*{box-sizing:border-box}
:root{color-scheme:light dark;
 --bg:#fcfdfd;--surf:#eff3f4;--surf2:#e5edee;--ink:#15222a;--mute:#50626b;--hair:#d3dbdd;
 --accent:#0b5d6b;--accent-bg:#dbeced;--on-accent:#fff;
 --good:#2c6a45;--good-bg:#dfeee6;--ok:#0b5d6b;--ok-bg:#dbeced;
 --mid:#8a6516;--mid-bg:#f6eedd;--low:#9d2c3c;--low-bg:#f7e5e7;
 --shadow:0 1px 2px rgba(21,34,42,.05),0 8px 24px -12px rgba(21,34,42,.18)}
@media(prefers-color-scheme:dark){:root:not([data-theme=light]){
 --bg:#0d1417;--surf:#151f23;--surf2:#1b262b;--ink:#e3ecee;--mute:#9bacb2;--hair:#26343a;
 --accent:#63c2ce;--accent-bg:#12333a;--on-accent:#08171b;
 --good:#6fb98d;--good-bg:#14291f;--ok:#63c2ce;--ok-bg:#12333a;
 --mid:#d6a44f;--mid-bg:#33280f;--low:#e08c96;--low-bg:#3a1d22;
 --shadow:0 1px 2px rgba(0,0,0,.4),0 10px 28px -14px rgba(0,0,0,.7)}}

html{scroll-behavior:smooth}
svg{width:18px;height:18px;flex:none}
body{margin:0;background:var(--bg);color:var(--ink);font-size:16px;line-height:1.62;
 font-family:'Be Vietnam Pro','Helvetica Neue',Arial,sans-serif;-webkit-font-smoothing:antialiased}
h1,h2,h3,h4{font-family:'Source Serif 4',Georgia,serif;font-weight:600;margin:0;text-wrap:balance;
 overflow-wrap:break-word}
p,li,dd,.note,.sub,.opt span,.ansrow .kv span{text-wrap:pretty;overflow-wrap:break-word;hyphens:none}
td,th{overflow-wrap:break-word}
p{margin:0 0 .8em}
a{color:var(--accent)}
.wrap{max-width:1120px;margin:0 auto;padding:0 22px}
.narrow{max-width:660px}

/* ── thanh trên ── */
.top{position:sticky;top:0;z-index:30;background:color-mix(in srgb,var(--bg) 90%,transparent);
 backdrop-filter:blur(10px);border-bottom:1px solid var(--hair)}
.top .wrap{display:flex;align-items:center;gap:14px;height:58px;justify-content:space-between}
.brand{display:flex;align-items:center;gap:9px;font-family:'IBM Plex Mono',monospace;font-size:11px;
 letter-spacing:.15em;text-transform:uppercase;color:var(--accent);font-weight:500;text-decoration:none}
.brand svg{width:20px;height:20px}
.top .who{font-size:13px;color:var(--mute);display:flex;align-items:center;gap:12px}
.top .who b{color:var(--ink);font-weight:600}

/* ── hero ── */
.hero{position:relative;overflow:hidden;border-bottom:1px solid var(--hair);
 padding:clamp(40px,6vw,78px) 0 clamp(32px,4vw,56px)}
.hero::before{content:'';position:absolute;inset:0;pointer-events:none;opacity:.55;
 background:repeating-linear-gradient(180deg,transparent 0 39px,var(--hair) 39px 40px);
 -webkit-mask-image:linear-gradient(180deg,rgba(0,0,0,.55),transparent 78%);
 mask-image:linear-gradient(180deg,rgba(0,0,0,.55),transparent 78%)}
.hero::after{content:'';position:absolute;width:520px;height:520px;right:-160px;top:-220px;
 border-radius:50%;background:radial-gradient(circle,var(--accent-bg),transparent 68%);opacity:.75;
 pointer-events:none;animation:float 14s ease-in-out infinite}
@keyframes float{0%,100%{transform:translate(0,0)}50%{transform:translate(-26px,26px)}}
.hero>*{position:relative;z-index:1}
.eyebrow{font-family:'IBM Plex Mono',monospace;font-size:11px;letter-spacing:.18em;
 text-transform:uppercase;color:var(--accent);font-weight:500;display:flex;align-items:center;gap:10px}
.eyebrow::after{content:'';height:1px;flex:1;max-width:150px;background:var(--hair)}
.hero h1{font-size:clamp(27px,4.6vw,50px);line-height:1.05;letter-spacing:-.024em;margin:16px 0 0;
 max-width:22ch}
.hero.slim{padding:clamp(26px,3.4vw,44px) 0 clamp(20px,2.4vw,30px)}
.hero.slim h1{font-size:clamp(23px,3.4vw,38px);max-width:26ch}
.hero .meta{display:flex;flex-wrap:wrap;gap:6px 18px;margin-top:14px;font-size:13.4px;color:var(--mute)}
.hero .meta b{color:var(--ink);font-weight:600}
.hero .sub{font-size:clamp(15px,1.5vw,18px);color:var(--mute);max-width:56ch;margin-top:16px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px}
.chip{display:flex;align-items:center;gap:7px;font-size:12.6px;color:var(--mute);
 border:1px solid var(--hair);border-radius:99px;padding:6px 14px;background:var(--bg)}
.chip svg{width:15px;height:15px;color:var(--accent)}

