.htg-container {
    max-width: 800px;
    margin: 20px 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
.htg-form {
    background: #f9f9f9;
    padding: 25px;
    border-radius: 8px;
    border: 1px solid #ddd;
}
.htg-field {
    margin-bottom: 15px;
}
.htg-field label {
    display: block;
    font-weight: 600;
    margin-bottom: 5px;
}
.htg-field input,
.htg-field select {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
}
.htg-field input[type="text"] {
    max-width: 400px;
}
.htg-field textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
    font-family: monospace;
    font-size: 14px;
    resize: vertical;
}
.htg-field small {
    display: block;
    color: #666;
    margin-top: 4px;
    font-size: 12px;
}
.htg-field select optgroup {
    font-style: normal;
    font-weight: 700;
    color: #555;
    background: #f0f0f0;
}
#htg-dynamic-fields .htg-field {
    display: none;
}
#htg-dynamic-fields .htg-field.active {
    display: block;
}
.htg-no-fields {
    color: #666;
    font-style: italic;
    margin-bottom: 15px;
}
.htg-buttons {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}
.htg-button {
    background: #0073aa;
    color: #fff;
    border: none;
    padding: 12px 30px;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.2s;
}
.htg-button:hover {
    background: #005a87;
}
.htg-reset-btn {
    background: #6c757d;
}
.htg-reset-btn:hover {
    background: #5a6268;
}
.htg-download-btn {
    background: #28a745;
}
.htg-download-btn:hover {
    background: #218838;
}
#htg-result {
    margin-top: 25px;
    background: #f0f7ff;
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid #0073aa;
}
#htg-rule-box {
    background: #1e1e1e;
    color: #d4d4d4;
    padding: 15px;
    border-radius: 6px;
    position: relative;
}
#htg-rule-code {
    margin: 0;
    white-space: pre-wrap;
    word-break: break-all;
    font-family: "Courier New", monospace;
    font-size: 14px;
    line-height: 1.6;
}
.htg-result-buttons {
    margin-top: 12px;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}
#htg-copy {
    background: #2c3e50;
}
#htg-copy:hover {
    background: #1a252f;
}
#htg-explanation {
    margin-top: 15px;
    padding: 12px;
    background: #fff;
    border-radius: 4px;
    border: 1px solid #cce5ff;
    color: #004085;
}
#htg-explanation code {
    background: #e9ecef;
    padding: 2px 6px;
    border-radius: 3px;
    font-size: 13px;
    word-break: break-all;
}