:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.1);
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    margin: 0;
    padding: 0;
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(16, 185, 129, 0.1) 0px, transparent 50%);
    background-attachment: fixed;
    min-height: 100vh;
}

.navbar {
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-main);
    text-decoration: none;
    background: linear-gradient(to right, #6366f1, #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s;
}

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

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.15), 0 4px 6px -2px rgba(0, 0, 0, 0.08);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    text-decoration: none;
    font-size: 0.875rem;
}

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

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

.table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.table th, .table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.table th {
    color: var(--text-muted);
    font-weight: 500;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

.table tr {
    transition: background-color 0.2s;
}

.table tbody tr:hover {
    background-color: rgba(255, 255, 255, 0.02);
}

.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    display: inline-block;
}

.badge-pending { background: rgba(245, 158, 11, 0.2); color: var(--warning); border: 1px solid rgba(245, 158, 11, 0.3); }
.badge-paid { background: rgba(16, 185, 129, 0.2); color: var(--success); border: 1px solid rgba(16, 185, 129, 0.3); }
.badge-overdue { background: rgba(239, 68, 68, 0.2); color: var(--danger); border: 1px solid rgba(239, 68, 68, 0.3); }

.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    box-sizing: border-box;
    padding: 0.75rem;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-main);
    transition: border-color 0.2s, box-shadow 0.2s;
    font-family: inherit;
    font-size: 0.95rem;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.25);
}

/* Print Specific Styles */
@media print {
    body {
        background: #ffffff !important;
        color: #000000 !important;
        background-image: none !important;
    }

    .navbar, .no-print, .btn, form {
        display: none !important;
    }

    .container {
        max-width: 100% !important;
        margin: 0 !important;
        padding: 0 !important;
    }

    .card {
        background: transparent !important;
        border: none !important;
        box-shadow: none !important;
        padding: 0 !important;
    }

    .invoice-sheet {
        background: #ffffff !important;
        color: #000000 !important;
        border: 1px solid #e2e8f0 !important;
        padding: 2rem !important;
    }

    .table th {
        color: #475569 !important;
        border-bottom: 2px solid #cbd5e1 !important;
    }

    .table td {
        border-bottom: 1px solid #e2e8f0 !important;
        color: #0f172a !important;
    }

    .badge-paid {
        background: #dcfce7 !important;
        color: #166534 !important;
        border: 1px solid #86efac !important;
    }

    .badge-pending {
        background: #fef3c7 !important;
        color: #92400e !important;
        border: 1px solid #fcd34d !important;
    }

    .badge-overdue {
        background: #fee2e2 !important;
        color: #991b1b !important;
        border: 1px solid #fca5a5 !important;
    }
}