/* Cẩm nang Cowork Giáo viên — giao diện chung
   Bố cục: trang giới thiệu dạng tạp chí giáo dục (serif cho tiêu đề, sans cho nội dung), app & quản trị dạng bảng điều khiển gọn. */
:root{
  --brand:#8E1B24; --brand-ink:#5E0F17; --brand-soft:#F6E9E6;
  --gold:#C9A227; --gold-soft:#FBF1D3;
  --paper:#FBF7F1; --surface:#FFFFFF; --ink:#24191A; --muted:#6E615B; --line:#E9DFD4;
  --ok:#1E7B45; --ok-soft:#E5F3EA; --warn:#9A6400; --warn-soft:#FFF3D6; --bad:#B3261E; --bad-soft:#FCE8E6;
  --zalo:#0068FF;
  --f-display:"Lora","Noto Serif",Georgia,"Times New Roman",serif;
  --f-body:"Be Vietnam Pro","Segoe UI",Roboto,Arial,sans-serif;
  --r:16px; --shadow:0 18px 40px -20px rgba(94,15,23,.35);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--f-body);font-size:16px;line-height:1.65;-webkit-text-size-adjust:100%}
img{max-width:100%}
a{color:var(--brand)}
h1,h2,h3{font-family:var(--f-display);line-height:1.2;text-wrap:balance;margin:0 0 .5em;color:var(--ink)}
h2{font-size:clamp(28px,4vw,42px)}
h3{font-size:20px}
.wrap{max-width:1180px;margin:0 auto;padding-inline:20px}
.eyebrow{font-size:13px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--brand)}
.lead{font-size:18px;color:var(--muted);max-width:62ch}
:focus-visible{outline:3px solid var(--gold);outline-offset:2px}
@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}

/* Nút */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:10px 22px;border-radius:999px;border:2px solid var(--brand);background:var(--brand);color:#fff;font:inherit;font-weight:700;text-decoration:none;cursor:pointer;transition:transform .15s,background .15s}
.btn:hover{transform:translateY(-1px);background:var(--brand-ink);border-color:var(--brand-ink)}
.btn.ghost{background:transparent;color:var(--brand)}
.btn.ghost:hover{background:var(--brand-soft)}
.btn.gold{background:var(--gold);border-color:var(--gold);color:#2B1F00}
.btn.zalo{background:var(--zalo);border-color:var(--zalo)}
.btn.sm{min-height:36px;padding:4px 14px;font-size:14px}
.btn.block{width:100%}
.btn.light{background:#fff;color:var(--ink);border-color:var(--line)}

/* Thanh điều hướng */
.nav{position:sticky;top:env(safe-area-inset-top,0px);z-index:40;background:rgba(251,247,241,.92);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;gap:18px;min-height:68px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-family:var(--f-display);font-weight:700;font-size:19px}
.logo i{width:38px;height:38px;border-radius:11px;background:var(--brand);color:var(--gold);display:grid;place-items:center;font-style:normal;font-size:20px}
.nav .links{display:flex;gap:20px;margin-left:auto}
.nav .links a{text-decoration:none;color:var(--ink);font-weight:600;font-size:15px}
.nav .links a:hover{color:var(--brand)}
.nav .acts{display:flex;gap:8px}
.burger{display:none;margin-left:auto;width:44px;height:44px;border-radius:12px;border:1px solid var(--line);background:#fff;font-size:20px;cursor:pointer}
@media (max-width:920px){
  .nav .links,.nav .acts{display:none}
  .burger{display:block}
  .nav.open .links,.nav.open .acts{display:flex;flex-direction:column;position:absolute;left:0;right:0;background:var(--paper);padding:12px 20px;border-bottom:1px solid var(--line)}
  .nav.open .links{top:68px}
  .nav.open .acts{top:calc(68px + 210px);flex-direction:row}
}

/* Hero */
.hero{padding-block:64px 40px;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:-30% -10% auto auto;width:620px;height:620px;border-radius:50%;background:radial-gradient(circle,var(--gold-soft) 0%,transparent 65%);z-index:-1}
.hero .wrap{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);gap:48px;align-items:center}
.hero h1{font-size:clamp(34px,4.8vw,56px);letter-spacing:-.01em}
.hero h1 em{font-style:italic;color:var(--brand)}
.hero .lead{font-size:19px;margin-bottom:26px}
.hero .ctas{display:flex;flex-wrap:wrap;gap:12px}
.trust{display:flex;flex-wrap:wrap;gap:22px;margin-top:30px;font-size:14px;color:var(--muted)}
.trust b{display:block;font-family:var(--f-display);font-size:30px;color:var(--brand);line-height:1.1}
@media (max-width:920px){.hero .wrap{grid-template-columns:1fr}.hero{padding-block:36px 24px}}

