@font-face{font-family:'Be Vietnam Pro';font-weight:400;font-display:swap;src:url(/font/bvp-400-vietnamese.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}
@font-face{font-family:'Be Vietnam Pro';font-weight:400;font-display:swap;src:url(/font/bvp-400-latin.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:'Be Vietnam Pro';font-weight:600;font-display:swap;src:url(/font/bvp-600-vietnamese.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}
@font-face{font-family:'Be Vietnam Pro';font-weight:600;font-display:swap;src:url(/font/bvp-600-latin.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:'Be Vietnam Pro';font-weight:800;font-display:swap;src:url(/font/bvp-800-vietnamese.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}
@font-face{font-family:'Be Vietnam Pro';font-weight:800;font-display:swap;src:url(/font/bvp-800-latin.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:"BVP Du Phong";src:local("Segoe UI"),local("Roboto"),local("Arial");size-adjust:106%;ascent-override:95%;descent-override:25%;line-gap-override:0%}
:root{
  --bg:#f6f8fc;--paper:#fff;--ink:#0b1f3a;--muted:#52627a;--line:#dfe6f0;--navy:#0b1f3a;--blue:#2563eb;--cyan:#06b6d4;--chip:#eef4ff;
  --dung:#047857;--dung-nen:#ecfdf5;--sai:#b91c1c;--sai-nen:#fef2f2;
  --f-sans:"Be Vietnam Pro","BVP Du Phong","Segoe UI",Arial,sans-serif;
  --bong:0 1px 2px rgba(11,31,58,.05),0 12px 32px -12px rgba(11,31,58,.14);
  color-scheme:light;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:84px;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.7 var(--f-sans);overflow-x:clip;-webkit-font-smoothing:antialiased}
[hidden]{display:none!important}
a{color:var(--blue)}
.wrap{max-width:1200px;margin:0 auto;padding-inline:24px}
h1,h2,h3{line-height:1.2;text-wrap:balance;margin:0}
h2{font-size:clamp(26px,3.4vw,38px);font-weight:800;letter-spacing:-.022em}
h3{font-size:18px;font-weight:700}
p{margin:0}
.eyebrow{font-size:12.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--blue)}
.muted{color:var(--muted)}
section{padding-block:80px}
section.nen{background:var(--bg)}
.dau-muc{max-width:720px;margin-bottom:36px}
.dau-muc h2{margin-top:8px}
.dau-muc p{margin-top:12px;color:var(--muted)}

header.top{position:fixed;inset:0 0 auto;z-index:20;background:rgba(255,255,255,.9);-webkit-backdrop-filter:saturate(170%) blur(16px);backdrop-filter:saturate(170%) blur(16px);border-bottom:1px solid rgba(11,31,58,.08);transition:box-shadow .25s}
header.top.cuon{box-shadow:0 10px 30px -18px rgba(11,31,58,.4)}
.nav{display:flex;align-items:center;gap:20px;height:68px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:800;white-space:nowrap;letter-spacing:-.01em}
.logo svg{width:30px;height:34px;flex:none}
.nav nav{display:flex;gap:4px;margin-left:auto;font-size:14.5px}
.nav nav a{color:var(--ink);opacity:.78;text-decoration:none;font-weight:600;padding:8px 11px;border-radius:9px}
.nav nav a:hover{opacity:1;background:var(--chip)}
.nav nav .chi-mb{display:none}
.nav-nut{display:flex;gap:8px;align-items:center}
.menu-nut{display:none;width:42px;height:42px;border:1px solid var(--line);border-radius:10px;background:#fff;cursor:pointer;padding:0;place-items:center;color:var(--ink)}
.menu-nut svg{width:20px;height:20px}
@media (max-width:980px){
  .nav nav{display:none;position:absolute;top:100%;left:0;right:0;flex-direction:column;gap:2px;margin:0;padding:10px 16px 16px;background:#fff;border-bottom:1px solid var(--line);box-shadow:0 22px 40px -20px rgba(11,31,58,.35)}
  .nav nav.mo{display:flex}
  .nav nav a{padding:12px;font-size:16px;opacity:1}
  .nav nav .chi-mb{display:block}
  .menu-nut{display:grid}
  .nav-nut{margin-left:auto}
}
@media (max-width:640px){.nav-nut .btn-zalo{display:none}.logo{font-size:15px}.nav{gap:10px}}
@media (max-width:380px){.logo span{display:none}}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:11px 22px;border-radius:11px;font:700 15px/1.3 var(--f-sans);text-decoration:none;border:1.5px solid transparent;cursor:pointer;transition:transform .18s,box-shadow .18s}
.btn:hover{transform:translateY(-2px)}
.btn:disabled{opacity:.55;cursor:default;transform:none}
.btn-xanh{background:linear-gradient(135deg,#2563eb,#1d4ed8);color:#fff;box-shadow:0 10px 22px -10px rgba(37,99,235,.75)}
.btn-cyan{background:linear-gradient(135deg,#0891b2,#06b6d4);color:#fff}
.btn-vien{border-color:var(--line);color:var(--ink);background:#fff}
.btn-vien:hover{border-color:var(--blue);color:var(--blue)}
.btn-sm{min-height:40px;padding:8px 15px;font-size:14px;border-radius:10px}
:focus-visible{outline:3px solid #67e8f9;outline-offset:2px}

