:root {
    --primary: #2c3e50;
    --secondary: #34495e;
    --accent: #3498db;
    --success: #27ae60;
    --danger: #e74c3c;
    --light: #f4f7f6;
    --text: #333;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--light);
    color: var(--text);
    margin: 0;
    display: flex;
}

/* Simple Sidebar Layout */
.sidebar {
    width: 250px;
    background: var(--primary);
    min-height: 100vh;
    color: white;
    padding-top: 20px;
}

.sidebar a {
    display: block;
    color: #bdc3c7;
    padding: 15px 25px;
    text-decoration: none;
    transition: 0.3s;
}

.sidebar a:hover {
    background: var(--secondary);
    color: white;
}

/* Main Content Area */
.main-content {
    flex: 1;
    padding: 40px;
}

.card {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

/* Professional Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th {
    background: var(--secondary);
    color: white;
    text-align: left;
    padding: 12px;
}

td {
    padding: 12px;
    border-bottom: 1px solid #ddd;
}

tr:hover {
    background-color: #f1f1f1;
}

/* Modern Forms & Buttons */
input, select {
    width: 100%;
    padding: 10px;
    margin: 8px 0;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
}

button, .btn {
    background: var(--accent);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
}

button:hover { background: #2980b9; }
.btn-danger { background: var(--danger); }