:root {
  --bg: #f4f7f6; --card: #ffffff; --text: #2c3e50; --text-muted: #7f8c8d;
  --border: #e0e6ed; --primary: #3498db; --success: #2ecc71; --error: #e74c3c;
  --q1-bg: #ffebee; --q1-border: #ef9a9a;
  --q2-bg: #e3f2fd; --q2-border: #90caf9;
  --q3-bg: #fff3e0; --q3-border: #ffcc80;
  --q4-bg: #f5f5f5; --q4-border: #e0e0e0;
}
* { margin: 0; padding: 0; box-sizing: border-box; font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
body { background: var(--bg); color: var(--text); -webkit-font-smoothing: antialiased; }
.hidden { display: none !important; }
.mt-10 { margin-top: 10px; } .mb-4 { margin-bottom: 4px; } .mb-10 { margin-bottom: 10px; } .mb-20 { margin-bottom: 20px; }
.text-sm { font-size: 14px; } .text-muted { color: var(--text-muted); }
.flex-row { display: flex; align-items: center; gap: 10px; }
.box-shadow { background: var(--card); border-radius: 12px; padding: 20px; box-shadow: 0 4px 6px rgba(0,0,0,.05); }
.screen { min-height: 100vh; }
.container { width: 100%; max-width: 960px; margin: 0 auto; padding: 20px; }

.app-header { display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 14px 20px; background: var(--card); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 5; flex-wrap: wrap; }
.logo { font-size: 24px; font-weight: 700; color: var(--primary); }
.logo-small { font-size: 20px; font-weight: 700; color: var(--primary); }
.subtitle { color: var(--text-muted); margin-bottom: 16px; font-size: 14px; }
.status-badge { font-size: 12px; font-weight: 600; padding: 4px 10px; border-radius: 999px; }
.sync-offline { background: #f0f0f0; color: var(--text-muted); }
.sync-online { background: #e8f8f0; color: var(--success); }

input[type="text"], input[type="password"] { width: 100%; padding: 12px 15px; border: 1px solid var(--border); border-radius: 8px; font-size: 16px; outline: none; }
input:focus { border-color: var(--primary); }
.btn-primary { padding: 12px 16px; background: var(--primary); color: #fff; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; font-size: 15px; white-space: nowrap; }
.btn-primary:hover { filter: brightness(1.05); }
.btn-secondary { width: 100%; padding: 12px; background: transparent; color: var(--primary); border: 1px solid var(--primary); border-radius: 8px; font-weight: 600; cursor: pointer; }
.btn-text { background: none; border: none; color: var(--text-muted); cursor: pointer; font-weight: 600; font-size: 14px; }
.btn-text:hover { color: var(--primary); }

.add-task-card { display: block; }
.add-task-card input { margin-bottom: 12px; }
.toggles { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.toggle-lbl { display: flex; align-items: center; gap: 6px; font-size: 14px; font-weight: 600; color: var(--text-muted); cursor: pointer; }
.toggles .btn-primary { margin-left: auto; }

.matrix-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 640px) { .matrix-grid { grid-template-columns: 1fr; } }
.quadrant { border-radius: 12px; padding: 14px; border: 1px solid; min-height: 120px; }
.q1 { background: var(--q1-bg); border-color: var(--q1-border); }
.q2 { background: var(--q2-bg); border-color: var(--q2-border); }
.q3 { background: var(--q3-bg); border-color: var(--q3-border); }
.q4 { background: var(--q4-bg); border-color: var(--q4-border); }
.quadrant h4 { font-size: 13px; font-weight: 600; color: var(--text-muted); margin-bottom: 10px; }
.qtag { display: inline-block; font-weight: 700; color: var(--text); margin-right: 4px; }
.task-list { display: flex; flex-direction: column; gap: 8px; }
.task-item { display: flex; align-items: center; gap: 8px; background: rgba(255,255,255,.75); border-radius: 8px; padding: 8px 10px; }
.task-item.completed .task-title { text-decoration: line-through; color: var(--text-muted); }
.task-check { width: 18px; height: 18px; flex-shrink: 0; }
.task-title { flex: 1; font-size: 14px; word-break: break-word; }
.task-del { background: none; border: none; color: var(--text-muted); font-size: 20px; line-height: 1; cursor: pointer; padding: 0 4px; }
.task-del:hover { color: var(--error); }
.empty { color: var(--text-muted); opacity: .5; font-size: 13px; padding: 4px; }
.error { background: #fdecea; color: var(--error); padding: 10px; border-radius: 8px; font-size: 14px; margin-bottom: 12px; }

/* Modal cuenta */
.modal-backdrop { position: fixed; inset: 0; background: rgba(20,20,30,.55); display: flex; align-items: center; justify-content: center; padding: 20px; z-index: 20; }
.auth-box { max-width: 380px; width: 100%; position: relative; }
.auth-box input { margin-bottom: 12px; }
.modal-close { position: absolute; top: 12px; right: 14px; background: none; border: none; font-size: 26px; line-height: 1; color: var(--text-muted); cursor: pointer; }