:root{--teal:#0f766e;--teal-dark:#115e59;--teal-light:#5eead4;--cream:#fbf7f0;--cream-2:#f5ede0;--rose:#be6a5a;--rose-soft:#e8c4bb;--ink:#1f2a2a;--ink-soft:#4a5757;--white:#fff;--shadow:0 10px 30px rgba(15,118,110,.12);--radius:18px}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Be Vietnam Pro',system-ui,-apple-system,sans-serif;color:var(--ink);background:var(--cream);font-size:18px;line-height:1.75;-webkit-font-smoothing:antialiased}
.wrap{max-width:820px;margin:0 auto;padding:0 20px}
.wrap-wide{max-width:1120px;margin:0 auto;padding:0 20px}
a{color:var(--teal);text-decoration:none}a:hover{text-decoration:underline}
img{max-width:100%}
h1{font-size:clamp(26px,5vw,40px);font-weight:800;line-height:1.25;margin:10px 0 14px;text-wrap:balance}
h2{font-size:clamp(21px,3.4vw,28px);font-weight:800;line-height:1.3;margin:34px 0 12px;color:var(--ink);text-wrap:balance}
p{margin-bottom:14px;color:var(--ink-soft);text-wrap:pretty}
ul{margin:0 0 16px 22px}li{margin-bottom:8px;color:var(--ink-soft)}
b{color:var(--ink)}
table{width:100%;border-collapse:collapse;margin:8px 0 16px;font-size:16px}
th,td{border:1px solid var(--cream-2);padding:10px 12px;text-align:left}
th{background:var(--teal);color:#fff;font-weight:700}
tr:nth-child(even) td{background:#fff}
header{position:sticky;top:0;z-index:50;background:rgba(251,247,240,.94);backdrop-filter:saturate(180%) blur(10px);border-bottom:1px solid var(--cream-2)}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{display:flex;align-items:center;gap:11px;font-weight:800;color:var(--ink);font-size:17px}
.brand .logo{width:42px;height:42px;border-radius:50%;background:linear-gradient(135deg,var(--teal),var(--teal-dark));color:#fff;display:grid;place-items:center;font-weight:800;font-size:18px}
.brand small{display:block;font-weight:500;font-size:11px;color:var(--teal);letter-spacing:.5px}
.nav-links a{margin-left:18px;font-weight:600;color:var(--ink-soft);font-size:15px}
.article{background:var(--white);margin:26px auto;border-radius:var(--radius);box-shadow:var(--shadow);padding:34px 30px}
@media(max-width:600px){.article{padding:26px 18px}}
.crumb{font-size:14px;color:var(--ink-soft);margin-bottom:6px}
.crumb a{color:var(--teal)}
.byline{display:flex;align-items:center;gap:12px;flex-wrap:wrap;font-size:14px;color:var(--ink-soft);border-bottom:1px solid var(--cream-2);padding-bottom:16px;margin-bottom:8px}
.byline .rev{background:#e7f5f2;color:var(--teal-dark);font-weight:700;padding:4px 12px;border-radius:999px;font-size:13px}
.quick{background:var(--cream);border-left:5px solid var(--teal);border-radius:12px;padding:18px 20px;margin:20px 0}
.quick b{color:var(--teal-dark)}.quick p{margin:0;color:var(--ink)}
.toc{background:var(--cream);border:1px solid var(--cream-2);border-radius:12px;padding:18px 22px;margin:20px 0}
.toc b{display:block;margin-bottom:8px;color:var(--ink)}
.toc ol{margin:0 0 0 20px}.toc li{margin-bottom:5px}.toc a{color:var(--teal)}
.faq-item{border:1px solid var(--cream-2);border-radius:12px;margin-bottom:12px;overflow:hidden}
.faq-item button{width:100%;text-align:left;background:none;border:none;cursor:pointer;padding:16px 18px;font-size:17px;font-weight:700;color:var(--ink);display:flex;justify-content:space-between;gap:14px;font-family:inherit}
.faq-item button .s{color:var(--teal);font-size:24px;transition:transform .2s}
.faq-item.open button .s{transform:rotate(45deg)}
.faq-item .a{max-height:0;overflow:hidden;transition:max-height .3s;padding:0 18px}
.faq-item.open .a{max-height:400px;padding-bottom:16px}
.faq-item .a p{margin:0;font-size:16px}
.cta{background:linear-gradient(160deg,var(--teal-dark),var(--teal));color:#fff;border-radius:var(--radius);padding:28px 26px;text-align:center;margin:30px 0}
.cta h3{color:#fff;font-size:22px;margin-bottom:8px}
.cta p{color:rgba(255,255,255,.9);margin-bottom:18px;font-size:16px}
.cta .btns{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.cta a{display:inline-flex;align-items:center;gap:8px;padding:14px 24px;border-radius:999px;font-weight:700;font-size:16px}
.cta .b-zalo{background:#0068ff;color:#fff}.cta .b-call{background:#fff;color:var(--teal-dark)}
.cta-slim{background:linear-gradient(0deg,rgba(20,140,130,.06),rgba(20,140,130,.06)),#fff;border:1px solid var(--teal);border-left:4px solid var(--teal);border-radius:12px;padding:13px 16px;margin:18px 0;font-size:15px;line-height:1.65}
.cta-slim a{font-weight:700;color:var(--teal-dark);text-decoration:underline}
