:root{--ink:#14302a;--mut:#56706a;--bg:#f7f8f4;--card:#fff;--line:#dfe5df;--g:#107c41;--g2:#0b5d30;--gl:#e4f3ea;--am:#f5b301;--aml:#fff5d6;--red:#c93a2b;--redl:#fdeae7;--r:14px;--sh:0 2px 10px rgba(20,48,42,.07)}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 'Be Vietnam Pro',system-ui,-apple-system,'Segoe UI',Roboto,Arial,sans-serif}
a{color:var(--g2)}h1,h2,h3{line-height:1.25;margin:0 0 .5em;letter-spacing:-.01em}img{max-width:100%}
.wrap{max-width:1120px;margin:auto;padding:0 16px}.narrow{max-width:760px}
code{background:#eef2ee;padding:1px 6px;border-radius:5px;font:600 .92em Consolas,Menlo,monospace;color:#0b5d30;word-break:break-word}
kbd{background:#fff;border:1px solid #bcc7c0;border-bottom-width:3px;border-radius:6px;padding:1px 7px;font:600 .85em Consolas,monospace;white-space:nowrap}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:46px;padding:10px 22px;border-radius:12px;border:1.5px solid var(--g);background:var(--g);color:#fff;font:600 16px inherit;font-family:inherit;text-decoration:none;cursor:pointer}
.btn:hover{background:var(--g2);border-color:var(--g2)}.btn.ghost{background:transparent;color:var(--g2)}.btn.ghost:hover{background:var(--gl)}.btn.sm{min-height:38px;padding:6px 14px;font-size:14px}.btn.lg{min-height:56px;padding:14px 32px;font-size:18px}.btn:disabled{opacity:.5;cursor:default}
.btn.zalo{background:#0068ff;border-color:#0068ff}
input,select{font:inherit;padding:10px 12px;border:1.5px solid var(--line);border-radius:10px;background:#fff;color:inherit;max-width:100%}
input:focus,select:focus,.btn:focus-visible,a:focus-visible{outline:2px solid var(--g);outline-offset:1px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px;box-shadow:var(--sh)}
.grid{display:grid;gap:16px}.g2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}.g3{grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}
.muted{color:var(--mut)}.small{font-size:14px}.center{text-align:center}section{padding:44px 0}
.hdr{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:30}
.hdr .wrap{display:flex;align-items:center;gap:14px;min-height:62px}
.logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:19px;color:var(--ink);text-decoration:none;white-space:nowrap}
.logo i{display:grid;place-items:center;width:32px;height:32px;border-radius:8px;background:var(--g);color:#fff;font-style:normal;font-size:17px}
.nav{display:flex;gap:4px;margin-left:auto;align-items:center}.nav a{padding:8px 11px;border-radius:9px;text-decoration:none;color:var(--ink);font-weight:500;font-size:15px;white-space:nowrap}.nav a:hover,.nav a.on{background:var(--gl);color:var(--g2)}
.pts{display:flex;gap:10px;font-size:14px;font-weight:700;white-space:nowrap}.menu-btn{display:none;margin-left:auto;background:none;border:0;font-size:26px;padding:6px 10px;cursor:pointer;color:inherit}
@media(max-width:1200px){.menu-btn{display:block}.pts{margin-left:auto}.pts+.menu-btn{margin-left:0}.nav{display:none;position:absolute;top:62px;left:0;right:0;background:#fff;flex-direction:column;align-items:stretch;padding:8px 16px 14px;border-bottom:1px solid var(--line);margin:0}.nav.open{display:flex}.nav a{padding:12px}}
.ftr{background:#12312b;color:#cfe0d8;padding:32px 0 92px;font-size:14px;margin-top:30px}.ftr a{color:#fff}.ftr .row{display:flex;flex-wrap:wrap;gap:8px 18px}
.float{position:fixed;right:14px;bottom:14px;z-index:40;box-shadow:0 6px 18px rgba(0,104,255,.35);border-radius:30px}
.hero{padding:44px 0 30px}.hero .wrap{display:grid;gap:30px;grid-template-columns:1fr 1.05fr;align-items:center}
.hero h1{font-size:clamp(30px,5vw,46px);font-weight:800}.hero mark{background:linear-gradient(transparent 62%,#ffe07a 62%);color:inherit}
.ticks{list-style:none;padding:0;margin:14px 0 22px;display:flex;flex-wrap:wrap;gap:6px 16px;font-size:15px}.ticks li:before{content:"✓ ";color:var(--g);font-weight:800}
.hero .wrap>*{min-width:0}
@media(max-width:860px){.hero .wrap{grid-template-columns:minmax(0,1fr)}}
.demo-msg{min-height:26px;font-weight:600;margin-top:10px}
.band{background:var(--ink);color:#fff;padding:18px 0}.band .row{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 34px;font-weight:600}.band b{color:#8ff0b5}
.cmp td,.cmp th{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}.cmp{border-collapse:collapse;width:100%;font-size:15px}
.price{position:relative;display:flex;flex-direction:column}.price.hot{border:2px solid var(--g)}.price .tag{position:absolute;top:-12px;left:16px;background:var(--am);border-radius:20px;padding:1px 12px;font-size:13px;font-weight:700}.price b.v{font-size:30px;font-weight:800}
