:root {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --border-color: #333;
    --input-bg: #1e1e1e;
    --button-bg: #007bff;
    --button-hover-bg: #0056b3;
    --success-color: #28a745;
    --error-color: #dc3545;
}
body {
    font-family: Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
}
.container {
    width: 100%;
    max-width: 900px;
    padding: 20px;
    background-color: #1e1e1e;
    border-radius: 8px;
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.5);
}
h1 {
    text-align: center;
    color: #ffffff;
    margin-bottom: 20px;
}
textarea, #outputJson {
    width: 100%;
    min-height: 150px;
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
    box-sizing: border-box;
    font-family: 'Courier New', Courier, monospace;
    resize: vertical;
}
.options {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    justify-content: center;
}
.options button {
    padding: 10px 20px;
    font-size: 16px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background-color: var(--button-bg);
    color: #fff;
    transition: background-color 0.3s;
}
.options button:hover {
    background-color: var(--button-hover-bg);
}
.output-section {
    margin-top: 20px;
}
.output-section h2 {
    margin-bottom: 10px;
    text-align: center;
    color: #e0e0e0;
}
.output-box {
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    padding: 15px;
    border-radius: 5px;
    min-height: 50px;
    overflow-x: auto;
    position: relative;
}
.copy-btn {
    padding: 5px 10px;
    background-color: var(--button-bg);
    color: white;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    font-size: 12px;
    display: none; /* Mặc định ẩn, sẽ hiển thị khi set 'block' */
}
.copy-btn[style*="display: block"] {
    display: block !important; /* Đảm bảo hiển thị khi JavaScript set */
}
.status-message {
    text-align: center;
    margin-top: 10px;
    font-weight: bold;
}
@media (max-width: 600px) {
    .container {
        padding: 10px;
    }
    .options {
        flex-direction: column;
        gap: 10px;
    }
    .options button {
        padding: 12px 24px;
        font-size: 18px;
    }
    textarea, #outputJson {
        min-height: 120px;
    }
}