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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 1rem;
    font-size: 2rem;
}

nav {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.nav-btn {
    padding: 0.7rem 1.2rem;
    border: none;
    background: #3498db;
    color: white;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.nav-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

.nav-btn.active {
    background: #e74c3c;
    box-shadow: 0 4px 15px rgba(231, 76, 60, 0.3);
}

main {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.content-section {
    display: none;
    animation: fadeIn 0.5s ease-in;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

h2 {
    color: white;
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.card h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
    font-size: 1.3rem;
    border-bottom: 2px solid #3498db;
    padding-bottom: 0.5rem;
}

.card ul {
    list-style: none;
    padding-left: 0;
}

.card li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #ecf0f1;
    position: relative;
    padding-left: 1.5rem;
}

.card li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #27ae60;
    font-weight: bold;
}

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

/* Problemas Comunes */
.problem-search {
    margin-bottom: 2rem;
    text-align: center;
}

#problem-search {
    padding: 1rem;
    border: none;
    border-radius: 25px;
    width: 100%;
    max-width: 400px;
    font-size: 1rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.problems-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.problem-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.problem-card:hover {
    transform: translateY(-5px);
}

.problem-card h3 {
    color: #e74c3c;
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.causes, .solutions {
    margin-bottom: 1rem;
}

.causes h4, .solutions h4 {
    color: #34495e;
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.causes ul, .solutions ul {
    list-style: none;
    padding-left: 1rem;
}

.causes li:before {
    content: "⚠️";
    margin-right: 0.5rem;
}

.solutions li:before {
    content: "🔧";
    margin-right: 0.5rem;
}

/* Presiones */
.refrigerant-selector {
    background: white;
    padding: 1.5rem;
    border-radius: 15px;
    margin-bottom: 2rem;
    text-align: center;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.refrigerant-selector label {
    font-weight: bold;
    margin-right: 1rem;
    color: #2c3e50;
}

.refrigerant-selector select {
    padding: 0.5rem 1rem;
    border: 2px solid #3498db;
    border-radius: 8px;
    font-size: 1rem;
}

.pressure-table {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    overflow-x: auto;
}

.pressure-table table {
    width: 100%;
    border-collapse: collapse;
}

.pressure-table th,
.pressure-table td {
    padding: 0.8rem;
    text-align: center;
    border-bottom: 1px solid #ecf0f1;
}

.pressure-table th {
    background: #3498db;
    color: white;
    font-weight: bold;
}

.pressure-table tr:hover {
    background: #f8f9fa;
}

/* Amperaje */
.amperage-calculator {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.amperage-calculator h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
    text-align: center;
}

.calc-inputs {
    display: flex;
    gap: 1rem;
    align-items: end;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 1rem;
}

.calc-inputs label {
    display: flex;
    flex-direction: column;
    font-weight: bold;
    color: #34495e;
}

.calc-inputs input,
.calc-inputs select {
    padding: 0.5rem;
    border: 2px solid #bdc3c7;
    border-radius: 8px;
    margin-top: 0.3rem;
    font-size: 1rem;
}

.calc-inputs button {
    padding: 0.7rem 1.5rem;
    background: #27ae60;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    transition: background 0.3s ease;
}

.calc-inputs button:hover {
    background: #219a52;
}

.result {
    background: #ecf0f1;
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
    font-weight: bold;
    color: #2c3e50;
    margin-top: 1rem;
}

.amperage-table {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    overflow-x: auto;
}

.amperage-table table {
    width: 100%;
    border-collapse: collapse;
}

.amperage-table th,
.amperage-table td {
    padding: 0.8rem;
    text-align: center;
    border-bottom: 1px solid #ecf0f1;
}

.amperage-table th {
    background: #e74c3c;
    color: white;
    font-weight: bold;
}

.amperage-table tr:hover {
    background: #f8f9fa;
}

/* Calculadoras */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.calculator-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.calculator-card h3 {
    color: #8e44ad;
    margin-bottom: 1rem;
    text-align: center;
    font-size: 1.3rem;
}

.calculator-card .calc-inputs {
    flex-direction: column;
    align-items: stretch;
}

.calculator-card .calc-inputs label {
    margin-bottom: 0.8rem;
}

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 1.5rem;
    }
    
    .nav-btn {
        padding: 0.5rem 0.8rem;
        font-size: 0.9rem;
    }
    
    .calc-inputs {
        flex-direction: column;
        align-items: stretch;
    }
    
    .problems-grid {
        grid-template-columns: 1fr;
    }
    
    .calculators-grid {
        grid-template-columns: 1fr;
    }
}

.hidden {
    display: none !important;
}