/* Bố cục: thanh tiêu đề, dải số liệu tổng quan, thanh lọc, rồi hai mục bảng (định kỳ / một lần) có đường kẻ cột rõ ràng */
:root {
  --bg: #eef2f6; --card: #ffffff; --head: #e3eaf3; --zebra: #f7f9fc;
  --text: #16202c; --muted: #5a6677; --line: #cfd8e3; --line-strong: #b4c1d1;
  --accent: #1f5fbf; --accent-soft: #e2ecfb; --on-accent: #ffffff;
  --danger: #b3261e; --late-bg: #fdecea; --late-fg: #a1231b;
  --soon-bg: #fff4dc; --soon-fg: #8a5a00; --ok-bg: #e6f4ea; --ok-fg: #1d6b3a;
  --s-todo: #5f6b7a; --s-doing: #1f5fbf; --s-hold: #9a6100; --s-done: #1d6b3a;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f141a; --card: #171e27; --head: #1f2934; --zebra: #1a222c;
    --text: #e6ebf2; --muted: #9aa6b6; --line: #2c3746; --line-strong: #3b4858;
    --accent: #7eabff; --accent-soft: #1d2d47; --on-accent: #0f141a;
    --danger: #ff8a80; --late-bg: #3a1d1c; --late-fg: #ffb4ab;
    --soon-bg: #3a2e14; --soon-fg: #f3c26b; --ok-bg: #18301f; --ok-fg: #8fd6a2;
    --s-todo: #9aa6b6; --s-doing: #7eabff; --s-hold: #f0b45a; --s-done: #8fd6a2;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
body { margin: 0; font: 15px/1.5 var(--font); background: var(--bg); color: var(--text); }

/* Thanh trên cùng */
.topbar { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: space-between;
  padding: 14px max(16px, env(safe-area-inset-right, 0px)) 14px max(16px, env(safe-area-inset-left, 0px));
  background: var(--card); border-bottom: 2px solid var(--accent); }
.topbar h1 { font-size: 20px; margin: 0; letter-spacing: .01em; }
.user-box { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; font-size: 14px; }
main { max-width: 1320px; margin: 0 auto; padding: 20px max(16px, env(safe-area-inset-right, 0px)) 40px max(16px, env(safe-area-inset-left, 0px)); }

/* Thẻ và biểu mẫu */
.card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 24px; }
.narrow { max-width: 440px; margin: 32px auto; }
h2 { margin: 0 0 12px; font-size: 18px; }
label { display: block; margin: 0 0 12px; font-size: 14px; color: var(--muted); }
input, select, textarea { display: block; width: 100%; margin-top: 4px; padding: 9px 11px; font: inherit; color: var(--text);
  background: var(--card); border: 1px solid var(--line-strong); border-radius: 8px; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
button { font: inherit; font-weight: 600; padding: 9px 16px; border-radius: 8px; border: 1px solid var(--accent);
  background: var(--accent); color: var(--on-accent); cursor: pointer; }
button:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
button.ghost { background: transparent; color: var(--accent); }
button.danger { color: var(--danger); border-color: var(--danger); background: transparent; }
button.danger-solid { background: var(--danger); border-color: var(--danger); color: var(--card); }
button.link { border: 0; background: none; color: var(--accent); padding: 8px 0; display: block; font-weight: 500; }
.badge { padding: 2px 10px; border-radius: 99px; background: var(--accent-soft); color: var(--accent); font-size: 12px; font-weight: 600; }
.message { padding: 10px 14px; border-radius: 8px; margin-bottom: 16px; border: 1px solid var(--line); background: var(--card); }
.message.error { border-color: var(--danger); color: var(--danger); }

/* Dải số liệu tổng quan */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin-bottom: 16px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; text-align: center; }
.stat-value { font-size: 26px; font-weight: 700; font-variant-numeric: tabular-nums; line-height: 1.2; }
.stat-label { font-size: 13px; color: var(--muted); }
.stat.is-doing .stat-value { color: var(--s-doing); }
.stat.is-soon .stat-value { color: var(--soon-fg); }
.stat.is-late .stat-value { color: var(--late-fg); }

/* Thanh lọc */
.toolbar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; align-items: stretch; }
.toolbar input { flex: 1 1 240px; margin: 0; }
.toolbar select { flex: 0 1 220px; width: auto; margin: 0; }

