Bits of .NET

🎨 CSS Variables = Theme Management

Hard-coded colors are a maintenance nightmare. CSS Variables enable consistent theming and easy updates.

📝 CSS Variables Setup

:root {
    /* Colors */
    --color-primary: #3498db;
    --color-secondary: #2ecc71;
    --color-accent: #e74c3c;
    --color-background: #ffffff;
    --color-text: #2c3e50;
    --color-text-secondary: #7f8c8d;

    /* Typography */
    --font-family: 'Inter', -apple-system, sans-serif;
    --font-size-base: 16px;
    --font-size-large: 1.25rem;
    --font-size-small: 0.875rem;

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    /* Borders */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    --border-color: #e0e0e0;

    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 8px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 16px rgba(0,0,0,0.15);
}

/* Using Variables */
.button-primary {
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    font-family: var(--font-family);
    box-shadow: var(--shadow-sm);
}

.card {
    background: var(--color-background);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
}

🎯 Dynamic Theming with CSS Variables

/* Light Theme */
:root {
    --bg-color: #ffffff;
    --text-color: #2c3e50;
    --card-bg: #f8fafc;
}

/* Dark Theme */
[data-theme='dark'] {
    --bg-color: #1a1a2e;
    --text-color: #e0e0e0;
    --card-bg: #2d3748;
}

/* Theme Toggle with JavaScript */
function toggleTheme() {
    const html = document.documentElement;
    const currentTheme = html.getAttribute('data-theme');
    const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
    html.setAttribute('data-theme', newTheme);
    localStorage.setItem('theme', newTheme);
}

/* Responsive Variables */
@media (max-width: 768px) {
    :root {
        --font-size-base: 14px;
        --spacing-lg: 16px;
        --spacing-xl: 24px;
    }
}

/* Component-Specific Variables */
.card {
    --card-bg: var(--color-background);
    --card-border: var(--border-color);
    --card-padding: var(--spacing-lg);
}

.card-dark {
    --card-bg: #2d3748;
    --card-border: #4a5568;
}

/* Fallback Values */
.element {
    color: var(--text-color, #2c3e50);
    background: var(--bg-color, #ffffff);
}

💡 CSS Variables Best Practices

• Use consistent naming conventions
• Define all variables in :root
• Use semantic names over color names
• Provide fallback values
• Update variables with JavaScript for theming