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+# Theme Creation Guide
+
+This guide covers everything you need to know about creating custom themes for BetterSEQTA+.
+
+## Table of Contents
+
+1. [Overview](#overview)
+2. [Theme Structure](#theme-structure)
+3. [CSS Variables](#css-variables)
+4. [CSS Selectors & Classes](#css-selectors--classes)
+5. [Custom Images](#custom-images)
+6. [Theme Settings](#theme-settings)
+7. [Best Practices](#best-practices)
+8. [Examples](#examples)
+
+## Overview
+
+Themes in BetterSEQTA+ allow you to completely customize the appearance of SEQTA Learn. A theme consists of:
+
+- **Custom CSS**: CSS rules that override default styles
+- **Custom Images**: Images that can be referenced via CSS variables
+- **Theme Metadata**: Name, description, default color, etc.
+- **Theme Settings**: Options like forcing dark/light mode
+
+Themes are applied by injecting CSS into the SEQTA page and setting CSS custom properties (variables) on the document root.
+
+## CSS Variables
+
+BetterSEQTA+ provides a comprehensive set of CSS variables that you can use in your themes. These variables automatically adapt to light/dark mode and user preferences.
+
+### Core Background Variables
+
+| Variable | Light Mode | Dark Mode | Description |
+|----------|------------|-----------|-------------|
+| `--background-primary` | `#ffffff` | `#232323` | Main background color |
+| `--background-secondary` | `#e5e7eb` | `#1a1a1a` | Secondary background color |
+| `--theme-primary` | `#ffffff` | `#232323` | Primary theme color (same as background-primary) |
+| `--theme-secondary` | `#e5e7eb` | `#1a1a1a` | Secondary theme color (same as background-secondary) |
+| `--text-primary` | `black` | `white` | Primary text color |
+| `--text-color` | `black` | `white` | Text color (alias for text-primary) |
+
+### BetterSEQTA+ Specific Variables
+
+| Variable | Description | Notes |
+|----------|-------------|-------|
+| `--better-main` | User's selected accent color | Dynamically set based on color picker |
+| `--better-sub` | Dark navy color | Always `#161616` |
+| `--better-pale` | Lightened version of accent color | Only available in light mode |
+| `--better-light` | Lighter version of accent color | Calculated based on brightness |
+| `--better-alert-highlight` | Alert/highlight color | `#c61851` |
+| `--betterseqta-logo` | Logo URL | Changes based on dark/light mode |
+| `--auto-background` | Auto background color | Falls back to `--better-pale` or `--background-secondary` |
+| `--navy` | Navy color | `#1a1a1a` |
+| `--theme-fg-parts` | Theme foreground parts | `white` |
+
+### Subject/Item Color Variables
+
+| Variable | Description |
+|----------|-------------|
+| `--item-colour` | Subject/item color | Set dynamically per subject/item |
+| `--colour` | Generic color variable | Used in various contexts |
+| `--person-colour` | Person/avatar color | `var(--better-light)` for staff |
+
+### Transparency Effects
+
+When transparency effects are enabled, background variables become semi-transparent:
+
+| Variable | Light Mode (Transparent) | Dark Mode (Transparent) |
+|----------|--------------------------|-------------------------|
+| `--background-primary` | `rgba(255, 255, 255, 0.6)` | `rgba(35, 35, 35, 0.6)` |
+| `--background-secondary` | `rgba(229, 231, 235, 0.6)` | `rgba(26, 26, 26, 0.6)` |
+
+### Using CSS Variables
+
+You can use these variables in your custom CSS:
+
+```css
+/* Example: Style a custom element */
+.my-custom-element {
+  background: var(--background-primary);
+  color: var(--text-primary);
+  border: 1px solid var(--better-main);
+}
+
+/* Example: Create a gradient */
+.gradient-box {
+  background: linear-gradient(
+    to bottom,
+    var(--better-main),
+    var(--background-secondary)
+  );
+}
+```
+
+## CSS Selectors & Classes
+
+BetterSEQTA+ uses specific CSS selectors and classes that you can target in your themes. Here are the most important ones:
+
+### Main Layout Elements
+
+| Selector | Description |
+|----------|-------------|
+| `#container` | Main container element |
+| `#content` | Content area |
+| `#main` | Main content wrapper |
+| `#title` | Top title bar |
+| `#menu` | Sidebar menu |
+
+### Dark Mode
+
+The `dark` class is added to `html` when dark mode is active:
+
+```css
+/* Target dark mode specifically */
+html.dark #main {
+  background: var(--background-primary);
+}
+
+/* Target light mode */
+html:not(.dark) #main {
+  background: var(--background-primary);
+}
+```
+
+### Transparency Effects
+
+When transparency effects are enabled, the `transparencyEffects` class is added to `html`:
+
+```css
+html.transparencyEffects .notice {
