:root {
    --primary: #007bff;
    --primary-hover: #0056b3;
    --bg-color: #f4f6f9;
    --sidebar-bg: #2c3e50;
    --sidebar-hover: #34495e;
    --text-color: #333;
    --text-light: #ecf0f1;
    --border-color: #dee2e6;
    --card-bg: #ffffff;
}

body {
    margin: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    color: var(--text-light);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    transition: all 0.3s ease;
}

.sidebar-header {
    padding: 20px;
    font-size: 1.5rem;
    font-weight: bold;
    text-align: center;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    letter-spacing: 1px;
}

.sidebar-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    flex-grow: 1;
}

.sidebar-menu li {
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.sidebar-menu a {
    display: block;
    padding: 15px 20px;
    color: var(--text-light);
    text-decoration: none;
    transition: background 0.3s;
}

.sidebar-menu a:hover, .sidebar-menu a.active {
    background-color: var(--sidebar-hover);
    border-left: 4px solid var(--primary);
}

.sidebar-footer {
    padding: 20px;
    text-align: center;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.sidebar-footer a {
    color: #e74c3c;
    text-decoration: none;
    font-weight: bold;
}

/* Main Content */
.main-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    overflow-x: hidden;
}

.topbar {
    background: var(--card-bg);
    padding: 15px 30px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.topbar h1 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--text-color);
}

.content-wrapper {
    padding: 30px;
    overflow-y: auto;
}

/* Card */
.card {
    background: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    padding: 20px;
    margin-bottom: 20px;
}

/* Forms & Inputs */
input[type="text"], input[type="number"], input[type="email"], input[type="password"], select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    box-sizing: border-box;
}
input:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 0.2rem rgba(0,123,255,.25);
}

/* Buttons */
.btn {
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    display: inline-block;
}
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-danger { background: #dc3545; color: white; }
.btn-danger:hover { background: #c82333; }
.btn-success { background: #28a745; color: white; }
.btn-success:hover { background: #218838; }
.btn:disabled { opacity: 0.6; cursor: not-allowed; }

/* Tables */
.table-responsive {
    overflow-x: auto;
    width: 100%;
}
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
    background-color: transparent;
}
th, td {
    padding: 12px;
    vertical-align: top;
    border-top: 1px solid var(--border-color);
    text-align: left;
}
th {
    background-color: #f8f9fa;
    border-bottom: 2px solid var(--border-color);
    font-weight: 600;
}
.text-center { text-align: center; }

/* Status Badges */
.badge {
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: bold;
}
.badge-success { background: #d4edda; color: #155724; }
.badge-danger { background: #f8d7da; color: #721c24; }

/* Stock Table Colors */
td.has-stock { background-color: #d4edda; color: #155724; font-weight: bold; }
td.out-of-stock { background-color: #f8d7da; color: #721c24; }

/* Responsive */
@media (max-width: 768px) {
    body { flex-direction: column; }
    .sidebar { width: 100%; flex-direction: row; flex-wrap: wrap; justify-content: space-between; align-items: center; }
    .sidebar-header { padding: 10px; border-bottom: none; width: auto; }
    .sidebar-menu { display: flex; overflow-x: auto; flex-grow: 1; margin: 0; padding: 0 10px; }
    .sidebar-menu li { border: none; }
    .sidebar-menu a { padding: 10px; font-size: 14px; white-space: nowrap; }
    .sidebar-footer { padding: 10px; border-top: none; }
    .topbar { padding: 10px 15px; }
    .content-wrapper { padding: 15px; }
}