/* SEO Gốc — NỀN SÁNG, chữ lớn. Thanh dưới chạy mọi khổ: điện thoại = thanh đáy, ≥768px = dock nổi giữa đáy (không ẩn ở khổ nào). */
:root{
  --xanh:#0e7a4e;--xanh-dam:#095c3a;--xanh-nhat:#e7f6ed;--xanh-vien:#bfe5cf;
  --nen:#f7faf8;--trang:#fff;--chu:#13201a;--phu:#4b5f55;--vien:#dde8e1;
  --vang:#f5b53d;--vang-nhat:#fff6e0;--cam:#e07b1a;--cam-nhat:#fff0e2;--do:#c93838;--do-nhat:#fdeaea;
  --bo:16px;--bong:0 1px 2px rgba(16,40,28,.06),0 6px 20px rgba(16,40,28,.06);
  --bn-cao:68px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:84px}
body{margin:0;background:var(--nen);color:var(--chu);font:400 18px/1.65 "Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;padding-bottom:calc(var(--bn-cao) + env(safe-area-inset-bottom) + 12px)}
a{color:var(--xanh);text-underline-offset:3px}
a:hover{color:var(--xanh-dam)}
img{max-width:100%;height:auto}
h1,h2,h3,h4{line-height:1.25;letter-spacing:-.01em;margin:0 0 .5em}
h1{font-size:clamp(30px,6vw,48px);font-weight:800}
h2{font-size:clamp(24px,4vw,32px);font-weight:800}
h3,.h3{font-size:21px;font-weight:700}
h4{font-size:19px;font-weight:700}
p{margin:0 0 1em}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.86em;background:#eef4f0;border-radius:6px;padding:.1em .35em;word-break:break-word}
pre{background:#f1f6f3;border:1px solid var(--vien);border-radius:12px;padding:14px 16px;overflow-x:auto;font-size:15px;line-height:1.55}
pre code{background:none;padding:0;font-size:inherit;word-break:normal}
.an{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.bo-qua{position:absolute;left:-999px;top:8px;background:var(--trang);padding:8px 14px;border-radius:10px;z-index:99}
.bo-qua:focus{left:8px}
.khung{max-width:1160px;margin:0 auto;padding:0 16px}
.khung-hep{max-width:780px;margin:0 auto;padding:0 16px}
.muc{padding:28px 16px}
.muc-mo{color:var(--phu)}
.muc-dau{display:flex;justify-content:space-between;align-items:baseline;gap:12px;flex-wrap:wrap}
.muc-dau a{font-weight:600;text-decoration:none}
.nhan-nho{display:inline-block;font-size:14px;font-weight:700;letter-spacing:.02em;color:var(--xanh);background:var(--xanh-nhat);border-radius:999px;padding:4px 12px;margin-bottom:14px}
.ghi-nho{font-size:15px;color:var(--phu)}
.dem-nho{font-size:.6em;vertical-align:middle;background:var(--xanh-nhat);color:var(--xanh);border-radius:999px;padding:2px 10px}

/* thanh trên */
.tb{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.94);backdrop-filter:saturate(1.4) blur(10px);-webkit-backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--vien)}
.tb-in{max-width:1160px;margin:0 auto;padding:10px 16px;display:flex;align-items:center;gap:16px}
.tb-logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--chu)}
.tb-logo svg{flex:none}
.tb-logo b{display:block;font-size:20px;font-weight:800;line-height:1.1}
.tb-logo small{display:block;font-size:13px;color:var(--phu);line-height:1.2}
.tb-nav{display:none;margin-left:auto;gap:4px}
.tb-nav a{text-decoration:none;color:var(--chu);font-weight:600;font-size:16px;padding:8px 12px;border-radius:10px}
.tb-nav a:hover,.tb-nav a.on{background:var(--xanh-nhat);color:var(--xanh-dam)}
.tb-mn{margin-left:auto;display:flex;align-items:center;gap:8px;border:1px solid var(--vien);background:var(--trang);border-radius:12px;padding:8px 12px;min-height:44px;font:600 16px "Be Vietnam Pro",sans-serif;color:var(--chu);cursor:pointer}
.hb{display:inline-flex;flex-direction:column;gap:4px}.hb i{display:block;width:18px;height:2px;background:currentColor;border-radius:2px}
@media(min-width:1024px){.tb-nav{display:flex}.tb-mn{margin-left:8px}}

