:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #ff6b6b;
    --success-color: #4CAF50;
    --warning-color: #FF9800;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-muted: #666666;
    --border-color: #e0e0e0;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #1a1a1a;
        --card-bg: #2d2d2d;
        --text-color: #e0e0e0;
        --text-muted: #b0b0b0;
        --border-color: #444444;
    }
}

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

body {
    font-family: 'Roboto', sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
}

.navbar {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar .logo {
    font-size: 1.5rem;
    font-weight: 700;
}

.navbar .user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: white;
    margin: 3px 0;
    transition: 300ms;
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--primary-color);
    flex-direction: column;
    padding: 1rem 0;
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
    z-index: 1000;
}

.mobile-menu.show {
    display: flex;
}

.mobile-menu a {
    color: white;
    text-decoration: none;
    padding: 0.75rem 2rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: background-color 0.3s;
}

.mobile-menu a:hover, .mobile-menu a.active {
    background: rgba(255,255,255,0.1);
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.nav-tabs {
    display: flex;
    background: var(--card-bg);
    border-radius: 8px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.nav-tab {
    flex: 1;
    padding: 1rem;
    text-align: center;
    text-decoration: none;
    color: var(--text-color);
    border-radius: 8px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.nav-tab:hover, .nav-tab.active {
    background: var(--primary-color);
    color: white;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: 500;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
}

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

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

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

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

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

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

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
}

.modal-content {
    background: var(--card-bg);
    margin: 5% auto;
    padding: 2rem;
    border-radius: 10px;
    width: 90%;
    max-width: 500px;
    position: relative;
}

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background: var(--bg-color);
    color: var(--text-color);
}

.form-group textarea {
    min-height: 80px;
    resize: vertical;
}

@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .user-info {
        display: none;
    }

    .navbar {
        padding: 1rem;
    }

    .navbar .logo {
        font-size: 1.2rem;
    }

    .nav-tabs {
        display: none;
    }

    .container {
        padding: 0 0.5rem;
    }

    .page-header {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
}