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

body {
    font-family: 'Arial', sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
    background-color: white;
    min-height: 100vh;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

h1 {
    text-align: center;
    margin-bottom: 30px;
    color: #2c3e50;
    font-size: 2.5em;
}

.menu {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.menu-item {
    padding: 12px 20px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    position: relative;
    transition: background-color 0.3s;
}

.menu-item.active {
    background-color: #2980b9;
    font-weight: bold;
}

.menu-item.disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

.menu-item:not(.disabled):hover {
    background-color: #2980b9;
}

.pending {
    font-size: 12px;
    display: block;
    margin-top: 5px;
    color: #7f8c8d;
}

.exercise-container {
    text-align: center;
    padding: 20px;
}

.exercise-container h2 {
    color: #2c3e50;
    margin-bottom: 10px;
    font-size: 1.8em;
}

.instructions {
    color: #7f8c8d;
    margin-bottom: 20px;
    font-size: 1.1em;
}

.words-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    min-height: 80px;
    margin: 30px 0;
    padding: 20px;
    border: 2px dashed #3498db;
    border-radius: 10px;
    background-color: #ecf0f1;
}

.word-item {
    padding: 12px 16px;
    background-color: #3498db;
    color: white;
    border-radius: 5px;
    cursor: move;
    user-select: none;
    transition: transform 0.2s, background-color 0.2s;
    min-width: 60px;
    text-align: center;
}

.word-item:hover {
    background-color: #2980b9;
    transform: scale(1.05);
}

.word-item.dragging {
    opacity: 0.7;
    transform: scale(0.95);
}

.actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 20px 0;
}

.btn-check, .btn-next {
    padding: 12px 25px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

.btn-check {
    background-color: #2ecc71;
    color: white;
}

.btn-check:hover {
    background-color: #27ae60;
}

.btn-next {
    background-color: #e74c3c;
    color: white;
}

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

.result {
    margin-top: 20px;
    padding: 15px;
    border-radius: 5px;
    font-weight: bold;
    min-height: 25px;
}

.result.correct {
    background-color: #d5f5e3;
    color: #27ae60;
    border: 1px solid #2ecc71;
}

.result.incorrect {
    background-color: #fadbd8;
    color: #c0392b;
    border: 1px solid #e74c3c;
}

.drag-over {
    background-color: #d6eaf8;
    border-style: solid;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 2em;
    }
    
    .menu {
        flex-direction: column;
        align-items: center;
    }
    
    .menu-item {
        width: 80%;
        max-width: 300px;
    }
    
    .actions {
        flex-direction: column;
        align-items: center;
    }
    
    .btn-check, .btn-next {
        width: 80%;
        max-width: 200px;
    }
}