/* ── thẻ chung ── */
.card{background:var(--surf);border:1px solid var(--hair);border-radius:12px;padding:22px;box-shadow:var(--shadow)}
.grid{display:grid;gap:14px}
.g2{grid-template-columns:repeat(auto-fit,minmax(min(260px,100%),1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(min(210px,100%),1fr))}

/* ── biểu mẫu ── */
form.auth{display:grid;gap:14px;margin-top:6px}
form.auth label{display:block;font-size:12px;font-family:'IBM Plex Mono',monospace;letter-spacing:.1em;
 text-transform:uppercase;color:var(--mute);margin-bottom:6px}
input[type=text],input[type=email],input[type=password]{width:100%;padding:12px 14px;font:inherit;
 font-size:15px;color:var(--ink);background:var(--bg);border:1px solid var(--hair);border-radius:9px}
input:focus{outline:2px solid var(--accent);outline-offset:1px;border-color:var(--accent)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid var(--accent);
 background:var(--accent);color:var(--on-accent);border-radius:9px;padding:12px 20px;font:inherit;
 font-size:15px;font-weight:500;cursor:pointer;text-decoration:none;transition:.15s}
.btn svg{width:17px;height:17px;flex:none}
.btn:hover{filter:brightness(1.08)}
.btn.ghost{background:transparent;color:var(--accent)}
.btn.sm{padding:7px 13px;font-size:13px;border-radius:7px}
.btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.err{background:var(--low-bg);color:var(--low);border-left:3px solid var(--low);
 padding:11px 15px;border-radius:0 8px 8px 0;font-size:14px;margin:0 0 4px}
.note{font-size:13.4px;color:var(--mute)}

/* ── đồng hồ đếm ngược ── */
.timerbar{position:sticky;top:58px;z-index:25;background:color-mix(in srgb,var(--bg) 93%,transparent);
 backdrop-filter:blur(8px);border-bottom:1px solid var(--hair);padding:11px 0}
.timerbar .wrap{display:flex;align-items:center;gap:10px 14px;flex-wrap:wrap}
@media(max-width:640px){
 .timerbar .prog{order:3;flex-basis:100%;min-width:0}
 .timerbar .count{font-size:12px}
 .timer{font-size:18px}}
.timer{display:flex;align-items:center;gap:9px;font-family:'IBM Plex Mono',monospace;font-size:20px;
 font-weight:500;font-variant-numeric:tabular-nums;color:var(--accent)}
.timer svg{width:19px;height:19px}
.timer.warn{color:var(--mid)} .timer.danger{color:var(--low);animation:pulse 1s ease-in-out infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.45}}
.prog{flex:1;min-width:140px;height:6px;background:var(--surf2);border-radius:99px;overflow:hidden}
.prog i{display:block;height:100%;background:var(--accent);border-radius:99px;transition:width .4s linear}
.prog i.warn{background:var(--mid)} .prog i.danger{background:var(--low)}
.count{font-size:13px;color:var(--mute);font-family:'IBM Plex Mono',monospace}

