/* Khung chung của lớp ÂY ZẦN: dùng cho /z4z (app) và các trang public
   /z4z/thonayzan, /z4z/ketqua. Sửa ở đây là đổi cả hai nơi. */
:root{
  --bg:#FFF8F1; --surface:#FFFFFF; --surface-2:#FFF0E4; --ink:#2A211A; --ink-soft:#7A6A5C; --line:#F0E2D4;
  --accent:#FF6A15; --accent-strong:#E85400; --accent-soft:#FFE6D2; --on-accent:#FFFFFF; --brand-2:#FFA51F;
  --good:#12924A; --good-soft:#DFF4E7; --bad:#E0412F; --bad-soft:#FCE5E1; --lock:#B6A493; --blue:#1D6FD6; --blue-soft:#EAF3FF;
  --shadow:0 1px 2px rgba(90,50,15,.05), 0 10px 26px rgba(200,100,25,.07);
  --font-body:"Be Vietnam Pro",system-ui,-apple-system,sans-serif; --font-head:"Lexend","Be Vietnam Pro",sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font-body);font-size:18px;line-height:1.6;-webkit-font-smoothing:antialiased}
h1,h2,h3,h4{font-family:var(--font-head);line-height:1.18;text-wrap:balance;margin:0}
a{color:inherit}
button{font-family:inherit}
[hidden]{display:none!important}
.eyebrow{font-family:var(--font-head);font-weight:700;font-size:.72rem;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-strong)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;border:none;border-radius:12px;padding:14px 22px;font-weight:700;font-family:var(--font-head);font-size:1.02rem;cursor:pointer;text-decoration:none;transition:background .15s,transform .05s}
.btn.primary{background:var(--accent);color:var(--on-accent);box-shadow:0 8px 20px rgba(251,106,21,.28)}
.btn.primary:hover{background:var(--accent-strong)} .btn.primary:active{transform:translateY(1px)}
.btn.ghost{background:var(--surface-2);color:var(--ink)} .btn.ghost:hover{background:var(--accent-soft);color:var(--accent-strong)}
.btn.big{width:100%;padding:16px}

/* shell: menu trái + main full rộng */
.app{display:grid;grid-template-columns:248px minmax(0,1fr);min-height:100vh;max-width:1440px;margin:0 auto}
.side{position:sticky;top:0;height:100vh;border-right:1px solid var(--line);background:var(--surface);padding:22px 16px;display:flex;flex-direction:column;gap:22px;overflow:auto}
.side .brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:inherit;border-radius:14px}
.side .brand:hover .mk{box-shadow:0 8px 20px rgba(251,106,21,.5)}
.side .brand .mk{width:44px;height:44px;border-radius:13px;background:linear-gradient(135deg,var(--accent),var(--brand-2));color:#fff;display:grid;place-items:center;font-family:var(--font-head);font-weight:800;font-size:.9rem;letter-spacing:-.03em;flex:none;box-shadow:0 6px 16px rgba(251,106,21,.35);transition:box-shadow .15s}
.side .brand b{font-family:var(--font-head);font-weight:800;font-size:1.15rem;display:block;line-height:1.1}
.side .brand small{color:var(--ink-soft);font-size:.72rem;font-weight:500}
.menu{display:flex;flex-direction:column;gap:4px}
.menu a,.menu button{display:flex;align-items:center;gap:12px;padding:12px 14px;border-radius:12px;border:none;background:none;text-align:left;width:100%;color:var(--ink-soft);font-weight:600;font-family:var(--font-head);font-size:1rem;cursor:pointer;text-decoration:none;transition:background .15s,color .15s}
.menu .ic{width:22px;text-align:center;font-size:1.15rem}
.menu a:hover,.menu button:hover{background:var(--surface-2);color:var(--ink)}
.menu a.on,.menu button.on{background:var(--accent-soft);color:var(--accent-strong)}
.side .learner{margin-top:auto;display:flex;align-items:center;gap:11px;padding:12px;border-radius:14px;background:var(--surface-2);text-decoration:none}
.side .learner .av{width:38px;height:38px;border-radius:50%;background:linear-gradient(135deg,var(--brand-2),var(--accent));color:#fff;display:grid;place-items:center;font-weight:700;font-family:var(--font-head);flex:none}
.side .learner .nm{min-width:0;font-weight:600;font-size:.9rem;line-height:1.2}
.side .learner .nm b{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-family:var(--font-head)}
.side .learner .nm .out{background:none;border:none;color:var(--ink-soft);font-size:.78rem;text-decoration:underline;cursor:pointer;padding:2px 0}
.side .learner .nm small{color:var(--ink-soft);font-size:.78rem;font-weight:500}
main{padding:32px 44px 90px;min-width:0}
.topbar{display:none}
.topbar .mk2{width:34px;height:34px;border-radius:10px;background:linear-gradient(135deg,var(--accent),var(--brand-2));color:#fff;display:grid;place-items:center;font-family:var(--font-head);font-weight:800;font-size:.72rem;letter-spacing:-.03em;flex:none;text-decoration:none}
.mnav{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none}
.mnav::-webkit-scrollbar{display:none}
.mnav a,.mnav button{white-space:nowrap;border:1px solid var(--line);background:#fff;color:var(--ink-soft);border-radius:999px;padding:8px 15px;font-weight:600;font-family:var(--font-head);font-size:.9rem;cursor:pointer;text-decoration:none}
.mnav a.on,.mnav button.on{background:var(--accent-soft);color:var(--accent-strong);border-color:var(--accent)}
.view{display:flex;flex-direction:column;gap:28px}
.sec-title{font-size:1.35rem;font-weight:800;letter-spacing:-.01em;margin-bottom:2px}
.sec-sub{color:var(--ink-soft);font-size:.95rem;margin-top:4px}
.back{display:inline-flex;align-items:center;gap:7px;background:none;border:none;color:var(--accent-strong);font-weight:600;cursor:pointer;padding:6px 0;font-size:.98rem;text-decoration:none}
.muted{color:var(--ink-soft)}
.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:var(--ink);color:#fff;padding:12px 22px;border-radius:12px;z-index:80;opacity:0;transition:opacity .2s;pointer-events:none;font-size:.95rem}
.toast.show{opacity:1}
@media (max-width:820px){
  .app{grid-template-columns:1fr;max-width:none}
  .side{display:none}
  main{padding:16px 16px 100px}
  .topbar{display:flex;align-items:center;gap:12px;position:sticky;top:0;z-index:30;background:rgba(255,248,241,.95);backdrop-filter:blur(8px);border-bottom:1px solid var(--line);padding:12px 16px;margin:-16px -16px 16px}
}
@media (prefers-reduced-motion: reduce){*{transition:none!important}}