:root{--bg:#f5f6f8;--card:#fff;--text:#1d2330;--muted:#6b7385;--line:#e3e6ec;--brand:#2563eb;--ok:#16a34a;--err:#dc2626;--warn:#d97706}
@media (prefers-color-scheme:dark){:root{--bg:#0f131a;--card:#171c26;--text:#e7eaf0;--muted:#98a1b3;--line:#272e3b;--brand:#4f8cff}}
*{box-sizing:border-box}body{margin:0;font:15px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--text)}
a{color:var(--brand);text-decoration:none}a:hover{text-decoration:underline}
header{background:var(--card);border-bottom:1px solid var(--line);padding:.6rem 1rem;display:flex;gap:1rem;align-items:center;flex-wrap:wrap;position:sticky;top:0;z-index:5}
header b{font-size:1.05rem}nav{display:flex;gap:.2rem;flex-wrap:wrap;flex:1}nav a{padding:.35rem .7rem;border-radius:8px;color:var(--text)}nav a:hover,nav a.on{background:var(--bg);text-decoration:none}
main{max-width:1200px;margin:1.2rem auto;padding:0 1rem}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:1rem;margin-bottom:1rem}
.grid{display:grid;gap:1rem;grid-template-columns:repeat(auto-fit,minmax(190px,1fr))}
.stat{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:1rem}.stat small{color:var(--muted);display:block}.stat b{font-size:1.4rem}
table{width:100%;border-collapse:collapse}th,td{padding:.55rem .6rem;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}th{color:var(--muted);font-weight:600;font-size:.85rem}
.table-wrap{overflow-x:auto}
input,select,textarea,button{font:inherit;padding:.5rem .65rem;border:1px solid var(--line);border-radius:8px;background:var(--card);color:var(--text)}
textarea{width:100%;min-height:90px}input[type=text],input[type=password],input[type=number],select{width:100%}
button,.btn{background:var(--brand);color:#fff;border:0;cursor:pointer;display:inline-block;border-radius:8px;padding:.5rem .9rem}button.ghost,.btn.ghost{background:transparent;color:var(--text);border:1px solid var(--line)}
button.danger{background:var(--err)}button.ok{background:var(--ok)}
.row{display:flex;gap:.6rem;flex-wrap:wrap;align-items:end}.row>*{flex:1;min-width:140px}.row>button{flex:0}
label{display:block;font-size:.85rem;color:var(--muted);margin-bottom:.15rem}
.badge{display:inline-block;padding:.1rem .55rem;border-radius:999px;font-size:.78rem;background:var(--bg);border:1px solid var(--line)}
.flash{padding:.7rem 1rem;border-radius:10px;margin-bottom:1rem;border:1px solid}.flash.ok{border-color:var(--ok);color:var(--ok)}.flash.err{border-color:var(--err);color:var(--err)}
.muted{color:var(--muted)}.right{text-align:right}pre{white-space:pre-wrap;word-break:break-word;background:var(--bg);padding:.6rem;border-radius:8px;margin:0}
.bars{display:flex;gap:.5rem;align-items:flex-end;height:140px}.bars div{flex:1;text-align:center;font-size:.75rem;color:var(--muted)}.bars span{display:block;background:var(--brand);border-radius:6px 6px 0 0;min-height:2px}
.pager{display:flex;gap:.4rem;margin-top:.8rem;align-items:center}.login{max-width:360px;margin:12vh auto}
h1{font-size:1.35rem;margin:.2rem 0 1rem}h2{font-size:1.05rem;margin:.2rem 0 .8rem}
.inline{display:inline}.inline button{padding:.25rem .6rem;font-size:.85rem}

/* ===================== MOBILE ===================== */
nav a{white-space:nowrap}
@media (max-width:820px){
  header{padding:.5rem .75rem;gap:.35rem .6rem}
  header b{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:1rem}
  header>.muted{font-size:.8rem;max-width:34vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  nav{order:3;flex:0 0 100%;flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none;margin:0 -.25rem;padding-bottom:.1rem}
  nav::-webkit-scrollbar{display:none}
  nav a{padding:.4rem .75rem;border:1px solid var(--line);border-radius:999px;font-size:.9rem}
  nav a.on{background:var(--brand);border-color:var(--brand);color:#fff}
}
@media (max-width:720px){
  body{font-size:15px}
  main{margin:.7rem auto;padding:0 .6rem}
  h1{font-size:1.2rem;margin:.1rem 0 .7rem}
  .card{padding:.8rem;border-radius:10px}
  .grid{gap:.6rem;grid-template-columns:repeat(2,1fr)}
  .stat{padding:.7rem}.stat b{font-size:1.15rem}
  /* ô nhập: chữ 16px để iPhone không tự phóng to khi chạm vào; nút đủ lớn để bấm */
  input,select,textarea{font-size:16px;min-height:42px}
  button,.btn{min-height:40px;padding:.55rem .9rem}
  .inline button{min-height:34px}
  .row{gap:.5rem}.row>*{min-width:calc(50% - .5rem);flex:1 1 calc(50% - .5rem)}
  .row>button{flex:1 1 100%}
  .row>.wide,.row>textarea{flex-basis:100%}
  /* bảng cuộn ngang thay vì làm vỡ trang */
  table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch;max-width:100%}
  th,td{padding:.45rem .5rem;font-size:.9rem}
  .pager{flex-wrap:wrap}
  .login{margin:6vh auto;padding:0 .6rem}
  .bars{height:110px}
}
@media (max-width:380px){.row>*{min-width:100%;flex-basis:100%}}

/* Bảng -> dạng thẻ trên điện thoại (nhãn cột lấy từ tiêu đề, gắn bằng script trong base.html) */
@media (max-width:720px){
  table.stack{display:block;overflow:visible}
  table.stack thead,table.stack tr.hdr{display:none}
  table.stack tbody{display:block}
  table.stack tr{display:block;border:1px solid var(--line);border-radius:10px;padding:.35rem .7rem;margin-bottom:.6rem;background:var(--card)}
  table.stack td{display:flex;gap:.7rem;justify-content:space-between;align-items:flex-start;border:0;padding:.28rem 0;text-align:right;word-break:break-word}
  table.stack td::before{content:attr(data-label);flex:0 0 36%;max-width:36%;text-align:left;color:var(--muted);font-size:.8rem;font-weight:600}
  table.stack td:empty{display:none}
  table.stack td[colspan]::before{content:none}
  table.stack td>form.inline,table.stack td>a{text-align:right}
}