:root {
  --bg: #f4f6fb;
  --primary-dark: #002147;
  --primary: #0055a4;
  --primary-light: #0075d4;
  --danger: #c62828;
  --warning: #ff9800;
  --success: #2e7d32;

  --shadow: 0 2px 5px rgba(0,0,0,0.2);
  --shadow-lg: 0 4px 10px rgba(0,0,0,0.15);
  --radius: 12px;
  --sp-sm: 8px;
  --sp-md: 16px;
  --sp-lg: 24px;
  --transition: 0.3s ease;
}

/* Dark Mode */
html[data-theme="dark"] {
  --bg: #1a1f2b;
  --primary-dark: #000814;
  --primary: #001f54;
  --primary-light: #003a8c;
  --danger: #b71c1c;
  --warning: #ff6d00;
  --success: #1b5e20;
  color: #e0e0e0;
}

/* Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg);
}
::-webkit-scrollbar-thumb {
  background: var(--primary);
  border-radius: var(--radius);
  border: 2px solid var(--bg);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--primary-light);
}

/* Global */
body {
  background: var(--bg);
  color: var(--primary-dark);
  transition: background var(--transition), color var(--transition);
  scroll-behavior: smooth;
  overflow-y: scroll;
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(90deg, var(--primary-dark), var(--primary));
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(255,255,255,0.2);
  box-shadow: var(--shadow);
  z-index: 100;
  transition: background var(--transition);
}
.nav-container {
  max-width: 1200px;
  margin: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-sm) var(--sp-md);
}
.nav-logo {
  font-weight: 600;
  font-size: 1.4rem;
  color: #fff;
  text-decoration: none;
  letter-spacing: 1px;
  transition: transform var(--transition);
}
.nav-logo:hover {
  transform: scale(1.05);
}
.nav-menu {
  display: flex;
  gap: var(--sp-md);
  align-items: center;
}
.nav-link,
.dropbtn {
  position: relative;
  color: #fff;
  text-decoration: none;
  background: transparent;
  border: none;
  font-size: .95rem;
  cursor: pointer;
  padding: var(--sp-sm) var(--sp-md);
  border-radius: var(--radius);
  transition: color var(--transition), background var(--transition);
}
.nav-link::after,
.dropdown-item::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 50%;
  width: 0;
  height: 2px;
  background: #fff;
  transition: width var(--transition), left var(--transition);
}
.nav-link:hover::after,
.dropdown-item:hover::after {
  width: 100%;
  left: 0;
}
.nav-link:hover,
.dropbtn:hover,
.dropdown-item:hover {
  background: rgba(255,255,255,0.2);
}
.nav-link.active,
.dropdown-item.active {
  background: var(--primary-light);
}
.dropdown {
  position: relative;
}
.dropdown-content {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--primary-dark);
  min-width: 160px;
  box-shadow: var(--shadow);
  border-radius: var(--radius);
  overflow: hidden;
  transition: opacity var(--transition);
  opacity: 0;
}
.dropdown:hover .dropdown-content {
  display: block;
  opacity: 1;
}
.dropdown-item {
  display: block;
  color: #fff;
  padding: var(--sp-sm) var(--sp-md);
  text-decoration: none;
  font-size: .9rem;
  transition: background var(--transition);
}

/* Sections */
.section {
  display: none;
  padding: 120px 20px 20px;
  max-width: 1200px;
  margin: auto;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.6s forwards;
}
.section.active {
  display: block;
}
@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Typography */
h2 {
  font-size: 1.8rem;
  margin-bottom: var(--sp-md);
  position: relative;
  display: inline-block;
}
h2::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -8px;
  width: 60px;
  height: 4px;
  background: var(--primary-light);
  border-radius: var(--radius);
}

/* Forms */
.field-group {
  margin-bottom: var(--sp-md);
  display: flex;
  flex-direction: column;
}
.field-group label {
  margin-bottom: 4px;
  font-weight: 500;
  color: var(--primary-dark);
  transition: color var(--transition);
}
.field-group input,
.field-group select,
.field-group textarea {
  padding: var(--sp-sm);
  border: 1px solid var(--primary-light);
  border-radius: var(--radius);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.field-group input:focus,
.field-group select:focus,
.field-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(0,85,164,0.2);
}

/* Buttons (Base) */
button {
  cursor: pointer;
  border: none;
  border-radius: var(--radius);
  padding: var(--sp-sm) var(--sp-md);
  background: var(--primary);
  color: #fff;
  font-weight: 500;
  box-shadow: var(--shadow);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
}
button:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
button:active {
  transform: translateY(0);
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: var(--sp-md);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
th, td {
  padding: 12px 10px;
  font-size: .9rem;
  text-align: left;
}
th {
  background: var(--primary-dark);
  color: #fff;
  font-weight: 600;
  box-shadow: inset 0 -2px 0 rgba(0,0,0,0.2);
}
tr:nth-child(even) td {
  background: #f8f8f8;
}
tr:hover td {
  background: rgba(0,85,164,0.05);
  transform: scale(1.002);
  transition: background var(--transition), transform var(--transition);
}

/* Priority Indicators */
.priority-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
  transition: transform var(--transition);
}
.priority-alta {
  background: var(--danger);
  animation: pulse 2s infinite;
}
.priority-media {
  background: var(--warning);
}
.priority-baja {
  background: var(--success);
}
@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.3); }
  100% { transform: scale(1); }
}

/* Combustible Boxes */
.combustible-container {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-lg);
}
.combustible-box {
  flex: 1 1 400px;
  min-width: 300px;
  box-shadow: var(--shadow);
  padding: var(--sp-md);
  border-radius: var(--radius);
  background: #fff;
  transition: transform var(--transition), box-shadow var(--transition);
}
.combustible-box h3 {
  text-align: center;
  margin-bottom: var(--sp-md);
}
.combustible-box:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-menu {
    flex-direction: column;
    background: var(--primary-dark);
    position: absolute;
    top: 60px;
    left: 0;
    width: 100%;
    transform: translateY(-100%);
    transition: transform var(--transition);
  }
  .nav-menu.open {
    transform: translateY(0);
  }
}

/* Ripple Effect for Buttons */
button {
  position: relative;
  overflow: hidden;
}
button::after {
  content: '';
  position: absolute;
  width: 100px;
  height: 100px;
  background: rgba(255,255,255,0.3);
  opacity: 0;
  border-radius: 50%;
  transform: scale(0);
  transition: transform 0.6s ease, opacity 1s ease;
  pointer-events: none;
}
button:active::after {
  transform: scale(2);
  opacity: 1;
  transition: 0s;
}

/* Skeleton Loader */
.skeleton {
  background: linear-gradient(90deg, var(--bg) 25%, rgba(255,255,255,0.2) 50%, var(--bg) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

/* Tooltips */
.tooltip {
  position: relative;
  cursor: pointer;
}
.tooltip[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 120%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-dark);
  color: #fff;
  padding: var(--sp-sm) var(--sp-md);
  border-radius: var(--radius);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
  z-index: 10;
}
.tooltip:hover[data-tooltip]::after {
  opacity: 1;
}

/* Back-to-Top Button */
.back-to-top {
  position: fixed;
  right: var(--sp-md);
  bottom: var(--sp-md);
  width: 50px;
  height: 50px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition);
}
.back-to-top.show {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  transform: translateY(-5px);
}