/* ── câu hỏi ── */
.sechead{display:flex;align-items:center;gap:12px;margin:34px 0 14px;padding-top:12px;
 border-top:1px solid var(--hair)}
.sechead:first-of-type{border-top:0;margin-top:18px}
.sechead .ic{width:38px;height:38px;flex:none;display:grid;place-items:center;border-radius:10px;
 background:var(--accent-bg);color:var(--accent)}
.sechead .ic svg{width:20px;height:20px}
.sechead h3{font-size:19px;line-height:1.2}
.sechead .n{font-size:12.4px;color:var(--mute);margin-top:1px}
.q{background:var(--surf);border:1px solid var(--hair);border-radius:12px;padding:18px 20px;margin:0 0 12px;
 transition:border-color .2s,box-shadow .2s;opacity:0;transform:translateY(12px);
 animation:qin .5s cubic-bezier(.2,.72,.3,1) forwards}
@keyframes qin{to{opacity:1;transform:none}}
.q.answered{border-color:var(--accent)}
.q .stem{display:flex;gap:11px;font-size:15.4px;line-height:1.5;margin-bottom:12px}
.q .no{font-family:'IBM Plex Mono',monospace;font-size:13px;color:var(--accent);font-weight:500;flex:none;
 min-width:26px}
.opts{display:grid;gap:7px;margin-left:37px}
@media(max-width:560px){.opts{margin-left:0}}
.opt{display:flex;gap:11px;align-items:flex-start;text-transform:none;letter-spacing:normal;font-family:inherit;color:var(--ink);margin:0;padding:11px 14px;border:1px solid var(--hair);
 border-radius:9px;background:var(--bg);cursor:pointer;font-size:14.6px;line-height:1.45;transition:.14s}
.opt:hover{border-color:var(--accent)}
.opt input{position:absolute;opacity:0;width:0;height:0}
.opt .l{font-family:'IBM Plex Mono',monospace;font-size:12.4px;color:var(--mute);border:1px solid var(--hair);
 border-radius:6px;width:24px;height:24px;display:grid;place-items:center;flex:none;transition:.14s}
.opt:has(input:checked){border-color:var(--accent);background:var(--accent-bg)}
.opt:has(input:checked) .l{background:var(--accent);color:var(--on-accent);border-color:var(--accent)}
.opt:has(input:focus-visible){outline:2px solid var(--accent);outline-offset:2px}
code{font-family:'IBM Plex Mono',monospace;font-size:.88em;background:var(--surf2);padding:1px 5px;border-radius:4px}

/* ── kết quả ── */
.score{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap}
.score b{font-family:'Source Serif 4',serif;font-size:clamp(44px,8vw,72px);line-height:1;
 font-variant-numeric:tabular-nums}
.score span{font-size:17px;color:var(--mute)}
.ring{--p:0;width:132px;height:132px;border-radius:50%;flex:none;display:grid;place-items:center;
 background:conic-gradient(var(--accent) calc(var(--p)*1%),var(--surf2) 0);position:relative}
.ring::after{content:'';position:absolute;inset:11px;border-radius:50%;background:var(--bg)}
.ring b{position:relative;z-index:1;font-family:'Source Serif 4',serif;font-size:30px}
.band{display:inline-flex;align-items:center;gap:8px;padding:6px 14px;border-radius:99px;
 font-size:13.4px;font-weight:600}
.band svg{width:16px;height:16px}
.band.good{background:var(--good-bg);color:var(--good)}
.band.ok{background:var(--ok-bg);color:var(--ok)}
.band.mid{background:var(--mid-bg);color:var(--mid)}
.band.low{background:var(--low-bg);color:var(--low)}
.secbar{display:grid;gap:9px;margin-top:8px}
.secbar .row{display:grid;grid-template-columns:minmax(130px,1.3fr) 1fr auto;gap:12px;align-items:center;
 font-size:13.8px}
.secbar .bar{height:8px;background:var(--surf2);border-radius:99px;overflow:hidden}
.secbar .bar i{display:block;height:100%;border-radius:99px;background:var(--accent);
 animation:grow .9s cubic-bezier(.2,.72,.3,1) both}
@keyframes grow{from{width:0!important}}
.secbar .v{font-family:'IBM Plex Mono',monospace;font-size:12.6px;color:var(--mute)}
@media(max-width:600px){.secbar .row{grid-template-columns:1fr auto}.secbar .bar{grid-column:1/-1}}

