/* Modern CSS with theme support */
:root {
    /* Base colors */
    --bg-primary: #f8f9fa;
    --bg-secondary: #e9ecef;
    --bg-tertiary: #dee2e6;
    --text-primary: #212529;
    --text-secondary: #495057;
    --text-tertiary: #6c757d;
    --accent-primary: #7048e8;
    --accent-secondary: #5f3dc4;
    --canvas-bg: #f0f0f0;
    
    /* UI Elements */
    --border-color: #ced4da;
    --input-bg: #ffffff;
    --input-text: var(--text-primary);
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 1px 3px rgba(0,0,0,0.08);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.1), 0 3px 6px rgba(0,0,0,0.05);
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

.dark-theme {
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --bg-tertiary: #2d2d2d;
    --text-primary: #e9ecef;
    --text-secondary: #ced4da;
    --text-tertiary: #adb5bd;
    --canvas-bg: #2c2c2c;
    --input-bg: #2d2d2d;
    
    /* Shadows get more subtle in dark mode */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.25);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.25);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.25);
}

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

html, body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.5;
    height: 100%;
    width: 100%;
    overflow: hidden;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

/* Header styles */
.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md);
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    z-index: 10;
}

.app-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

.header-controls {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.logo-link {
    display: flex;
    align-items: center;
}

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

.canvas-container {
    flex: 1;
    background-color: var(--canvas-bg);
    overflow: hidden;
    position: relative;
}

/* Sidebar styles */
.sidebar {
    width: 320px;
    background-color: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-tertiary);
}

.tab-button {
    flex: 1;
    padding: var(--space-md);
    background: transparent;
    border: none;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.tab-button:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.tab-button.active {
    color: var(--accent-primary);
    border-bottom: 2px solid var(--accent-primary);
    background-color: var(--bg-secondary);
}

.tab-panel {
    display: none;
    padding: var(--space-md);
    overflow-y: auto;
    flex: 1;
}

.tab-panel.active {
    display: block;
}

/* Form elements */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--space-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

.checkbox-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-sm);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    cursor: pointer;
    margin-bottom: var(--space-sm);
}

/* Toggle switch */
.toggle-switch {
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: var(--space-md);
    cursor: pointer;
}

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

.toggle-slider {
    position: relative;
    display: inline-block;
    width: 36px;
    height: 20px;
    background-color: var(--bg-tertiary);
    border-radius: 20px;
    transition: background-color var(--transition-fast);
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 2px;
    bottom: 2px;
    background-color: white;
    border-radius: 50%;
    transition: transform var(--transition-fast);
}

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

input:checked + .toggle-slider:before {
    transform: translateX(16px);
}

/* File input */
.file-input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.file-input-button {
    padding: var(--space-sm) var(--space-md);
    background-color: var(--accent-primary);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.file-input-button:hover {
    background-color: var(--accent-secondary);
}

.file-input-wrapper input[type="file"] {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

#file-name {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.9rem;
    color: var(--text-tertiary);
}

/* Color picker */
.color-picker-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

input[type="color"] {
    -webkit-appearance: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    padding: 0;
    background: none;
}

input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
}

input[type="color"]::-webkit-color-swatch {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
}

/* Select and text inputs */
.select-input, .text-input {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background-color: var(--input-bg);
    color: var(--input-text);
    font-size: 0.9rem;
}

.select-input {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%23888%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E");
    background-repeat: no-repeat;
    background-position: right 0.7rem top 50%;
    background-size: 0.65rem auto;
}

/* Buttons */
.primary-button, .icon-button {
    border: none;
    border-radius: var(--radius-sm);
    padding: var(--space-sm) var(--space-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    font-weight: 500;
}

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

.primary-button:hover {
    background-color: var(--accent-secondary);
}

.icon-button {
    background-color: transparent;
    color: var(--text-secondary);
    padding: var(--space-sm);
}

.icon-button:hover {
    background-color: rgba(0, 0, 0, 0.1);
}

.icon {
    display: inline-block;
}

/* Fieldset */
fieldset {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: var(--space-md);
    margin-bottom: var(--space-lg);
}

legend {
    padding: 0 var(--space-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

/* Toast notifications */
.toast-container {
    position: fixed;
    bottom: var(--space-lg);
    right: var(--space-lg);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    max-width: 300px;
}

.toast {
    padding: var(--space-md);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    opacity: 0;
    transform: translateY(20px);
    animation: toast-in 0.3s forwards, toast-out 0.3s forwards 3s;
}

@keyframes toast-in {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes toast-out {
    from { opacity: 1; transform: translateY(0); }
    to { opacity: 0; transform: translateY(-20px); }
}

/* Responsive styles */
@media (max-width: 768px) {
    .main-content {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        height: 40%;
        border-left: none;
        border-top: 1px solid var(--border-color);
    }
    
    .canvas-container {
        height: 60%;
    }
}

@media (max-width: 480px) {
    .app-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-sm);
    }
    
    .header-controls {
        width: 100%;
        justify-content: space-between;
    }
    
    .checkbox-grid {
        grid-template-columns: 1fr;
    }
}