/* ========================================
   Hyperinflation Banknote Visualizer
   Global Styles
   ======================================== */

/* CSS Variables */
:root {
    /* Colors */
    --color-bg: #0f0f0f;
    --color-bg-secondary: #1a1a1a;
    --color-bg-tertiary: #242424;
    --color-text: #f5f5f5;
    --color-text-secondary: #a0a0a0;
    --color-text-muted: #666;
    --color-primary: #d4af37;
    --color-primary-hover: #e5c654;
    --color-accent: #c9302c;
    --color-border: #333;
    --color-card-bg: #1a1a1a;
    --color-card-hover: #222;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Playfair Display', Georgia, serif;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.4);

    /* Layout */
    --container-max: 1400px;
    --header-height: 80px;
}

/* Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-hover);
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ========================================
   Header
   ======================================== */
.header {
    background: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-lg) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-lg);
}

.logo h1 {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    font-size: 0.9375rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-primary:hover {
    background: var(--color-primary-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--color-bg-tertiary);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

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

/* ========================================
   Filters
   ======================================== */
.filters {
    background: var(--color-bg-secondary);
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--color-border);
}

.filter-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

.search-box {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    flex: 1;
    max-width: 400px;
}

.search-box svg {
    color: var(--color-text-muted);
    flex-shrink: 0;
}

.search-box input {
    flex: 1;
    background: none;
    border: none;
    color: var(--color-text);
    font-size: 0.9375rem;
    outline: none;
}

.search-box input::placeholder {
    color: var(--color-text-muted);
}

.filter-buttons {
    display: flex;
    gap: var(--space-sm);
}

.filter-select {
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    color: var(--color-text);
    font-size: 0.875rem;
    cursor: pointer;
    outline: none;
}

.filter-select:focus {
    border-color: var(--color-primary);
}

/* ========================================
   Stats Bar
   ======================================== */
.stats-bar {
    background: linear-gradient(135deg, var(--color-bg-secondary), var(--color-bg-tertiary));
    padding: var(--space-xl) 0;
    border-bottom: 1px solid var(--color-border);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
}

.stat-item {
    text-align: center;
}

.stat-value {
    display: block;
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.stat-label {
    display: block;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-top: var(--space-xs);
}

/* ========================================
   Main Content
   ======================================== */
.main-content {
    padding: var(--space-2xl) 0;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.section-header .section-title {
    margin-bottom: 0;
}

.section-title {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: var(--space-xl);
    color: var(--color-text);
}

.featured-section {
    margin-bottom: var(--space-3xl);
}

/* ========================================
   Cards Grid
   ======================================== */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--space-xl);
}

.featured-grid {
    grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
}

/* Period Card */
.period-card {
    background: var(--color-card-bg);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
    cursor: pointer;
}

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

.card-image {
    position: relative;
    height: 200px;
    overflow: hidden;
    background: var(--color-bg-tertiary);
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.period-card:hover .card-image img {
    transform: scale(1.05);
}

.card-badge {
    position: absolute;
    top: var(--space-sm);
    right: var(--space-sm);
    background: var(--color-accent);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
}

.card-badge:empty {
    display: none;
}

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

.card-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.card-flag {
    width: 40px;
    height: 30px;
    border-radius: var(--radius-sm);
    object-fit: cover;
    box-shadow: var(--shadow-sm);
}

.card-title-group {
    flex: 1;
}

.card-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 2px;
}

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

.card-stats {
    display: flex;
    gap: var(--space-lg);
    margin-bottom: var(--space-md);
    padding: var(--space-md) 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.card-stat {
    flex: 1;
}

.card-stat-value {
    display: block;
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-primary);
}

.card-stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--color-text-muted);
    margin-top: 2px;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.card-link {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-primary);
}

.card-link:hover {
    color: var(--color-primary-hover);
}

/* No Results */
.no-results {
    text-align: center;
    padding: var(--space-3xl);
    color: var(--color-text-secondary);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: var(--space-xl) 0;
    margin-top: var(--space-3xl);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

.footer-info p {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.footer-disclaimer {
    font-size: 0.75rem !important;
    color: var(--color-text-muted) !important;
    margin-top: var(--space-xs);
}

.footer-links a {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    color: var(--color-text-secondary);
}

.footer-links a:hover {
    color: var(--color-text);
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 1024px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .featured-grid {
        grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    }
}

@media (max-width: 768px) {
    :root {
        --header-height: 60px;
    }

    .header-content {
        flex-direction: column;
        text-align: center;
    }

    .logo h1 {
        font-size: 1.5rem;
    }

    .filter-bar {
        flex-direction: column;
    }

    .search-box {
        max-width: 100%;
        width: 100%;
    }

    .filter-buttons {
        width: 100%;
        justify-content: center;
    }

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

    .stat-value {
        font-size: 1.75rem;
    }

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

    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }

    .filter-buttons {
        flex-direction: column;
    }

    .filter-select {
        width: 100%;
    }
}

/* ========================================
   Utility Classes
   ======================================== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.loading {
    opacity: 0.5;
    pointer-events: none;
}

/* ========================================
   Animations
   ======================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.period-card {
    animation: fadeIn var(--transition-base) ease-out;
}