/* Invoice Application - Design System */

:root {
    /* Color Palette - Modern Dark Theme */
    --bg-primary: #0f0f14;
    --bg-secondary: #1a1a24;
    --bg-tertiary: #252532;
    --bg-card: rgba(30, 30, 45, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.05);
    
    /* Accent Colors */
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --accent-success: #22c55e;
    --accent-warning: #f59e0b;
    --accent-error: #ef4444;
    
    /* Text Colors */
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    /* Borders */
    --border-subtle: rgba(255, 255, 255, 0.08);
    --border-glass: rgba(255, 255, 255, 0.12);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Background Effects */
.bg-pattern {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(ellipse at top left, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at bottom right, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.25;
    color: var(--text-primary);
}

h1 { font-size: 2.5rem; letter-spacing: -0.025em; }
h2 { font-size: 2rem; letter-spacing: -0.02em; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

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

a:hover {
    color: var(--accent-secondary);
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.container-sm {
    max-width: 640px;
}

.container-lg {
    max-width: 1400px;
}

/* Glass Card Effect */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

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

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

.card-glow {
    position: relative;
}

.card-glow::before {
    content: '';
    position: absolute;
    inset: -1px;
    border-radius: inherit;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity var(--transition-base);
    z-index: -1;
}

.card-glow:hover::before {
    opacity: 0.2;
}

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

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: var(--shadow-sm), 0 4px 16px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), 0 8px 24px rgba(99, 102, 241, 0.4);
}

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

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

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
}

.btn-ghost:hover {
    background: var(--bg-glass);
    color: var(--text-primary);
}

.btn-lg {
    padding: var(--space-md) var(--space-xl);
    font-size: 1rem;
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
}

/* Forms */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--space-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-input {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    font-family: inherit;
    font-size: 1rem;
    color: var(--text-primary);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

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

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-lg);
}

.stat-card {
    padding: var(--space-lg);
    background: var(--bg-glass);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
}

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

.stat-change {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: 0.8125rem;
    margin-top: var(--space-sm);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
}

.stat-change.positive {
    color: var(--accent-success);
    background: rgba(34, 197, 94, 0.1);
}

.stat-change.negative {
    color: var(--accent-error);
    background: rgba(239, 68, 68, 0.1);
}

/* Tables */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
}

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

th, td {
    padding: var(--space-md);
    text-align: left;
}

th {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-subtle);
}

td {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-subtle);
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background: var(--bg-glass);
}

/* Badge */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-xs) var(--space-sm);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: var(--radius-full);
}

.badge-primary {
    background: rgba(99, 102, 241, 0.15);
    color: #a5b4fc;
}

.badge-success {
    background: rgba(34, 197, 94, 0.15);
    color: #86efac;
}

.badge-warning {
    background: rgba(245, 158, 11, 0.15);
    color: #fcd34d;
}

/* Progress Bar */
.progress {
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

/* Chart Container */
.chart-container {
    position: relative;
    height: 300px;
    width: 100%;
}

/* Navbar */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    padding: var(--space-md) 0;
    background: rgba(15, 15, 20, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-subtle);
}

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

.navbar-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.navbar-nav {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    list-style: none;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
    color: var(--text-primary);
}

/* Hero Section */
.hero {
    padding: var(--space-2xl) 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto var(--space-xl);
}

/* Steps */
.steps {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.step {
    display: flex;
    gap: var(--space-lg);
    padding: var(--space-lg);
    background: var(--bg-glass);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    transition: all var(--transition-base);
}

.step:hover {
    border-color: var(--accent-primary);
}

.step-number {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-full);
}

.step-content h4 {
    margin-bottom: var(--space-xs);
}

.step-content p {
    margin-bottom: 0;
    font-size: 0.9375rem;
}

.step.completed .step-number {
    background: var(--accent-success);
    color: white;
}

.step.active .step-number {
    background: var(--accent-gradient);
    color: white;
}

/* Utilities */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-muted { color: var(--text-muted); }
.text-success { color: var(--accent-success); }
.text-warning { color: var(--accent-warning); }
.text-error { color: var(--accent-error); }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }

.grid { display: grid; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.animate-fade-in {
    animation: fadeIn var(--transition-base) ease-out;
}

.animate-slide-up {
    animation: slideUp var(--transition-slow) ease-out;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

/* Responsive */
@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }
    
    .hero h1 { font-size: 2.25rem; }
    .hero p { font-size: 1rem; }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .grid-2, .grid-3 {
        grid-template-columns: 1fr;
    }
    
    .navbar-nav {
        display: none;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .card {
        padding: var(--space-lg);
    }
}