:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --border-radius: 5px;
    --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

body {
    font-family: var(--font-family);
    background-color: var(--light-color);
    color: var(--dark-color);
    margin: 0;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    box-sizing: border-box;
}

.container {
    background-color: #fff;
    padding: 25px 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    width: 100%;
    max-width: 700px;
    text-align: center;
}

header {
    margin-bottom: 25px;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

header h1 {
    color: var(--primary-color);
    margin-bottom: 5px;
}

.tagline {
    color: var(--secondary-color);
    font-size: 1.1em;
}

.controls {
    margin-bottom: 25px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.control-group {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
}

.control-group label {
    margin-bottom: 8px;
    font-weight: bold;
    color: #555;
}

select,
input[type="text"] {
    width: 100%;
    padding: 12px;
    font-size: 16px;
    border: 1px solid #ccc;
    border-radius: var(--border-radius);
    box-sizing: border-box;
    transition: border-color 0.3s ease;
}

select:focus,
input[type="text"]:focus {
    border-color: var(--primary-color);
    outline: none;
}

.action-buttons {
    margin-bottom: 20px;
    display: flex;
    gap: 15px;
    justify-content: center;
}

.btn {
    padding: 12px 25px;
    font-size: 16px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.1s ease;
    color: white;
    font-weight: bold;
}

.btn:hover {
    opacity: 0.9;
}

.btn:active {
    transform: translateY(1px);
}

.btn-primary {
    background-color: var(--primary-color);
}

.btn-danger {
    background-color: var(--danger-color);
}

.btn-success {
    background-color: var(--success-color);
}

.btn:disabled {
    background-color: var(--secondary-color);
    cursor: not-allowed;
    opacity: 0.7;
}

.status-message {
    margin: 20px 0;
    font-size: 1.1em;
    color: var(--secondary-color);
    min-height: 1.5em;
}

.preview-container {
    margin-top: 20px;
    background-color: #f0f0f0;
    border: 1px dashed #ccc;
    border-radius: var(--border-radius);
    padding: 10px;
    min-height: 200px;
    display: flex;
    justify-content: center;
    align-items: center;
}

#preview {
    max-width: 100%;
    max-height: 400px;
    border-radius: var(--border-radius);
    display: none;
}

.download-section {
    margin-top: 25px;
    padding-top: 20px;
    border-top: 1px solid #eee;
    display: none;
}

.mp4-info {
    margin-top: 20px;
    background-color: #eef7ff;
    border: 1px solid #bde0ff;
    color: #004085;
    padding: 15px;
    border-radius: var(--border-radius);
    text-align: left;
    font-size: 0.95em;
}

.mp4-info p {
    margin: 8px 0;
}

.mp4-info a {
    color: var(--primary-color);
    font-weight: bold;
    text-decoration: none;
}

.mp4-info a:hover {
    text-decoration: underline;
}


@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    .control-group {
        align-items: center;
    }

    .action-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}