/* nút, ô nhập */
.nut{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 20px;border-radius:12px;font:700 17px "Be Vietnam Pro",sans-serif;text-decoration:none;cursor:pointer;border:2px solid transparent;transition:transform .08s,background .15s}
.nut:active{transform:scale(.98)}
.nut-chinh{background:var(--xanh);color:#fff}
.nut-chinh:hover{background:var(--xanh-dam);color:#fff}
.nut-vien{background:var(--trang);color:var(--xanh-dam);border-color:var(--xanh-vien)}
.nut-vien:hover{border-color:var(--xanh);color:var(--xanh-dam)}
.nut-nho{min-height:42px;padding:6px 14px;font-size:15px}
.o-nhap{display:flex;gap:8px;background:var(--trang);border:2px solid var(--vien);border-radius:16px;padding:6px;box-shadow:var(--bong)}
.o-nhap:focus-within{border-color:var(--xanh)}
.o-nhap input{flex:1;min-width:0;border:0;outline:0;font:500 18px "Be Vietnam Pro",sans-serif;padding:8px 10px;background:transparent;color:var(--chu)}
.o-lon input{font-size:20px;padding:12px}
.o-lon .nut{min-height:54px;padding:10px 22px}
@media(max-width:480px){.o-lon{flex-direction:column}.o-lon .nut{width:100%}}
.form-d{max-width:760px;margin:18px 0 10px}

/* hero */
.hero{background:linear-gradient(180deg,#ffffff 0%,var(--nen) 100%);padding:36px 0 24px;border-bottom:1px solid var(--vien)}
.hero h1{max-width:900px}
.hero-mo{font-size:clamp(18px,2.4vw,21px);color:var(--phu);max-width:780px}
.hero-vd{font-size:16px;color:var(--phu)}
.dau-cc{background:#fff;border-bottom:1px solid var(--vien);padding:30px 0 18px}

/* thẻ */
.luoi2,.luoi3{display:grid;gap:16px;grid-template-columns:1fr}
@media(min-width:720px){.luoi2{grid-template-columns:1fr 1fr}.luoi3{grid-template-columns:1fr 1fr}}
@media(min-width:1024px){.luoi3{grid-template-columns:1fr 1fr 1fr}}
.the{display:block;background:var(--trang);border:1px solid var(--vien);border-radius:var(--bo);padding:20px;box-shadow:var(--bong);color:var(--chu);text-decoration:none}
a.the:hover{border-color:var(--xanh-vien);transform:translateY(-1px)}
.the p{color:var(--phu);margin-bottom:.6em}
.the-so{display:block;font-size:40px;font-weight:800;color:var(--xanh);line-height:1}
.the-lon h3{margin-top:8px}
.the-di{font-weight:700;color:var(--xanh);font-size:16px}
.the-cm{display:inline-block;font-size:13px;font-weight:700;color:var(--xanh);text-transform:uppercase;letter-spacing:.04em;margin-bottom:6px}
.the-bai h3,.the-bai .h3{font-size:19px}

.bang-ts{display:grid;grid-template-columns:1fr;gap:8px;margin:16px 0}
@media(min-width:720px){.bang-ts{grid-template-columns:1fr 1fr}}
@media(min-width:1024px){.bang-ts{grid-template-columns:1fr 1fr 1fr 1fr}}
.bang-ts a{display:flex;justify-content:space-between;gap:10px;background:var(--trang);border:1px solid var(--vien);border-radius:12px;padding:10px 14px;text-decoration:none;color:var(--chu);font-size:16px}
.bang-ts b{color:var(--xanh);font-size:18px}
.bang-ts a:hover{border-color:var(--xanh)}

