:root {
    /* Color Palette */
    --primary: #4F46E5;
    --primary-hover: #4338CA;
    --secondary: #10B981;
    --danger: #EF4444;
    --warning: #F59E0B;
    --text-main: #111827;
    --text-muted: #6B7280;
    --bg-main: #F3F4F6;
    --bg-card: #FFFFFF;
    --border-color: #E5E7EB;
    
    /* Layout & Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.3);
    --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-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

[data-theme="dark"] {
    --primary: #6366F1;
    --primary-hover: #818CF8;
    --text-main: #F9FAFB;
    --text-muted: #9CA3AF;
    --bg-main: #111827;
    --bg-card: #1F2937;
    --border-color: #374151;
    --glass-bg: rgba(31, 41, 55, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-main);
    color: var(--text-main);
    transition: background-color 0.3s, color 0.3s;
    line-height: 1.5;
}

/* Navbar */
.navbar {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.brand {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-item {
    cursor: pointer;
    font-weight: 500;
    color: var(--text-muted);
    transition: color 0.2s;
}

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

.controls {
    display: flex;
    gap: 1rem;
    align-items: center;
}

/* Buttons */
.btn {
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    border: none;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

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

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
}
.btn-outline:hover { background: var(--border-color); }

/* Layout */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 2rem;
}

/* Cards */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s, box-shadow 0.2s;
}
.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* View Container */
.view-section {
    display: none;
    animation: fadeIn 0.4s ease-out;
}
.view-section.active {
    display: block;
}

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

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}
.stat-title {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
}
.stat-value {
    font-size: 2rem;
    font-weight: 700;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}
table {
    width: 100%;
    border-collapse: collapse;
}
th, td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}
th {
    font-weight: 600;
    color: var(--text-muted);
    background: rgba(0,0,0,0.02);
}
[data-theme="dark"] th {
    background: rgba(255,255,255,0.02);
}

/* Badges */
.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
}
.badge-success { background: rgba(16, 185, 129, 0.1); color: var(--secondary); }
.badge-warning { background: rgba(245, 158, 11, 0.1); color: var(--warning); }
.badge-danger { background: rgba(239, 68, 68, 0.1); color: var(--danger); }
.badge-primary { background: rgba(79, 70, 229, 0.1); color: var(--primary); }

/* Modal */
.modal-backdrop {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 100;
}
.modal-backdrop.active { display: flex; }
.modal {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    animation: scaleIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}
@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* Forms */
.form-group { margin-bottom: 1rem; }
.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}
.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-main);
    color: var(--text-main);
    font-family: inherit;
}
.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Canvas */
.signature-pad {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: white;
    cursor: crosshair;
    touch-action: none;
}