:root {
  --primary: #0E7490; --primary-dark: #0B5A70; --brand-a: #2CB5A8; --brand-b: #2B7BB9;
  --bg: #F6F8FA; --surface: #FFFFFF; --text: #2E2E3F; --muted: #6B6B80; --border: #E3E6EC;
  --success: #15803D; --warning: #B45309; --error: #B91C1C;
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 400 15px/1.45 system-ui, "Segoe UI", "Noto Sans Tamil", "Nirmala UI", sans-serif;
  padding-bottom: 64px;
}
h1 { font-size: 22px; font-weight: 600; } h2 { font-size: 18px; font-weight: 600; }
h3 { font-size: 16px; font-weight: 600; } small { font-size: 13px; }
.muted { color: var(--muted); }
.strip { height: 48px; display: flex; align-items: center; padding: 0 16px; color: #fff;
  font-weight: 600; background: linear-gradient(90deg, var(--brand-a), var(--brand-b)); }
main { padding: 16px; max-width: 960px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 16px; }
.btn { min-height: 44px; padding: 0 16px; border-radius: 8px; border: 1px solid var(--primary);
  background: var(--primary); color: #fff; font: inherit; cursor: pointer; }
.btn:active { background: var(--primary-dark); }
.btn.secondary { background: transparent; color: var(--primary); }
.btn.danger { background: transparent; color: var(--error); border-color: var(--error); }
.btn:disabled { opacity: .6; cursor: default; }
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
input, select { min-height: 44px; border: 1px solid var(--border); border-radius: 8px; padding: 0 12px; font: inherit; }
.error { color: var(--error); }
.banner { border: 1px solid var(--error); color: var(--error); border-radius: 8px; padding: 12px; background: var(--surface); }

/* Navigation: bottom bar on phone, left rail from 900px */
#nav { position: fixed; left: 0; right: 0; bottom: 0; display: flex; background: var(--surface);
  border-top: 1px solid var(--border); }
#nav a { flex: 1; min-height: 48px; display: flex; align-items: center; justify-content: center;
  color: var(--muted); text-decoration: none; }
#nav a[aria-current="page"] { color: var(--primary); font-weight: 600; box-shadow: inset 0 -3px var(--primary); }
@media (min-width: 900px) {
  body { padding: 0 0 0 160px; }
  .strip { margin-left: -160px; }
  #nav { top: 48px; right: auto; bottom: 0; width: 160px; flex-direction: column; border-top: 0;
    border-right: 1px solid var(--border); }
  #nav a { flex: 0 0 48px; justify-content: flex-start; padding: 0 16px; }
  #nav a[aria-current="page"] { box-shadow: inset 3px 0 var(--primary); }
}

#toast { position: fixed; left: 50%; bottom: 80px; transform: translateX(-50%); background: var(--text);
  color: #fff; padding: 12px 16px; border-radius: 8px; max-width: 90vw; }
#toast[hidden] { display: none; }

/* Tasks */
label { display: block; margin-bottom: 12px; }
textarea, label select, label input:not([type=checkbox]) { display: block; width: 100%; margin-top: 4px; }
textarea { border: 1px solid var(--border); border-radius: 8px; padding: 8px 12px; font: inherit; }
label.check input { display: inline; width: auto; min-height: 0; margin-right: 8px; }
.filters { display: grid; grid-template-columns: 1fr; gap: 0 12px; }
.task { display: block; margin-bottom: 8px; color: inherit; text-decoration: none; }
.chip { display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: 13px; background: #E3E6EC; color: var(--text); }
.chip.s-doing { background: var(--primary); color: #fff; }
.chip.s-review, .chip.s-changes { background: var(--warning); color: #fff; }
.chip.s-approved, .chip.s-sent { background: var(--primary-dark); color: #fff; }
.chip.s-done { background: var(--success); color: #fff; }
.col h3 { margin: 16px 0 8px; }
.col:not(:has(.task)) { display: none; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.history { list-style: none; padding: 0; }
.history li { padding: 8px 0; border-bottom: 1px solid var(--border); }
@media (min-width: 600px) { .filters { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 900px) {
  .board { display: grid; grid-auto-flow: column; grid-auto-columns: minmax(200px, 1fr); gap: 12px; overflow-x: auto; }
  .col:not(:has(.task)) { display: block; }
  main { max-width: none; }
}