.fq{border-bottom:1px solid var(--line);padding:12px 0}.fq summary{font-weight:600;cursor:pointer}
/* Bảng tính */
.xl{border:1px solid #b9c6be;border-radius:10px;background:#fff;overflow:hidden;outline:none;max-width:100%}.xl:focus-within{border-color:var(--g)}
.xl-bar{display:flex;align-items:center;border-bottom:1px solid var(--line);background:#f4f6f3;min-height:42px}
.xl-name{min-width:62px;padding:0 8px;font:600 13px Consolas,monospace;border-right:1px solid var(--line);text-align:center;line-height:42px;white-space:nowrap;overflow:hidden;max-width:92px}
.xl-fx{padding:0 8px;color:var(--mut);font-style:italic;font-weight:700}
.xl-input{flex:1;min-width:0;border:0;border-radius:0;background:#fff;font:15px Consolas,Menlo,monospace;padding:10px 8px;min-height:42px}.xl-input:focus{outline:none}
.xl-keys{display:flex;gap:5px;overflow-x:auto;padding:6px;background:#eef2ee;border-bottom:1px solid var(--line)}.xl-keys[hidden]{display:none}
.xl-keys button{min-width:38px;height:38px;border:1px solid #c5cfc8;background:#fff;border-radius:8px;font:700 16px Consolas,monospace;flex:none;color:var(--ink)}.xl-keys .ok{background:var(--g);color:#fff;border-color:var(--g);padding:0 12px;font-family:inherit;font-size:14px}
.xl-scroll{overflow:auto;max-height:430px;-webkit-overflow-scrolling:touch}
.xl-grid{border-collapse:separate;border-spacing:0;font-size:14px;min-width:100%;user-select:none;-webkit-user-select:none}
.xl-grid th{background:#f1f4f1;color:#4b625c;font-weight:500;border-right:1px solid #dbe2dc;border-bottom:1px solid #dbe2dc;font-size:12.5px;position:sticky;z-index:2;cursor:pointer}
.xl-grid thead th{top:0;height:26px;min-width:92px}.xl-grid tbody th{left:0;min-width:34px;width:34px;z-index:1}.xl-corner{left:0;z-index:3!important;min-width:34px!important}
.xl-grid th.on{background:#cfe8d9;color:var(--g2);font-weight:700}
.xl-grid td{border-right:1px solid #e7ece8;border-bottom:1px solid #e7ece8;height:30px;padding:2px 6px;white-space:nowrap;max-width:190px;overflow:hidden;text-overflow:ellipsis;cursor:cell;position:relative}
.xl-grid td.num{text-align:right}.xl-grid td.bool{text-align:center}.xl-grid td.err{color:var(--red);font-weight:600;text-align:center}
.xl-grid td.sel{background:#e4f3ea}.xl-grid td.cur{box-shadow:inset 0 0 0 2px var(--g)}
.xl-tabs{display:flex;gap:2px;background:#f1f4f1;padding:0 6px}.xl-tabs:empty{display:none}.xl-tabs button{border:0;background:none;padding:9px 14px;font:inherit;font-size:14px;cursor:pointer;color:inherit}.xl-tabs .on{background:#fff;font-weight:700;color:var(--g2);border-bottom:2px solid var(--g)}
/* Trang học */
.learn{display:grid;grid-template-columns:270px 1fr;gap:18px;padding:14px 16px 120px;max-width:1240px;margin:auto}
.side{position:sticky;top:76px;align-self:start;max-height:calc(100vh - 90px);overflow:auto;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:8px}
.side h4{margin:10px 8px 4px;font-size:12.5px;text-transform:uppercase;letter-spacing:.04em;color:var(--mut)}
.side a{display:flex;gap:6px;padding:6px 8px;border-radius:8px;text-decoration:none;color:var(--ink);font-size:14px;line-height:1.35}.side a:hover{background:var(--gl)}.side a.on{background:var(--g);color:#fff}.side a .d{margin-left:auto;flex:none}
.side-btn{display:none;margin-bottom:10px}
@media(max-width:860px){.learn{grid-template-columns:minmax(0,1fr);padding:10px 12px 150px}.side{display:none;position:static;max-height:50vh}.side.open{display:block}.side-btn{display:inline-flex}.xl-scroll{max-height:320px}}
.main{min-width:0}.prog{height:10px;border-radius:9px;background:#e4e9e4;overflow:hidden;flex:1}.prog i{display:block;height:100%;background:var(--g);transition:width .3s}
.q{font-size:17px;margin-bottom:14px}.opts{display:grid;gap:8px;margin-bottom:6px}.opt{text-align:left;padding:13px 14px;border:1.5px solid var(--line);border-radius:11px;background:#fff;font:inherit;cursor:pointer;color:inherit}.opt:hover{border-color:var(--g)}.opt.good{background:var(--gl);border-color:var(--g)}.opt.bad{background:var(--redl);border-color:var(--red)}
.foot{position:fixed;left:0;right:0;bottom:0;z-index:20;background:#fff;border-top:1px solid var(--line);padding:10px 16px}.foot .in{max-width:1240px;margin:auto;display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.foot .msg{flex:1 1 220px;font-weight:600;min-width:0}.foot.ok{background:var(--gl)}.foot.no{background:var(--redl)}.foot.ok .msg{color:var(--g2)}.foot.no .msg{color:var(--red)}