+  backdrop-filter: blur(80px);
+}
+```
+
+### Common SEQTA Classes
+
+| Class/Selector | Description |
+|----------------|-------------|
+| `.notice` | Notice cards |
+| `.day` | Day containers in timetable |
+| `.dashboard` | Dashboard sections |
+| `.dashlet` | Dashboard widgets |
+| `.document` | Document elements |
+| `.quickbar` | Quick action bar |
+| `.calendar` | Calendar elements |
+| `.message` | Message elements |
+| `.thread` | Forum threads |
+| `.shortcut` | Shortcut buttons |
+| `.upcoming-assessment` | Upcoming assessments |
+| `.entry.class` | Timetable entries |
+
+### BetterSEQTA+ Specific Classes
+
+| Class | Description |
+|-------|-------------|
+| `.addedButton` | BetterSEQTA+ added buttons |
+| `.tooltip` | Tooltip elements |
+| `.notice-unified-content` | Unified notice content |
+| `.home-container` | Home page container |
+| `.timetable-container` | Timetable container |
+| `.notices-container` | Notices container |
+
+### Attribute Selectors
+
+SEQTA uses data attributes that you can target:
+
+```css
+/* Target specific data types */
+[data-type="student"] .header {
+  color: var(--text-primary);
+}
+
+/* Target specific labels */
+[data-label="inbox"] {
+  /* Styles */
+}
+```
+
+### CSS Modules
+
+SEQTA uses CSS modules with hashed class names. You can target them using attribute selectors:
+
+```css
+/* Target CSS module classes */
+[class*="MessageList__MessageList___"] {
+  background: var(--background-primary);
+}
+
+[class*="BasicPanel__BasicPanel___"] {
+  border-radius: 16px;
+}
+```
+
+## Custom Images
+
+Themes can include custom images that are made available as CSS variables.
+
+### Adding Images
+
+1. Upload an image in the theme creator
+2. Set a CSS variable name (e.g., `custom-background`)
+3. The image will be available as `var(--custom-background)`
+
+### Using Image Variables
+
+```css
+/* Use as background */
+.my-element {
+  background-image: var(--custom-background);
+  background-size: cover;
+  background-position: center;
+}
+
+/* Use in content */
+.my-icon::before {
+  content: '';
+  background-image: var(--custom-icon);
+  width: 24px;
+  height: 24px;
+}
+```
+
+### Image Variable Format
+
+Images are stored as `url()` values:
+
+```css
+/* The variable contains: url(blob:...) */
+--custom-background: url(blob:chrome-extension://...);
+```
+
+## Theme Settings
+
+### Force Dark/Light Mode
+
+You can force a theme to always use dark or light mode:
+
+```typescript
+forceDark: true   // Force dark mode
+forceDark: false  // Force light mode
+forceDark: undefined  // Use user's preference (default)
+```
+
+When `forceDark` is set, users cannot toggle dark/light mode while the theme is active.
+
+### Default Color
+
+Set a default accent color for your theme:
+
+```typescript
+defaultColour: "rgba(0, 123, 255, 1)"  // Blue
+defaultColour: "#ff6b6b"                // Red (hex format)
+```
+
+### Allow Color Changes
+
+Control whether users can change the accent color:
+
+```typescript
+CanChangeColour: true   // Users can change color
+CanChangeColour: false  // Color is locked
+```
+
+## Best Practices
+
+### 1. Use CSS Variables
+
+Always use CSS variables instead of hardcoded colors:
+
+```css
+/* Good */
+.my-element {
+  background: var(--background-primary);
+  color: var(--text-primary);
+}
+
+/* Bad */
+.my-element {
+  background: #ffffff;
+  color: #000000;
+}
+```
+
+### 2. Support Both Light and Dark Modes
+
+Unless your theme forces a specific mode, ensure it works in both:
+
+```css
+/* Use variables that adapt automatically */
+.my-element {
+  background: var(--background-primary);
+  color: var(--text-primary);
+}
+
+/* Or explicitly handle both modes */
+html.dark .my-element {
+  background: #1a1a1a;
+}
+
+html:not(.dark) .my-element {
+  background: #ffffff;
+}
+```
+
+### 3. Use !important Sparingly
+
+Only use `!important` when necessary to override SEQTA's default styles:
+
+```css
+/* Good - necessary override */
+#title {
+  background: var(--background-primary) !important;
+}
+
+/* Bad - unnecessary */
+.my-element {
+  color: var(--text-primary) !important;
+}
+```
+
+### 4. Test Responsive Design
+
+SEQTA is responsive. Test your theme at different screen sizes:
+
+```css
+/* Example: Mobile-specific styles */
+@media (max-width: 900px) {
+  #menu {
+    transform: translate(-270px);
+  }
+}
+```
+
+### 5. Use Semantic Selectors
+
+Prefer semantic selectors over fragile ones:
+
+```css
+/* Good - stable selector */
+#main > .dashboard > section {
+  border-radius: 16px;
+}
+
+/* Caution - CSS module classes may change */
+[class*="Dashboard__Dashboard___"] {
+  border-radius: 16px;
+}
+```
