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

/* ===================================
   CSS CUSTOM PROPERTIES
   =================================== */
:root {
    /* Colors - Vibrant Dark Theme */
    --color-bg-primary: #0a0a0f;
    --color-bg-secondary: #13131a;
    --color-bg-tertiary: #1a1a24;
    --color-bg-card: rgba(26, 26, 36, 0.6);
    --color-bg-card-hover: rgba(26, 26, 36, 0.8);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #8B5CF6 0%, #3B82F6 100%);
    --gradient-secondary: linear-gradient(135deg, #06B6D4 0%, #3B82F6 100%);
    --gradient-success: linear-gradient(135deg, #10B981 0%, #059669 100%);
    --gradient-warning: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
    --gradient-danger: linear-gradient(135deg, #EF4444 0%, #DC2626 100%);
    --gradient-overlay: linear-gradient(180deg, rgba(139, 92, 246, 0.1) 0%, rgba(59, 130, 246, 0.05) 100%);

    /* Text Colors */
    --color-text-primary: #F9FAFB;
    --color-text-secondary: #D1D5DB;
    --color-text-tertiary: #9CA3AF;
    --color-text-muted: #6B7280;

    /* Accent Colors */
    --color-primary: #8B5CF6;
    --color-primary-light: #A78BFA;
    --color-primary-dark: #7C3AED;
    --color-secondary: #3B82F6;
    --color-success: #10B981;
    --color-warning: #F59E0B;
    --color-danger: #EF4444;
    --color-info: #06B6D4;

    /* Status Colors */
    --color-draft: #6B7280;
    --color-sent: #3B82F6;
    --color-paid: #10B981;
    --color-overdue: #EF4444;

    /* Border & Divider */
    --color-border: rgba(255, 255, 255, 0.1);
    --color-border-light: rgba(255, 255, 255, 0.05);
    --color-divider: rgba(255, 255, 255, 0.08);

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 10px 10px -5px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(139, 92, 246, 0.3);

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

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Layout */
    --sidebar-width: 260px;
    --header-height: 70px;
}

/* ===================================
   BASE STYLES
   =================================== */
body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at 20% 50%, rgba(139, 92, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(59, 130, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(6, 182, 212, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
    animation: backgroundPulse 15s ease-in-out infinite;
}

@keyframes backgroundPulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.7;
    }
}

/* ===================================
   LAYOUT
   =================================== */
.app-container {
    display: flex;
    min-height: 100vh;
    position: relative;
    z-index: 1;
}

/* ===================================
   SIDEBAR
   =================================== */
.sidebar {
    width: var(--sidebar-width);
    background: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
    padding: var(--spacing-xl) 0;
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    overflow-y: auto;
    backdrop-filter: blur(10px);
    z-index: 100;
    transition: transform var(--transition-base);
}

.sidebar-header {
    padding: 0 var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.logo h1 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: 0 var(--spacing-md);
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--color-text-secondary);
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.nav-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.nav-item svg {
    position: relative;
    z-index: 1;
    transition: transform var(--transition-base);
}

.nav-item span {
    position: relative;
    z-index: 1;
    font-weight: 500;
}

.nav-item:hover {
    color: var(--color-text-primary);
    background: rgba(139, 92, 246, 0.1);
    transform: translateX(4px);
}

.nav-item:hover svg {
    transform: scale(1.1);
}

.nav-item.active {
    color: var(--color-text-primary);
    background: rgba(139, 92, 246, 0.15);
    box-shadow: var(--shadow-glow);
}

.nav-item.active::before {
    opacity: 0.1;
}

/* ===================================
   MAIN CONTENT
   =================================== */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    min-height: 100vh;
}

.content-wrapper {
    padding: var(--spacing-2xl);
    max-width: 1400px;
    margin: 0 auto;
}

/* ===================================
   CARDS & GLASSMORPHISM
   =================================== */
.card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.card:hover {
    background: var(--color-bg-card-hover);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-divider);
}

.card-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

.card-body {
    color: var(--color-text-secondary);
}

/* ===================================
   STATS CARDS
   =================================== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.stat-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    transition: all var(--transition-base);
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-overlay);
    opacity: 0;
    transition: opacity var(--transition-base);
}