.cta-slim a.cs-zalo{color:#0068ff}
.nextsteps{margin:26px 0 18px;padding:16px 18px;background:#fbfaf8;border:1px solid #e6e1da;border-radius:14px}
.nextsteps>b{display:block;font-size:15px;color:var(--ink);margin-bottom:10px}
.nextsteps a{display:flex;gap:11px;align-items:flex-start;padding:11px 12px;margin-top:8px;background:#fff;border:1px solid #e6e1da;border-radius:11px;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.nextsteps a:hover,.nextsteps a:focus-visible{border-color:var(--teal);transform:translateX(2px)}
.nextsteps .ns-ic{font-size:20px;line-height:1.3;flex:0 0 auto}
.nextsteps a b{display:block;font-size:15px;line-height:1.5;color:var(--teal-dark)}
.nextsteps a small{display:block;margin-top:3px;font-size:13.5px;line-height:1.6;color:#6b6560}
.sources{background:var(--cream);border-radius:12px;padding:16px 20px;margin:24px 0;font-size:14px}
.authorbox{display:flex;gap:15px;align-items:flex-start;background:var(--cream);border:1px solid var(--cream-2);border-radius:16px;padding:18px 20px;margin:28px 0}
.authorbox img{width:74px;height:74px;border-radius:50%;object-fit:cover;object-position:center 42%;flex:none;border:3px solid var(--white);box-shadow:var(--shadow)}
.authorbox .ab-label{display:block;font-size:12px;font-weight:800;color:var(--teal);text-transform:uppercase;letter-spacing:.05em}
.authorbox b{display:block;font-size:18px;color:var(--ink);margin:2px 0 6px}
.authorbox p{font-size:14.5px;color:var(--ink-soft);margin:0 0 8px;line-height:1.65}
.authorbox a{color:var(--teal-dark);font-weight:700}
.sources b{display:block;margin-bottom:6px}
.disc{font-size:13.5px;color:var(--ink-soft);border-left:4px solid var(--rose);background:var(--cream);border-radius:10px;padding:14px 18px;margin:22px 0}
.related{margin:26px 0}
.related h3{font-size:20px;margin-bottom:14px}
.related-grid{display:grid;gap:14px}
@media(min-width:640px){.related-grid{grid-template-columns:1fr 1fr}}
.rel-card{display:block;background:var(--white);border:1px solid var(--cream-2);border-radius:12px;padding:16px 18px;color:var(--ink);font-weight:600}
.rel-card:hover{box-shadow:var(--shadow);text-decoration:none;transform:translateY(-2px);transition:.15s}
.rel-card small{display:block;color:var(--teal);font-weight:700;font-size:12px;text-transform:uppercase;margin-bottom:4px}
footer{background:var(--ink);color:rgba(255,255,255,.7);padding:32px 0 90px;font-size:14px;margin-top:30px}
footer a{color:rgba(255,255,255,.8)}
.foot-b{text-align:center;border-top:1px solid rgba(255,255,255,.12);margin-top:18px;padding-top:16px;font-size:12.5px;color:rgba(255,255,255,.5)}
/* blog index */
.hero-b{background:linear-gradient(180deg,var(--cream),var(--cream-2));padding:44px 0;text-align:center}
.hero-b p{max-width:640px;margin:8px auto 0}
.cluster{margin:34px 0}
.cluster h2{margin-bottom:14px}
.post-grid{display:grid;gap:16px}
@media(min-width:680px){.post-grid{grid-template-columns:1fr 1fr}}
.post-card{background:#fff;border:1px solid var(--cream-2);border-radius:14px;padding:22px;transition:.15s}
.post-card:hover{box-shadow:var(--shadow);transform:translateY(-3px)}
.post-card small{color:var(--teal);font-weight:700;font-size:12px;text-transform:uppercase}
.post-card h3{font-size:19px;margin:6px 0 8px}
.post-card p{font-size:15px;margin:0}
.sticky-bar{position:fixed;left:0;right:0;bottom:0;z-index:65;display:flex;background:#fff;box-shadow:0 -6px 20px rgba(0,0,0,.12);border-top:1px solid var(--cream-2)}
.sticky-bar a{flex:1;display:flex;align-items:center;justify-content:center;gap:8px;padding:14px 8px;font-weight:800;font-size:16px}
.sticky-bar .s-call{color:var(--teal-dark)}.sticky-bar .s-zalo{background:#0068ff;color:#fff}
@media(min-width:820px){.sticky-bar{display:none}footer{padding-bottom:32px}}
.fab-z{position:fixed;right:18px;bottom:18px;z-index:60;display:none;align-items:center;gap:8px;background:#0068ff;color:#fff;font-weight:800;font-size:15px;padding:13px 20px;border-radius:999px;box-shadow:0 10px 26px rgba(0,104,255,.4);text-decoration:none}
.fab-z:hover{background:#0057d8;transform:translateY(-1px)}
@media(min-width:820px){.fab-z{display:inline-flex}}
.hero-svg{display:block;width:100%;height:auto;border-radius:14px;margin:14px 0 4px;box-shadow:0 6px 18px rgba(15,118,110,.10)}
.hero-photo{display:block;width:100%;height:clamp(200px,34vw,300px);object-fit:cover;border-radius:14px;margin:14px 0 4px;box-shadow:0 6px 18px rgba(15,118,110,.12)}