:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border: #e5e7eb;
    --status-pending: #4b5563;
    --status-warning: #d97706;
    --status-danger: #dc2626;
    --status-success: #059669;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: system-ui, -apple-system, sans-serif; }

body { background-color: var(--bg-color); color: var(--text-main); padding-bottom: 80px; }

.header { background: var(--card-bg); padding: 1rem; box-shadow: 0 1px 3px rgba(0,0,0,0.1); position: sticky; top: 0; z-index: 10; }
.header h1 { font-size: 1.5rem; margin-bottom: 1rem; color: var(--primary); }
.summary-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.75rem; }
@media (min-width: 600px) { .summary-grid { grid-template-columns: repeat(4, 1fr); } }
.summary-card { background: var(--bg-color); padding: 0.75rem; border-radius: 8px; display: flex; flex-direction: column; }
.summary-card.danger { background: #fef2f2; color: var(--status-danger); }
.summary-label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px;}
.summary-card.danger .summary-label { color: var(--status-danger); }
.summary-value { font-size: 1.25rem; font-weight: bold; margin-top: 0.25rem; }
.filter-container { margin-top: 1rem; font-size: 0.9rem; color: var(--text-muted); }

.container { padding: 1rem; max-width: 800px; margin: 0 auto; }
.payments-list { display: flex; flex-direction: column; gap: 1rem; }
.card { background: var(--card-bg); border-radius: 12px; padding: 1rem; box-shadow: 0 2px 4px rgba(0,0,0,0.05); border-left: 5px solid var(--border); position: relative; }
.card.status-vencido { border-left-color: var(--status-danger); }
.card.status-proximo { border-left-color: var(--status-warning); }
.card.status-pagado { border-left-color: var(--status-success); opacity: 0.7; }
.card-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 0.5rem; }
.card-title { font-size: 1.1rem; font-weight: 600; }
.card-amount { font-size: 1.2rem; font-weight: bold; color: var(--primary); }
.card-details { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 1rem; display: flex; flex-direction: column; gap: 0.25rem;}
.badge { display: inline-flex; align-items: center; gap: 0.25rem; padding: 0.25rem 0.5rem; border-radius: 99px; font-size: 0.75rem; font-weight: bold; width: fit-content; }
.badge.vencido { background: #fef2f2; color: var(--status-danger); }
.badge.proximo { background: #fffbeb; color: var(--status-warning); }
.badge.pendiente { background: #f3f4f6; color: var(--status-pending); }
.badge.pagado { background: #ecfdf5; color: var(--status-success); }
.card-actions { display: flex; gap: 0.5rem; flex-wrap: wrap; border-top: 1px solid var(--border); padding-top: 0.75rem;}

.btn { border: none; padding: 0.5rem 1rem; border-radius: 6px; cursor: pointer; font-size: 0.9rem; font-weight: 500; transition: background 0.2s; }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-secondary { background: var(--border); color: var(--text-main); }
.btn-success { background: var(--status-success); color: white; }
.btn-text { background: transparent; color: var(--text-muted); text-decoration: underline; padding: 0.5rem 0;}

.fab { position: fixed; bottom: 1.5rem; right: 1.5rem; background: var(--primary); color: white; border: none; border-radius: 99px; padding: 0.75rem 1.5rem; font-size: 1rem; font-weight: bold; box-shadow: 0 4px 10px rgba(37, 99, 235, 0.3); cursor: pointer; display: flex; align-items: center; gap: 0.5rem; z-index: 100; }

.modal { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); display: flex; justify-content: center; align-items: center; z-index: 1000; padding: 1rem; }
.modal.hidden { display: none; }
.modal-content { background: var(--card-bg); width: 100%; max-width: 400px; padding: 1.5rem; border-radius: 12px; }
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; margin-bottom: 0.25rem; font-size: 0.9rem; font-weight: 500;}
.form-group input, .form-group textarea { width: 100%; padding: 0.5rem; border: 1px solid var(--border); border-radius: 6px; font-size: 1rem; }
.notes-group details { font-size: 0.9rem; color: var(--text-muted); cursor: pointer; }
.modal-actions { display: flex; justify-content: flex-end; gap: 0.5rem; margin-top: 1.5rem; }
.error-msg { color: var(--status-danger); font-size: 0.85rem; margin-top: 0.5rem; }
.hidden { display: none !important; }