.hero{background:radial-gradient(900px 420px at 85% 0,rgba(6,182,212,.22),transparent 65%),radial-gradient(800px 420px at 8% 100%,rgba(37,99,235,.32),transparent 65%),var(--navy);color:#fff;padding-block:136px 72px}
.hero .eyebrow{color:#67e8f9}
.hero h1{font-size:clamp(32px,5vw,54px);font-weight:800;letter-spacing:-.03em;margin-top:12px;max-width:760px}
.hero .dan{margin-top:16px;max-width:620px;color:#c5d3e6;font-size:17px}
.hero .cta{display:flex;gap:10px;flex-wrap:wrap;margin-top:26px}
.hero .btn-vien{background:rgba(255,255,255,.08);border-color:rgba(255,255,255,.28);color:#fff}
.hero .so{display:flex;gap:32px;flex-wrap:wrap;margin-top:30px;color:#c5d3e6;font-size:14px}
.hero .so b{display:block;color:#fff;font-size:24px;line-height:1.2}

.the{background:#fff;border:1px solid var(--line);border-radius:18px;padding:26px;box-shadow:var(--bong);min-width:0}
.nhom{display:flex;gap:8px;flex-wrap:wrap;margin-top:8px}
.lua{border:1.5px solid var(--line);background:#fff;color:var(--ink);border-radius:999px;padding:8px 15px;min-height:40px;font:600 14.5px/1.3 var(--f-sans);cursor:pointer}
.lua:hover{border-color:var(--blue)}
.lua[aria-pressed=true]{background:var(--blue);border-color:var(--blue);color:#fff}
.nhan{font-weight:700;font-size:14.5px}
.dong+.dong{margin-top:20px}
.day{margin-top:24px;display:flex;gap:10px;flex-wrap:wrap;align-items:center}

.tien{display:flex;justify-content:space-between;gap:12px;font-size:14px;color:var(--muted);font-weight:600}
.thanh{height:6px;background:var(--chip);border-radius:9px;margin:8px 0 20px;overflow:hidden}
.thanh i{display:block;height:100%;width:0;background:linear-gradient(90deg,#2563eb,#06b6d4);transition:width .25s}
.hoi{font-size:18px;font-weight:600;line-height:1.5;overflow-wrap:anywhere}
.dap{display:grid;gap:10px;margin-top:18px}
.dap button{display:flex;gap:12px;align-items:flex-start;text-align:left;width:100%;padding:12px 14px;min-height:48px;border:1.5px solid var(--line);border-radius:12px;background:#fff;color:var(--ink);font:400 15.5px/1.5 var(--f-sans);cursor:pointer;overflow-wrap:anywhere}
.dap button:hover:not(:disabled){border-color:var(--blue)}
.dap button b{flex:none;width:26px;height:26px;display:grid;place-items:center;border-radius:8px;background:var(--chip);color:var(--blue);font-size:13.5px}
.dap button.chon{border-color:var(--blue);background:var(--chip)}
.dap button.dung{border-color:var(--dung);background:var(--dung-nen)}
.dap button.sai{border-color:var(--sai);background:var(--sai-nen)}
.dap button:disabled{cursor:default;color:var(--ink)}
.giai{margin-top:16px;padding:14px 16px;border-radius:12px;background:var(--bg);font-size:15px;overflow-wrap:anywhere}
.giai b{display:block;margin-bottom:2px}
.giai.ok b{color:var(--dung)}.giai.ko b{color:var(--sai)}
.diem{font-size:clamp(40px,7vw,60px);font-weight:800;letter-spacing:-.03em;line-height:1.1;color:var(--blue)}

