:root{
  --bg:#0b1120; --bg2:#172b4b; --nav:#080e1d; --card:rgba(255,255,255,.14);
  --line:rgba(255,255,255,.20); --active:#3f7f73; --active2:#89f3e3;
  --gold:#e9c652; --red:#b52f2b; --text:#f8fafc; --ink:#0f172a; --blue:#14315d;
}
*{box-sizing:border-box}
html,body{min-height:100%}
body{margin:0;font-family:Arial,"Helvetica Neue","Segoe UI",Roboto,sans-serif;background:linear-gradient(145deg,var(--bg),#1d3559 58%,#0b1325);color:var(--text);font-size:15px;line-height:1.45}
a{color:#ffefad}
/* LOGIN - khôi phục phong cách bản trước, font Arial để tiếng Việt ổn định */
.login{background:radial-gradient(circle at center,#1b3358 0%,#0f172a 62%,#090f1d 100%);display:flex;align-items:center;justify-content:center;min-height:100vh;color:var(--ink);padding:22px}
.loginbox{width:520px;background:#fff;border-radius:16px;padding:34px 42px 32px;box-shadow:0 24px 80px rgba(0,0,0,.48);border:1px solid rgba(255,255,255,.65);text-align:left}
.login-logo{display:block;width:126px;height:126px;object-fit:contain;margin:0 auto 14px}
.login-title{text-align:center;text-transform:uppercase;margin:0 0 12px;letter-spacing:.2px}
.login-title .t1{font-size:24px;line-height:1.15;font-weight:900;color:#a72420;letter-spacing:.3px}
.login-title .t2{font-size:34px;line-height:1.08;font-weight:950;color:#14315d;letter-spacing:.4px;text-shadow:none;white-space:normal}
.login-title .t3{font-size:21px;line-height:1.2;font-weight:900;color:#15315b;letter-spacing:.35px;margin-top:6px}
.goldline{height:30px;display:flex;align-items:center;gap:12px;color:var(--gold);margin:10px 0 18px;justify-content:center}
.goldline:before,.goldline:after{content:"";height:2px;background:linear-gradient(90deg,transparent,var(--gold));flex:1;max-width:210px}.goldline:after{background:linear-gradient(90deg,var(--gold),transparent)}
.loginbox label{display:block;color:#0f172a;font-size:14px;margin:13px 0 0;font-weight:900;letter-spacing:.2px;text-align:left}
.loginbox input{width:100%;height:46px;border-radius:10px;border:1px solid #d8dee9;background:#fff;color:#111827;font-size:16px;padding:10px 18px;margin-top:7px;font-family:inherit}
.loginbox input::placeholder{color:#7b8493}.loginbox button{width:100%;background:linear-gradient(180deg,#c93a35,#ae2825);border-radius:10px;padding:15px 18px;font-size:18px;margin-top:22px;letter-spacing:.6px;box-shadow:0 8px 18px rgba(181,47,43,.28);border:0;color:#fff;font-weight:900;cursor:pointer;font-family:inherit}
.forgot{display:block;margin:16px 0 0;padding:12px;border:1px solid #f0d24a;background:#fffbe5;border-radius:9px;text-align:center;color:#1d4ed8!important;font-weight:900;text-decoration:underline;letter-spacing:.4px}
.copyright{border-top:1px solid #e5e7eb;margin-top:22px;padding-top:16px;text-align:center;color:#273553;font-size:13px;text-transform:uppercase}
.loginbox .err,.loginbox .ok,.loginbox .hint{color:#0e1628;background:#fffbe8}
/* SIDEBAR - gọn như bản trước */
aside{position:fixed;left:0;top:0;bottom:0;width:250px;padding:18px 14px;background:linear-gradient(180deg,var(--nav),#0c1426);border-right:1px solid rgba(255,255,255,.16);overflow-y:auto;overflow-x:hidden;scrollbar-width:thin}
.brand{display:flex;gap:10px;align-items:center;padding:0 4px 16px;margin-bottom:12px;border-bottom:1px solid rgba(255,255,255,.16)}
.brand img{width:46px;height:46px;object-fit:contain;background:#fff;border-radius:50%;padding:4px;flex:0 0 auto}
.brand b{display:block;text-align:center;line-height:1.05;font-size:17px;font-weight:900;color:#ffe98c;text-shadow:0 1px 0 #7f1d1d,0 2px 7px rgba(0,0,0,.45);letter-spacing:.1px}.brand b span{display:block}
nav a{display:block;color:#fff;text-decoration:none;padding:9px 15px;border-radius:15px;margin:7px 0;background:transparent;font-size:15px;line-height:1.15;font-weight:700;letter-spacing:-.1px;transition:.15s ease;border:1px solid transparent}
nav a:hover{background:rgba(255,255,255,.08)}nav a.on{background:var(--active);box-shadow:inset 5px 0 var(--active2);font-weight:800;border-color:rgba(157,255,233,.35)}
