/* Giao diện của bai-tap-engine.js. Tách khỏi style.css vì chỉ các trang có bài
   tập mới cần — và để engine mang theo đủ style của chính nó, đừng để một trang
   mới quên nạp rồi vỡ bố cục. Nạp KÈM bai-tap-engine.js, luôn đi cùng nhau. */

.bte-block { background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 20px 22px; margin: 18px 0; }
.bte-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 14px; flex-wrap: wrap; }
.bte-head h3 { margin: 0; color: var(--navy); font-size: 18px; }
.bte-sub { margin: 3px 0 0; color: var(--muted); font-size: 13.5px; }
.bte-diem { font-weight: 800; font-size: 15px; white-space: nowrap; }
.bte-diem.tot { color: #15803D; } .bte-diem.tam { color: #B45309; } .bte-diem.yeu { color: #B91C1C; }

.bte-hd { background: #F1F5FB; border-left: 3px solid var(--navy-2); border-radius: 0 8px 8px 0;
  padding: 10px 14px; margin: 12px 0 4px; font-size: 14.5px; color: #334155; }
.bte-trong-bai { color: var(--muted); margin: 0; }

.bte-list { list-style: none; margin: 14px 0 0; padding: 0; counter-reset: bte; }
.bte-cau { counter-increment: bte; padding: 14px 0 14px 34px; border-top: 1px solid #EEF1F5; position: relative; }
.bte-cau::before { content: counter(bte); position: absolute; left: 0; top: 14px;
  width: 24px; height: 24px; border-radius: 50%; background: #EEF2F8; color: var(--navy);
  font-size: 12.5px; font-weight: 800; display: grid; place-items: center; }
.bte-cau.bte-ok::before   { background: #DCFCE7; color: #15803D; }
.bte-cau.bte-sai::before  { background: #FEE2E2; color: #B91C1C; }

.bte-de { font-size: 15.5px; line-height: 1.7; }
.bte-trong { color: var(--pink); letter-spacing: 1px; }
.bte-goi { display: inline-block; margin-left: 8px; font-size: 13px; color: var(--muted);
  background: #F8FAFC; border: 1px dashed #CBD5E1; border-radius: 999px; padding: 1px 10px; }

.bte-cau input[type=text], .bte-cau input:not([type]), .bte-cau textarea {
  margin-top: 8px; padding: 9px 12px; border: 1px solid #D7DDE5; border-radius: 9px;
  width: min(560px, 100%); font: inherit; font-size: 15px; background: #fff; }
.bte-cau textarea { resize: vertical; }
.bte-cau input:focus, .bte-cau textarea:focus, .bte-cau select:focus {
  outline: none; border-color: var(--navy-2); box-shadow: 0 0 0 3px rgba(39,75,133,.12); }

.bte-chon { display: block; padding: 7px 0; cursor: pointer; font-size: 15px; }
.bte-chon input { margin-right: 8px; }
.bte-chon:hover span { color: var(--navy); }

.bte-ghep-hang { display: flex; align-items: center; gap: 12px; padding: 6px 0; flex-wrap: wrap; }
.bte-ghep-trai { flex: 1 1 220px; font-size: 15px; }
.bte-ghep select { padding: 7px 10px; border: 1px solid #D7DDE5; border-radius: 8px;
  font: inherit; font-size: 14.5px; background: #fff; flex: 1 1 220px; max-width: 320px; }

.bte-xep-ra { margin-top: 10px; min-height: 44px; padding: 11px 14px; border-radius: 10px;
  background: #F8FAFC; border: 1px dashed #CBD5E1; font-size: 15.5px; }
.bte-xep-ra[data-trong="1"] { color: #9AA3AF; font-style: italic; font-size: 14px; }
.bte-xep-kho { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.bte-chip { background: #fff; border: 1px solid #CBD5E1; border-radius: 999px;
  padding: 6px 14px; font: inherit; font-size: 14.5px; cursor: pointer; }
.bte-chip:hover { border-color: var(--navy-2); color: var(--navy); }
.bte-chip.dung-roi { opacity: .3; pointer-events: none; }
.bte-xoa { margin-top: 8px; background: none; border: none; color: var(--muted);
  font: inherit; font-size: 13.5px; cursor: pointer; text-decoration: underline; padding: 0; }

.bte-kq:empty { display: none; }
.bte-gt { margin-top: 10px; border-radius: 9px; padding: 10px 13px; font-size: 14.5px; }
.bte-gt.ok  { background: #F0FDF4; border-left: 3px solid #15803D; }
.bte-gt.sai { background: #FEF2F2; border-left: 3px solid #B91C1C; }
.bte-gt-dau { font-weight: 700; color: var(--navy); }
.bte-gt.ok .bte-gt-dau  { color: #15803D; }
.bte-gt.sai .bte-gt-dau { color: #B91C1C; }
.bte-gt-than { margin-top: 5px; color: #334155; line-height: 1.65; }
.bte-them { margin-top: 5px; font-size: 13.5px; color: var(--muted); }
.bte-them code { background: #fff; border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px; }

.bte-foot { display: flex; align-items: center; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.bte-luu { font-size: 13.5px; color: var(--muted); }
.bte-block .hidden { display: none; }

@media (max-width: 600px) {
  .bte-block { padding: 16px 14px; border-radius: 12px; }
  .bte-cau { padding-left: 30px; }
  .bte-de { font-size: 15px; }
}