:root {
    --primary-color: #2D6A4F;
    --secondary-color: #40916C;
    --background-color: #F8F9FA;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.1);
    --border-radius: 12px;
}

body {
    background-color: var(--background-color);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

.container {
    max-width: 800px;
    padding: 20px;
}

.navbar {
    background-color: var(--primary-color) !important;
    border-radius: var(--border-radius);
    padding: 15px 20px;
    margin-bottom: 2rem;
}

.navbar-brand {
    color: white !important;
    margin-bottom: 1rem;
}

.nav-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
}

.nav-button {
    display: block;
    width: 100%;
    padding: 12px;
    text-align: center;
    color: white !important;
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: all 0.2s ease;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.nav-button:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.nav-button.active {
    background-color: white;
    color: var(--primary-color) !important;
    font-weight: 600;
}

.card {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    border: none;
    margin-bottom: 1.5rem;
}

.add-word-form {
    background-color: white;
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    margin-bottom: 2rem;
}

.words-list, .learned-words {
    background-color: white;
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
}

h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.form-control {
    border-radius: 8px;
    padding: 12px;
    border: 1px solid #E2E8F0;
}

.form-control:focus {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 2px rgba(64, 145, 108, 0.2);
}

.btn {
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.2s ease;
}

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

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

.btn-learned {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 16px;
    font-size: 0.9rem;
}

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

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .table {
        font-size: 0.9rem;
    }
}