* { box-sizing: border-box; }
:root {
  --bg: #0f172a;
  --card: #111827;
  --muted: #94a3b8;
  --text: #e2e8f0;
  --accent: #22c55e;
  --danger: #ef4444;
  --border: #1f2937;
}
html, body { height: 100%; }
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: linear-gradient(135deg, #0f172a 0%, #111827 100%);
  color: var(--text);
}
#app { display: grid; grid-template-columns: 280px 1fr; min-height: 100vh; }
.sidebar {
  border-right: 1px solid var(--border);
  background: rgba(17,24,39,0.9);
  backdrop-filter: blur(6px);
  padding: 16px;
}
.month-nav { display: grid; grid-template-columns: 40px 1fr 40px; align-items: center; gap: 8px; margin-bottom: 12px; }
.month-nav button {
  border: 1px solid var(--border);
  background: #0b1220;
  color: var(--text);
  border-radius: 8px;
  cursor: pointer;
  height: 36px;
}
#currentMonth { text-align: center; font-weight: 700; }
.days-list { list-style: none; padding: 0; margin: 0; max-height: calc(100vh - 100px); overflow: auto; }
.days-list li {
  display: flex; align-items: center; justify-content: space-between;
  border: 1px solid var(--border); border-radius: 10px;
  padding: 10px 12px; margin-bottom: 8px; cursor: pointer; background: #0b1220;
}
.days-list li.active { outline: 2px solid var(--accent); }
.days-list .total { color: var(--muted); font-size: 12px; }

.hidden { display: none !important; }

.main { padding: 20px; }
.header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.header h1 { margin: 0; font-size: 20px; }
.actions { display: flex; gap: 8px; }
button.primary, button.secondary, button.danger, .footer .big {
  border: 1px solid var(--border); color: var(--text);
  border-radius: 10px; padding: 10px 14px; cursor: pointer; background: #0b1220;
}
button.primary { background: linear-gradient(135deg, #065f46, #059669); border-color: #064e3b; }
button.secondary { background: linear-gradient(135deg, #1e3a8a, #2563eb); border-color: #1e40af; }
button.danger { background: linear-gradient(135deg, #7f1d1d, #dc2626); border-color: #7f1d1d; }

.form-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 16px; }
.card { border: 1px solid var(--border); background: var(--card); border-radius: 14px; padding: 14px; }
.card h2 { margin: 0 0 10px 0; font-size: 16px; }
.span-2 { grid-column: span 2; }
.row { display: grid; gap: 8px; }
input[type="number"], input[type="text"] { width: 100%; background: #0b1220; border: 1px solid var(--border); color: var(--text); border-radius: 10px; padding: 10px 12px; }
.add-expense { display: grid; grid-template-columns: 1.5fr 0.8fr auto; gap: 8px; margin-bottom: 10px; }
.list { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; max-height: 220px; overflow: auto; }
.list li { display: grid; grid-template-columns: 1fr 120px 32px; align-items: center; gap: 8px; background: #0b1220; border: 1px solid var(--border); border-radius: 10px; padding: 8px 10px; }
.list .amount { text-align: right; }
.list .del { background: transparent; border: 1px solid var(--border); color: var(--danger); border-radius: 8px; cursor: pointer; height: 30px; }

.resume { display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 12px; margin-top: 16px; }
.resume-card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 12px; }
.resume-title { color: var(--muted); font-size: 12px; }
.resume-value { font-size: 20px; font-weight: 700; }
.resume-card.ingresos .resume-value { color: #6ee7b7; }
.resume-card.total .resume-value { color: #93c5fd; }

.footer { display: flex; align-items: center; gap: 12px; margin-top: 16px; }
.footer .big { padding: 12px 16px; font-weight: 700; background: linear-gradient(135deg, #065f46, #059669); }
.status { color: var(--muted); font-size: 12px; }

@media (max-width: 900px) {
  #app { grid-template-columns: 1fr; }
  .sidebar { order: 2; }
  .main { order: 1; }
  .form-grid { grid-template-columns: 1fr; }
  .span-2 { grid-column: span 1; }
  .resume { grid-template-columns: repeat(2, minmax(0,1fr)); }
}