.tool{display:flex;flex-wrap:wrap;gap:8px;align-items:end;margin-top:12px;padding:12px;background:#f4f6f3;border-radius:10px}.tool label{font-size:13px;font-weight:600;display:grid;gap:3px}
.pv{border-collapse:collapse;margin-top:10px;font-size:14px}.pv th,.pv td{border:1px solid var(--line);padding:5px 12px}.pv th{background:var(--gl)}.pv td:last-child{text-align:right}
.tip{background:var(--aml);border-radius:10px;padding:9px 12px;font-size:14px;margin-top:10px}
/* Bảng điều khiển */
.mods{display:grid;gap:12px}.mod summary{cursor:pointer;font-weight:700;display:flex;gap:8px;align-items:center;flex-wrap:wrap}.mod summary small{font-weight:400;color:var(--mut)}.mod .list{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:6px;margin-top:12px}
.les{display:flex;gap:8px;align-items:center;padding:9px 10px;border:1px solid var(--line);border-radius:10px;text-decoration:none;color:var(--ink);font-size:14.5px;background:#fff}.les:hover{border-color:var(--g)}.dot{width:11px;height:11px;border-radius:50%;background:#d6ddd7;flex:none}.dot.g{background:var(--g)}.dot.y{background:var(--am)}.dot.r{background:var(--red)}
.stat b{font-size:28px;display:block;line-height:1.2}.legend{display:flex;flex-wrap:wrap;gap:4px 14px;font-size:13px;color:var(--mut);margin-top:8px}.legend span{display:flex;align-items:center;gap:5px}
.lb{width:100%;border-collapse:collapse;font-size:15px}.lb td{padding:4px 0}.lb td:last-child{text-align:right;font-weight:700}
/* Thẻ ôn tập */
.flash{min-height:230px;display:flex;flex-direction:column;justify-content:center;text-align:center;cursor:pointer;font-size:19px}.flash b{font-size:26px}
/* Chứng chỉ */
.cert{background:#fff;border:10px double var(--g);padding:44px 24px;text-align:center;border-radius:6px}.cert .nm{font-size:clamp(26px,5vw,40px);font-weight:800;color:var(--g2);margin:12px 0;border-bottom:1px solid var(--line);display:inline-block;padding:0 22px 6px}
@media print{.hdr,.ftr,.float,.noprint{display:none!important}body{background:#fff}}
/* Thư viện hàm */
.fn-list{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}.fn-list a{display:block;text-decoration:none;color:inherit}.fn-list a:hover{border-color:var(--g)}.chip{display:inline-block;font-size:12px;font-weight:700;color:var(--g2);background:var(--gl);border-radius:20px;padding:1px 10px}
.article h2{margin-top:1.5em}.syntax{background:var(--ink);color:#c8f7d9;padding:14px;border-radius:10px;font:600 16px Consolas,monospace;overflow-x:auto}.tbl-w{overflow-x:auto}

/* Lộ trình theo mục tiêu */
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 4px}
.chip-b{font-family:inherit;font-weight:600;font-size:14px;padding:8px 14px;border-radius:30px;border:1.5px solid var(--line);background:#fff;color:var(--ink);cursor:pointer;min-height:40px}
.chip-b:hover{border-color:var(--g)}.chip-b.on{background:var(--g);border-color:var(--g);color:#fff}
.goal-in{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);gap:18px;margin-top:12px;padding-top:12px;border-top:1px solid var(--line)}
@media(max-width:700px){.goal-in{grid-template-columns:minmax(0,1fr)}}
.les.off{opacity:.55}
.goals{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));margin-top:20px}
.goals a{display:block;text-decoration:none;color:inherit}.goals a:hover{border-color:var(--g)}
/* Thuật ngữ */
.gl td,.gl th{padding:9px 10px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}.gl{border-collapse:collapse;width:100%;font-size:15px}.gl th{background:#eef2ee;font-size:14px}
.gl td:first-child{font-weight:600;white-space:nowrap}
@media(max-width:600px){.gl,.gl tbody,.gl tr,.gl td{display:block;width:100%}.gl thead{display:none}.gl tr{border-bottom:1px solid var(--line);padding:8px 0}.gl td{border:0;padding:2px 0}}
/* Thi thử MOS */
.ex-top{display:flex;align-items:center;gap:12px;margin-bottom:12px;flex-wrap:wrap}.ex-top>div:first-child{flex:1 1 240px;min-width:0}
.ex-clock{font:800 22px Consolas,monospace;color:var(--g2);background:var(--gl);padding:4px 12px;border-radius:10px}.ex-clock.low{color:var(--red);background:var(--redl)}
.ex-bar{position:fixed;left:0;right:0;bottom:0;z-index:25;background:#fff;border-top:1px solid var(--line);padding:8px 0;box-shadow:0 -4px 14px rgba(20,48,42,.06)}
.ex-nums{display:flex;gap:5px;overflow-x:auto;padding-bottom:6px;align-items:center;-webkit-overflow-scrolling:touch}
.ex-p{font-family:inherit;font-weight:700;font-size:12px;color:var(--mut);margin:0 2px 0 8px;white-space:nowrap}.ex-p:first-child{margin-left:0}
.ex-n{flex:0 0 auto;width:34px;height:34px;border-radius:8px;border:1.5px solid var(--line);background:#fff;font-family:inherit;font-weight:600;font-size:14px;cursor:pointer;color:var(--ink);position:relative}
