:root {
    --bg-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-secondary: white;
    --text-primary: #333;
    --text-secondary: #666;
    --accent: linear-gradient(45deg, #667eea, #764ba2);
    --control-bg: #f8f9fa;
    --border-radius: 15px;
    --shadow: 0 10px 30px rgba(0,0,0,0.1);
}

[data-theme="dark"] {
    --bg-primary: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    --bg-secondary: #0f0f23;
    --text-primary: #e4e4e7;
    --text-secondary: #a1a1aa;
    --accent: linear-gradient(45deg, #3b82f6, #8b5cf6);
    --control-bg: #1f1f36;
    --shadow: 0 10px 30px rgba(0,0,0,0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    min-height: 100vh;
    padding: 10px;
    transition: all 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--shadow);
    color: var(--text-primary);
}

header {
    text-align: center;
    margin-bottom: 30px;
    position: relative;
}

header h1 {
    font-weight: 300;
    margin-bottom: 10px;
    font-size: clamp(1.5rem, 4vw, 2.5rem);
}

header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.dark-toggle {
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent);
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    font-size: 1.2rem;
}

.upload-section {
    text-align: center;
    margin-bottom: 30px;
}

input[type="file"] {
    display: none;
}

label[for="imageInput"] {
    display: inline-block;
    padding: 15px 30px;
    background: var(--accent);
    color: white;
    border-radius: 50px;
    cursor: pointer;
    transition: transform 0.2s;
    font-weight: 500;
}

label[for="imageInput"]:hover {
    transform: translateY(-2px);
}

.help-text {
    margin-top: 10px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.main-content {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.preview {
    flex: 1;
    display: flex;
    align-items: flex-start;
    justify-content: center;
}

.controls {
    width: 350px;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    gap: 15px;
    padding: 20px;
    background: var(--control-bg);
    border-radius: var(--border-radius);
    max-height: 80vh;
    overflow-y: auto;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: #ddd;
    outline: none;
    -webkit-appearance: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: none;
}

.action-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 20px;
}

#canvas {
    max-width: 100%;
    max-height: 80vh;
    border-radius: 10px;
    box-shadow: var(--shadow);
}

button, .donate-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 25px;
    background: var(--accent);
    color: white;
    cursor: pointer;
    font-weight: 500;
    transition: transform 0.2s;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

button:hover, .donate-btn:hover {
    transform: translateY(-2px);
}

.donate-btn {
    background: linear-gradient(45deg, #ff6b6b, #ee5a24);
}

@media (max-width: 1024px) {
    .main-content {
        flex-direction: column;
    }
    
    .controls {
        width: 100%;
        max-height: none;
        overflow-y: visible;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 15px;
    }
    
    .action-buttons {
        grid-column: 1 / -1;
        flex-direction: row;
        justify-content: center;
        flex-wrap: wrap;
    }
    
    button, .donate-btn {
        flex: 1;
        min-width: 150px;
    }
}

footer {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid var(--text-secondary);
    color: var(--text-secondary);
    font-size: 0.85rem;
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .controls {
        grid-template-columns: 1fr;
        gap: 12px;
        padding: 15px;
    }
    
    .action-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    button, .donate-btn {
        width: 100%;
        max-width: 300px;
    }
    
    .dark-toggle {
        position: static;
        margin: 10px auto;
    }
    
    header {
        text-align: center;
    }
}