:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --light-gray: #ecf0f1;
    --dark-gray: #34495e;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

/* Navigation */
.navbar {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar .logo {
    font-size: 1.5rem;
    font-weight: bold;
}

.navbar .nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.navbar .nav-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
}

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

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

/* Card */
.card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    padding: 2rem;
    margin-bottom: 2rem;
}

.card-header {
    border-bottom: 2px solid var(--light-gray);
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
}

.card-header h2 {
    color: var(--primary-color);
    margin: 0;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark-gray);
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="date"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
input[type="date"]:focus,
input[type="number"]:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}

textarea {
    resize: vertical;
    min-height: 100px;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

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

.btn-success:hover {
    background-color: #229954;
}

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

.btn-danger:hover {
    background-color: #c0392b;
}

.btn-secondary {
    background-color: var(--dark-gray);
    color: white;
    margin-left: 0.5rem;
}

.btn-secondary:hover {
    background-color: #2c3e50;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

table th {
    background-color: var(--light-gray);
    color: var(--dark-gray);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
}

table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid #ddd;
}

table tbody tr:hover {
    background-color: #f9f9f9;
}

/* Alerts */
.alert {
    padding: 1rem;
    margin-bottom: 1.5rem;
    border-radius: 4px;
    border-left: 4px solid;
}

.alert-success {
    background-color: #d4edda;
    border-color: var(--success-color);
    color: #155724;
}

.alert-danger {
    background-color: #f8d7da;
    border-color: var(--danger-color);
    color: #721c24;
}

.alert-warning {
    background-color: #fff3cd;
    border-color: var(--warning-color);
    color: #856404;
}

.alert-info {
    background-color: #d1ecf1;
    border-color: var(--secondary-color);
    color: #0c5460;
}

/* Headings */
h1, h2, h3, h4, h5, h6 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Top Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 3rem 2rem;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    color: white;
    margin-bottom: 0.5rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* Login Form */
.login-container {
    max-width: 400px;
    margin: 5rem auto;
}

.login-form {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    border-top: 4px solid var(--secondary-color);
}

.stat-card h3 {
    color: var(--dark-gray);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
}

.stat-card .number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--secondary-color);
}

/* Responsive */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
    }
    
    .navbar .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .hero h1 {
        font-size: 1.8rem;
    }
    
    .card {
        padding: 1rem;
    }
}