:root {
    --background-color: #f5f5f5;
    --text-color: #212529;
    --container-bg-color: #fff;
    --container-shadow-color: rgba(0, 0, 0, 0.1);
    --response-bg-color: #fafafa;
    --response-border-color: #ddd;
    --upload-area-border-color: #ddd;
    --modal-bg-color: rgba(0, 0, 0, 0.6);
    --modal-content-bg-color: #fefefe;
    --button-primary-bg: #007bff;
    --button-primary-hover-bg: #0056b3;
}

/* Tự động áp dụng khi hệ điều hành ở chế độ tối */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #121212;
        --text-color: #e0e0e0;
        --container-bg-color: #1e1e1e;
        --container-shadow-color: rgba(0, 0, 0, 0.5);
        --response-bg-color: #2a2a2a;
        --response-border-color: #444;
        --upload-area-border-color: #444;
        --modal-bg-color: rgba(0, 0, 0, 0.8);
        --modal-content-bg-color: #2a2a2a;
        --button-primary-bg: #0d6efd;
        --button-primary-hover-bg: #0b5ed7;
    }
}

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: var(--background-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

#container {
    position: relative;
    max-width: 800px;
    margin: 40px auto;
    text-align: center;
    background-color: var(--container-bg-color);
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 12px var(--container-shadow-color);
    transition: background-color 0.3s;
}

h1, p {
    color: var(--text-color);
}

.upload-area {
    padding: 20px;
    border: 2px dashed var(--upload-area-border-color);
    border-radius: 8px;
    margin-bottom: 20px;
    transition: border-color 0.3s, background-color 0.3s;
}

/* Hiệu ứng khi kéo tệp vào khu vực */
.upload-area.drag-over {
    border-color: var(--button-primary-bg);
    background-color: var(--response-bg-color);
}

#preview {
    display: none;
    margin: 20px auto;
    max-width: 100%;
    max-height: 300px;
    border-radius: 8px;
    box-shadow: 0 4px 8px var(--container-shadow-color);
}

#response {
    padding: 12px;
    border: 1px solid var(--response-border-color);
    border-radius: 8px;
    margin-bottom: 20px;
    min-height: 20px;
    word-wrap: break-word;
    background-color: var(--response-bg-color);
    transition: background-color 0.3s, border-color 0.3s;
}

.action-button {
    padding: 10px 20px;
    background-color: var(--button-primary-bg);
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    font-size: 16px;
    margin: 5px;
}

.action-button:hover {
    background-color: var(--button-primary-hover-bg);
}

#copyButton {
    display: none; /* Sẽ hiển thị bằng JS */
    background-color: #28a745;
}

#copyButton:hover {
    background-color: #218838;
}

#fileInput {
    display: none;
}

.alert {
    padding: 10px;
    border-radius: 4px;
    margin-top: 15px;
    text-align: center;
}

#tokenModal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: var(--modal-bg-color);
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--modal-content-bg-color);
    color: var(--text-color);
    padding: 30px;
    border: 1px solid var(--response-border-color);
    width: 90%;
    max-width: 500px;
    border-radius: 8px;
    box-shadow: 0 5px 15px var(--container-shadow-color);
}

.modal-content h2 {
    margin-top: 0;
}

.modal-content input[type="text"] {
    width: 100%;
    padding: 10px;
    margin: 10px 0 5px 0;
    display: inline-block;
    border: 1px solid var(--response-border-color);
    border-radius: 4px;
    box-sizing: border-box;
    background-color: var(--response-bg-color);
    color: var(--text-color);
}

#modalError {
    color: #d9534f;
    font-size: 14px;
    margin-bottom: 15px;
    min-height: 18px;
}

.modal-content button {
    background-color: var(--button-primary-bg);
    color: white;
    padding: 12px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    width: 100%;
    font-size: 16px;
}

.modal-content button:hover {
    background-color: var(--button-primary-hover-bg);
}

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