@import url('https://fonts.googleapis.com/css2?family=Nanum+Gothic&display=swap');

body {
    font-family: 'Nanum Gothic', sans-serif;
    background-color: #f0f8ff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    background-color: #ffffff;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 90%;
    max-width: 600px;
}

h1 {
    color: #333;
    font-size: 2em;
    margin-bottom: 20px;
}

#subject-selector {
    margin-bottom: 20px;
}

.subject-btn {
    background-color: #e0e0e0;
    border: none;
    border-radius: 20px;
    padding: 10px 20px;
    margin: 0 5px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s;
}

.subject-btn:hover {
    background-color: #d0d0d0;
}

.subject-btn.active {
    background-color: #4CAF50;
    color: white;
}

#sentence-container {
    background-color: #fafafa;
    border: 1px solid #ddd;
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 20px;
    min-height: 80px;
    display: flex;
    justify-content: center;
    align-items: center;
}

#sentence {
    font-size: 1.5em;
    color: #555;
    line-height: 1.6;
}

button {
    background-color: #4CAF50;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2em;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #45a049;
}

button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
}

#result-container {
    margin-top: 20px;
    text-align: left;
    background: #f9f9f9;
    padding: 15px;
    border-radius: 10px;
    border: 1px solid #eee;
}

#result-container p {
    font-size: 1.1em;
    margin: 10px 0;
}

#result {
    font-weight: bold;
}

#result.correct {
    color: #28a745;
}

#result.incorrect {
    color: #dc3545;
}

#next-btn {
    background-color: #008CBA;
    margin-top: 15px;
}

#next-btn:hover {
    background-color: #007B9A;
}