:root {
    --background-color: #08041b;
    --container-color: #211e33;
    --text-color: #FFFFFF;
    --error-color: #FF0000;
    --button-gradient-left: #FF6200;
    --button-gradient-right: #FF0000;
    --secondary-button-bg: #E0E0E0;
    --secondary-button-text: #000000;
    --border-radius: 10px;
    --transition-speed: 0.3s;
}

/* Reset básico */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--background-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    background-color: var(--container-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    max-width: 700px;
    width: 100%;
    box-shadow: none;
}

h1, h2 {
    color: var(--text-color);
    text-align: center;
    margin-bottom: 20px;
    font-weight: 600;
}

h1 {
    font-size: 2rem;
}

h2 {
    font-size: 1.5rem;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    color: var(--text-color);
    font-weight: 500;
}

.form-group input[type="file"],
.form-group select,
.form-group input[type="range"] {
    width: 100%;
    padding: 10px;
    border: 1px solid #FFFFFF;
    border-radius: var(--border-radius);
    background-color: #FFFFFF;
    color: #333;
    font-size: 16px;
}

.form-group input[type="file"]:invalid:not(:focus),
.form-group select:invalid:not(:focus) {
    border-color: var(--error-color);
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='none' stroke='%23FF0000' viewBox='0 0 12 12'%3E%3Ccircle cx='6' cy='6' r='4.5'/%3E%3Cpath stroke-linejoin='round' d='M5.8 3.6h.4L6 6.5z'/%3E%3Ccircle cx='6' cy='8.2' r='.6' fill='%23FF0000' stroke='none'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right calc(0.375em + 0.1875rem) center;
    background-size: calc(0.75em + 0.375rem) calc(0.75em + 0.375rem);
}

.form-group input[type="file"]:focus,
.form-group select:focus {
    border-color: #FFFFFF;
    box-shadow: none;
}

.form-group input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    background: #D3D3D3;
    height: 5px;
    border-radius: 5px;
    outline: none;
}

.form-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--button-gradient-left);
    border-radius: 50%;
    cursor: pointer;
}

.form-group input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--button-gradient-left);
    border-radius: 50%;
    cursor: pointer;
}

.preview-container,
.result-container {
    width: 100%;
    max-width: 100%;
    max-height: 500px;
    margin: 10px auto;
    border: 1px solid #FFFFFF;
    border-radius: var(--border-radius);
    overflow: auto;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--container-color);
}

.preview-container img,
.result-container img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

button[type="submit"],
.download-btn {
    display: block;
    margin: 0 auto;
    padding: 10px 20px;
    background: linear-gradient(90deg, var(--button-gradient-left), var(--button-gradient-right));
    color: var(--text-color);
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform var(--transition-speed) ease;
}

button[type="submit"]:hover,
.download-btn:hover {
    transform: translateY(-2px);
    background: linear-gradient(90deg, var(--button-gradient-right), var(--button-gradient-left));
}

button[type="submit"]:active,
.download-btn:active {
    transform: translateY(0);
}

.result {
    text-align: center;
}

.button-container {
    position: relative;
    width: 100%;
    max-width: 100%;
    margin: 10px auto 0;
    padding: 0;
    height: 50px;
    display: flex;
    justify-content: space-between;
}

.download-btn {
    position: static;
    text-decoration: none;
    text-align: center;
}

.process-another-btn {
    position: static;
    padding: 10px 20px;
    background-color: var(--secondary-button-bg);
    color: var(--secondary-button-text);
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
}

.process-another-btn:hover {
    background-color: #CCCCCC;
}

.error {
    color: var(--error-color);
    text-align: center;
    margin: 10px 0;
}

/* Responsividad */
@media (max-width: 600px) {
    .container {
        padding: 1.5rem;
        max-width: 100%;
    }

    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    .preview-container,
    .result-container {
        max-height: 300px;
    }

    .button-container {
        flex-direction: column;
        height: auto;
        gap: 10px;
    }

    .download-btn,
    .process-another-btn {
        width: 100%;
    }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-color);
}

::-webkit-scrollbar-thumb {
    background: #FFFFFF;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #CCCCCC;
}