/* Màn hình minh hoạ */
.mock{background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);overflow:hidden;min-width:0}
.mock-bar{display:flex;align-items:center;gap:8px;background:var(--brand);color:#fff;padding:10px 14px;font-size:14px;font-weight:600}
.mock-bar span{width:10px;height:10px;border-radius:50%;background:rgba(255,255,255,.35)}
.mock-bar b{margin-left:8px}
.mock-body{padding:16px;display:grid;gap:12px}
.mock-chips{display:flex;flex-wrap:wrap;gap:6px}
.mock-chips i{font-style:normal;font-size:12px;border:1.5px solid var(--c);color:var(--c);border-radius:999px;padding:2px 10px}
.mock-card{border:1px solid var(--line);border-top:5px solid var(--c,#1F5FAF);border-radius:14px;padding:12px 14px}
.mock-card small{color:var(--muted)}
.mock-card h4{margin:2px 0 8px;font-size:15px}
.mock-card pre{margin:0;background:#2B2320;color:#F8EFE3;border-radius:10px;padding:10px 12px;font-size:12.5px;white-space:pre-wrap;font-family:"Times New Roman",serif;line-height:1.5}
.mock-card mark{background:var(--gold);color:#1d1400;border-radius:3px;padding:0 3px}
.mock-foot{display:flex;justify-content:space-between;align-items:center;font-size:13px;color:var(--ok);font-weight:600}

/* Khối */
.sec{padding-block:72px}
.sec.alt{background:#fff;border-block:1px solid var(--line)}
.sec.dark{background:#22181A;color:#F4EAE0}
.sec.dark h2,.sec.dark h3{color:#fff}
.sec.dark .lead{color:#CBBDB2}
.head{margin-bottom:34px}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
@media (max-width:900px){.grid3{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:620px){.grid3,.grid2{grid-template-columns:1fr}}
.feat{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:22px}
.feat .ic{font-size:28px}
.feat p{margin:0;color:var(--muted)}
.pain{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:0;border:1px solid var(--line);border-radius:20px;overflow:hidden;background:#fff}
.pain>div{padding:26px}
.pain>div+div{background:var(--brand);color:#fff}
.pain>div+div h3{color:#fff}
.pain ul{margin:0;padding-left:20px;display:grid;gap:8px}
@media (max-width:720px){.pain{grid-template-columns:1fr}}

/* Cấp học */
.lv-tabs{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:18px}
.lv-tabs button{min-height:44px;padding:6px 18px;border-radius:999px;border:2px solid var(--brand);background:#fff;color:var(--brand);font:inherit;font-weight:700;cursor:pointer}
.lv-tabs button.on{background:var(--brand);color:#fff}
.subj{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,230px),1fr));gap:10px}
.subj div{background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px 14px;display:flex;justify-content:space-between;gap:8px;align-items:center;font-weight:600}
.tag{display:inline-block;font-size:12px;font-weight:700;border-radius:999px;padding:2px 10px;white-space:nowrap}
.tag.ok{background:var(--ok-soft);color:var(--ok)}
.tag.soon{background:#F1ECE6;color:var(--muted)}
.tag.warn{background:var(--warn-soft);color:var(--warn)}
.tag.bad{background:var(--bad-soft);color:var(--bad)}
.tag.role{background:var(--brand-soft);color:var(--brand)}

/* Các bước */
.steps{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;counter-reset:s}
.steps li{counter-increment:s;position:relative;padding:22px 22px 22px 22px;border-radius:var(--r);background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.14)}
.steps li::before{content:counter(s);font-family:var(--f-display);font-size:44px;color:var(--gold);line-height:1;display:block;margin-bottom:8px}
.steps p{margin:0;color:#CBBDB2}
@media (max-width:820px){.steps{grid-template-columns:1fr}}

/* Bảng giá */
.notice{display:flex;gap:12px;align-items:flex-start;background:var(--gold-soft);border:1px solid #EBD38A;border-radius:14px;padding:14px 18px;margin-bottom:26px}
.prices{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:14px;align-items:stretch}
@media (max-width:1100px){.prices{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media (max-width:700px){.prices{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:440px){.prices{grid-template-columns:1fr}}
.price{position:relative;background:#fff;border:1.5px solid var(--line);border-radius:18px;padding:22px 18px;display:flex;flex-direction:column;gap:8px}
.price .nm{font-weight:700}
.price .amt{font-family:var(--f-display);font-size:34px;color:var(--ink);line-height:1.1;font-variant-numeric:tabular-nums}
.price .amt small{font-family:var(--f-body);font-size:14px;color:var(--muted);font-weight:500}
.price .per{font-size:13px;color:var(--muted)}
.price ul{margin:4px 0 10px;padding-left:18px;font-size:14px;color:var(--muted);flex:1}
.price .save{font-size:13px;color:var(--ok);font-weight:700}
.price.hot{border-color:var(--brand);box-shadow:var(--shadow)}
.price.best{border-color:var(--gold)}
.price .rib{position:absolute;top:-12px;left:18px;font-size:12px;font-weight:700;padding:3px 10px;border-radius:999px;background:var(--brand);color:#fff}
.price.best .rib{background:var(--gold);color:#2B1F00}
.extra{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:18px}
@media (max-width:720px){.extra{grid-template-columns:1fr}}
.extra>div{display:flex;gap:16px;align-items:center;background:#22181A;color:#F4EAE0;border-radius:18px;padding:20px 22px}
.extra .big{font-family:var(--f-display);font-size:28px;color:var(--gold);white-space:nowrap}
.extra h3{color:#fff;margin:0 0 4px;font-size:19px}
.extra p{margin:0;font-size:14px;color:#CBBDB2}

