:root {
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --primary-blue: #2563eb;
    --primary-green: #16a34a;
    --border-radius: 12px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 24px;
}

h1 {
    color: var(--primary-blue);
    font-size: 1.8rem;
}

main {
    max-width: 400px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.converter-card {
    background-color: var(--card-bg);
    padding: 16px;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

h2 {
    font-size: 0.9rem;
    margin-bottom: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
}

.input-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.input-field {
    flex: 1;
}

label {
    display: block;
    font-size: 0.75rem;
    margin-bottom: 4px;
    font-weight: 600;
}

input[type="number"] {
    width: 100%;
    padding: 12px 8px;
    /* Obligatorio en 16px para evitar el zoom automático en iOS */
    font-size: 16px;
    font-weight: bold;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    text-align: center;
    -moz-appearance: textfield; 
}

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
    -webkit-appearance: none; 
    margin: 0;
}

/* Colores de las columnas */
.input-left {
    color: var(--primary-blue);
    border-color: #dbeafe !important;
}

.input-right {
    color: var(--primary-green);
    border-color: #dcfce7 !important;
}

input:focus {
    outline: none;
    border-color: #9ca3af !important;
}

.equals {
    font-size: 1.2rem;
    color: #9ca3af;
    padding-top: 20px;
}