body {
    font-family: 'Arial', sans-serif;
    background-color: #f9f9f9;
    color: #333;
    text-align: center;
}

.container {
    margin: 20px auto;
    padding: 20px;
    border-radius: 10px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    max-width: 600px;
}

h1 {
    color: #e74c3c;
}

form {
    margin-bottom: 20px;
}

input[type="text"] {
    padding: 10px;
    font-size: 16px;
    border-radius: 5px;
    border: 1px solid #ccc;
    margin-right: 10px;
}

button {
    padding: 10px 20px;
    margin: 10px 5px;
    font-size: 16px;
    border-radius: 5px;
    border: none;
    color: #fff;
    background-color: #3498db;
    cursor: pointer;
}

button:hover {
    background-color: #2980b9;
}

#errorContainer {
    color: #e74c3c;
    margin: 20px 0;
}

#wordList {
    margin: 20px 0;
}

#wordList .word-item {
    display: inline-block;
    margin: 5px;
    padding: 5px 10px;
    background-color: #ecf0f1;
    border: 1px solid #bdc3c7;
    border-radius: 5px;
    position: relative;
    white-space: nowrap;
}

#wordList .word-item .remove-word {
    position: absolute;
    top: 0;
    right: -10px;
    cursor: pointer;
    color: #e74c3c;
    font-size: 16px;
    border: none;
    background: none;
}

#gridContainer {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 0;
    justify-content: center;
    margin-top: 20px;
}

.grid-item {
    padding: 20px;
    background-color: #ecf0f1;
    border: 1px solid #bdc3c7;
    font-size: 24px;
    font-weight: bold;
    text-align: center;
}

#printContent {
    margin-top: 20px;
}

#problemList {
    margin-top: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

#problemList .problem-row {
    display: flex;
    justify-content: center;
    width: 100%;
}

#problemList .problem-item {
    border: 1px solid #bdc3c7;
    padding: 10px;
    font-size: 24px;
    margin: 10px;
    background-color: #ecf0f1;
    border-radius: 10px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    flex: 1 0 30%;
    max-width: 30%;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
}

@media print {
    body {
        margin: 0;
    }
    .container {
        max-width: 100%;
        box-shadow: none;
        padding: 0;
    }
    #problemList .problem-item {
        font-size: 25px;
        margin: 5px;
        flex: 1 0 30%;
        max-width: 30%;
    }
}