/* Đội ngũ, hỗ trợ */
.people{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
@media (max-width:860px){.people{grid-template-columns:1fr}}
.person{background:#fff;border:1px solid var(--line);border-radius:18px;padding:22px;display:flex;gap:16px;align-items:center}
.person .av{flex:none;width:64px;height:64px;border-radius:50%;background:var(--brand);color:var(--gold);display:grid;place-items:center;font-family:var(--f-display);font-size:24px;font-weight:700}
.person .av.z{background:var(--zalo);color:#fff;font-family:var(--f-body);font-size:16px}
.person small{display:block;color:var(--muted);font-size:13px;text-transform:uppercase;letter-spacing:.06em;font-weight:700}
.person b{display:block;font-size:18px}
.person a.tel{font-weight:700;text-decoration:none;font-variant-numeric:tabular-nums}

.faq details{background:#fff;border:1px solid var(--line);border-radius:14px;margin-bottom:10px}
.faq summary{cursor:pointer;padding:14px 18px;font-weight:700;list-style:none;display:flex;justify-content:space-between;gap:12px}
.faq summary::after{content:"+";color:var(--brand);font-size:22px;line-height:1}
.faq details[open] summary::after{content:"–"}
.faq details>div{padding:0 18px 16px;color:var(--muted)}

.cta{background:linear-gradient(135deg,var(--brand) 0%,var(--brand-ink) 100%);color:#fff;border-radius:24px;padding:40px;display:flex;flex-wrap:wrap;gap:20px;align-items:center;justify-content:space-between}
.cta h2{color:#fff;margin:0}
.cta p{margin:6px 0 0;color:#F1D9D5}

footer.site{background:#1B1214;color:#CBBDB2;padding-block:36px;font-size:14px}
footer.site .wrap{display:flex;flex-wrap:wrap;gap:20px;justify-content:space-between}
footer.site a{color:#F4EAE0}
.zalo-fab{position:fixed;right:16px;bottom:calc(16px + env(safe-area-inset-bottom,0px));z-index:50;display:flex;align-items:center;gap:8px;background:var(--zalo);color:#fff;text-decoration:none;font-weight:700;padding:10px 16px;border-radius:999px;box-shadow:0 10px 24px -8px rgba(0,104,255,.6)}

/* Biểu mẫu đăng nhập/đăng ký */
.auth{min-height:calc(100vh - 69px);display:grid;place-items:center;padding:32px 16px}
.auth-card{width:100%;max-width:520px;background:#fff;border:1px solid var(--line);border-radius:22px;padding:30px;box-shadow:var(--shadow)}
.auth-card.wide{max-width:760px}
.auth-card h1{font-size:30px;margin-bottom:4px}
.auth-card .sub{color:var(--muted);margin:0 0 20px}
.fg{display:grid;gap:6px;margin-bottom:14px}
.fg label{font-weight:700;font-size:14px}
.fg .hint{font-size:13px;color:var(--muted)}
input[type=text],input[type=email],input[type=tel],input[type=password],input[type=number],input[type=search],select,textarea{width:100%;min-height:46px;border:1.5px solid var(--line);border-radius:12px;padding:10px 14px;font:inherit;background:#fff;color:var(--ink)}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--brand)}
.row2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
@media (max-width:560px){.row2{grid-template-columns:1fr}}
.planpick{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,150px),1fr));gap:10px;margin-bottom:6px}
.planpick label{position:relative;display:block;border:1.5px solid var(--line);border-radius:14px;padding:12px;cursor:pointer;background:#fff}
.planpick input{position:absolute;opacity:0}
.planpick b{display:block}
.planpick span{font-size:13px;color:var(--muted)}
.planpick label:has(input:checked){border-color:var(--brand);background:var(--brand-soft);box-shadow:0 0 0 2px var(--brand) inset}
.planpick label:has(input:focus-visible){outline:3px solid var(--gold)}
.check{display:flex;gap:10px;align-items:flex-start;background:var(--gold-soft);border:1px solid #EBD38A;border-radius:12px;padding:12px 14px;cursor:pointer;margin-bottom:14px}
.check input{width:20px;height:20px;margin-top:3px;accent-color:var(--brand);flex:none}
.alert{border-radius:12px;padding:12px 16px;margin-bottom:14px;border:1px solid}
.alert.ok{background:var(--ok-soft);border-color:#B9DEC6;color:#14532D}
.alert.err{background:var(--bad-soft);border-color:#F4C2BD;color:#7F1D1D}
.alert.warn{background:var(--warn-soft);border-color:#F1D38E;color:#6B4400}
.links-row{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;margin-top:14px;font-size:14px}

