:root {
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --accent-color: #007bff;
    --hover-color: #0056b3;
    --border-color: #333;
    --input-bg: #2c2c2c;
    --input-border: #444;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.container {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 500px;
    text-align: center;
}

h1 {
    color: var(--text-color);
    margin-bottom: 1.5rem;
    font-weight: 300;
}

.drop-zone {
    border: 2px dashed var(--input-border);
    background-color: var(--input-bg);
    border-radius: 8px;
    padding: 2rem;
    cursor: pointer;
    transition: border-color 0.3s ease, background-color 0.3s ease;
    margin-bottom: 1.5rem;
    position: relative;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--accent-color);
    background-color: #252a30;
}

.drop-zone input[type="file"] {
    display: none;
}

.drop-zone p {
    margin: 0;
    color: #aaa;
}

.options {
    text-align: left;
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #ccc;
}

input[type="number"], select {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    color: var(--text-color);
    border-radius: 4px;
    box-sizing: border-box;
}

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

input[type="range"] {
    width: 100%;
    accent-color: var(--accent-color);
}

.btn {
    background-color: var(--accent-color);
    color: white;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    width: 100%;
    transition: background-color 0.3s ease;
    font-weight: 500;
}

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

.btn:disabled {
    background-color: #444;
    color: #888;
    cursor: not-allowed;
}

#result {
    margin-top: 1.5rem;
    display: none;
    background-color: var(--input-bg);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.preview-img {
    max-width: 100%;
    border-radius: 4px;
    margin-top: 1rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.success-message {
    color: #4caf50;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.error-message {
    color: #f44336;
    font-weight: bold;
    margin-top: 1rem;
}

.loader {
    border: 4px solid #333;
    border-top: 4px solid var(--accent-color);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin: 1rem auto;
    display: none;
}

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

.dimensions-group {
    display: flex;
    gap: 10px;
}

small {
    color: #888;
}

output {
    display: inline-block;
    margin-top: 5px;
    color: var(--accent-color);
    font-weight: bold;
}