font-size:1.16rem;line-height:1.4;font-weight:700;letter-spacing:-.01em}
.card h3 a{color:var(--ink)}
.card h3 a:hover{color:var(--brand)}
.card .excerpt{margin:0;color:var(--ink-soft);font-size:.95rem;flex:1}
.card .meta{display:flex;gap:14px;color:var(--muted);font-size:.84rem;border-top:1px solid var(--line);padding-top:12px;margin-top:2px}

.featured{display:grid;grid-template-columns:1.4fr 1fr;gap:24px}
.featured .lead{position:relative;border-radius:var(--radius);overflow:hidden;min-height:340px;
  box-shadow:var(--shadow-md);background:linear-gradient(135deg,#4f46e5,#7c3aed);color:#fff;display:flex}
.featured .lead img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;opacity:1}
.featured .lead .fl-body{position:relative;margin-top:auto;padding:26px;
  background:linear-gradient(0deg,rgba(8,10,26,.92) 0%,rgba(8,10,26,.55) 45%,rgba(8,10,26,0) 100%)}
.featured .lead .tag{display:inline-block;background:rgba(255,255,255,.9);color:var(--brand-ink);
  font-size:.74rem;font-weight:700;padding:4px 11px;border-radius:999px;margin-bottom:10px}
.featured .lead h3{margin:0 0 8px;font-size:1.5rem;line-height:1.3;color:#fff}
.featured .lead h3 a{color:#fff}
.featured .side{display:flex;flex-direction:column;gap:16px}
.mini{display:flex;gap:14px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:12px;box-shadow:var(--shadow-sm);transition:.15s}
.mini:hover{box-shadow:var(--shadow-md);transform:translateX(3px)}
.mini .mthumb{width:92px;height:66px;border-radius:8px;object-fit:cover;flex-shrink:0;background:#eef0fb;display:grid;place-items:center}
.mini .mbody{min-width:0}
.mini .mbody .tag{font-size:.72rem;color:var(--brand);font-weight:700}
.mini .mbody h4{margin:3px 0 0;font-size:1rem;line-height:1.35;font-weight:700}
.mini .mbody h4 a{color:var(--ink)}
.mini .mbody h4 a:hover{color:var(--brand)}

/* ---------- Article ---------- */
.article-wrap{max-width:800px;margin:0 auto;padding:34px 22px 20px}
.crumbs{font-size:.86rem;color:var(--muted);margin-bottom:16px}
.crumbs a{color:var(--muted)}
.article-head .kicker{color:var(--brand);font-weight:700;text-transform:uppercase;font-size:.8rem;letter-spacing:.06em}
.article-head h1{margin:8px 0 14px;font-size:2.3rem;line-height:1.22;font-weight:800;letter-spacing:-.02em}
.article-head .meta{display:flex;gap:16px;flex-wrap:wrap;color:var(--muted);font-size:.92rem;margin-bottom:22px}
.cover{width:100%;aspect-ratio:16/9;object-fit:cover;border-radius:var(--radius);box-shadow:var(--shadow-md);margin-bottom:30px}
.article-body{font-size:1.08rem;color:#242a40}
.article-body h2{font-size:1.6rem;font-weight:800;margin:38px 0 14px;letter-spacing:-.01em;
  padding-bottom:8px;border-bottom:2px solid var(--line)}
.article-body h3{font-size:1.24rem;font-weight:700;margin:26px 0 10px}
.article-body p{margin:0 0 18px}
.article-body ul,.article-body ol{margin:0 0 18px;padding-left:24px}
.article-body li{margin-bottom:8px}
.article-body li::marker{color:var(--brand)}
.article-body strong{color:var(--ink)}
.article-body a{text-decoration:underline;text-underline-offset:2px}
.tags{display:flex;gap:8px;flex-wrap:wrap;margin:28px 0}
.tag-pill{background:var(--surface);border:1px solid var(--line);padding:6px 14px;border-radius:999px;font-size:.85rem;color:var(--ink-soft)}

.refs{background:linear-gradient(135deg,#f5f3ff,#eef2ff);border:1px solid #ddd6fe;border-radius:var(--radius);padding:22px 24px;margin:30px 0}
.refs h3{margin:0 0 14px;font-size:1.15rem;display:flex;align-items:center;gap:8px}
.refs ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:10px}
.refs li a{display:inline-flex;align-items:center;gap:10px;font-weight:600;background:var(--surface);
  border:1px solid var(--line);padding:11px 15px;border-radius:10px;width:100%;box-shadow:var(--shadow-sm);transition:.15s}
.refs li a:hover{border-color:var(--brand);transform:translateX(3px)}
.refs li a::before{content:"↗";color:var(--brand);font-weight:800}

.notice{border:1px solid #fcd34d;background:var(--warn-soft);color:#7c5307;
  border-radius:var(--radius);padding:16px 20px;font-size:.95rem;margin:26px 0}
.notice strong{color:var(--warn)}

.related-block{border-top:1px solid var(--line);margin-top:44px;padding-top:30px}
.related-block h2{font-size:1.4rem;font-weight:800;margin:0 0 20px}

/* ---------- Buttons ---------- */
.btn{display:inline-flex;align-items:center;gap:8px;background:linear-gradient(135deg,var(--brand),var(--brand-2));
  color:#fff;border:none;padding:12px 22px;border-radius:11px;font-weight:700;cursor:pointer;font-size:.96rem;
  box-shadow:var(--shadow-sm);transition:.15s;font-family:inherit}
.btn:hover{filter:brightness(1.06);color:#fff;box-shadow:var(--shadow-md)}
.btn.ghost{background:var(--surface);border:1px solid var(--line);color:var(--ink)}
.btn.ghost:hover{border-color:var(--brand);color:var(--brand);filter:none}

/* ---------- Footer ---------- */
.site-footer{background:#0f1424;color:#c7cbdd;margin-top:40px;padding:52px 0 26px}
.site-footer .cols{display:grid;grid-template-columns:1.6fr 1fr 1fr;gap:36px}
.site-footer h4{color:#fff;font-size:1rem;margin:0 0 14px}
.site-footer .logo{color:#fff;margin-bottom:12px}
.site-footer p{color:#9aa1bd;font-size:.92rem;margin:0 0 10px}
.site-footer ul{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:9px}
.site-footer a{color:#c7cbdd;font-size:.92rem}
.site-footer a:hover{color:#fff}
.site-footer .bottom{border-top:1px solid #232941;margin-top:34px;padding-top:20px;
  display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;color:#7b8299;font-size:.86rem}

.empty,.loading{text-align:center;color:var(--muted);padding:50px 0}

@media(max-width:820px){
  .featured{grid-template-columns:1fr}
  .site-footer .cols{grid-template-columns:1fr;gap:26px}
}
@media(max-width:640px){
  .hero h1{font-size:2rem}.hero .container{padding:54px 22px 46px}
  .article-head h1{font-size:1.7rem}.article-body{font-size:1.03rem}
  .nav{height:62px;gap:12px}.nav-links a:not(.cta){display:none}
}