:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --border: #e3e6ea;
  --text: #16191d;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-text: #ffffff;
  --done: #16a34a;
  --danger: #dc2626;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .05);
  --radius: 12px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --surface: #171a20;
    --border: #262b33;
    --text: #e8eaed;
    --muted: #9aa3af;
    --accent: #3b82f6;
    --done: #22c55e;
    --danger: #f87171;
    --shadow: none;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

h1, h2 { margin: 0; font-weight: 650; letter-spacing: -.01em; }
h1 { font-size: 1.45rem; }
h2 { font-size: .95rem; }
.muted { color: var(--muted); }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 16px; }

/* ------------------------------ brand ---------------------------------- */
.brand { display: flex; align-items: center; gap: 9px; }
.brand-mark {
  width: 22px; height: 22px; border-radius: 7px; flex: none;
  background: linear-gradient(135deg, var(--accent), #7c3aed);
}
.brand-name { font-weight: 650; letter-spacing: -.01em; }

/* ------------------------------- auth ---------------------------------- */
.auth { min-height: 100dvh; display: grid; place-items: center; padding: 24px 16px; }
.auth-card {
  width: 100%; max-width: 380px; background: var(--surface);
  border: 1px solid var(--border); border-radius: 16px; padding: 28px 24px;
  box-shadow: var(--shadow);
}
.auth-card .brand { margin-bottom: 20px; }
.auth-card h1 { margin-bottom: 4px; }
.auth-card > .muted { margin: 0 0 20px; font-size: .9rem; }
.auth-card form { display: grid; gap: 14px; }
.switch { margin: 16px 0 0; font-size: .875rem; color: var(--muted); text-align: center; }

/* ------------------------------ fields --------------------------------- */
.field { display: grid; gap: 6px; }
.field > span { font-size: .8rem; font-weight: 600; color: var(--muted); }
.field.grow { flex: 1 1 260px; }

input[type=text], input[type=email], input[type=password], input[type=search] {
  width: 100%; padding: 10px 12px; font: inherit; color: var(--text);
  background: var(--bg); border: 1px solid var(--border); border-radius: 9px;
  outline: none; transition: border-color .12s, box-shadow .12s;
}
input:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 22%, transparent);
}

/* ------------------------------ buttons -------------------------------- */
.btn {
  font: inherit; font-weight: 550; padding: 10px 16px; border-radius: 9px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  cursor: pointer; transition: filter .12s, background .12s;
}
.btn:hover { filter: brightness(.97); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn:disabled { opacity: .6; cursor: default; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text); }
.btn.ghost { background: transparent; }
.btn.block { width: 100%; }
.link {
  background: none; border: 0; padding: 0; font: inherit; font-weight: 600;
  color: var(--accent); cursor: pointer; text-decoration: underline;
}

.error {
  margin: 0; font-size: .85rem; color: var(--danger);
  background: color-mix(in srgb, var(--danger) 10%, transparent);
  border-radius: 8px; padding: 8px 10px;
}

/* ------------------------------ topbar --------------------------------- */
.topbar {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
  padding-top: env(safe-area-inset-top);
}
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.topbar-right { display: flex; align-items: center; gap: 12px; font-size: .875rem; }
.topbar-right .btn { padding: 6px 12px; }

/* ------------------------------- stats --------------------------------- */
.stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin: 20px 0;
}
.stat {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 16px; box-shadow: var(--shadow); display: grid; gap: 2px;
}
.stat-label { font-size: .75rem; font-weight: 600; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.stat-value { font-size: 1.75rem; font-weight: 680; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }

/* -------------------------------- card --------------------------------- */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 18px 20px; margin-bottom: 20px; box-shadow: var(--shadow);
}
.card h2 { margin-bottom: 14px; }

.task-form { display: flex; flex-wrap: wrap; gap: 12px; align-items: end; }
.task-form .btn { height: 41px; }

/* ------------------------------- list ---------------------------------- */
.list-head { display: flex; gap: 12px; align-items: center; justify-content: space-between; flex-wrap: wrap; margin-bottom: 14px; }
.tabs { display: inline-flex; background: var(--bg); border: 1px solid var(--border); border-radius: 9px; padding: 3px; }
.tab {
  font: inherit; font-size: .875rem; font-weight: 550; color: var(--muted);
  background: none; border: 0; border-radius: 7px; padding: 6px 14px; cursor: pointer;
}
.tab.is-active { background: var(--surface); color: var(--text); box-shadow: var(--shadow); }
.search { max-width: 240px; }

.tasks { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.task {
  display: flex; align-items: flex-start; gap: 12px; padding: 12px;
  border: 1px solid var(--border); border-radius: 10px; background: var(--bg);
}
.task-check {
  appearance: none; width: 20px; height: 20px; flex: none; margin-top: 1px;
  border: 1.5px solid var(--muted); border-radius: 6px; cursor: pointer; position: relative;
  transition: background .12s, border-color .12s;
}
.task-check:checked { background: var(--done); border-color: var(--done); }
.task-check:checked::after {
  content: ""; position: absolute; left: 6px; top: 2px; width: 5px; height: 10px;
  border: solid #fff; border-width: 0 2px 2px 0; transform: rotate(45deg);
}
.task-check:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.task-body { flex: 1; min-width: 0; }
.task-desc { display: block; word-wrap: break-word; }
.task-meta { display: block; margin-top: 3px; font-size: .78rem; color: var(--muted); }
.task-client {
  display: inline-block; font-weight: 600; color: var(--text);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border-radius: 5px; padding: 1px 6px; margin-right: 6px;
}
.task.done .task-desc { text-decoration: line-through; color: var(--muted); }
.task-delete {
  background: none; border: 0; color: var(--muted); font-size: 1.1rem; line-height: 1;
  padding: 4px 6px; border-radius: 6px; cursor: pointer;
}
.task-delete:hover { color: var(--danger); background: color-mix(in srgb, var(--danger) 10%, transparent); }

.empty { text-align: center; color: var(--muted); padding: 24px 0; margin: 0; }

.offline-banner {
  position: fixed; left: 50%; bottom: 16px; transform: translateX(-50%);
  background: var(--text); color: var(--bg); font-size: .8rem;
  padding: 8px 14px; border-radius: 999px; margin: 0; z-index: 10;
}

@media (max-width: 620px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  .task-form .btn, .task-form .field { flex: 1 1 100%; }
  .tabs { flex: 1; justify-content: space-between; }
  .tab { flex: 1; }
  .search { flex: 1 1 100%; max-width: none; }
}