.thi-luoi{display:grid;grid-template-columns:minmax(0,1fr) 260px;gap:20px;align-items:start}
.thi-ben{position:sticky;top:84px}
.gio{font-size:30px;font-weight:800;font-variant-numeric:tabular-nums;line-height:1.2}
.gio.gap{color:var(--sai)}
.o-so{display:grid;grid-template-columns:repeat(6,1fr);gap:6px;margin-top:14px}
.o-so button{aspect-ratio:1;min-height:34px;padding:0;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink);font:600 13px var(--f-sans);cursor:pointer}
.o-so button.co{background:var(--chip);border-color:#bfd2fb;color:var(--blue)}
.o-so button.dang{outline:2px solid var(--blue)}
@media (max-width:860px){.thi-luoi{grid-template-columns:minmax(0,1fr)}.thi-ben{position:static;order:-1}.o-so{grid-template-columns:repeat(10,1fr)}}
@media (max-width:480px){.o-so{grid-template-columns:repeat(8,1fr)}}

.form{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.form label{display:grid;gap:4px;font-weight:600;font-size:14.5px}
.form input,.form select{width:100%;min-height:46px;padding:10px 12px;border:1.5px solid var(--line);border-radius:10px;font:400 16px var(--f-sans);color:var(--ink);background:#fff}
.form .rong{grid-column:1/-1}
.form .kiem{display:flex;gap:10px;align-items:flex-start;font-weight:400;font-size:14.5px;line-height:1.5}
.form .kiem input{width:20px;height:20px;min-height:0;flex:none;margin-top:2px}
.bay{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
.loi{color:var(--sai);font-size:14.5px;font-weight:600}
@media (max-width:620px){.form{grid-template-columns:minmax(0,1fr)}}

.giai-luoi{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-bottom:24px}
.giai-the{padding:20px;border:1px solid var(--line);border-radius:16px;background:#fff}
.giai-the:first-child{border-color:var(--blue);box-shadow:var(--bong)}
.giai-the small{display:block;font-weight:700;color:var(--blue);letter-spacing:.06em;text-transform:uppercase;font-size:12.5px}
.giai-the b{display:block;margin-top:6px;line-height:1.4}
@media (max-width:760px){.giai-luoi{grid-template-columns:minmax(0,1fr)}}

.bang{width:100%;border-collapse:collapse;font-size:15px}
.bang th{text-align:left;font-size:13px;color:var(--muted);padding:8px 10px;border-bottom:1px solid var(--line)}
.bang td{padding:10px;border-bottom:1px solid var(--line);font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.bang .so-p{text-align:right}
.le{margin:0;padding-left:20px;display:grid;gap:8px;max-width:820px}
.lien-he{background:var(--navy);color:#fff;text-align:center}
.lien-he p{margin:10px auto 20px;color:#c5d3e6;max-width:620px}
footer{display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;padding-block:30px 44px;font-size:14px;color:var(--muted)}
@media (max-width:760px){section{padding-block:56px}.wrap{padding-inline:16px}.hero{padding-block:112px 56px}.the{padding:18px}.hero .btn{flex:1 1 100%}.day .btn{flex:1 1 100%}}
#lt-lam,#thi-lam,#thi-xong{scroll-margin-top:84px}
.nav-nut .btn{white-space:nowrap}
body.dang-lam>[class^="hntl"]{display:none!important}
body.dang-thi #luyen-tap,body.dang-thi #xep-hang,body.dang-thi #the-le,body.dang-thi .hero{display:none}
body.dang-thi #thi{padding-top:92px}
@media (max-width:560px){.nav-nut .btn-xanh{padding:8px 11px;font-size:13px}.bang th:nth-child(3),.bang td:nth-child(3){display:none}.bang th,.bang td{padding:9px 6px}}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}.btn:hover{transform:none}}