body {
    font-family: Arial, sans-serif;
    background-color: #1a1a1a;
    color: #f0f0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.container {
    background-color: #2b2b2b;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.5);
    text-align: center;
    width: 90%;
    max-width: 500px;
}

h1 {
    color: #00aaff;
}

.image-preview-container {
    border: 2px dashed #555;
    border-radius: 8px;
    margin: 20px 0;
    padding: 10px;
    height: 150px;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    background-color: #222;
}

#imagePreview {
    max-width: 100%;
    max-height: 100%;
    display: none; /* Ẩn đi lúc đầu */
}

#previewText {
    color: #888;
}

input[type="file"] {
    display: block;
    margin: 20px auto;
}

button {
    background-color: #00aaff;
    color: white;
    border: none;
    padding: 12px 25px;
    font-size: 16px;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0088cc;
}

.result-container {
    margin-top: 25px;
}

#resultText {
    background-color: #333;
    padding: 15px;
    border-radius: 5px;
    font-size: 20px;
    font-weight: bold;
    min-height: 30px;
    word-wrap: break-word;
}

/* Hiệu ứng loading "xịn sò" */
.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #00aaff;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin: 10px auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}