/* ── bảng quản trị ── */
.tw{overflow-x:auto;border:1px solid var(--hair);border-radius:12px;margin:16px 0}
table{border-collapse:collapse;width:100%;font-size:13.8px;min-width:720px}
th{background:var(--surf);color:var(--accent);text-align:left;font-size:10.6px;letter-spacing:.09em;
 text-transform:uppercase;padding:12px 14px;font-weight:600;border-bottom:1px solid var(--hair);white-space:nowrap}
td{padding:12px 14px;border-bottom:1px solid var(--hair);vertical-align:middle}
tbody tr:last-child td{border-bottom:0}
tbody tr:hover td{background:var(--surf)}
td.mono{font-family:'IBM Plex Mono',monospace;font-size:12.6px;white-space:nowrap}
td.acts{white-space:nowrap}
td.acts form{display:inline;margin-left:6px}
.hist{display:grid;gap:6px}
.hist a{display:grid;grid-template-columns:auto auto auto 1fr;gap:6px 16px;align-items:baseline;
 padding:10px 14px;border:1px solid var(--hair);border-radius:8px;text-decoration:none;color:var(--ink);
 font-size:13.6px;transition:.15s}
.hist a:hover{border-color:var(--accent);background:var(--surf)}
.hist a span{color:var(--mute);font-family:'IBM Plex Mono',monospace;font-size:12.4px}
@media(max-width:600px){.hist a{grid-template-columns:1fr 1fr}}
.pill{display:inline-block;padding:3px 10px;border-radius:99px;font-size:11.6px;font-weight:600;white-space:nowrap}
.pill.good{background:var(--good-bg);color:var(--good)}.pill.ok{background:var(--ok-bg);color:var(--ok)}
.pill.mid{background:var(--mid-bg);color:var(--mid)}.pill.low{background:var(--low-bg);color:var(--low)}
.pill.wait{background:var(--surf2);color:var(--mute)}
.stat{background:var(--surf);border:1px solid var(--hair);border-radius:11px;padding:16px 18px}
.stat b{display:block;font-family:'Source Serif 4',serif;font-size:32px;line-height:1;color:var(--accent);
 font-variant-numeric:tabular-nums}
.stat span{display:block;font-size:12.6px;color:var(--mute);margin-top:5px}
.ansrow{border:1px solid var(--hair);border-radius:10px;padding:14px 16px;margin:0 0 9px;background:var(--surf)}
.ansrow.wrong{border-left:3px solid var(--low)}
.ansrow.right{border-left:3px solid var(--good)}
.ansrow .h{display:flex;gap:10px;align-items:baseline;font-size:14.6px;margin-bottom:7px}
.ansrow .h .no{font-family:'IBM Plex Mono',monospace;font-size:12.4px;color:var(--accent);flex:none}
.ansrow .kv{font-size:13.4px;color:var(--mute);margin:3px 0;display:flex;gap:8px}
.ansrow .kv b{font-family:'IBM Plex Mono',monospace;font-size:10.6px;letter-spacing:.08em;
 text-transform:uppercase;flex:none;min-width:76px;padding-top:2px}
.ansrow .ok{color:var(--good)}.ansrow .no2{color:var(--low)}
.ansrow .why{font-size:13px;color:var(--mute);border-top:1px dashed var(--hair);margin-top:9px;padding-top:8px}
.kflag{font-family:'IBM Plex Mono',monospace;font-size:10.4px;background:var(--mid-bg);color:var(--mid);
 padding:2px 7px;border-radius:5px;letter-spacing:.06em}
.assess{display:grid;gap:12px}
.assess ul{margin:0;padding-left:18px;font-size:14.4px;color:var(--mute)}
.assess li{margin:5px 0}
.reveal{opacity:0;transform:translateY(14px);transition:opacity .55s ease,transform .55s cubic-bezier(.2,.72,.3,1)}
.reveal.in{opacity:1;transform:none}
.demo{background:var(--mid-bg);color:var(--mid);border:1px solid var(--mid);border-radius:9px;
 padding:12px 16px;font-size:13.8px;margin:0 0 16px;display:flex;gap:10px;align-items:flex-start}
.demo svg{color:var(--mid);margin-top:2px}
footer{border-top:1px solid var(--hair);margin-top:52px;padding:26px 0 44px;font-size:13px;color:var(--mute);
 display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}
 .q{opacity:1;transform:none}.reveal{opacity:1;transform:none}}