/* ========================================
   CALCULADORA DE INTERÉS COMPUESTO
   Sistema de diseño y estilos globales
   ======================================== */

/* === PALETA DE COLORES === */
:root {
    /* Colores primarios */
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-primary-light: #3b82f6;

    /* Colores secundarios */
    --color-secondary: #7c3aed;
    --color-secondary-dark: #6d28d9;
    --color-secondary-light: #8b5cf6;

    /* Colores de acento */
    --color-accent: #10b981;
    --color-accent-dark: #059669;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;

    /* Fondos */
    --color-bg-primary: #f8fafc;
    --color-bg-secondary: #ffffff;
    --color-bg-card: #ffffff;

    /* Textos */
    --color-text-primary: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-light: #94a3b8;

    /* Bordes y sombras */
    --color-border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

    /* Espaciados */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Bordes redondeados */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transiciones */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
}

/* === RESET Y BASE === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    min-height: 100vh;
    color: var(--color-text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* === CONTENEDORES === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
}

.container-narrow {
    max-width: 600px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
}

/* === TARJETAS === */
.card {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 25px 35px -5px rgba(0, 0, 0, 0.15);
}

.card-header {
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.card-title {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-sm);
}

.card-subtitle {
    font-size: 1rem;
    color: var(--color-text-secondary);
}

/* === BOTONES === */
.btn {
    display: inline-block;
    width: 100%;
    padding: 0.875rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary));
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--color-bg-primary);
    color: var(--color-text-primary);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-secondary);
    border-color: var(--color-primary);
}

.btn-accent {
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
    color: white;
}

.btn-accent:hover {
    background: linear-gradient(135deg, var(--color-accent-dark), var(--color-accent));
}

/* === FORMULARIOS === */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    color: var(--color-text-primary);
    font-size: 0.95rem;
}

.form-input,
.form-select {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: all var(--transition-base);
    background: var(--color-bg-secondary);
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-row {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-end;
}

.form-row .form-group {
    flex: 1;
    margin-bottom: 0;
}

/* === GRID DE CALCULADORAS === */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.calculator-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: all var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
}

.calculator-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.calculator-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.calculator-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.calculator-description {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

/* === SECCIÓN EDUCATIVA === */
.education-section {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-xl);
}

.formula-display {
    background: var(--color-bg-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
    margin: var(--spacing-md) 0;
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
    text-align: center;
}

.info-box {
    background: #eff6ff;
    border-left: 4px solid var(--color-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin: var(--spacing-md) 0;
}

.info-box-title {
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.variables-list {
    list-style: none;
    margin-top: var(--spacing-md);
}

.variables-list li {
    padding: var(--spacing-xs) 0;
    border-bottom: 1px solid var(--color-border);
}

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

.variable-symbol {
    font-weight: 700;
    color: var(--color-primary);
    font-family: 'Courier New', monospace;
}

/* === PROCESO PASO A PASO === */
.steps-container {
    margin-top: var(--spacing-xl);
}

.step {
    background: var(--color-bg-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    border-left: 4px solid var(--color-primary);
}

.step-number {
    display: inline-block;
    width: 2rem;
    height: 2rem;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    text-align: center;
    line-height: 2rem;
    font-weight: 700;
    margin-right: var(--spacing-sm);
}

.step-title {
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.step-content {
    color: var(--color-text-secondary);
    font-family: 'Courier New', monospace;
    margin-top: var(--spacing-xs);
}

/* === RESULTADO === */
.result-box {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    margin: var(--spacing-xl) 0;
}

.result-label {
    font-size: 1rem;
    opacity: 0.9;
    margin-bottom: var(--spacing-xs);
}

.result-value {
    font-size: 2.5rem;
    font-weight: 700;
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
    .container,
    .container-narrow {
        padding: var(--spacing-md);
    }

    .card {
        padding: var(--spacing-lg);
    }

    .card-title {
        font-size: 1.5rem;
    }

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

    .form-row {
        flex-direction: column;
    }

    .form-row .form-group {
        width: 100%;
    }

    .result-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .card-title {
        font-size: 1.25rem;
    }

    .calculator-icon {
        font-size: 2.5rem;
    }
}

/* === UTILIDADES === */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }