:root {
    --color-primary: #3b82f6;
    --color-success: #10b981;
    --color-danger: #ef4444;
    --color-warning: #f59e0b;
    --color-neutral: #6b7280;
    --color-bg: #f9fafb;
    --color-card: #ffffff;
    --color-text: #111827;
    --color-text-secondary: #6b7280;
    --color-border: #e5e7eb;
    --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);
    --radius: 12px;
    --radius-sm: 8px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
}

/* Header */
.header {
    text-align: center;
    padding: 2rem 0 3rem;
    margin-bottom: 2rem;
}

.header-content {
    margin-bottom: 1.5rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.emoji {
    font-size: 2.5rem;
}

.logo-text {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

.social-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s;
}

.social-link:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    transform: translateY(-2px);
}

/* Loading & Error States */
.loading, .error {
    text-align: center;
    padding: 3rem 1rem;
}

.spinner {
    width: 40px;
    height: 40px;
    margin: 0 auto 1rem;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* CARDS CORE STYLE */
.card {
    background: var(--color-card);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    width: 100%;
}

.card-header h2 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge {
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    background: var(--color-bg);
    border-radius: 4px;
    color: var(--color-text-secondary);
    font-weight: 500;
}

/* CARDS GRID (Ajustado para centrar manteniendo estética) */
.cards-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1.5rem;
    justify-content: center; /* Centra los cuadros de variación */
}

.card-primary {
    flex: 0 0 100%; /* Ocupa el 100% del ancho */
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
    border: none;
}

.card-primary .card-header h2,
.card-primary .update-time,
.card-primary .location {
    color: rgba(255, 255, 255, 0.9);
}

/* Configuración para los dos cuadros de abajo */
.cards-grid .card:not(.card-primary) {
    flex: 1;
    min-width: 280px;
    max-width: 450px; /* Tamaño máximo ideal */
}

/* Price Display */
.price-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    margin: 1.5rem 0;
}

.currency {
    font-size: 2rem;
    font-weight: 600;
    margin-right: 0.25rem;
}

.price {
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
}

.update-time {
    font-size: 0.75rem;
    opacity: 0.9;
}

.location {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    justify-content: center;
    font-size: 0.875rem;
    opacity: 0.9;
}

/* Change Display */
.change-display {
    padding: 1rem 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex-grow: 1;
}

.change-amount {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.trend-icon {
    font-size: 1.5rem;
}

.change-status, .change-percent {
    text-align: center;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

.positive { color: var(--color-danger); }
.negative { color: var(--color-success); }
.neutral { color: var(--color-neutral); }

/* Chart Section */
.chart-card {
    margin-bottom: 1.5rem;
}

.chart-controls {
    display: flex;
    gap: 0.5rem;
}

.chart-btn {
    padding: 0.375rem 0.75rem;
    border: 1px solid var(--color-border);
    background: white;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

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

.chart-container {
    margin-top: 1.5rem;
    position: relative;
    height: 300px;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.25rem;
    text-align: center;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.stat-date {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

/* Info Section */
.info-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.info-card {
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem 0;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

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

/* Responsive */
@media (max-width: 768px) {
    .container { padding: 0.5rem; }
    .logo-text { font-size: 1.5rem; }
    .price { font-size: 3rem; }
    
    .cards-grid {
        flex-direction: column;
    }
    
    .cards-grid .card:not(.card-primary) {
        max-width: 100%;
    }

    .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

/* USD Button Styles */
.usd-button {
    display: inline-block;
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    padding: 1rem 2rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
    transition: all 0.3s ease;
}

.usd-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(16, 185, 129, 0.4);
    background: linear-gradient(135deg, #059669 0%, #047857 100%);
}

.usd-button:active {
    transform: translateY(0);
}