:root {
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-2: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --primary: #38bdf8;
  --primary-hover: #0ea5e9;
  --success: #22c55e;
  --danger: #ef4444;
  --warning: #f59e0b;
  --border: #475569;
  --shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  --radius: 16px;
  --radius-sm: 10px;
  --max-width: 1100px;
  --transition: 0.25s ease;
  --font: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: linear-gradient(135deg, #0f172a, #111827);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

img {
  max-width: 100%;
  display: block;
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
  border: none;
  transition: var(--transition);
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
  color: inherit;
}

/* Layout general */
.container {
  width: min(90%, var(--max-width));
  margin: 0 auto;
  padding: 2rem 0 3rem;
}

/* Header */
.app-header {
  margin-bottom: 2rem;
  text-align: center;
}

.app-header h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: 0.5rem;
  color: #f8fafc;
}

.app-header p {
  color: var(--muted);
  font-size: 1rem;
}

/* Tarjetas */
.card {
  background: rgba(30, 41, 59, 0.92);
  border: 1px solid rgba(71, 85, 105, 0.5);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  backdrop-filter: blur(6px);
}

/* Grid principal */
.main-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

/* Resumen */
.summary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.summary-card {
  padding: 1.25rem;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
}

.summary-card h3 {
  font-size: 0.95rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.summary-card p {
  font-size: 1.5rem;
  font-weight: 700;
}

.summary-card.income p {
  color: var(--success);
}

.summary-card.expense p {
  color: var(--danger);
}

.summary-card.balance p {
  color: var(--primary);
}

/* Secciones */
.section-title {
  font-size: 1.25rem;
  margin-bottom: 1rem;
  color: #f8fafc;
}

/* Formulario */
.form-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-group.full {
  grid-column: 1 / -1;
}

label {
  margin-bottom: 0.45rem;
  color: var(--muted);
  font-size: 0.95rem;
}

input,
select,
textarea {
  width: 100%;
  padding: 0.85rem 1rem;
  background: #0f172a;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: var(--transition);
}

input:focus,
select:focus,
textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.2);
}

textarea {
  resize: vertical;
  min-height: 100px;
}

/* Botones */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.9rem 1.2rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.btn-primary {
  background: var(--primary);
  color: #082f49;
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-danger {
  background: var(--danger);
  color: white;
}

.btn-danger:hover {
  opacity: 0.9;
}

.btn-secondary {
  background: var(--surface-2);
  color: var(--text);
}

.btn-secondary:hover {
  background: #475569;
}

/* Filtros */
.filters {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-bottom: 1rem;
}

/* Lista de transacciones */
.transaction-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.transaction-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  align-items: center;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: #0f172a;
  transition: var(--transition);
}

.transaction-item:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.transaction-info h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
  color: #f8fafc;
}

.transaction-info p {
  font-size: 0.92rem;
  color: var(--muted);
}

.transaction-meta {
  text-align: right;
}

.transaction-meta .amount {
  display: block;
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 0.35rem;
}

.amount.income {
  color: var(--success);
}

.amount.expense {
  color: var(--danger);
}

.transaction-meta .date {
  display: block;
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 0.6rem;
}

.actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
}

.actions button {
  padding: 0.6rem 0.85rem;
  border-radius: 8px;
  font-size: 0.9rem;
}

/* Estado vacío */
.empty-state {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--muted);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
}

/* Utilidades */
.mt-2 {
  margin-top: 1rem;
}

.mt-3 {
  margin-top: 1.5rem;
}

.hidden {
  display: none;
}

.filters {
  display: flex;
  gap: 10px;
  margin: 10px 0 20px;
}

.filters select,
.filters input {
  padding: 8px;
  border-radius: 8px;
  border: 1px solid #ccc;
}

/* Responsive */
@media (max-width: 900px) {
  .summary {
    grid-template-columns: 1fr;
  }

  .filters {
    grid-template-columns: 1fr;
  }

  .form-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  .container {
    width: min(92%, var(--max-width));
    padding: 1.25rem 0 2rem;
  }

  .card {
    padding: 1rem;
  }

  .transaction-item {
    grid-template-columns: 1fr;
  }

  .transaction-meta {
    text-align: left;
  }

  .actions {
    justify-content: flex-start;
  }

  .app-header h1 {
    font-size: 2rem;
  }
}