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

.stat-card:hover::before {
    opacity: 1;
}

.stat-card-content {
    position: relative;
    z-index: 1;
}

.stat-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
}

.stat-card-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    box-shadow: var(--shadow-glow);
}

.stat-card-icon svg {
    width: 24px;
    height: 24px;
    color: white;
}

.stat-card-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.stat-card-value {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--color-text-primary);
    margin: var(--spacing-sm) 0;
    line-height: 1;
}

.stat-card-trend {
    font-size: var(--font-size-sm);
    color: var(--color-success);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

/* ===================================
   BUTTONS
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width var(--transition-slow), height var(--transition-slow);
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    transform: translateY(-2px);
}

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

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

.btn-success {
    background: var(--gradient-success);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-danger {
    background: var(--gradient-danger);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
}

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

.btn-ghost-danger:hover {
    background: rgba(239, 68, 68, 0.1);
    color: var(--color-danger);
}

.btn-icon {
    padding: var(--spacing-md);
    width: 44px;
    height: 44px;
    flex-shrink: 0;
}

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

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--spacing-md);
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    color: var(--color-text-primary);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 100px;
}

/* ===================================
   TABLE
   =================================== */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-border);
}

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

.table thead {
    background: var(--color-bg-tertiary);
}

.table th {
    padding: var(--spacing-md) var(--spacing-lg);
    text-align: left;
    font-size: var(--font-size-sm);
    font-weight: 700;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--color-border);
}

.table td {
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--color-text-secondary);
    border-bottom: 1px solid var(--color-border-light);
}

.table tbody tr {
    transition: background var(--transition-fast);
}

.table tbody tr:hover {
    background: var(--color-bg-tertiary);
}

/* ===================================
   BADGES
   =================================== */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-full);
}

.badge-draft {
    background: rgba(107, 114, 128, 0.2);
    color: var(--color-draft);
}

.badge-sent {
    background: rgba(59, 130, 246, 0.2);
    color: var(--color-sent);
}

.badge-paid {
    background: rgba(16, 185, 129, 0.2);
    color: var(--color-paid);
}

.badge-overdue {
    background: rgba(239, 68, 68, 0.2);
    color: var(--color-overdue);
}

/* ===================================
   MODAL
   =================================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-base);
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.modal {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-2xl);
    max-width: 900px;
    width: 95%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    transform: scale(0.9);
    transition: transform var(--transition-base);
}

.modal-overlay.active .modal {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xl);
    border-bottom: 1px solid var(--color-divider);
}

.modal-header h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

.modal-close {
    background: none;
    border: none;
    color: var(--color-text-tertiary);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.modal-close:hover {
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
}

.modal-body {
    padding: var(--spacing-xl);
}

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

.text-right {
    text-align: right;
}

.mt-1 {
    margin-top: var(--spacing-md);
}

.mt-2 {
    margin-top: var(--spacing-lg);
}

.mb-1 {
    margin-bottom: var(--spacing-md);
}

.mb-2 {
    margin-bottom: var(--spacing-lg);
}

.flex {
    display: flex;
}

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

.gap-1 {
    gap: var(--spacing-md);
}

.gap-2 {
    gap: var(--spacing-lg);
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* ===================================
   RESPONSIVE
   =================================== */
@media (max-width: 768px) {
    :root {
        --sidebar-width: 0;
    }

    .sidebar {
        transform: translateX(-100%);
    }

    .main-content {
        margin-left: 0;
    }

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

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

/* Image Upload Modernization */
.image-upload-box {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    background: rgba(0, 0, 0, 0.02);
    position: relative;
    overflow: hidden;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.image-upload-box:hover {
    border-color: var(--color-primary);
    background: rgba(139, 92, 246, 0.05);
}

.upload-icon {
    width: 48px;
    height: 48px;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
    transition: transform var(--transition-base);
}

.image-upload-box:hover .upload-icon {
    transform: scale(1.1);
    color: var(--color-primary);
}

.upload-text {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

.upload-preview-image {
    max-width: 100%;
    max-height: 150px;
    object-fit: contain;
    border-radius: var(--radius-md);
}

.upload-actions {
    margin-top: var(--spacing-md);
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
}