.sieu{display:flex;flex-direction:column;gap:16px;background:linear-gradient(135deg,#f0faf4,#fffaf0);border:1px solid var(--xanh-vien);border-radius:20px;padding:24px}
.sieu p{color:var(--phu);margin:0}
@media(min-width:900px){.sieu{flex-direction:row;align-items:center;justify-content:space-between}.sieu>.nut{flex:none}}
.sieu-nho{display:block}
.sieu-nho .form-d{margin:12px 0 0}

.hoi details{background:var(--trang);border:1px solid var(--vien);border-radius:14px;margin-bottom:10px;padding:2px 18px}
.hoi summary{cursor:pointer;font-weight:700;padding:14px 0;list-style:none}
.hoi summary::-webkit-details-marker{display:none}
.hoi summary::after{content:"+";float:right;color:var(--xanh);font-size:22px;line-height:1}
.hoi details[open] summary::after{content:"–"}
.hoi details p{color:var(--phu)}

.bao{border-radius:14px;padding:14px 16px;margin:12px 0;font-size:17px}
.bao-do{background:var(--do-nhat);border:1px solid #f3c2c2;color:#7d1f1f}
.bao-vang{background:var(--vang-nhat);border:1px solid #f4dc9e;color:#6a4b00}
.bao-xanh{background:var(--xanh-nhat);border:1px solid var(--xanh-vien);color:#164d33}