+
+### 6. Optimize Images
+
+Keep image file sizes reasonable:
+
+- Use appropriate formats (PNG for transparency, JPG for photos)
+- Compress images before uploading
+- Consider using CSS for simple graphics instead of images
+
+### 7. Document Your Theme
+
+Include comments in your CSS explaining complex styles:
+
+```css
+/* 
+ * Custom gradient background for dashboard
+ * Uses the user's accent color for a cohesive look
+ */
+#main > .dashboard {
+  background: linear-gradient(
+    135deg,
+    var(--better-main),
+    var(--background-secondary)
+  );
+}
+```
+
+## Examples
+
+### Example 1: Simple Color Theme
+
+```css
+/* Change accent color throughout */
+:root {
+  --better-main: #ff6b6b;
+}
+
+/* Style the menu */
+#menu {
+  background: var(--background-primary);
+  border-right: 3px solid var(--better-main);
+}
+
+/* Style buttons */
+.uiButton {
+  background: var(--better-main);
+  color: var(--text-color);
+  border-radius: 8px;
+}
+```
+
+### Example 2: Custom Background Image
+
+```css
+/* Use a custom background image */
+body {
+  background-image: var(--custom-background);
+  background-size: cover;
+  background-attachment: fixed;
+}
+
+/* Add overlay for readability */
+#main::before {
+  content: '';
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: rgba(0, 0, 0, 0.3);
+  z-index: -1;
+}
+```
+
+### Example 3: Rounded Corners Theme
+
+```css
+/* Make everything more rounded */
+#main > .dashboard > section,
+.dashlet,
+.notice,
+.document {
+  border-radius: 20px !important;
+}
+
+/* Round buttons */
+.uiButton {
+  border-radius: 25px !important;
+}
+```
+
+### Example 4: Minimal Theme
+
+```css
+/* Remove shadows and borders */
+#main > .dashboard > section,
+.dashlet,
+.notice {
+  box-shadow: none !important;
+  border: 1px solid var(--background-secondary) !important;
+}
+
+/* Simplify colors */
+#menu {
+  background: var(--background-primary) !important;
+}
+
+/* Remove gradients */
+.day {
+  background: var(--background-primary) !important;
+}
+```
+
+### Example 5: High Contrast Theme
+
+```css
+/* Increase contrast */
+:root {
+  --background-primary: #000000;
+  --background-secondary: #1a1a1a;
+  --text-primary: #ffffff;
+}
+
+html:not(.dark) {
+  --background-primary: #ffffff;
+  --background-secondary: #f0f0f0;
+  --text-primary: #000000;
+}
+
+/* Add borders for clarity */
+.dashlet,
+.notice,
+.document {
+  border: 2px solid var(--better-main) !important;
+}
+```
+
+## Advanced Techniques
+
+### CSS Custom Properties Override
+
+You can override CSS variables in your theme:
+
+```css
+/* Override a variable */
+:root {
+  --better-main: #your-color;
+}
+
+/* Override conditionally */
+html.dark {
+  --background-primary: #your-dark-color;
+}
+```
+
+### Animations
+
+Add smooth transitions:
+
+```css
+/* Smooth color transitions */
+#menu li {
+  transition: background-color 0.3s ease;
+}
+
+/* Hover effects */
+.dashlet:hover {
+  transform: translateY(-2px);
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+  transition: all 0.3s ease;
+}
+```
+
+### Pseudo-elements
+
+Use pseudo-elements for decorative elements:
+
+```css
+/* Add decorative border */
+.notice::before {
+  content: '';
+  position: absolute;
+  left: 0;
+  top: 0;
+  bottom: 0;
+  width: 4px;
+  background: var(--better-main);
+}
+```
+
+## Troubleshooting
+
+### Theme Not Applying
+
+1. Check browser console for CSS errors
+2. Verify CSS syntax is correct
+3. Ensure selectors are specific enough
+4. Check if `!important` is needed
+
+### Colors Not Changing
+
+1. Verify you're using CSS variables
+2. Check if `forceDark` is overriding your styles
+3. Ensure variables are set on `:root` or `html`
+
+### Images Not Showing
+
+1. Verify image variable name matches CSS
+2. Check image format is supported
+3. Ensure image size is reasonable
+4. Verify `url()` wrapper in CSS
+
+### Dark Mode Issues
+
+1. Test with `forceDark: true` and `forceDark: false`
+2. Check if transparency effects are interfering
+3. Verify `html.dark` selector is correct
+
+## Resources
+
+- **Theme Creator**: Access via BetterSEQTA+ settings
+- **CSS Variables Reference**: See [CSS Variables](#css-variables) section above
+- **SEQTA DOM Structure**: Inspect SEQTA pages in browser DevTools
+- **BetterSEQTA+ Source**: Check `src/css/injected.scss` for default styles
+
+## Contributing Themes
+
+If you create a great theme, consider sharing it:
+
+1. Export your theme (Share button in theme creator)
+2. Submit to the BetterSEQTA+ theme store
+3. Or share on GitHub/Discord
+
+---
+
+**Note**: This documentation is based on BetterSEQTA+ v3.4.13. Some details may change in future versions.
+