.ex-n.ok{background:var(--gl);border-color:#9fd3b4}.ex-n.on{border-color:var(--g);box-shadow:0 0 0 2px var(--g) inset}.ex-n.fl:after{content:"★";position:absolute;top:-8px;right:-5px;font-size:12px;color:var(--am)}
.ex-act{display:flex;gap:8px;justify-content:flex-end;flex-wrap:wrap}
.opt.pick{background:#eef6ff;border-color:#2b6fd6;box-shadow:0 0 0 1px #2b6fd6 inset}
.ex-modal{position:fixed;inset:0;background:rgba(10,30,25,.45);z-index:50;display:grid;place-items:center;padding:16px}.ex-modal .card{max-width:440px;width:100%}
.ex-score{font-size:64px;font-weight:800;color:var(--red);line-height:1.1;margin:6px 0}.ex-score.pass{color:var(--g2)}.ex-score small{font-size:22px;color:var(--mut)}
.ex-dom{display:grid;grid-template-columns:minmax(0,1fr) 50px minmax(80px,200px);gap:12px;align-items:center;padding:8px 0;border-bottom:1px solid var(--line)}.ex-dom:last-child{border:0}
@media(max-width:600px){.ex-dom{grid-template-columns:minmax(0,1fr) 40px}.ex-dom .prog{grid-column:1/-1}}
.ex-rev summary{font-weight:600;cursor:pointer}.ex-rev.ok summary{color:var(--g2)}.ex-rev.no summary{color:var(--red)}
.mos-x{display:grid;gap:16px;grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}
.facts{list-style:none;padding:0;margin:10px 0 14px}.facts li{padding:5px 0;border-bottom:1px dashed var(--line);font-size:15px}.facts li:last-child{border:0}
.chk{display:flex;gap:10px;align-items:flex-start;padding:8px 0;border-bottom:1px solid var(--line);cursor:pointer}.chk input{margin-top:5px;width:18px;height:18px;flex:0 0 auto}
[hidden]{display:none!important}
@media(min-width:1201px){.nav{gap:2px}.nav a{padding:8px 8px;font-size:14.5px}}
/* Tìm kiếm, dashboard, tài khoản, quản trị */
.find{background:var(--gl)}.find input{width:100%;font-size:18px;padding:14px 16px;border-color:var(--g)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}.chips button.chip{border:1px solid #bfe0cb;background:#fff;font-size:14px;padding:5px 12px;cursor:pointer;font-family:inherit}
#qOut{display:grid;gap:8px}.sr{display:block;background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px 14px;text-decoration:none;color:inherit;min-width:0}a.sr:hover{border-color:var(--g)}
.sr .chip{margin-right:8px}.sr-l{display:flex;flex-wrap:wrap;gap:6px 14px;margin-top:6px;font-size:15px}
#dv:not(:empty){display:flex;flex-wrap:wrap;gap:10px;margin-top:10px}.dv{display:flex;align-items:center;gap:8px;font-size:14px;background:var(--aml);border-radius:10px;padding:6px 10px}.dv select{padding:6px 10px}
.chart{margin:12px 0 0;border:1px solid var(--line);border-radius:12px;padding:10px 12px;background:#fff;max-width:560px}.chart figcaption{font-weight:700;font-size:14px}.chart svg{width:100%;height:auto;display:block;font:12px 'Be Vietnam Pro',sans-serif;fill:var(--ink)}
.tabs{display:flex;gap:4px;border-bottom:1.5px solid var(--line);margin-bottom:10px}.tabs button{background:none;border:0;border-bottom:3px solid transparent;padding:8px 14px;font:600 16px inherit;font-family:inherit;color:var(--mut);cursor:pointer;margin-bottom:-1.5px}.tabs button.on{color:var(--g2);border-color:var(--g)}
.stat{background:var(--gl);border-radius:12px;padding:12px;display:grid;gap:2px}.stat b{font-size:22px;color:var(--g2)}.stat span{font-size:13px;color:var(--mut)}
.copy{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.copy code{font-size:17px;padding:4px 10px;background:var(--gl);border-radius:8px}
.tbl-w{overflow-x:auto;max-width:100%}.adm{border-collapse:collapse;font-size:14px;min-width:760px;width:100%}.adm th,.adm td{border-bottom:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}.adm th{background:var(--gl);white-space:nowrap}.adm td.n{text-align:right;white-space:nowrap}
.learn .xl-scroll{max-height:max(380px,calc(100vh - 140px))}@media(max-width:860px){.learn .xl-scroll{max-height:65vh}}
.verify{text-align:center;display:grid;gap:10px;justify-items:center}.verify .ico{font-size:56px;line-height:1}.verify h2{margin:0}.verify p{margin:0;max-width:520px}
/* ===== Giao diện chung: đầu trang xám đậm, logo chữ, thẻ có tiêu đề tô màu ===== */
:root{--hd:#2d3236;--hd2:#3a4044;--o:#f07c1b;--o2:#d96a0d;--ol:#fff1e4}
.hdr{background:var(--hd);border-bottom:0;box-shadow:0 2px 12px rgba(0,0,0,.18)}
.logo{font-size:25px;letter-spacing:-.02em;color:#fff;gap:0}.logo span{color:var(--o)}
.hdr .pts{color:#fff}.menu-btn{color:#fff}
.nav a{color:#e3e7e9}.nav a:hover{background:rgba(255,255,255,.09);color:#fff}.nav a.on{background:rgba(255,255,255,.14);color:#fff;box-shadow:inset 0 -2px 0 var(--o)}