/* Mục bảng */
.group { margin-bottom: 28px; }
.group-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 14px; padding: 0 2px 10px; }
.group-head h2 { margin: 0; font-size: 18px; padding-left: 10px; border-left: 4px solid var(--accent); }
.group-note { font-size: 13px; color: var(--muted); }
.count { margin-left: auto; font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums; }
.table-wrap { overflow-x: auto; background: var(--card); border: 1px solid var(--line-strong); border-radius: 10px; }

table { width: 100%; border-collapse: collapse; }
table.grid { min-width: 900px; }
.grid th, .grid td { padding: 9px 10px; border-bottom: 1px solid var(--line); border-right: 1px solid var(--line);
  text-align: center; vertical-align: middle; }
.grid th:last-child, .grid td:last-child { border-right: 0; }
.grid thead th { background: var(--head); font-size: 13px; font-weight: 700; color: var(--text);
  border-bottom: 2px solid var(--line-strong); line-height: 1.3; }
.grid tbody tr:nth-child(even) td { background: var(--zebra); }
.grid tbody tr:last-child td { border-bottom: 0; }
.grid tbody tr.overdue td { background: var(--late-bg); }
.grid tbody tr.done td { color: var(--muted); }
.grid .c-no { width: 52px; color: var(--muted); font-variant-numeric: tabular-nums; }
.grid .c-title { text-align: left; min-width: 180px; }
.grid .num { font-variant-numeric: tabular-nums; white-space: nowrap; }
.grid .strong { font-weight: 600; }
.task-title { font-weight: 600; }
.small { font-size: 13px; color: var(--muted); }
.muted { color: var(--muted); }

/* Nhãn trạng thái và hạn */
.chip { display: inline-block; padding: 3px 10px; border-radius: 99px; font-size: 12.5px; font-weight: 600; white-space: nowrap; }
.chip-late { background: var(--late-bg); color: var(--late-fg); border: 1px solid var(--late-fg); }
.chip-soon { background: var(--soon-bg); color: var(--soon-fg); }
.chip-ok { background: var(--ok-bg); color: var(--ok-fg); }
.chip-done { background: var(--head); color: var(--muted); }
.chip-repeat { background: var(--accent-soft); color: var(--accent); white-space: normal; border-radius: 8px; }
.grid .c-repeat { min-width: 128px; }
.status { display: inline-block; font-size: 13px; font-weight: 700; white-space: nowrap; padding: 3px 10px; border-radius: 6px; border: 1px solid currentColor; }
.s-chua_bat_dau { color: var(--s-todo); } .s-dang_lam { color: var(--s-doing); }
.s-tam_dung { color: var(--s-hold); } .s-hoan_thanh { color: var(--s-done); }

td.actions { white-space: nowrap; }
.action-row { display: inline-grid; grid-template-columns: auto auto; gap: 6px; justify-content: center; }
button.mini { padding: 4px 9px; font-size: 13px; font-weight: 600; background: transparent; color: var(--accent); }
button.mini.ok { background: var(--ok-bg); color: var(--ok-fg); border-color: var(--ok-fg); }
button.mini.danger { color: var(--danger); border-color: var(--danger); }
.empty { text-align: center; color: var(--muted); padding: 20px; background: var(--card); border: 1px dashed var(--line-strong); border-radius: 10px; margin-top: 8px; }

/* Hộp thoại */
dialog { border: 1px solid var(--line); border-radius: 12px; background: var(--card); color: var(--text); width: min(600px, calc(100vw - 32px)); padding: 22px; }
dialog::backdrop { background: rgba(0, 0, 0, .45); }
.row { display: flex; gap: 12px; flex-wrap: wrap; } .row label { flex: 1 1 200px; }
.repeat-box { border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px 12px; margin: 0 0 12px; }
.repeat-box legend { font-size: 14px; color: var(--muted); padding: 0 6px; }
.weekdays { display: flex; flex-wrap: wrap; gap: 6px 12px; align-items: center; margin-top: 10px; }
label.chk { display: inline-flex; align-items: center; gap: 4px; margin: 0; color: var(--text); font-weight: 600; }
label.chk input { width: auto; margin: 0; }
#repeat-hint { margin: 10px 0 0; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 12px; }
.qr { display: block; width: 200px; height: 200px; margin: 12px auto; background: #fff; padding: 8px; border-radius: 8px; }
.history { padding-left: 18px; max-height: 60vh; overflow: auto; }
.history li { margin-bottom: 10px; }
[hidden] { display: none !important; }
#view-users table th, #view-users table td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; }