/* CSS Reset and Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #475569;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --radius: 8px;
    --transition: all 0.2s ease;
}

html {
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.5;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    background: var(--surface);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.25rem;
}

.logo-img {
    width: 40px;
    height: 40px;
    object-fit: contain;
}

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Main Content */
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Toolbar */
.toolbar {
    width: 280px;
    background: var(--surface);
    padding: 1rem;
    overflow-y: auto;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.tool-section {
    background: var(--surface-light);
    border-radius: var(--radius);
    padding: 1rem;
}

.tool-section h3 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

/* Tools */
.tools {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.tool-btn {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.875rem;
}

.tool-btn svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

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

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

/* Color Picker */
.color-picker-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.color-picker {
    width: 50px;
    height: 50px;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    padding: 0;
    background: none;
}

.color-picker::-webkit-color-swatch-wrapper {
    padding: 0;
}

.color-picker::-webkit-color-swatch {
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
}

#colorValue {
    font-family: monospace;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Color Palette */
.color-palette {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 4px;
}

.palette-color {
    width: 100%;
    aspect-ratio: 1;
    border: 2px solid transparent;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
}

.palette-color:hover {
    transform: scale(1.1);
    z-index: 1;
}

.palette-color.active {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px var(--primary-color);
}

/* Canvas Size Controls */
.canvas-size {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.canvas-size label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.canvas-size input[type="number"] {
    width: 70px;
    padding: 0.5rem;
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 0.875rem;
}

/* Action Buttons */
.actions {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.action-btn {
    padding: 0.75rem 1rem;
    border: none;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.action-btn:hover {
    background: var(--surface-light);
}

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

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

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

.action-btn.secondary:hover {
    background: #4b5563;
}

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

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

.file-input-label {
    display: block;
}

/* Reference Controls */
.reference-controls {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.reference-controls label {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

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

.no-reference {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* Canvas Area */
.canvas-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background: var(--background);
    overflow: auto;
}

.canvas-wrapper {
    position: relative;
    background: #ffffff;
    box-shadow: var(--shadow);
    border-radius: 4px;
}

.pixel-canvas,
.grid-canvas,
.reference-canvas {
    position: absolute;
    top: 0;
    left: 0;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

.pixel-canvas {
    z-index: 2;
}

.grid-canvas {
    z-index: 3;
    pointer-events: none;
}

.reference-canvas {
    z-index: 1;
}

.canvas-info {
    margin-top: 1rem;
    display: flex;
    gap: 2rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Footer */
.footer {
    background: var(--surface);
    padding: 1rem;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.footer a:hover {
    color: var(--text-primary);
    text-decoration: underline;
}

/* Mobile Responsive */
@media (max-width: 900px) {
    .main-content {
        flex-direction: column;
    }

    .toolbar {
        width: 100%;
        flex-direction: row;
        flex-wrap: wrap;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        overflow-x: auto;
        overflow-y: visible;
        padding: 0.75rem;
        gap: 0.75rem;
    }

    .tool-section {
        flex: 1 1 auto;
        min-width: 200px;
        padding: 0.75rem;
    }

    .tools {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .tool-btn {
        flex: 1;
        min-width: 80px;
        justify-content: center;
    }

    .tool-btn span {
        display: none;
    }

    .color-palette {
        grid-template-columns: repeat(8, 1fr);
    }

    .canvas-area {
        padding: 1rem;
    }

    .actions {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .action-btn {
        flex: 1;
        min-width: 120px;
    }
}

@media (max-width: 600px) {
    .header {
        padding: 0.75rem 1rem;
    }

    .header h1 {
        font-size: 1.25rem;
    }

    .logo-img {
        width: 32px;
        height: 32px;
    }

    .tool-section {
        min-width: 150px;
    }

    .color-palette {
        grid-template-columns: repeat(6, 1fr);
    }

    .canvas-size label {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.25rem;
    }

    .canvas-size input[type="number"] {
        width: 100%;
    }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
    .tool-btn, .action-btn, .palette-color {
        min-height: 44px;
    }

    .palette-color {
        min-width: 30px;
        min-height: 30px;
    }
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--surface-light);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-color);
}