@media(max-width:1200px){.nav{background:var(--hd);border-bottom:0;box-shadow:0 10px 18px rgba(0,0,0,.2)}}
.ftr{background:var(--hd);color:#c9cfd2}
.btn{transition:transform .15s,box-shadow .15s,background .15s}.btn:hover{transform:translateY(-1px);box-shadow:0 6px 16px rgba(16,124,65,.22)}
.btn.or{background:var(--o);border-color:var(--o);color:#fff}.btn.or:hover{background:var(--o2);border-color:var(--o2);box-shadow:0 6px 16px rgba(240,124,27,.3)}
.hero{background:radial-gradient(900px 420px at 85% 10%,#e2f2e8 0,transparent 70%),radial-gradient(700px 360px at 0% 100%,var(--ol) 0,transparent 70%);padding:56px 0 44px}
.hero .card{box-shadow:0 18px 40px rgba(20,48,42,.12);border:0}
.band{background:var(--ink)}
section{padding:56px 0}section.alt{background:#fff}
.eyebrow{font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--o2);margin:0 0 6px}
section h2{font-size:clamp(24px,3.2vw,32px);font-weight:800}
/* 6 ô chia 3 trên 3 dưới, căn giữa */
.six{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;max-width:1040px;margin:26px auto 0}
@media(max-width:900px){.six{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:600px){.six{grid-template-columns:minmax(0,1fr)}}
.hcard{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden;box-shadow:var(--sh);text-decoration:none;color:inherit;transition:transform .18s,box-shadow .18s,border-color .18s}
.hcard:hover{transform:translateY(-3px);box-shadow:0 12px 28px rgba(20,48,42,.12);border-color:#b9dcc6}
.hcard .hd{display:flex;align-items:center;gap:12px;background:var(--gl);padding:16px 20px;border-bottom:1px solid #cfe8d9;min-height:78px}
.hcard .hd h3{margin:0;font-size:18px;font-weight:700;color:var(--g2)}
.hcard .ic{flex:none;display:grid;place-items:center;width:42px;height:42px;border-radius:12px;background:#fff;font-size:22px;box-shadow:0 2px 6px rgba(16,124,65,.12)}
.hcard p{margin:0;padding:16px 20px 20px;flex:1}
.hcard .meta{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;padding:12px 20px;border-top:1px dashed var(--line);font-size:14px}.hcard .go{color:var(--o2);font-weight:700}
section.alt .hcard{background:#fbfcfa}
.promo{display:flex;flex-wrap:wrap;gap:14px;align-items:center;justify-content:space-between;max-width:1040px;margin:26px auto 0;padding:22px 26px;border-radius:16px;background:linear-gradient(120deg,var(--hd),#1d4a37);color:#fff}
.roadmap{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px;margin-top:26px}
.mcard{display:flex;gap:14px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-left:4px solid var(--g);border-radius:14px;padding:16px 18px;box-shadow:var(--sh)}
.mcard .n{flex:none;display:grid;place-items:center;width:34px;height:34px;border-radius:50%;background:var(--gl);color:var(--g2);font-weight:800}
.find{background:linear-gradient(180deg,var(--gl),#f2f9f4)}.find input{box-shadow:0 8px 24px rgba(16,124,65,.12);border-radius:14px}
.cta{background:linear-gradient(120deg,var(--g2),var(--g));color:#fff}.cta h2{color:#fff}.cta p{opacity:.9;margin:0 0 18px}
.card{border-radius:16px}
.roadmap{max-width:1088px;margin-left:auto;margin-right:auto}
/* Căn giữa trang phụ: tiêu đề trang, câu hỏi thường gặp, chân trang luôn nằm cuối màn hình */
body{display:flex;flex-direction:column;min-height:100vh}body>*{flex-shrink:0}body>.wrap,body>main{margin-top:0;margin-bottom:0;width:100%;padding-bottom:48px}
.ftr{margin-top:auto}
.wrap>h1:first-child,main>h1:first-child,#out>h1:first-child,.article>h1{text-align:center;font-size:clamp(26px,3.4vw,36px);font-weight:800;margin-bottom:.35em}
.wrap>h1:first-child+p,main>h1:first-child+p{text-align:center;max-width:680px;margin-left:auto;margin-right:auto}
.narrow>h2:first-child,.narrow>h2{text-align:center}
.fq{background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin-top:10px;transition:border-color .15s}.fq:hover,.fq[open]{border-color:#b9dcc6}.fq summary{list-style:none;display:flex;justify-content:space-between;gap:12px}.fq summary::-webkit-details-marker{display:none}.fq summary:after{content:"+";font-size:20px;line-height:1;color:var(--g)}.fq[open] summary:after{content:"–"}.fq p{margin:10px 0 0}
.ftr .wrap{text-align:center}.ftr .row{justify-content:center}.ftr{padding-top:36px}
body>.learn{margin-top:0;margin-bottom:0;width:100%}
/* Đầu trang và chân trang cùng màu xanh với nút bấm */
.hdr,.ftr{background:var(--g)}@media(max-width:1200px){.nav{background:var(--g)}}.hdr .logo span{color:#ffb059}.ftr{color:#e3f2e9}
/* Đồng bộ một tông xanh Excel (#107C41 và bản đậm #0B5D30) cho mọi khối màu */