/* kết quả */
.kq-dau{display:flex;flex-direction:column;gap:18px;align-items:flex-start}
@media(min-width:720px){.kq-dau{flex-direction:row;align-items:center;gap:28px}}
.vong-diem a{position:relative;display:block;width:168px;height:168px;text-decoration:none;color:var(--chu)}
.vong-diem svg{width:100%;height:100%;transform:rotate(-90deg)}
.vd-nen{fill:none;stroke:#e6eee9;stroke-width:12}
.vd-chay{fill:none;stroke-width:12;stroke-linecap:round;transition:stroke-dashoffset .8s}
.vd-tot .vd-chay{stroke:var(--xanh)}.vd-kha .vd-chay{stroke:#5aa832}.vd-can .vd-chay{stroke:var(--cam)}.vd-yeu .vd-chay{stroke:var(--do)}
.vong-diem b{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;font-size:46px;font-weight:800;padding-bottom:14px}
.vong-diem small{position:absolute;left:0;right:0;bottom:44px;text-align:center;color:var(--phu);font-size:15px}
.kq-tt h1,.kq-h1{font-size:clamp(26px,4.4vw,38px);word-break:break-word}
.xl{display:inline-block;vertical-align:middle;font-size:16px;font-weight:700;border-radius:999px;padding:3px 12px}
.xl-tot{background:var(--xanh-nhat);color:var(--xanh-dam)}.xl-kha{background:#eef7e3;color:#3d6b17}.xl-can{background:var(--cam-nhat);color:#8a4700}.xl-yeu{background:var(--do-nhat);color:#8b1d1d}
.kq-luc,.kq-dem{color:var(--phu);font-size:15px;margin:.2em 0 .8em}
.chip-hang{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0}
.chip{display:inline-flex;gap:6px;align-items:center;border-radius:999px;padding:7px 14px;font-size:16px;text-decoration:none;border:1px solid var(--vien);background:var(--trang);color:var(--chu);min-height:40px}
.chip-do{background:var(--do-nhat);border-color:#f3c2c2;color:#7d1f1f}
.chip-cam{background:var(--cam-nhat);border-color:#f6d1ac;color:#7c4100}
.chip-vang{background:var(--vang-nhat);border-color:#f4dc9e;color:#6a4b00}
.chip-xanh{background:var(--xanh-nhat);border-color:var(--xanh-vien);color:#164d33}
.chip-0{opacity:.55}
.kq-nut{display:flex;flex-wrap:wrap;gap:8px}
.nl-td{font-size:18px;margin:22px 0 10px;padding-left:12px;border-left:5px solid var(--vien)}
.nl-1{border-color:var(--do)}.nl-2{border-color:var(--cam)}.nl-3{border-color:var(--vang)}
.loi{background:var(--trang);border:1px solid var(--vien);border-left:5px solid var(--vien);border-radius:14px;padding:14px 16px;margin-bottom:10px}
.loi-1{border-left-color:var(--do)}.loi-2{border-left-color:var(--cam)}.loi-3{border-left-color:var(--vang)}
.loi h4{margin-bottom:.35em}
.loi p{margin:.3em 0;font-size:17px}
.loi-do{color:var(--phu)}
.loi-bai a{font-weight:600}
.bang-diem{background:var(--trang);border:1px solid var(--vien);border-radius:var(--bo);padding:6px 16px}
.bd-dong{display:grid;grid-template-columns:1fr auto;grid-template-areas:"ten so" "thanh thanh";gap:4px 12px;padding:10px 0;border-bottom:1px solid #edf2ef}
.bd-dong:last-child{border-bottom:0}
@media(min-width:720px){.bd-dong{grid-template-columns:minmax(220px,1.2fr) 2fr 140px;grid-template-areas:"ten thanh so";align-items:center}}
.bd-ten{grid-area:ten;font-size:17px}
.bd-thanh{grid-area:thanh;height:10px;background:#edf2ef;border-radius:99px;overflow:hidden}
.bd-thanh i{display:block;height:100%;border-radius:99px}
.bd-thanh .du{background:var(--xanh)}.bd-thanh .nua{background:var(--vang)}.bd-thanh .khong{background:var(--do);min-width:6px}
.bd-so{grid-area:so;text-align:right;font-weight:700;white-space:nowrap}
.bd-na .bd-ten,.bd-na .bd-so{color:var(--phu);font-weight:500}
.bd-na .bd-so{font-size:15px}
.so{text-decoration:none;font-weight:700}
.so:hover{text-decoration:underline}
.so-do{color:var(--do)}.so-xanh{color:var(--xanh)}
.luoi-so{display:grid;grid-template-columns:1fr 1fr;gap:10px}
@media(min-width:720px){.luoi-so{grid-template-columns:repeat(3,1fr)}}
@media(min-width:1024px){.luoi-so{grid-template-columns:repeat(4,1fr)}}
.o-so{background:var(--trang);border:1px solid var(--vien);border-radius:14px;padding:12px 14px;display:flex;flex-direction:column;gap:2px}
.o-so span{font-size:14px;color:var(--phu);line-height:1.35}
.o-so .so{font-size:22px}
.o-so-lon .so{font-size:28px}
.the-doc{background:var(--trang);border:1px solid var(--vien);border-radius:var(--bo);padding:14px 18px;margin:16px 0 0}
.the-doc dt{font-weight:700;margin-top:10px;font-size:16px}
.the-doc dt small{font-weight:500;margin-left:6px}
.the-doc dd{margin:2px 0 0;color:var(--phu);word-break:break-word;font-size:17px}
.bang-bot{background:var(--trang);border:1px solid var(--vien);border-radius:var(--bo);padding:4px 16px}
.bb-dong{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:12px 0;border-bottom:1px solid #edf2ef}
.bb-dong:last-child{border-bottom:0}
.bb-ten small{display:block;color:var(--phu);font-size:14px;line-height:1.4}
.bb-tt{flex:none;font-weight:700;font-size:15px;border-radius:999px;padding:5px 12px;text-align:center}
.bb-cho{background:var(--xanh-nhat);color:var(--xanh-dam)}.bb-chan{background:var(--do-nhat);color:#8b1d1d}
.pre-nho{max-height:220px;white-space:pre-wrap}