/* Ứng dụng (sau đăng nhập) */
.appbar{background:var(--brand);color:#fff;position:sticky;top:env(safe-area-inset-top,0px);z-index:40}
.appbar .wrap{display:flex;align-items:center;gap:14px;min-height:62px;flex-wrap:wrap}
.appbar .logo{color:#fff}
.appbar .logo i{background:#fff;color:var(--brand)}
.appbar nav{display:flex;gap:6px;margin-left:auto;flex-wrap:wrap}
.appbar nav a{color:#fff;text-decoration:none;font-weight:600;font-size:15px;padding:6px 12px;border-radius:999px}
.appbar nav a.on,.appbar nav a:hover{background:rgba(255,255,255,.16)}
.page{padding-block:28px 60px}
.panel{background:#fff;border:1px solid var(--line);border-radius:18px;padding:22px;margin-bottom:18px;min-width:0}
.kpis{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,190px),1fr));gap:12px;margin-bottom:18px}
.kpi{background:#fff;border:1px solid var(--line);border-radius:16px;padding:16px 18px}
.kpi small{display:block;color:var(--muted);font-size:13px;font-weight:600}
.kpi b{font-family:var(--f-display);font-size:28px;font-variant-numeric:tabular-nums}
.kpi.hl{border-left:5px solid var(--brand)}
.tw{overflow-x:auto;border:1px solid var(--line);border-radius:14px}
table.t{width:100%;border-collapse:collapse;font-size:14px;min-width:720px}
table.t th,table.t td{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
table.t th{background:#F7F0E8;font-size:13px;color:var(--muted);text-transform:uppercase;letter-spacing:.04em;white-space:nowrap}
table.t td.num,table.t th.num{text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
table.t tr:last-child td{border-bottom:0}
table.t tfoot td{font-weight:700;background:#FBF6EF}
.acts-cell{display:flex;flex-wrap:wrap;gap:6px}
.acts-cell form{display:inline}
.mini{min-height:32px;padding:3px 10px;border-radius:8px;border:1.5px solid var(--line);background:#fff;font:inherit;font-size:13px;font-weight:600;cursor:pointer;color:var(--ink)}
.mini:hover{border-color:var(--brand);color:var(--brand)}
.mini.pri{background:var(--brand);border-color:var(--brand);color:#fff}
.mini.danger{color:var(--bad)}
.mini.danger:hover{border-color:var(--bad)}
.tabs{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:16px}
.tabs a{text-decoration:none;font-weight:700;font-size:14px;color:var(--ink);background:#fff;border:1.5px solid var(--line);border-radius:999px;padding:7px 14px}
.tabs a.on{background:var(--ink);border-color:var(--ink);color:#fff}
.tabs a .n{display:inline-block;min-width:20px;margin-left:4px;padding:0 6px;border-radius:999px;background:var(--brand);color:#fff;font-size:12px;text-align:center}
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:12px}
.filters input,.filters select{width:auto;min-width:160px;flex:1 1 160px;min-height:40px}
.muted{color:var(--muted)}
.lvl-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,250px),1fr));gap:12px}
.hb{display:flex;flex-direction:column;gap:8px;background:#fff;border:1px solid var(--line);border-radius:16px;padding:16px;text-decoration:none;color:var(--ink);min-height:110px}
.hb.ready{border-top:5px solid var(--brand)}
.hb.ready:hover{box-shadow:var(--shadow);transform:translateY(-2px);transition:.15s}
.hb.soon{opacity:.72;border-top:5px solid #E2D7CC}
.hb b{font-size:16px}
.hb .tag{align-self:flex-start}
.lv-head{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin:22px 0 10px}
.lv-head h2{font-size:26px;margin:0}
.viewer{display:flex;flex-direction:column;height:calc(100vh - 62px)}
.viewer .vbar{display:flex;gap:10px;align-items:center;padding:8px 16px;background:#fff;border-bottom:1px solid var(--line);flex-wrap:wrap}
.viewer iframe{flex:1;width:100%;border:0;background:#fff}

[hidden]{display:none!important}