:root{--hd:var(--g2)}.band{background:var(--g2)}.promo{background:linear-gradient(120deg,var(--g2),var(--g))}.syntax{background:var(--g2)}
/* Chúc mừng khi làm đúng: pháo giấy và chữ bật lên giữa màn hình */
.confetti{position:fixed;inset:0;width:100%;height:100%;pointer-events:none;z-index:60}
.cheer{position:fixed;left:50%;top:42%;z-index:61;pointer-events:none;display:flex;flex-direction:column;align-items:center;gap:6px;background:#fff;border:3px solid var(--g);border-radius:22px;padding:16px 30px;box-shadow:0 12px 40px rgba(16,124,65,.28);animation:cheer 1.5s cubic-bezier(.2,1.4,.4,1) forwards;text-align:center}
.cheer b{font-size:30px;font-weight:800;color:var(--g2);line-height:1.1}.cheer span{font-size:19px;font-weight:700;color:#b77a00}.cheer.big b{font-size:38px}
@keyframes cheer{0%{transform:translate(-50%,-50%) scale(.3);opacity:0}18%{transform:translate(-50%,-50%) scale(1.12);opacity:1}30%{transform:translate(-50%,-50%) scale(1)}80%{opacity:1;transform:translate(-50%,-50%) scale(1)}100%{opacity:0;transform:translate(-50%,-70%) scale(.9)}}
@media(prefers-reduced-motion:reduce){.cheer{animation-duration:1.5s;animation-timing-function:linear}}
.foot.ok .msg{font-size:18px;animation:pop .45s cubic-bezier(.2,1.6,.4,1)}@keyframes pop{0%{transform:scale(.7)}100%{transform:scale(1)}}
.foot .snd{min-height:38px;padding:4px 10px;font-size:18px;order:-1}
/* Ứng dụng cài trên máy: thanh phím tắt ở đáy */
.apptabs{position:fixed;left:0;right:0;bottom:0;z-index:30;display:flex;background:#fff;border-top:1px solid var(--line);padding:4px 4px calc(4px + env(safe-area-inset-bottom))}
.apptabs a{flex:1;display:flex;flex-direction:column;align-items:center;gap:1px;padding:5px 2px;text-decoration:none;color:var(--mut);font-size:12px;font-weight:600;border-radius:10px}.apptabs a i{font-style:normal;font-size:20px;line-height:1.2;font-weight:800}.apptabs a.on{color:var(--g2);background:var(--gl)}
.is-app body{padding-bottom:calc(64px + env(safe-area-inset-bottom))}.is-app .foot{padding-bottom:calc(10px + env(safe-area-inset-bottom))}.is-app .float{display:none}
/* Huy hiệu Google Play / App Store */
.badges{display:flex;gap:10px;flex-wrap:wrap;margin:14px 0}
.badge{display:inline-flex;align-items:center;gap:9px;background:#000;color:#fff;border:1px solid #a6a6a6;border-radius:10px;padding:6px 16px 6px 12px;min-width:160px;text-decoration:none;line-height:1.05}.badge:hover{background:#1c1c1c}
.badge span{display:flex;flex-direction:column;font-size:20px;font-weight:600;letter-spacing:-.2px}.badge small{font-size:10px;font-weight:500;letter-spacing:.2px}
.ftr .badges{margin:16px 0 0;justify-content:center}.soon{margin-bottom:16px;padding-bottom:14px;border-bottom:1px solid var(--line)}.soon .badges{margin-top:0}.soon .badge{opacity:.92}
/* Trang tài khoản */
.join h2{margin:0;font-size:22px;color:var(--g2)}
.refrow{display:flex;gap:10px;flex-wrap:wrap;margin-top:6px}.refitem{display:flex;flex-direction:column;gap:3px;min-width:0}.refitem.grow{flex:1 1 280px}
.refval{display:flex;align-items:center;border:1.5px solid var(--line);border-radius:10px;background:#fff;min-height:46px;padding-left:12px}
.refval input{flex:1;min-width:0;border:0;padding:0;background:none;font-size:15px;outline:none}.refcode{font:800 20px Consolas,monospace;color:var(--g2);letter-spacing:.5px;margin-right:4px}
.cp{display:inline-flex;align-items:center;gap:4px;align-self:stretch;border:0;border-left:1.5px solid var(--line);background:var(--gl);color:var(--g2);padding:0 13px;font:600 13px inherit;font-family:inherit;cursor:pointer;border-radius:0 9px 9px 0;white-space:nowrap}.cp:hover{background:#d3ecdd}
/* Lời chào sau khi xác minh email */
.welcome{position:fixed;left:50%;top:84px;transform:translateX(-50%);z-index:59;width:min(440px,calc(100% - 32px));background:#fff;border:2px solid var(--g);border-radius:16px;padding:16px 18px;box-shadow:0 12px 40px rgba(16,124,65,.25);display:flex;flex-direction:column;gap:6px;text-align:center}
.welcome b{font-size:19px;color:var(--g2)}.welcome div{display:flex;gap:8px;justify-content:center;margin-top:6px}
/* Trang tải ứng dụng */
.store{display:flex;gap:12px;flex-wrap:wrap;margin:14px 0}.store .btn{min-width:210px}.steps-i{padding-left:20px}.steps-i li{margin:6px 0}

/* Khung trợ lý: hỗ trợ ảo + AI làm file (assets/tro-ly.js) */
.learn.has-tl{grid-template-columns:270px minmax(0,1fr) 370px;max-width:1720px}
.tl{background:#fff;border:1px solid var(--line);border-radius:var(--r);display:flex;flex-direction:column;overflow:hidden;font-size:15px}
.tl[hidden]{display:none}