/* cách chấm */
.bang-cach{display:grid;gap:10px}
.bc-dong{background:var(--trang);border:1px solid var(--vien);border-radius:14px;padding:14px 16px}
.bc-dong:target{border-color:var(--xanh);box-shadow:0 0 0 3px var(--xanh-nhat)}
.bc-dau{display:flex;justify-content:space-between;gap:10px;align-items:baseline;margin-bottom:4px}
.bc-w{color:var(--xanh);font-weight:800;white-space:nowrap}
.bc-dong p{margin:0;color:var(--phu)}
.ds li,.ds-loi li{margin-bottom:.5em}
.ds-loi li:target{background:var(--vang-nhat);border-radius:8px}

/* bài */
.vet{font-size:15px;color:var(--phu);margin-bottom:10px}
.vet a{color:var(--phu)}
.bai-dau{padding-top:28px}
.bai-dau h1{font-size:clamp(30px,5.4vw,44px)}
.bai-tt{font-size:20px;color:var(--chu);font-weight:500;border-left:4px solid var(--xanh);padding-left:14px}
.bai-meta{font-size:15px;color:var(--phu)}
.bai-than{font-size:19px;line-height:1.75}
.bai-than h2{margin-top:1.6em;font-size:clamp(24px,3.6vw,29px)}
.bai-than h3{margin-top:1.3em}
.bai-than ul,.bai-than ol{padding-left:1.3em}
.bai-than li{margin-bottom:.45em}
.bai-than blockquote{margin:1.2em 0;padding:12px 18px;background:var(--xanh-nhat);border-radius:12px;border-left:4px solid var(--xanh)}
.bai-than table{width:100%;border-collapse:collapse;font-size:16px;margin:1em 0;display:block;overflow-x:auto}
.bai-than th,.bai-than td{border:1px solid var(--vien);padding:8px 10px;text-align:left;vertical-align:top}
.bai-than th{background:#eef5f1}
.bai-hoi,.bai-cc,.bai-lq{margin-top:28px}

/* chân trang */
.ft{background:#fff;border-top:1px solid var(--vien);margin-top:40px;padding:32px 0 16px}
.ft-in{max-width:1160px;margin:0 auto;padding:0 16px;display:grid;gap:24px;grid-template-columns:1fr}
@media(min-width:720px){.ft-in{grid-template-columns:1.4fr 1fr 1fr 1fr}}
.ft-c1 p{color:var(--phu);font-size:16px;margin-top:12px}
.ft-c b{display:block;margin-bottom:6px}
.ft-c a{display:block;color:var(--phu);text-decoration:none;font-size:16px;padding:3px 0}
.ft-c a:hover{color:var(--xanh)}
.ft-duoi{max-width:1160px;margin:16px auto 0;padding:12px 16px 0;border-top:1px solid var(--vien);font-size:14px;color:var(--phu)}

