/* Core Color Variables */
:root {
    --primary: #1e3a8a;
    --primary-hover: #1d4ed8;
    --accent: #16a34a;
    --dark: #0f172a;
    --light: #f8fafc;
    --gray-border: #cbd5e1;
    --text-muted: #64748b;
    --card-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.6;
}

/* Layout Containers */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Navigation Header */
.navbar {
    background: #ffffff;
    border-bottom: 1px solid var(--gray-border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--dark);
    text-decoration: none;
}

.navbar-brand span {
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
    list-style: none;
}

.nav-links a {
    color: var(--dark);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s;
}

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

.cart-badge {
    background: var(--primary);
    color: white;
    padding: 0.2rem 0.6rem;
    border-radius: 999px;
    font-size: 0.8rem;
    margin-left: 0.3rem;
}

/* Data Tables */
.table-container {
    overflow-x: auto;
    background: #ffffff;
    border-radius: 8px;
    border: 1px solid var(--gray-border);
    box-shadow: var(--card-shadow);
    margin: 1.5rem 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

th, td {
    padding: 1rem;
    border-bottom: 1px solid var(--gray-border);
}

th {
    background: #f1f5f9;
    color: var(--dark);
    font-weight: 700;
}

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

/* Forms & UI Controls */
.form-card {
    background: #ffffff;
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--gray-border);
    box-shadow: var(--card-shadow);
    max-width: 600px;
    margin: 2rem auto;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.form-group input, 
.form-group select, 
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--gray-border);
    border-radius: 6px;
    font-size: 1rem;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    border: none;
    background: var(--primary);
    color: #ffffff;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.2s;
}

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

/* Printable Invoice Styles */
@media print {
    body {
        background: #ffffff;
        color: #000000;
    }
    .navbar, .btn, footer, .no-print {
        display: none !important;
    }
    .container, .form-card, .table-container {
        box-shadow: none !important;
        border: none !important;
        width: 100% !important;
        max-width: 100% !important;
        margin: 0 !important;
        padding: 0 !important;
    }
}