.tl.dock{position:sticky;top:76px;align-self:start;height:calc(100vh - 170px);min-height:420px}
.tl.pop{position:fixed;right:14px;bottom:14px;width:min(400px,calc(100vw - 28px));height:min(640px,calc(100vh - 96px));z-index:45;box-shadow:0 18px 44px rgba(20,48,42,.25)}
.has-foot .tl.pop{bottom:84px;height:min(600px,calc(100vh - 170px))}
.tl-hd{display:flex;align-items:center;gap:6px;padding:8px 8px 0;border-bottom:1px solid var(--line);background:var(--gl)}
.tl-tabs{display:flex;gap:4px;flex:1;min-width:0}
.tl-tabs button{flex:1;border:0;background:transparent;font:600 14.5px inherit;font-family:inherit;color:var(--mut);padding:9px 6px;border-radius:10px 10px 0 0;cursor:pointer;white-space:nowrap}
.tl-tabs button.on{background:#fff;color:var(--g2);box-shadow:0 -1px 0 var(--line) inset}
.tl-x{border:0;background:transparent;font-size:16px;color:var(--mut);width:34px;height:34px;border-radius:8px;cursor:pointer;flex:none}.tl-x:hover{background:#fff}
.tl-p{display:flex;flex-direction:column;flex:1;min-height:0}.tl-p[hidden]{display:none}
.tl-pad{padding:16px}
.tl-log{flex:1;overflow:auto;padding:12px;display:flex;flex-direction:column;gap:8px;overscroll-behavior:contain}
.tl-m{max-width:88%;padding:8px 12px;border-radius:14px;line-height:1.5;word-wrap:break-word}
.tl-m.bot{background:#f1f4f1;align-self:flex-start;border-bottom-left-radius:4px}
.tl-m.me{background:var(--g);color:#fff;align-self:flex-end;border-bottom-right-radius:4px}
.tl-typing{display:flex;gap:4px;padding:12px 14px}.tl-typing i{width:7px;height:7px;border-radius:50%;background:#9bb0a6;animation:tlDot 1s infinite}.tl-typing i:nth-child(2){animation-delay:.15s}.tl-typing i:nth-child(3){animation-delay:.3s}
@keyframes tlDot{0%,80%,100%{opacity:.3;transform:translateY(0)}40%{opacity:1;transform:translateY(-3px)}}
.tl-wait{margin:0 0 0 4px}
.tl-chips{display:flex;flex-wrap:wrap;gap:6px;padding:0 12px 8px}.tl-chips:empty{display:none}
.tl-chips .chip{border:1.5px solid var(--g);background:#fff;color:var(--g2);border-radius:20px;padding:5px 11px;font:500 13.5px inherit;font-family:inherit;cursor:pointer;text-align:left}.tl-chips .chip:hover{background:var(--gl)}
.tl-in{display:flex;gap:6px;align-items:flex-end;padding:8px 10px;border-top:1px solid var(--line)}
.tl-in textarea{flex:1;min-width:0;resize:none;font:inherit;padding:9px 11px;border:1.5px solid var(--line);border-radius:12px;max-height:130px;line-height:1.4}
.tl-in textarea:focus{outline:2px solid var(--g);outline-offset:0;border-color:transparent}
.tl-human{font-size:13px;color:var(--mut);padding:0 12px 9px;text-align:center}
.tl-lock ul{padding-left:20px;margin:8px 0}.tl-lock li{margin:4px 0}.tl-hero{font-size:40px;line-height:1}
.tl-why{background:var(--aml);border-radius:10px;padding:8px 10px;font-weight:600;font-size:14px}
.tl-filebar{padding:10px 10px 0}
.tl-drop{display:flex;flex-direction:column;align-items:center;gap:2px;border:2px dashed #b9d3c3;border-radius:12px;padding:10px;cursor:pointer;text-align:center;background:#fbfdfb}
.tl-drop:hover,.tl-drop.over{border-color:var(--g);background:var(--gl)}.tl-drop span{font-size:13px;color:var(--mut)}
.tl-drop b{max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.tl-sum{margin-top:6px;font-size:13.5px}.tl-sum summary{cursor:pointer;font-weight:600;color:var(--g2)}.tl-sum div{margin:3px 0;word-break:break-all}
.tl-acts{margin-top:8px;gap:6px}
.tl-btn{position:fixed;right:14px;bottom:14px;z-index:44;display:flex;align-items:center;gap:6px;border:0;border-radius:30px;padding:11px 18px;background:var(--g);color:#fff;font:700 15px inherit;font-family:inherit;cursor:pointer;box-shadow:0 8px 22px rgba(16,124,65,.4)}
.tl-btn:hover{background:var(--g2)}.tl-btn[hidden]{display:none}
.has-foot .tl-btn{bottom:84px}
.is-app .tl-btn{bottom:calc(76px + env(safe-area-inset-bottom))}.is-app.has-foot .tl-btn,.is-app .has-foot .tl-btn{bottom:calc(84px + env(safe-area-inset-bottom))}
@media(max-width:600px){.tl.pop,.has-foot .tl.pop{left:0;right:0;bottom:0;width:auto;height:88vh;border-radius:16px 16px 0 0}.tl-btn{padding:10px 14px}}
@media print{.tl,.tl-btn{display:none!important}}

/* ===== tinhocviet.vn: logo, menu "Khóa học" sổ xuống 4 môn ===== */
.logo{font-size:23px;align-items:center}.logo em{font-style:normal;font-weight:600;color:#cfeedd;font-size:.78em;margin-left:1px}
.lg-ic{flex:none;width:31px;height:31px;margin-right:9px;display:block}
.mi{flex:none;display:grid;place-items:center;width:34px;height:34px;border-radius:9px;color:#fff;font:800 17px/1 'Be Vietnam Pro',system-ui,sans-serif;font-style:normal}