/* thanh dưới: điện thoại = đáy màn hình; ≥768px = dock nổi giữa đáy */
.bn{position:fixed;left:0;right:0;bottom:0;z-index:45;display:flex;justify-content:space-around;align-items:stretch;background:rgba(255,255,255,.97);border-top:1px solid var(--vien);padding:6px 4px calc(6px + env(safe-area-inset-bottom));backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px)}
.bn a,.bn button{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;min-height:52px;text-decoration:none;color:var(--phu);font:600 12.5px "Be Vietnam Pro",sans-serif;background:none;border:0;cursor:pointer;border-radius:12px;padding:2px}
.bn svg{width:25px;height:25px;fill:none;stroke:currentColor;stroke-width:1.9;stroke-linecap:round;stroke-linejoin:round}
.bn a.on{color:var(--xanh-dam)}
.bn a.on svg{stroke-width:2.3}
.bn-giua i{display:flex;align-items:center;justify-content:center;width:50px;height:50px;margin-top:-22px;border-radius:50%;background:var(--xanh);color:#fff;box-shadow:0 6px 16px rgba(14,122,78,.35);border:3px solid #fff}
.bn-giua svg{stroke:#fff;width:26px;height:26px}
.bn-giua span{color:var(--xanh-dam)}
@media(min-width:768px){
  .bn{left:50%;right:auto;bottom:16px;transform:translateX(-50%);width:max-content;max-width:calc(100vw - 24px);gap:4px;border:1px solid var(--vien);border-radius:22px;padding:6px 10px;box-shadow:0 10px 30px rgba(16,40,28,.14)}
  .bn a,.bn button{flex:none;flex-direction:row;gap:8px;padding:8px 14px;min-height:48px;font-size:15px}
  .bn a:hover,.bn button:hover{background:var(--xanh-nhat);color:var(--xanh-dam)}
  .bn svg{width:22px;height:22px}
  .bn a.bn-giua i{width:auto;height:auto;margin:0;background:none;box-shadow:none;border:0;color:inherit}
  .bn a.bn-giua{background:var(--xanh);color:#fff}
  .bn a.bn-giua svg{stroke:#fff;width:22px;height:22px}
  .bn a.bn-giua span{color:#fff}
  .bn a.bn-giua:hover,.bn a.bn-giua.on{background:var(--xanh-dam);color:#fff}
  body{padding-bottom:100px}
}

/* menu bên */
.dr-nen{position:fixed;inset:0;background:rgba(16,32,24,.32);z-index:60}
.dr{position:fixed;top:0;right:0;bottom:0;width:min(380px,92vw);background:#fff;z-index:61;overflow-y:auto;padding:14px 16px 40px;box-shadow:-10px 0 30px rgba(0,0,0,.12)}
.dr-dau{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}
.dr-x{border:1px solid var(--vien);background:#fff;border-radius:12px;min-height:44px;padding:6px 12px;font:600 15px "Be Vietnam Pro",sans-serif;cursor:pointer;color:var(--chu)}
.dr-form label{display:block;font-weight:700;font-size:15px;margin-bottom:6px}
.dr-form .nut{min-height:44px;padding:6px 14px}
.dr-nhom{margin:18px 0 4px;font-size:13px;font-weight:800;text-transform:uppercase;letter-spacing:.06em;color:var(--phu)}
.dr-a{display:flex;justify-content:space-between;align-items:center;padding:11px 10px;border-radius:10px;text-decoration:none;color:var(--chu);font-weight:600;font-size:17px}
.dr-a:hover{background:var(--xanh-nhat)}
.dr-a em{font-style:normal;font-size:14px;color:var(--phu);font-weight:500}

/* màn chờ chấm */
.cho{position:fixed;inset:0;z-index:80;background:rgba(247,250,248,.92);display:flex;align-items:center;justify-content:center;padding:16px}
.cho[hidden]{display:none}
.cho-hop{background:#fff;border:1px solid var(--vien);border-radius:20px;box-shadow:var(--bong);padding:28px 24px;max-width:420px;width:100%;text-align:center}
.cho-vong{width:56px;height:56px;margin:0 auto 14px;border-radius:50%;border:5px solid var(--xanh-nhat);border-top-color:var(--xanh);animation:xoay 1s linear infinite}
@keyframes xoay{to{transform:rotate(360deg)}}
.cho-td{font-size:20px;font-weight:700;margin-bottom:6px;word-break:break-word}
.cho-buoc{color:var(--xanh-dam);font-weight:600;min-height:1.6em}
.cho-phu{color:var(--phu);font-size:15px;margin:0}
@media(prefers-reduced-motion:reduce){.cho-vong{animation-duration:3s}}