Remove debug logging and consolidate duplicate CSS media queries

[Copilot]

The codebase contained production debug logging and redundant CSS causing unnecessary overhead.

Changes

JavaScript (docs/js/script.js)

• Removed 21 console.log statements
• Cached DOM element references (htmlElement, themeToggle, themeToggleIcon) instead of repeated queries
• Reduced from 83 to 52 lines

SCSS (scss/_main.scss)

• Consolidated duplicate @media (prefers-color-scheme: dark) blocks into single declaration
• Removed 3 empty media query blocks
• Added missing class-based dark theme selectors (:root.dark-theme) for JavaScript-driven theme toggle
• Fixed CSS formatting (semicolons, spacing)

Before/After

Before:

document.addEventListener('DOMContentLoaded', () => {
  console.log('JavaScript loaded successfully!');
  const themeToggle = document.getElementById('theme-toggle');
  
  const setTheme = (isDark) => {
    console.log('DEBUG: setTheme called with isDark =', isDark);
    document.documentElement.classList.add('dark-theme');
    // ...more console logs
  };
});

After:

document.addEventListener('DOMContentLoaded', () => {
  const themeToggle = document.getElementById('theme-toggle');
  const htmlElement = document.documentElement;
  
  const setTheme = (isDark) => {
    htmlElement.classList.add('dark-theme');
  };
});

CSS consolidation:

• Before: Dark theme styles duplicated across lines 79-93 and 327-356
• After: Single consolidated block with both media query and class-based selectors

Original prompt

Identify and suggest improvements to slow or inefficient code

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