.dd{position:relative}
.dd-b{display:flex;align-items:center;gap:5px;padding:8px 12px;border-radius:9px;border:0;background:none;color:#e3e7e9;font:500 15px inherit;font-family:inherit;cursor:pointer;white-space:nowrap}
.dd-b:hover,.dd.open .dd-b{background:rgba(255,255,255,.09);color:#fff}.dd-b.on{background:rgba(255,255,255,.14);color:#fff;box-shadow:inset 0 -2px 0 var(--o)}
.dd-b .car{font-size:11px;transition:transform .15s}.dd.open .car{transform:rotate(180deg)}
.dd-m{display:none;position:absolute;left:0;top:calc(100% + 8px);z-index:40;width:330px;background:#fff;border-radius:14px;box-shadow:0 16px 40px rgba(0,0,0,.2);padding:8px}
.dd.open .dd-m{display:grid;gap:2px}
.dd-m:before{content:"";position:absolute;top:-6px;left:28px;width:12px;height:12px;background:#fff;transform:rotate(45deg)}
.nav .dd-i{display:flex;gap:12px;align-items:center;padding:9px 10px;border-radius:10px;color:var(--ink);white-space:normal;box-shadow:none}
.nav .dd-i:hover,.nav .dd-i.on{background:#f1f5f2;color:var(--ink)}.nav .dd-i.on{box-shadow:inset 3px 0 0 var(--o)}
.dd-i b{display:block;font-size:15.5px;line-height:1.25}.dd-i small{display:block;font-size:13px;color:var(--mut);line-height:1.35}
@media(min-width:761px){.menu-btn{display:none}.pts{margin-left:auto}.nav{display:flex;position:static;flex-direction:row;padding:0;box-shadow:none;background:none;margin-left:14px}.nav a{padding:8px 12px;font-size:15px}}
@media(min-width:761px) and (hover:hover){.dd:hover .dd-m{display:grid;gap:2px}.dd:hover .dd-m{animation:ddin .12s ease-out}@keyframes ddin{from{opacity:0;transform:translateY(-4px)}}
.dd:after{content:"";position:absolute;left:0;right:0;top:100%;height:10px}}
@media(max-width:760px){.menu-btn{display:block}.pts{margin-left:auto}.pts+.menu-btn{margin-left:0}.nav{display:none;position:absolute;top:62px;left:0;right:0;background:var(--g);flex-direction:column;align-items:stretch;padding:8px 16px 14px;margin:0;box-shadow:0 10px 18px rgba(0,0,0,.2)}.nav.open{display:flex}.nav>a{padding:12px}
.dd-b{width:100%;padding:12px;justify-content:space-between}.dd-m{position:static;width:auto;box-shadow:none;margin:4px 0 6px}.dd-m:before{display:none}.dd.open .dd-m{display:grid}}
.ftr .row b{color:#fff}
/* Trang khóa học từng môn */
.mon-hero{color:#fff;padding:30px 0 34px;background:linear-gradient(120deg,var(--mc2),var(--mc))}
.mon-hero .wrap{display:flex;gap:18px;align-items:center;flex-wrap:wrap}.mon-hero h1{margin:0;font-size:clamp(26px,4vw,38px);font-weight:800;text-align:left!important}
.mon-hero p{margin:4px 0 0;opacity:.92;max-width:640px}.mon-hero .mi{width:64px;height:64px;font-size:34px;border-radius:16px;background:rgba(255,255,255,.18)!important;box-shadow:inset 0 0 0 2px rgba(255,255,255,.35)}
.mon-page .prog i,.mon-page .btn{background:var(--mc);border-color:var(--mc)}.mon-page .btn.ghost{background:transparent;color:var(--mc)}.mon-page .les:hover{border-color:var(--mc)}
.mon-cards{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;max-width:1088px;margin:26px auto 0}
@media(max-width:960px){.mon-cards{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:520px){.mon-cards{grid-template-columns:minmax(0,1fr)}}
.mcrd{display:flex;flex-direction:column;gap:10px;background:#fff;border:1px solid var(--line);border-top:5px solid var(--mc);border-radius:16px;padding:18px;text-decoration:none;color:inherit;box-shadow:var(--sh);transition:transform .18s,box-shadow .18s}
.mcrd:hover{transform:translateY(-3px);box-shadow:0 12px 28px rgba(20,48,42,.12)}.mcrd h3{margin:0;font-size:20px}.mcrd p{margin:0;font-size:14.5px;color:var(--mut);flex:1}
.mcrd .go{font-weight:700;color:var(--mc);font-size:14.5px}.mcrd .top{display:flex;gap:12px;align-items:center}
.mcrd .prog i{background:var(--mc)}
.side-mon{display:flex!important;align-items:center;gap:10px;padding:8px!important;margin-bottom:4px;border-bottom:1px solid var(--line);border-radius:8px 8px 0 0!important}.side-mon .mi{width:28px;height:28px;font-size:14px;border-radius:7px}
.mon-card .q{margin-bottom:10px}.mon-card #opts:empty,.mon-card #tip:empty{display:none}.mon-card #sim{margin-top:12px}
.xl-tools{display:flex;flex-wrap:wrap;justify-content:center;gap:8px;margin:6px 0 4px}.xl-tools a{background:#fff;border:1px solid var(--line);border-radius:20px;padding:6px 14px;text-decoration:none;color:var(--g2);font-weight:600;font-size:14.5px}.xl-tools a:hover{border-color:var(--g);background:var(--gl)}
.mon-page .stat{background:color-mix(in srgb,var(--mc) 9%,#fff)}.mon-page .stat b{color:var(--mc)}.mon-page .mod summary small{color:var(--mut)}