/* Reset & Base */
:root {
    --bg-color: #f4f6f9;
    --text-color: #333;
    --sidebar-width: 250px;
    --header-height: 60px;
    --card-shadow: 0 4px 6px rgba(0,0,0,0.1);
    --transition-speed: 0.3s;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Layout */
.wrapper {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: var(--sidebar-width);
    background: var(--primary-color);
    color: #fff;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    transition: var(--transition-speed);
}

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

.sidebar-nav {
    flex: 1;
    padding: 20px 0;
}

.nav-link {
    display: block;
    padding: 12px 20px;
    color: rgba(255,255,255,0.8);
    text-decoration: none;
    transition: var(--transition-speed);
}

.nav-link:hover, .nav-link.active {
    background: rgba(255,255,255,0.1);
    color: #fff;
    border-left: 4px solid var(--accent-color);
}

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
}

.top-bar {
    height: var(--header-height);
    background: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.content-area {
    padding: 20px;
    flex: 1;
    overflow-y: auto;
}

/* Components */
.card {
    background: #fff;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    padding: 20px;
    margin-bottom: 20px;
}

.card-header {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 15px;
    border-bottom: 1px solid #eee;
    padding-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.btn {
    display: inline-block;
    padding: 8px 16px;
    border-radius: 4px;
    text-decoration: none;
    cursor: pointer;
    border: none;
    font-size: 0.9rem;
    transition: var(--transition-speed);
}

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

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

.btn-danger {
    background: #e74c3c;
    color: #fff;
}

.btn-success {
    background: #2ecc71;
    color: #fff;
}

/* Forms */
.form-group {
    margin-bottom: 15px;
}

.form-label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.form-control:focus {
    border-color: var(--primary-color);
    outline: none;
}

/* Tables */
.table {
    width: 100%;
    border-collapse: collapse;
}

.table th, .table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.table th {
    background-color: #f8f9fa;
    font-weight: 600;
}

/* Utilities */
.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mb-20 { margin-bottom: 20px; }
.flex { display: flex; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }
.gap-10 { gap: 10px; }

/* Login Page */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
}

.login-box {
    width: 400px;
    background: #fff;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

.login-title {
    text-align: center;
    margin-bottom: 30px;
    color: var(--primary-color);
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        z-index: 1000;
    }
    .sidebar.active {
        transform: translateX(0);
    }
    .main-content {
        margin-left: 0;
    }
}