/* Variables globales - Estilo Twitter Cards */
:root {
  --bg: #f7f9fb;
  --card: #ffffff;
  --text: #0f1419;
  --muted: #536471;
  --border: #cfd9de;
  --shadow: 0 1px 3px rgba(0,0,0,.08);
  --radius: 16px;
  --primary: #1d9bf0;
  --primary-hover: #1a8cd8;
  --success: #00ba7c;
  --warning: #ffad1f;
  --danger: #f4212e;
}

/* Reset básico */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  font-size: 15px;
  line-height: 1.5;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Layout principal */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
}

/* Top bar de navegación */
.topbar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 12px 24px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.topbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.topbar-logo {
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
}

.topbar-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.topbar-nav a {
  color: var(--muted);
  padding: 8px 12px;
  border-radius: 9999px;
  font-size: 14px;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}

.topbar-nav a:hover {
  background: rgba(29, 155, 240, 0.1);
  color: var(--primary);
  text-decoration: none;
}

.topbar-nav a.active {
  background: var(--primary);
  color: white;
}

/* Cards estilo Twitter */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  margin: 16px 0;
}

.card-header {
  margin-bottom: 16px;
}

.card h2, .card h3 {
  margin: 0 0 8px 0;
  color: var(--text);
}

.card h2 {
  font-size: 20px;
}

.card h3 {
  font-size: 17px;
}

.card p {
  margin: 0 0 12px 0;
  color: var(--muted);
}

.card-footer {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* Chips */
.chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 12px 0;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 9999px;
  padding: 6px 12px;
  font-size: 13px;
  color: var(--muted);
}

.chip.primary {
  background: rgba(29, 155, 240, 0.1);
  border-color: var(--primary);
  color: var(--primary);
}

.chip.success {
  background: rgba(0, 186, 124, 0.1);
  border-color: var(--success);
  color: var(--success);
}

.chip.warning {
  background: rgba(255, 173, 31, 0.1);
  border-color: var(--warning);
  color: #996600;
}

.chip.danger {
  background: rgba(244, 33, 46, 0.1);
  border-color: var(--danger);
  color: var(--danger);
}

/* Tablas tipo Excel */
.table-container {
  overflow-x: auto;
  margin: 16px 0;
}

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.table th,
.table td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: right;
}

.table th {
  background: #f3f6f9;
  text-align: left;
  font-weight: 600;
  position: sticky;
  top: 0;
}

.table td:first-child {
  text-align: left;
  font-weight: 500;
}

.table tr:nth-child(even) {
  background: #fbfdff;
}

.table tr:hover {
  background: rgba(29, 155, 240, 0.05);
}

.table td.number {
  font-family: "SF Mono", Monaco, Consolas, monospace;
  font-size: 13px;
}

/* Formularios e inputs */
.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  margin-bottom: 6px;
  font-weight: 500;
  font-size: 14px;
}

.form-group .hint {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-top: 4px;
}

input[type="text"],
input[type="number"],
select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="text"]:focus,
input[type="number"]:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(29, 155, 240, 0.2);
}

input[type="number"] {
  font-family: "SF Mono", Monaco, Consolas, monospace;
}

input.error {
  border-color: var(--danger);
}

.error-message {
  color: var(--danger);
  font-size: 12px;
  margin-top: 4px;
}

/* Grid para inputs */
.input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

/* Botones */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: 9999px;
  font-size: 14px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

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

.btn:active {
  transform: translateY(0);
}

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

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-secondary {
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--primary);
}

.btn-secondary:hover {
  background: rgba(29, 155, 240, 0.1);
}

.btn-small {
  padding: 6px 12px;
  font-size: 13px;
}

/* Bloque de fórmulas */
.formula-block {
  background: #f8f9fa;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  margin: 16px 0;
  overflow-x: auto;
  text-align: center;
}

.formula-block .katex {
  font-size: 1.2em;
}

/* Grid de cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 16px;
}

/* Hero section para inicio */
.hero {
  text-align: center;
  padding: 48px 24px;
  background: linear-gradient(135deg, #1d9bf0 0%, #1a8cd8 100%);
  color: white;
  border-radius: var(--radius);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 32px;
  margin: 0 0 12px 0;
}

.hero p {
  font-size: 18px;
  opacity: 0.9;
  margin: 0 0 24px 0;
}

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

.hero .btn:hover {
  background: #f0f0f0;
}

/* Lista de pasos para ruta de aprendizaje */
.step-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.step-list li {
  display: flex;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.step-list li:last-child {
  border-bottom: none;
}

.step-number {
  width: 32px;
  height: 32px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  flex-shrink: 0;
}

.step-content h4 {
  margin: 0 0 4px 0;
  font-size: 16px;
}

.step-content p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

/* Glosario */
.glossary-term {
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.glossary-term:last-child {
  border-bottom: none;
}

.glossary-term dt {
  font-weight: 600;
  font-size: 16px;
  color: var(--primary);
}

.glossary-term dd {
  margin: 8px 0 0 0;
  color: var(--muted);
}

/* Alertas y notas */
.alert {
  padding: 16px;
  border-radius: 8px;
  margin: 16px 0;
}

.alert-info {
  background: rgba(29, 155, 240, 0.1);
  border-left: 4px solid var(--primary);
}

.alert-warning {
  background: rgba(255, 173, 31, 0.1);
  border-left: 4px solid var(--warning);
}

.alert-success {
  background: rgba(0, 186, 124, 0.1);
  border-left: 4px solid var(--success);
}

/* Navegación entre páginas */
.page-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.page-nav a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-weight: 500;
  transition: border-color 0.2s;
}

.page-nav a:hover {
  border-color: var(--primary);
  text-decoration: none;
}

.page-nav .prev::before {
  content: "←";
}

.page-nav .next::after {
  content: "→";
}

/* Resultados de calculadora */
.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin: 16px 0;
}

.result-item {
  background: #f8f9fa;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  text-align: center;
}

.result-item .label {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 4px;
}

.result-item .value {
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  font-family: "SF Mono", Monaco, Consolas, monospace;
}

.result-item .unit {
  font-size: 12px;
  color: var(--muted);
}

/* Simulación - barra de progreso */
.progress-bar {
  width: 100%;
  height: 8px;
  background: #e0e0e0;
  border-radius: 4px;
  overflow: hidden;
  margin: 12px 0;
}

.progress-bar .fill {
  height: 100%;
  background: var(--primary);
  transition: width 0.3s;
}

/* Tabs */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 16px;
}

.tab {
  padding: 12px 20px;
  border: none;
  background: none;
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.2s, border-color 0.2s;
}

.tab:hover {
  color: var(--text);
}

.tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

/* Muted text */
.muted {
  color: var(--muted);
}

.text-center {
  text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
  .topbar-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .topbar-nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 8px;
  }

  .container {
    padding: 16px;
  }

  .hero {
    padding: 32px 16px;
  }

  .hero h1 {
    font-size: 24px;
  }

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

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