.author{margin-top:22px;padding:13px 14px;border:1px solid rgba(255,255,255,.18);border-radius:22px;background:rgba(255,255,255,.06);font-size:13px;line-height:1.7;box-shadow:0 10px 30px rgba(0,0,0,.16)}
.author b{font-size:15px;font-weight:900;color:#fff}.author hr{border:0;border-top:1px solid rgba(255,255,255,.18);margin:10px 0}.online{display:grid;grid-template-columns:1fr 1fr;align-items:center;text-align:center}.online b{display:block;font-size:26px;line-height:1;color:#9ffcff}
main{margin-left:250px;padding:26px 34px 44px;max-width:1760px}.topbar{display:flex;align-items:flex-start;justify-content:space-between;gap:20px}h1,.topbar h1{margin:0 0 22px;font-size:32px;line-height:1.15;letter-spacing:-.4px;font-weight:900}.userbox{background:rgba(255,255,255,.12);border:1px solid var(--line);border-radius:14px;padding:10px 14px;text-align:right;min-width:190px}.userbox b{display:block}.userbox span{font-size:12px;opacity:.8}
.box,.cards>div,table,.hint,.ok,.err{background:var(--card);border:1px solid var(--line);border-radius:18px;backdrop-filter:blur(14px);box-shadow:0 14px 38px rgba(0,0,0,.18)}.box{padding:20px;margin-bottom:20px}.box h2{margin:0 0 12px;font-size:18px;color:#ffefad}.grid{display:grid;grid-template-columns:repeat(3,minmax(220px,1fr));gap:16px}label{display:block;font-weight:750;color:#fff}input,select,textarea{width:100%;margin-top:7px;padding:11px 13px;border-radius:12px;border:1px solid #d8dee9;background:#f8fafc;color:#111827;font-size:15px;font-family:inherit}textarea{min-height:72px}input[type=checkbox]{width:auto;transform:scale(1.05);margin-right:8px}.check{display:flex;align-items:center;gap:10px}button,.btn{border:0;border-radius:13px;padding:11px 17px;background:var(--red);color:#fff!important;font-weight:800;text-decoration:none;display:inline-block;margin:4px;cursor:pointer;font-family:inherit}button:hover,.btn:hover{filter:brightness(1.08)}table{width:100%;border-collapse:separate;border-spacing:0;overflow:hidden}th,td{padding:10px 12px;border-bottom:1px solid rgba(255,255,255,.18);text-align:center;vertical-align:middle}th{background:rgba(0,0,0,.18);color:#ffefad}td.left{text-align:left}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-bottom:20px}.cards>div{padding:22px}.cards b{display:block;font-size:40px;line-height:1}.hint{background:rgba(255,255,255,.12);border:1px solid var(--line);border-radius:14px;padding:14px}.ok{background:rgba(194,255,220,.16);color:#d4ffe8}.err{background:#ffe1e1;color:#7f0000;border-radius:12px;padding:12px;margin-bottom:14px}.small{font-size:13px}.hamb{display:none;position:fixed;z-index:9;top:12px;left:12px}
@media(max-width:1100px){aside{width:220px;padding:16px 12px}main{margin-left:220px;padding:22px}.brand b{font-size:16px}nav a{font-size:14px;padding:9px 13px}.grid{grid-template-columns:repeat(2,minmax(190px,1fr))}.cards{grid-template-columns:1fr 1fr}.topbar h1{font-size:30px}}
@media(max-width:760px){.hamb{display:block}body{background:linear-gradient(145deg,var(--bg),#1d3559)}aside{position:fixed;width:230px;min-height:auto;padding:12px 10px;transform:translateX(-105%);transition:.2s;z-index:8}.showmenu aside{transform:translateX(0)}.brand{padding-bottom:10px;margin-bottom:8px}.brand img{width:40px;height:40px}.brand b{font-size:15px}nav a{font-size:14px;padding:9px 12px;margin:5px 0;border-radius:13px}.author{display:none}main{margin-left:0;padding:60px 12px 28px}h1,.topbar h1{font-size:26px}.topbar{display:block}.userbox{text-align:left;margin-bottom:16px}.grid,.cards{grid-template-columns:1fr}.cards>div{padding:18px}.cards b{font-size:34px}.box{padding:14px;border-radius:16px}table{display:block;overflow-x:auto;white-space:nowrap}.login{align-items:flex-start;padding-top:28px}.loginbox{width:min(520px,94vw);padding:28px 24px}.login-logo{width:90px;height:90px}.login-title .t1{font-size:19px}.login-title .t2{font-size:28px}.login-title .t3{font-size:17px}.loginbox input{height:44px}}