:root {
    --bg-dark: #0f172a;
    --card-bg: #1e293b;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --border: #334155;
    --success: #10b981;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
    line-height: 1.5;
}

.container {
    width: 100%;
    max-width: 900px;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.025em;
}

p.subtitle {
    color: var(--text-muted);
}

.card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    border: 1px solid var(--border);
    padding: 2rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

.drop-zone {
    border: 2px dashed var(--border);
    border-radius: 0.75rem;
    padding: 3rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-bottom: 1.5rem;
}

.drop-zone:hover, .drop-zone.active {
    border-color: var(--accent);
    background-color: rgba(59, 130, 246, 0.05);
}

.controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.slider-group {
    display: flex;
    align-items: center;
    gap: 1rem;
}

label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
}

select, input[type="range"] {
    background: var(--bg-dark);
    border: 1px solid var(--border);
    color: var(--text-main);
    padding: 0.6rem;
    border-radius: 0.5rem;
    font-size: 0.9rem;
    outline: none;
    width: 100%;
}

input[type="range"] {
    flex: 1;
}

.slider-value {
    font-size: 0.9rem;
    font-weight: 600;
    min-width: 3ch;
    text-align: right;
}

.actions {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
    justify-content: flex-end;
}

#processBtnContainer {
    flex: 1;
}

#downloadBtn {
    flex: 1;
}


/* Toggle Switch styles */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 110px;
    height: 34px;
    align-self: flex-start;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--bg-dark);
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    transition: .4s;
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 50px;
    left: 4px;
    bottom: 3px;
    background-color: var(--accent);
    border-radius: 0.375rem;
    transition: .4s;
}

input:checked + .toggle-slider {
    background-color: var(--bg-dark);
}

input:checked + .toggle-slider:before {
    transform: translateX(50px);
}

.toggle-label {
    color: var(--text-muted);
    position: relative;
    pointer-events: none;
    display: block;
    text-align: center;
    line-height: 34px;
    font-size: 0.8rem;
    font-weight: 600;
}

.toggle-label:after, .toggle-label:before {
    position: absolute;
}

.toggle-label:before {
    content: attr(data-on);
    left: 28px;
    transform: translateX(-50%);
    opacity: 0.5;
}

.toggle-label:after {
    content: attr(data-off);
    right: -28px;
    transform: translateX(50%);
}

input:checked ~ .toggle-label:before {
    opacity: 1;
}

input:not(:checked) ~ .toggle-label:after {
    opacity: 1;
}

button {
    flex: 1;
    padding: 0.75rem;
    border-radius: 0.5rem;
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, opacity 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--accent-hover);
}

.btn-secondary {
    background-color: var(--border);
    color: var(--text-main);
}

.preview-area {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.preview-box {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

#originalPreviewBox {
    cursor: pointer;
    position: relative;
}

#originalPreviewBox .canvas-container {
    transition: border-color 0.2s ease;
}

#originalPreviewBox:hover .canvas-container,
#originalPreviewBox.active .canvas-container {
    border-color: var(--accent);
}

#originalPreviewBox::after {
    content: 'Click or drag here to upload a new image';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 0.5rem 1rem;
    background: rgba(0,0,0,0.75);
    color: white;
    border-radius: 0.5rem;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.2s ease;
    text-align: center;
    z-index: 10;
}

#originalPreviewBox:hover::after,
#originalPreviewBox.active::after {
    opacity: 1;
}

.canvas-container {
    background-image: 
        linear-gradient(45deg, #161b22 25%, transparent 25%), 
        linear-gradient(-45deg, #161b22 25%, transparent 25%), 
        linear-gradient(45deg, transparent 75%, #161b22 75%), 
        linear-gradient(-45deg, transparent 75%, #161b22 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    background-color: #0d1117;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    overflow: auto;
    max-height: 400px;
    display: flex;
    justify-content: center;
    align-items: center;
}

canvas {
    max-width: 100%;
    height: auto;
    display: block;
}

.hidden {
    display: none;
}

.stats {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

@media (max-width: 768px) {
    .preview-area {
        grid-template-columns: 1fr;
    }
    .controls {
        grid-template-columns: 1fr;
    }
}