:root { --mau-chinh:#2e7d32; --mau-chinh-dam:#1b5e20; --mau-nen:#f4f7f3; --mau-chu:#1a1a1a; --mau-canh-bao:#c62828; }
* { box-sizing: border-box; }
body { font-family:-apple-system,Roboto,Arial,sans-serif; background:var(--mau-nen); color:var(--mau-chu); margin:0; font-size:20px; line-height:1.5; }
header { background:var(--mau-chinh); color:#fff; padding:18px 20px; font-size:24px; font-weight:bold; text-align:center; }
main { max-width:480px; margin:0 auto; padding:20px 16px 80px; }
label { display:block; margin-top:16px; font-weight:600; font-size:18px; }
input, select, textarea { width:100%; font-size:20px; padding:14px; margin-top:6px; border:2px solid #ccc; border-radius:10px; }
button, .nut { display:block; width:100%; font-size:22px; font-weight:bold; padding:16px; margin-top:24px; background:var(--mau-chinh); color:#fff; border:none; border-radius:12px; cursor:pointer; text-align:center; text-decoration:none; }
button:active, .nut:active { background:var(--mau-chinh-dam); }
.nut-phu { background:#fff; color:var(--mau-chinh); border:2px solid var(--mau-chinh); }
.loi { color:var(--mau-canh-bao); font-weight:bold; margin-top:12px; }
.thanh-cong { color:var(--mau-chinh-dam); font-weight:bold; margin-top:12px; }
.the { background:#fff; border-radius:14px; padding:16px; margin-top:16px; box-shadow:0 1px 4px rgba(0,0,0,.1); }
a { color:var(--mau-chinh-dam); }
nav { display:flex; background:var(--mau-chinh-dam); }
nav a { flex:1; color:#fff; text-align:center; padding:14px 4px; text-decoration:none; font-size:18px; font-weight:600; }
nav a.dang-chon { background:var(--mau-chinh); }
.canh-bao { background:#fff3e0; border-left:6px solid #ef6c00; padding:10px 12px; margin-top:10px; border-radius:8px; font-size:18px; }
.nho { font-size:16px; color:#555; }
.nut-nho { display:inline-block; width:auto; font-size:18px; padding:10px 14px; margin:8px 8px 0 0; }
.hang-doi { background:#e3f2fd; border-left:6px solid #1565c0; padding:10px 12px; margin-top:12px; border-radius:8px; }
.dong { border-bottom:1px solid #ddd; padding:8px 0; }
table { width:100%; border-collapse:collapse; }
td, th { text-align:left; padding:8px 4px; border-bottom:1px solid #ddd; }
[hidden] { display:none !important; }
.qr { width:100%; max-width:300px; background:#fff; }
.cl-input { width:60%; display:inline-block; }